WO2021060024A1 - Organic electroluminescent element manufacturing method and organic electroluminescent element - Google Patents

Organic electroluminescent element manufacturing method and organic electroluminescent element Download PDF

Info

Publication number
WO2021060024A1
WO2021060024A1 PCT/JP2020/034478 JP2020034478W WO2021060024A1 WO 2021060024 A1 WO2021060024 A1 WO 2021060024A1 JP 2020034478 W JP2020034478 W JP 2020034478W WO 2021060024 A1 WO2021060024 A1 WO 2021060024A1
Authority
WO
WIPO (PCT)
Prior art keywords
layer
light emitting
organic
emitting layer
substrate
Prior art date
Application number
PCT/JP2020/034478
Other languages
French (fr)
Japanese (ja)
Inventor
隆太郎 菅原
一磨 小田
Original Assignee
コニカミノルタ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by コニカミノルタ株式会社 filed Critical コニカミノルタ株式会社
Priority to JP2021548803A priority Critical patent/JP7416079B2/en
Publication of WO2021060024A1 publication Critical patent/WO2021060024A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/10—Apparatus or processes specially adapted to the manufacture of electroluminescent light sources
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/11—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers
    • H10K50/12—OLEDs or polymer light-emitting diodes [PLED] characterised by the electroluminescent [EL] layers comprising dopants

Definitions

  • the present invention relates to a method for manufacturing an organic electroluminescent device and an organic electroluminescent device. More specifically, the present invention relates to a method for producing an organic electroluminescent device in which brightness unevenness is improved by a simple process, and an organic electroluminescent device manufactured by the manufacturing method.
  • organic electroluminescence element also referred to as an “organic electroluminescent element” or “organic EL element” using an organic material electroluminescence (hereinafter abbreviated as "EL") is a new type that enables planar light emission. This is a technology that has already been put into practical use as a light emitting system. Organic EL elements have recently been applied not only to electronic displays but also to lighting equipment, and their development is expected.
  • the organic electroluminescence element has a structure in which a light emitting layer containing a light emitting compound is sandwiched between a cathode and an anode, and excitons (excitons) are generated by injecting electrons and holes into the light emitting layer and recombining them.
  • excitons excitons
  • It is an element that emits light by utilizing the emission of light (fluorescence / phosphorescence) when the excitons are deactivated, and can emit light at a voltage of about several to several tens of volts.
  • Luminous efficiency and uneven brightness are issues for practical use of an organic electroluminescent element as a light source for illumination or a backlight for a display.
  • a so-called host-guest structure in which materials having different functions are mixed in a part of the organic functional layer constituting the organic electroluminescence element. It has become. Specific examples thereof include a combination of a host compound and a luminescent dopunt in the light emitting layer. Since uneven brightness is caused by variations in the thickness and composition of the organic functional layer, there is a demand for a method for uniformly forming a large area.
  • Patent Document 1 and Non-Patent Document 1 show that the ratio of luminescent dopants to luminescent host compounds in the light emitting layer is continuously changed in the light emitting layer to improve efficiency.
  • control of the vapor deposition rate in the vacuum vapor deposition method is specified as a means for continuously changing the concentration of the luminescent dopant, and it cannot be said that the means suitable for productivity is proposed.
  • a method for manufacturing an organic electroluminescence element there are a vapor deposition method, a wet process (spin coating method, die coating method, casting method, inkjet method, spray method, printing method) and the like, but the vacuum process is not required.
  • a manufacturing method in a wet process has attracted attention because continuous production is easy.
  • Patent Document 2 in the wet process, two or more kinds of solutions having different ratios of the host compound and the luminescent dopant are prepared in advance, and they are sequentially laminated and coated, and the host compound and the luminescent dopant are diffused to each other during drying.
  • a method for producing a continuous change in concentration is disclosed.
  • Non-Patent Document 2 discloses a method of forming a light emitting layer by dropping a liquid of a light emitting dopant onto a host layer by inkjet and dissolving the host layer in the liquid of light emitting dopant.
  • Patent Document 2 and Non-Patent Document 2 disclose a method for producing an organic EL element by a wet process having excellent productivity, but as a result of examination by the present inventor, non-uniformity in film thickness and composition is disclosed. It was found that uneven brightness, which is considered to be caused by the above, occurs.
  • the present invention has been made in view of the above problems and situations, and the problem to be solved is a method for manufacturing an organic electroluminescence element in which brightness unevenness is improved by a simple process, and an organic electroluminescence manufactured by the manufacturing method. It is to provide an element.
  • the present inventor In the process of investigating the cause of the above problem in order to solve the above-mentioned problems, the present inventor, when a specific organic functional layer is heated and melted, the compounds constituting the organic functional layer form an adjacent layer. We have found the behavior of mixing with the constituent compounds and arrived at the present invention. That is, the above problem according to the present invention is solved by the following means.
  • a method for manufacturing an organic electroluminescence device having an anode, an organic functional layer including at least one light emitting layer, and a cathode on a substrate. It has a step of forming the light emitting layer by a wet process, and It has a heating / melting step of continuously or intermittently changing the composition of the host compound and the luminescent dopant contained in the light emitting layer in the thickness direction of the light emitting layer.
  • a method for manufacturing an organic electroluminescent device having an anode, an organic functional layer including at least one light emitting layer, and a cathode on a substrate. It has a step of forming the light emitting layer by a wet process, and It has a heating / melting step of continuously or intermittently changing the composition of the host compound and the luminescent dopant contained in the light emitting layer in the thickness direction of the light emitting layer.
  • the host layer containing the host compound and the dopant layer containing the light emitting dopant are formed in this order from the substrate side, and then the light emitting layer is formed.
  • the heating / melting step at least the host layer is melted to mix the respective constituent components of the host layer and the dopant layer, and The composition of the host compound and the luminescent dopant is continuously or intermittently changed in the thickness direction of the light emitting layer.
  • the luminescent dopant is a thermally activated delayed fluorescent compound.
  • the host compound is an insulating polymer compound.
  • the host compound is polystyrene.
  • An organic electroluminescence device having an anode, an organic functional layer including at least one light emitting layer, and a cathode on a substrate.
  • the light emitting layer is composed of a coating film of a host layer containing the host compound and a dopant layer containing the light emitting dopant from the substrate side.
  • the host layer and the dopant layer are melt-bonded and The composition of the host compound and the luminescent dopant changes continuously or intermittently in the thickness direction of the light emitting layer.
  • the luminescent dopant is a thermally activated delayed fluorescent compound.
  • the host compound is an insulating polymer compound. 8.
  • Schematic diagram showing an example of a method for manufacturing an organic EL element using an inkjet printing method Schematic external view showing an example of the structure of an inkjet head applicable to an inkjet printing method. Schematic external view showing an example of the structure of an inkjet head applicable to an inkjet printing method. Schematic diagram of lighting equipment Schematic diagram of lighting equipment
  • the method for manufacturing an organic electroluminescence device of the present invention is a method for manufacturing an organic electroluminescence device having an anode, an organic functional layer including at least one light emitting layer, and a cathode on a substrate, wherein the light emitting layer is formed.
  • a heating / melting step that has a step of forming by a wet process and continuously or intermittently changes the composition of the host compound and the luminescent dopant contained in the light emitting layer in the thickness direction of the light emitting layer. It is characterized by having. This feature is a technical feature common to or corresponding to each of the following embodiments.
  • the host layer containing the host compound and the dopant layer containing the light emitting dopant are arranged in this order from the substrate side.
  • the heating / melting step at least the host layer is melted to mix the respective components of the host layer and the dopant layer, and in the thickness direction of the light emitting layer, the said It is preferable that the composition of the host compound and the luminescent dopant is continuously or intermittently changed.
  • the heating / melting step forming a region in which the concentration of the luminescent dopant continuously or intermittently decreases in the thickness direction from the cathode side to the anode side of the light emitting layer causes light emission. It is preferable from the viewpoint of improving efficiency and preventing uneven emission brightness.
  • the luminous dopant is preferably a thermally activated delayed fluorescent compound from the viewpoint of luminous efficiency.
  • the host compound is an insulating polymer compound.
  • the host compound is preferably polystyrene.
  • the organic electroluminescence element of the present invention is an organic electroluminescence element having an anode, an organic functional layer including at least one light emitting layer, and a cathode on a substrate, and the light emitting layer is said to be from the substrate side. It is composed of a coating film of a host layer containing a host compound and a dopant layer containing the light emitting dopant, and the host layer and the dopant layer are melt-bonded, and in the thickness direction of the light emitting layer, the said It is characterized in that the composition of the host compound and the luminescent dopant is continuously or intermittently changed.
  • organic electroluminescent device (Outline of manufacturing method of organic electroluminescence device)
  • organic EL device (hereinafter, referred to as "organic EL device”) is an organic electroluminescent device having an anode, an organic functional layer including at least one light emitting layer, and a cathode on a substrate.
  • the method for producing the above which comprises a step of forming the light emitting layer by a wet process, and the composition of the host compound and the luminescent dopant contained in the light emitting layer is continuously formed in the thickness direction of the light emitting layer. It is characterized by having a heating / melting step that changes the target or intermittently.
  • composition of the host compound and the luminescent dopant is continuously or intermittently changed in the thickness direction of the light emitting layer
  • the host concerned at regular intervals in the thickness direction of the light emitting layer.
  • continuous means a straight line having a substantially constant slope or a substantially constant value when plotting the value of the concentration obtained by measuring at regular intervals with respect to the distance from the surface in the thickness direction of the light emitting layer.
  • intermittent means that when a plot similar to the above is made, a straight line or a curve as described above can be drawn, but a concentration value that does not appear on the straight line or the curve is observed in some places in the thickness direction. Such a changing state.
  • the change state of the concentration is measured by, for example, surface etching using time-of-flight secondary ion mass spectrometry (TOF-SIMS: Time-of-Flight Second Element Mass Spectrometry) and ion sputtering.
  • TOF-SIMS Time-of-Flight Second Element Mass Spectrometry
  • ion sputtering ion sputtering
  • Typical configuration examples of the organic EL device to which the production method of the present invention can be used include, but are not limited to, the following configuration examples.
  • Anode / light emitting layer / cathode ii) anode / light emitting layer / electron transport layer / cathode (iii) anode / hole transport layer / light emitting layer / cathode (iv) anode / hole transport layer / light emitting layer / electron Transport layer / cathode (v) anode / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode (vi) anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / cathode ( vi) Anophode / hole injection layer / hole transport layer / (electron blocking layer /) light emitting layer / (hole blocking layer /) electron transport layer / electron
  • the light emitting layer according to the present invention is composed of a single layer or a plurality of layers, and when there are a plurality of light emitting layers, a non-light emitting intermediate layer may be provided between the light emitting layers.
  • a hole blocking layer also referred to as a hole barrier layer
  • an electron injection layer also referred to as a cathode buffer layer
  • An electron blocking layer also referred to as an electron barrier layer
  • a hole injection layer also referred to as an anode buffer layer
  • the “electron transport layer” according to the present invention is a layer having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. Further, it may be composed of a plurality of layers.
  • the "hole transport layer” according to the present invention is a layer having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. Further, it may be composed of a plurality of layers. In the above typical device configuration, the layer excluding the anode and the cathode is also referred to as an "organic functional layer".
  • the method for forming a light emitting layer according to the present invention includes a step of forming the light emitting layer by a wet process, and the composition of the host compound and the light emitting dopant contained in the light emitting layer is determined by the thickness of the light emitting layer. It is characterized by having a heating / melting step that changes continuously or intermittently in the longitudinal direction. Further, in the formation of the light emitting layer, the host layer containing the host compound and the dopant layer containing the light emitting dopant are formed in this order from the substrate side, and then at least in the heating / melting step, at least the host. By melting the layer, the respective constituent components of the host layer and the dopant layer are mixed, and the composition of the host compound and the luminescent dopant is continuously or intermittently formed in the thickness direction of the light emitting layer. It is preferable to change to.
  • the light emitting layer according to the present invention is characterized by being formed by a wet process.
  • the wet process also referred to as "wet method" used in the present invention includes a spin coating method, a casting method, an inkjet printing method, a die coating method, a blade coating method, a roll coating method, a spray coating method, and a curtain coating method.
  • LB method Liuir-Brojet method
  • roll-to-roll method such as die coating method, roll coating method, inkjet printing method, spray coating method, etc.
  • a method with high suitability for the roll method is preferable.
  • the liquid medium for dissolving or dispersing the organic EL material (compound or mixture) according to the present invention is not particularly limited, and for example, halogen-based solvents such as chloroform, carbon tetrachloride, dichloromethane, 1,2-dichloroethane, dichlorobenzene, and dichlorohexanone.
  • halogen-based solvents such as chloroform, carbon tetrachloride, dichloromethane, 1,2-dichloroethane, dichlorobenzene, and dichlorohexanone.
  • Solvents such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, n-propyl methyl ketone, cyclohexanone, aromatic solvents such as benzene, toluene, xylene, mesitylen, cyclohexylbenzene, cyclohexane, decalin, dodecane and the like.
  • ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, n-propyl methyl ketone, cyclohexanone
  • aromatic solvents such as benzene, toluene, xylene, mesitylen, cyclohexylbenzene, cyclohexane, decalin, dodecane and the like.
  • Aliper solvent ethyl acetate, n-propyl acetate, n-butyl acetate, methyl propionate, ethyl propionate, ⁇ -butyrolactone, diethyl carbonate and other ester solvents, tetrahydrofuran, dioxane and other ether solvents, dimethylformamide
  • amide solvents such as dimethylacetamide
  • alcohol solvents such as methanol, ethanol, 1-butanol and ethylene glycol
  • nitrile solvents such as acetonitrile and propionitrile, dimethyl sulfoxide, water or a mixed solution medium thereof.
  • the boiling point of these liquid media is preferably a boiling point lower than the temperature of the drying treatment from the viewpoint of quickly drying the liquid medium, specifically in the range of 60 to 200 ° C, more preferably 80 to 180 ° C. Is within the range of.
  • the coating liquid may contain a surfactant depending on the purpose of controlling the coating range and suppressing the liquid flow (for example, the liquid flow that causes a phenomenon called coffee ring) associated with the surface tension gradient after coating.
  • a surfactant for example, the liquid flow that causes a phenomenon called coffee ring
  • the surfactant include anionic or nonionic surfactants from the viewpoint of the influence of water contained in the solvent, leveling property, wettability to the substrate and the like.
  • the surfactants listed in International Publication No. 08/146681, JP-A-2-41308, etc. such as fluorine-containing activators, can be used.
  • the coating liquid used in the wet method may be a solution in which the material forming the organic functional layer is uniformly dissolved in the liquid medium, or a dispersion liquid in which the material is dispersed in the liquid medium as a solid content.
  • a dispersion method dispersion can be performed by a dispersion method such as ultrasonic waves, high shear force dispersion, or media dispersion.
  • the viscosity of the coating film can be appropriately selected depending on the function required as the organic functional layer and the solubility or dispersibility of the organic material. Specifically, for example, 0.3 to 100 mPa. -Can be selected within the range of s.
  • the film thickness of the coating film can be appropriately selected depending on the function required as the organic functional layer and the solubility or dispersibility of the organic material, and specifically, can be selected in the range of, for example, 1 to 90 ⁇ m. ..
  • the temperature of the drying step is not particularly limited, but it is preferable to perform the drying treatment at a temperature that does not damage the organic functional layer, the transparent electrode, or the base material. Specifically, it cannot be said unconditionally because it differs depending on the composition of the coating liquid and the like, but for example, the temperature can be set to 80 ° C. or higher, and the upper limit is considered to be a possible range up to about 300 ° C.
  • the time is preferably about 10 seconds or more and 10 minutes or less. Under such conditions, drying can be performed quickly.
  • FIG. 1 is a schematic view showing an example of a method for manufacturing an organic EL element using an inkjet printing method.
  • an inkjet printing apparatus provided with an inkjet head (30) is used to form an organic functional material or the like for forming an organic layer of an organic EL element on a base material (2) (if necessary, the present invention).
  • An example of a method of discharging (including a ⁇ -conjugated compound) is shown.
  • the organic functional material or the like is sequentially transferred onto the base material (2) as ink droplets by the inkjet head (30). It is injected to form an organic functional layer of the organic EL element (1).
  • the inkjet head (30) applicable to the method for manufacturing an organic EL element according to the present invention is not particularly limited.
  • an ink pressure chamber has a diaphragm provided with a piezoelectric element, and the ink pressure chamber using the diaphragm.
  • It may be a shear mode type (piezo type) head that ejects the ink composition by the pressure change of the above, or it has a heat generating element, and the nozzle due to a sudden volume change due to the film boiling of the ink composition due to the heat energy from the heat generating element.
  • It may be a thermal type head that ejects the ink composition from the ink composition.
  • An ink composition supply mechanism for injection is connected to the inkjet head (30).
  • the ink composition is supplied to the inkjet head (30) by a tank (38A).
  • the liquid level in the tank is kept constant so that the pressure of the ink composition in the inkjet head (30) is always kept constant.
  • the ink composition is overflowed from the tank (38A) and returned to the tank (38B) by natural flow.
  • the ink composition is supplied from the tank (38B) to the tank (38A) by the pump (31), and the liquid level of the tank (38A) is controlled to be stable according to the injection conditions. Has been done.
  • the filter (32) When returning the ink composition to the tank (38A) by the pump (31), it is performed after passing through the filter (32).
  • the ink composition is passed through a filter medium having an absolute filtration accuracy or a quasi-absolute filtration accuracy of 0.05 to 50 ⁇ m at least once before being supplied to the inkjet head (30).
  • the ink composition is forced from the tank (36) and the cleaning solvent is forced from the tank (37) to the inkjet head (30) by the pump (39).
  • the tank pumps may be divided into a plurality of such tank pumps with respect to the inkjet head (30), a branch of a pipe may be used, or a combination thereof may be used.
  • the piping branch (33) is used. Further, in order to sufficiently remove the air in the inkjet head (30), the ink composition is forcibly sent from the tank (36) to the inkjet head (30) by the pump (39) while the ink composition is discharged from the air bleeding pipe. In some cases, an object is taken out and sent to a waste liquid tank (34).
  • ⁇ Inkjet head ⁇ 2A and 2B are schematic external views showing an example of an inkjet head structure applicable to an inkjet printing method.
  • FIG. 2A is a schematic perspective view showing an inkjet head (100) applicable to the present invention
  • FIG. 2B is a bottom view of the inkjet head (100).
  • the inkjet head (100) applicable to the present invention is mounted on an inkjet recording device (not shown), and includes a head chip that ejects ink from a nozzle, a wiring board on which the head chip is arranged, and a wiring board.
  • a drive circuit board connected to the wiring board via a flexible board, a manifold for introducing ink into the channel of the head chip via a filter, a housing (56) in which the manifold is housed, and this housing.
  • the cap receiving plate (57) attached so as to close the bottom opening of (56), the first and second joints (81a, 81b) attached to the first ink port and the second ink port of the manifold, and the manifold.
  • a third joint (82) attached to the third ink port of No. 1 and a cover member (59) attached to the housing (56) are provided. Further, mounting holes (68) for mounting the housing (56) on the printer main body side are formed.
  • the cap receiving plate (57) shown in FIG. 2B is formed as a substantially rectangular plate whose outer shape is elongated in the left-right direction corresponding to the shape of the cap receiving plate mounting portion (62), and is formed at a substantially central portion thereof.
  • a long nozzle opening (71) is provided in the left-right direction.
  • FIGS. 2A and 2B Representative examples of the inkjet head are shown in FIGS. 2A and 2B, but in addition, for example, Japanese Patent Application Laid-Open No. 2012-140017, Japanese Patent Application Laid-Open No. 2013-010227, Japanese Patent Application Laid-Open No. 2014-058171 and JP-A-2014- 097644, 2015-142979, 2015-142980, 2016-002675, 2016-002682, 2016-107401, 2017-109476
  • An inkjet head having the configuration described in Japanese Patent Application Laid-Open No. 2017-177626 can be appropriately selected and applied.
  • Inkjet heads applicable to the present invention are, for example, JP-A-2012-140017, JP-A-2013-010227, JP-A-2014-058171, JP-A-2014-097644, JP-A-2015-142979. , JP-A-2015-142980, JP-A-2016-002675, JP-A-2016-002682, JP-A-2016-107401, JP-A-2017-109476, JP-A-2017-177626, etc.
  • An inkjet head having the described configuration can be appropriately selected and applied.
  • the method for forming a light emitting layer according to the present invention includes a step of forming the light emitting layer by a wet process, and the composition of the host compound and the light emitting dopant contained in the light emitting layer is determined by the thickness of the light emitting layer. It is characterized by having a heating / melting step that changes continuously or intermittently in the longitudinal direction.
  • heating / melting means heating and melting a solid substance, that is, heating a solid substance to change it into a liquid state.
  • the heating temperature in the heating / melting step differs depending on the compound and composition constituting the host layer, but at least a part of the host layer is melted and the constituent components (compounds) of the host layer permeate and diffuse into the dopant layer. It is preferable that the constituent components of both layers are mixed and the temperature is such that the composition of the host compound and the luminescent dopant can be continuously changed in the thickness direction. Specifically, it is preferable to heat at a temperature within the range of the melting temperature or higher and the sublimation temperature or lower of the host compound constituting the host layer.
  • the heating means include heating with a hot plate, heating with a heat-dried gas (for example, an inert gas such as nitrogen gas or helium gas), heating with infrared irradiation, and the like.
  • an organic functional layer other than the light emitting layer for example, a hole injection layer, a hole transport layer, a hole blocking layer, an electron transport layer, an electron injection layer, etc.
  • a forming method such as a vacuum deposition method or a wet process can be used.
  • a method similar to the method for forming the light emitting layer can be adopted.
  • a different film forming method may be applied to each organic functional layer.
  • the vapor deposition conditions differ depending on the type of compound used, etc., but generally, the boat heating temperature is 50 to 450 ° C., the degree of vacuum is 10-6 to 10-2 Pa, and the vapor deposition rate is 0.01 to. It is desirable to appropriately select within the range of 50 nm / sec, substrate temperature -50 to 300 ° C., film thickness 0.1 nm to 5 ⁇ m, preferably 5 to 200 nm.
  • the light emitting layer according to the present invention comprises a coating film of a host layer containing a host compound (also simply referred to as “host”) and a dopant layer containing a light emitting dopant (also simply referred to as “dopant”) from the substrate side.
  • the host layer and the dopant layer are melt-bonded, and the composition of the host compound and the light emitting dopant contained in the light emitting layer is continuously or intermittently changed in the thickness direction. It is a feature.
  • the light emitting layer according to the present invention is a layer that provides a place where electrons and holes injected from an electrode or an adjacent layer are recombined and emit light via excitons, and the light emitting portion is a layer of the light emitting layer. It may be inside or at the interface between the light emitting layer and the adjacent layer.
  • the total thickness of the light emitting layer is not particularly limited, but the homogeneity of the formed layer, prevention of applying an unnecessary high voltage at the time of light emission, and improvement of the stability of the light emitting color with respect to the driving current are improved.
  • each light emitting layer is preferably adjusted within the range of 2 nm to 5 ⁇ m, more preferably adjusted within the range of 2 to 500 nm, and further preferably adjusted within the range of 5 to 200 nm.
  • the thickness of each light emitting layer is preferably adjusted within the range of 2 nm to 1 ⁇ m, more preferably adjusted within the range of 2 to 200 nm, and further preferably adjusted within the range of 3 to 150 nm.
  • Organic EL light emission method There are two types of light emission methods for organic EL: "phosphorescence emission” that emits light when returning from the triplet excited state to the ground state, and “fluorescence emission” that emits light when returning from the singlet excited state to the ground state. is there. When excited by an electric field such as an organic EL element, triplet excitons are generated with a 75% probability and singlet excitons are generated with a 25% probability. It is possible to increase the efficiency and it is an excellent method to realize low power consumption.
  • the rate constant of the forbidden transition increases by three orders of magnitude or more due to the heavy atom effect of the central metal, and depending on the selection of the ligand, 100 It is also possible to obtain a phosphorus photon yield of%.
  • a general fluorescent material does not need to be a heavy metal complex like a phosphorescent material, and is a so-called organic compound composed of a combination of general elements such as carbon, oxygen, nitrogen and hydrogen.
  • other non-metal elements such as phosphorus, sulfur, and silicon can be used, and complexes of typical metals such as aluminum and zinc can also be used, so that the variety can be said to be almost infinite.
  • high-efficiency light emission such as phosphorescence light emission cannot be expected.
  • TTA triplet-triplet annihilation
  • the TADF method which is another high-efficiency fluorescent emission, is a method that can solve the problems of TTA.
  • Fluorescent compounds have the advantage of being able to design an infinite number of molecules as described above. That is, in the molecular design compounds, specifically triplet excited state and the energy level difference between the singlet excited state (hereinafter, appropriately abbreviated as "Delta] E ST".) Is very close compound present To do. Such compounds, even though in the molecule does not have a heavy atom, reverse intersystem crossing from a triplet excited state is usually not occur because Delta] E ST is smaller to the singlet excited state occurs.
  • TADF can theoretically emit 100% fluorescent light.
  • an electron-withdrawing skeleton such as a cyano group or triazine and an electron-donating property such as a carbazole or a diphenylamino group.
  • LUMO and HOMO are localized by introducing the skeleton of. It is also effective to reduce the change in molecular structure between the ground state and triplet excited state of the compound. As a method for reducing the structural change, for example, making the compound rigid is effective.
  • Rigidity described here means that there are few parts in the molecule that can move freely, such as suppressing free rotation in the bond between rings in the molecule and introducing a fused ring with a large ⁇ -conjugated surface. To do. In particular, it is possible to reduce the structural change in the excited state by making the portion involved in light emission rigid.
  • Luminescent dopant of the present invention a fluorescent luminescent compound and a phosphorescent luminescent compound are preferably used.
  • the luminescent dopant is contained in the light emitting layer in the range of 5 to 80% by mass, and particularly preferably in the range of 20 to 40% by mass.
  • the concentration of the luminescent compound in the light emitting layer can be arbitrarily determined based on the specific luminescent compound used and the requirements of the device. Further, the luminescent compound used in the present invention may be used in combination of a plurality of types, and may be used in combination of fluorescent compounds having different structures or in combination of a fluorescent compound and a phosphorescent compound. You may. Thereby, an arbitrary emission color can be obtained.
  • the emission colors of the organic EL element of the present invention and the compound used in the present invention are shown in FIG. 3.16 on page 108 of the "New Color Science Handbook" (edited by the Color Society of Japan, The University of Tokyo Press, 1985). It is determined by the color when the result measured by the luminometer CS-1000 (manufactured by Konica Minolta Co., Ltd.) is applied to the CIE chromaticity coordinates.
  • the light emitting layer of one layer or a plurality of layers contains a plurality of light emitting compounds having different light emitting colors and exhibits white light emission.
  • the combination of luminescent compounds showing white color is not particularly limited, and examples thereof include a combination of blue and orange and a combination of blue and green and red.
  • fluorescent luminescent compound the above-mentioned specific organic compound may be used, a known fluorescent luminescent compound used in the light emitting layer of an organic EL element, or a compound that emits delayed fluorescence. (Delayed fluorescent luminescent compound) may be appropriately selected and used.
  • fluorescent compounds examples include anthracene derivatives, pyrene derivatives, chrysene derivatives, fluorantene derivatives, perylene derivatives, fluorene derivatives, arylacetylene derivatives, styrylarylene derivatives, styrylamine derivatives, arylamine derivatives, boron.
  • Examples thereof include complexes, coumarin derivatives, pyran derivatives, cyanine derivatives, croconium derivatives, squalium derivatives, oxobenzanthracene derivatives, fluorescein derivatives, rhodamine derivatives, pyrylium derivatives, perylene derivatives, polythiophene derivatives, and rare earth complex compounds.
  • Examples of compounds that emit delayed fluorescence are International Publication No. 2011/156793, JP-A-2011-21364, JP-A-2010-93181, and Patent No. 5366106. No., International Publication No. 2013/161437, International Publication No. 2016/158540, and the like can be mentioned, but the present invention is not limited thereto.
  • thermally activated delayed fluorescent compound compounds having structures represented by the following general formulas (1) to (6) are preferable.
  • Ar 1 to Ar 3 each independently represent a substituted or unsubstituted aryl group, and at least one is substituted with a group having a structure represented by the following general formula (2). Represents an aryl group.
  • R 1 to R 8 each independently represent a hydrogen atom or a substituent.
  • Ar 4 represents a substituted or unsubstituted aryl group. Adjacent groups of R 1 to R 8 may form a bond with each other or form a ring via a linking group.
  • R 1 ⁇ R 5 represents a cyano group
  • at least one of R 1 ⁇ R 5 is a group having the structure represented by the following general formula (4)
  • the remaining R 1 to R 5 represent hydrogen atoms or substituents.
  • R 21 to R 28 each independently represent a hydrogen atom or a substituent. However, at least one of the following requirements (A) or (B) is satisfied.
  • R 1 and R 2 each independently represent a group having a structure represented by the following general formula (6).
  • R 1 to R 8 each independently represent a hydrogen atom or a substituent.
  • Ar 4 represents a substituted or unsubstituted aryl group. Adjacent groups of R 1 to R 8 may form a bond with each other or form a ring via a linking group.
  • the TADF compound is given as an example below, but the present invention is not limited to this.
  • HOMO and LUMO are substantially separated in the molecule from the viewpoint of reducing ⁇ Est.
  • the distribution state of these HOMO and LUMO can be obtained from the electron density distribution when the structure is optimized obtained by the calculation of the molecular orbital.
  • a molecular orbital calculation software using B3LYP as a functional and 6-31G (d) as a basis function is used as a calculation method. It can be calculated by using it, and the software is not particularly limited, and it can be calculated in the same manner by using any of them.
  • Gaussian 09 (Revision C.01, MJ Frisch, et al, Gaussian, Inc., 2010.) manufactured by Gaussian, USA was used as the software for calculating the molecular orbital.
  • "HOMO and LUMO are substantially separated” means that the central parts of the HOMO orbital distribution and the LUMO orbital distribution calculated by the above molecular calculation are separated, and more preferably, the HOMO orbital distribution and the LUMO orbital are separated. It means that the distributions of are almost non-overlapping.
  • ⁇ Est E (S 1 ) -E (T 1). Is.
  • ⁇ Est calculated by using the same calculation method as described above is preferably 0.5 eV or less, more preferably 0.2 eV or less, and further preferably 0.1 eV or less.
  • Minimum excitation singlet energy S 1 For the lowest excited singlet energy S 1 luminescent compound according to the present invention is defined by what is calculated in the same manner as the conventional method in the present invention. That is, a compound to be measured is vapor-deposited on a quartz substrate to prepare a sample, and the absorption spectrum (vertical axis: absorbance, horizontal axis: wavelength) of this sample is measured at room temperature (25 ° C.). A tangent line is drawn with respect to the rising edge of the absorption spectrum on the long wavelength side, and the calculation is performed from a predetermined conversion formula based on the wavelength value at the intersection of the tangent line and the horizontal axis.
  • the luminescent compound used in the present invention has a relatively high cohesiveness of the molecule itself, an error may occur due to the cohesiveness in the measurement of the thin film.
  • Luminescent compound in the present invention that the Stokes shift is relatively small, considering that further structural changes in the excited state and the ground state is small, the lowest excited singlet energy S 1 according to the present invention, at room temperature (25 ° C.) The peak value of the maximum emission wavelength in the solution state of the luminescent compound was used as an approximate value.
  • a solvent that does not affect the aggregated state of the luminescent compound that is, a solvent that is less affected by the solvent effect, for example, a non-polar solvent such as cyclohexane or toluene can be used.
  • the excitation (absorption) spectrum and the emission spectrum of the solution of the luminescent compound are measured with a fluorescence spectrophotometer (for example, RF-5300 type fluorescence spectrometer manufactured by Shimadzu Corporation, F manufactured by Hitachi, Ltd.). It can be measured using a -4500 type fluorescence spectrometer or the like), and the difference between the fluorescence maximum wavelength and the excitation (absorption) maximum wavelength can be obtained as a “Stokes shift”.
  • a fluorescence spectrophotometer for example, RF-5300 type fluorescence spectrometer manufactured by Shimadzu Corporation, F manufactured by Hitachi, Ltd.
  • the phosphorescent dopant used in the present invention is a compound in which light emission from an excited triplet is observed. Specifically, phosphorescence is performed at room temperature (25 ° C.). It is a compound that emits light and is defined as a compound having a phosphorescence quantum yield of 0.01 or more at 25 ° C., but a preferable phosphorescence quantum yield is 0.1 or more.
  • the phosphorus photon yield can be measured by the method described on page 398 (1992 edition, Maruzen) of Spectroscopy II of the 4th edition Experimental Chemistry Course 7.
  • the phosphorescence quantum yield in a solution can be measured using various solvents, but the phosphorescence-emitting dopant used in the present invention has the above-mentioned phosphorescence quantum yield (0.01 or more) in any of the solvents. It should be achieved.
  • the phosphorescent dopant can be appropriately selected from known ones used for the light emitting layer of the organic EL device.
  • Specific examples of known phosphorescent dopants that can be used in the present invention include compounds described in the following documents. Nature 395, 151 (1998), Appl. Phys. Lett. 78, 1622 (2001), Adv. Mater. 19,739 (2007), Chem. Mater. 17, 3532 (2005), Adv. Mater. 17,1059 (2005), International Publication No. 2009/10991, International Publication No. 2008/101842, International Publication No. 2003/040257, US Patent Application Publication No. 2006/835469, US Patent Application Publication No. 2006 / 0202194, US Patent Application Publication No.
  • preferred phosphorescent dopants include organometallic complexes having Ir as the central metal. More preferably, a complex containing at least one coordination mode of metal-carbon bond, metal-nitrogen bond, metal-oxygen bond and metal-sulfur bond is preferable.
  • the host compound used in the present invention is a compound mainly responsible for the dispersion of the luminescent compound in the light emitting layer, and its own luminescence is not substantially observed in the organic EL element.
  • the host compound may be used alone or in combination of two or more. By using a plurality of types of host compounds, it is possible to adjust the charge transfer, and it is possible to improve the efficiency of the organic electroluminescence element.
  • the host compound is preferably one having an excitation energy larger than the excitation triplet energy of the luminescent dopant, and more preferably one having an excitation triplet energy larger than the excitation triplet energy of the luminescent dopant. preferable.
  • the host compound can exist stably in all active species states such as cation radical state, anion radical state, and excited state, and does not cause chemical changes such as decomposition and addition reaction. It is preferable that the host molecules do not move at the angstrom level in the layer over time of energization.
  • the "insulating property" of the insulating polymer used in the present invention means that the electrical resistivity is 1 ⁇ 10 6 ⁇ ⁇ m or more, preferably 1 ⁇ 10 8 ⁇ ⁇ m or more. Yes, more preferably 1 ⁇ 10 10 ⁇ ⁇ m or more. It is considered that the leakage current flowing through the light emitting layer can be suppressed when the electrical resistivity of the insulating polymer alone is 1 ⁇ 10 6 ⁇ ⁇ m or more.
  • the type of insulating polymer is not particularly limited as long as a light emitting layer can be formed together with the light emitting dopant compound.
  • a polymer having a higher stability and whose main chain is composed of carbon atoms is used as the insulating polymer.
  • the insulating polymer is preferably a soluble polymer and preferably exhibits solubility in an aprotic polar solvent so that a light emitting layer containing the insulating polymer can be formed by a coating method.
  • the solubility of the insulating polymer in 1 g of N, N-dimethylformamide at 25 ° C. is preferably 0.5 mg or more, more preferably 1.0 mg or more, and more preferably 2.0 mg or more. More preferably.
  • nonionic polymers such as polystyrene, polymethylmethacrylate, polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, polyvinylpolypyrrolidone, polyethylene glycol, polymethylvinyl ether, and polyisopropylacrylamide; Cationic polymers such as sodium polyacrylate, sodium polystyrene sulfonate, sodium polyisopropylene sulfonate, polynaphthalene sulfonic acid condensate salt, polyethylene iminsantate salt; dimethylaminomethyl (meth) acrylate quaternary salt, dimethyldialylammonium Anionic polymers such as chloride, polyamidine, polyvinyl imidazoline, dicyandiamide-based condensate, epichlorohydrin dimethylamine condensate, polyethyleneimine; dimethylaminoethyl (meth)
  • the weight average molecular weight of the insulating polymer is not particularly limited, but is preferably 5 ⁇ 10 3 or more, and more preferably 10 ⁇ 10 3 or more. Also, preferably at 1000 ⁇ 10 3 or less, more preferably 400 ⁇ 10 3 or less. It is considered that when the weight average molecular weight is in this range, the diffusion of the luminescent dopant can be appropriately controlled.
  • the electron transport layer is a layer made of a material having a function of transporting electrons and having a function of transmitting electrons injected from a cathode to a light emitting layer.
  • the total film thickness of the electron transport layer is not particularly limited, but is usually in the range of 2 nm to 5 ⁇ m, more preferably in the range of 2 to 500 nm, and further preferably in the range of 5 to 200 nm. ..
  • the material used for the electron transport layer may have any of electron injection property, transport property, and hole barrier property, and is a conventionally known compound. Any one can be selected and used from the above.
  • Conventionally known compounds include, for example, nitrogen-containing aromatic heterocyclic derivatives (carbazole derivatives, azacarbazole derivatives (one or more carbon atoms constituting the carbazole ring substituted with nitrogen atoms), pyridine derivatives, pyrimidine derivatives, etc.
  • Pyrazine derivative pyridazine derivative, triazine derivative, quinoline derivative, quinoxalin derivative, phenanthroline derivative, azatriphenylene derivative, oxazole derivative, thiazole derivative, oxadiazole derivative, thiadiazol derivative, triazole derivative, benzimidazole derivative, benzoxazole derivative, benzthiazole derivative Etc.), dibenzofuran derivatives, dibenzothiophene derivatives, silol derivatives, aromatic hydrocarbon ring derivatives (naphthalene derivatives, anthracene derivatives, triphenylene, etc.) and the like.
  • metal complexes having a quinolinol skeleton or a dibenzoquinolinol skeleton as ligands for example, tris (8-quinolinol) aluminum (Alq 3 ), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-) Dibromo-8-quinolinol) aluminum, tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and metal complexes thereof.
  • a metal complex in which the central metal is replaced with In, Mg, Cu, Ca, Sn, Ga or Pb can also be used as an electron transport material.
  • metal-free or metal phthalocyanine or those whose terminals are substituted with an alkyl group, a sulfonic acid group, or the like can also be preferably used as an electron transport material.
  • the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and an inorganic semiconductor such as n-type-Si or n-type-SiC is used like the hole injection layer and the hole transport layer. Can also be used as an electron transport material.
  • a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.
  • the electron transport layer may be doped with a doping material as a guest material to form a highly n-type (electron-rich) electron transport layer.
  • the doping material include n-type dopants such as metal complexes and metal compounds such as metal halides.
  • Specific examples of the electron transport layer having such a structure include, for example, JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, JP-A-2001-102175, J. Mol. Apple. Phys. , 95, 5773 (2004) and the like.
  • More preferable electron transporting materials include pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, carbazole derivatives, azacarbazole derivatives, and benzimidazole derivatives.
  • the electron transport material may be used alone or in combination of two or more.
  • the hole blocking layer is, in a broad sense, a layer having a function of an electron transporting layer, preferably made of a material having a function of transporting electrons and a small ability to transport holes, while transporting electrons. A layer that can improve the recombination probability of electrons and holes by blocking holes.
  • the above-mentioned structure of the electron transport layer can be used as a hole blocking layer, if necessary.
  • the hole blocking layer is preferably provided adjacent to the cathode side of the light emitting layer.
  • the thickness of the hole blocking layer is preferably in the range of 3 to 100 nm, and more preferably in the range of 5 to 30 nm.
  • the material used for the hole blocking layer the material used for the electron transporting layer described above is preferably used, and the material used as the host compound described above is also preferably used for the hole blocking layer.
  • the electron injection layer (also referred to as “cathode buffer layer”) refers to a layer provided between the cathode and the light emitting layer in order to reduce the driving voltage and improve the emission brightness, and refers to "organic EL element and its forefront of industrialization (also referred to as” cathode buffer layer "). It is described in detail in Volume 2, Chapter 2, "Electrode Materials” (pages 123-166) of "November 30, 1998, published by NTS Co., Ltd.).
  • the electron injection layer may be provided as needed and may be present between the cathode and the light emitting layer or between the cathode and the electron transport layer as described above.
  • the electron injection layer is preferably a very thin film, and the layer thickness is preferably in the range of 0.1 to 5 nm, although it depends on the material. Further, it may be a non-uniform film in which the constituent material is intermittently present.
  • the details of the electron-injected layer are also described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like, and specific examples of materials preferably used for the electron-injected layer include , Metals such as strontium and aluminum, alkali metal compounds such as lithium fluoride, sodium fluoride and potassium fluoride, alkaline earth metal compounds such as magnesium fluoride and calcium fluoride, oxidation Examples thereof include metal oxides typified by aluminum, metal complexes typified by lithium 8-hydroxyquinolate (Liq) and the like. It is also possible to use the above-mentioned electron transport material. Further, the material used for the above-mentioned electron injection layer may be used alone or in combination of two or more.
  • the hole transport layer is a layer made of a material having a function of transporting holes and having a function of transmitting holes injected from an anode to a light emitting layer.
  • the total film thickness of the hole transport layer is not particularly limited, but is usually in the range of 5 nm to 5 ⁇ m, more preferably in the range of 2 to 500 nm, and further preferably in the range of 5 to 200 nm. Is.
  • hole transport material may have any of hole injection property, transport property, and electron barrier property, and is conventionally known. Any compound can be selected and used.
  • porphyrin derivatives for example, porphyrin derivatives, phthalocyanine derivatives, oxazole derivatives, oxadiazole derivatives, triazole derivatives, imidazole derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, hydrazone derivatives, stillben derivatives, polyarylalkane derivatives, triarylamine derivatives, carbazole derivatives, Indrocarbazole derivatives, isoindole derivatives, acene derivatives such as anthracene and naphthalene, fluorene derivatives, fluorenone derivatives, and polymer materials or oligomers with polyvinylcarbazole and aromatic amines introduced into the main and side chains, polysilanes, and conductivity. Examples thereof include polymers or oligomers (for example, PEDOT: PSS, aniline-based copolymers, polyaniline, polythiophene, etc.).
  • Examples of the triarylamine derivative include a benzidine type represented by ⁇ -NPD, a starburst type represented by MTDATA, and a compound having fluorene or anthracene in the triarylamine connecting core portion.
  • Hexaazatriphenylene derivatives as described in JP-A-2003-591432 and JP-A-2006-135145 can also be used as the hole transport material in the same manner.
  • a hole transport layer having a high p property doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, and JP-A-2001-102175. Apple. Phys. , 95, 5773 (2004) and the like.
  • the hole transporting material the above-mentioned materials can be used, but a triarylamine derivative, a carbazole derivative, an indolocarbazole derivative, an azatriphenylene derivative, an organic metal complex, and an aromatic amine are introduced into the main chain or side chain. High molecular weight materials or oligomers are preferably used.
  • the electron blocking layer is a layer having a function of a hole transporting layer in a broad sense, and is preferably made of a material having a function of transporting holes and a small ability to transport electrons, while transporting holes. A layer that can improve the recombination probability of electrons and holes by blocking electrons.
  • the structure of the hole transport layer described above can be used as an electron blocking layer, if necessary.
  • the electron blocking layer is preferably provided adjacent to the anode side of the light emitting layer.
  • the thickness of the electron blocking layer is preferably in the range of 3 to 100 nm, and more preferably in the range of 5 to 30 nm.
  • the material used for the electron blocking layer the material used for the hole transporting layer described above is preferably used, and the material used as the host compound described above is also preferably used for the electron blocking layer.
  • the hole injection layer (also referred to as “anode buffer layer”) is a layer provided between the anode and the light emitting layer in order to reduce the driving voltage and improve the emission brightness. For example, it is described in detail in Volume 2, Chapter 2, "Electrode Materials” (pages 123-166) of "Organic EL Devices and Their Industrialization Frontline (November 30, 1998, published by NTS)". ..
  • the hole injection layer may be provided as needed and may be present between the anode and the light emitting layer or between the anode and the hole transport layer as described above.
  • the details of the hole injection layer are also described in JP-A-9-45479, 9-2660062, 8-288609, etc., and examples of the material used for the hole injection layer include. Examples thereof include materials used for the hole transport layer described above.
  • phthalocyanine derivatives typified by copper phthalocyanine, hexaazatriphenylene derivatives as described in JP-A-2003-591432 and JP-A-2006-135145, metal oxides typified by vanadium oxide, amorphous carbon.
  • Polyaniline (emeraldine), polythiophene and other conductive polymers, tris (2-phenylpyridine) iridium complexes and the like, orthometallated complexes, triarylamine derivatives and the like are preferable.
  • the material used for the hole injection layer described above may be used alone or in combination of two or more.
  • the organic functional layer according to the present invention described above may further contain other additives.
  • the additive include halogen elements such as bromine, iodine and chlorine, halogenated compounds, alkali metals and alkaline earth metals such as Pd, Ca and Na, compounds and complexes of transition metals, salts and the like.
  • the content of the additive can be arbitrarily determined, but is preferably 1000 ppm or less, more preferably 500 ppm or less, still more preferably 50 ppm or less, based on the total mass% of the contained layer. .. However, it is not within this range depending on the purpose of improving the transportability of electrons and holes and the purpose of favoring the energy transfer of excitons.
  • anode As the anode in the organic EL element, a metal having a large work function (4 eV or more, preferably 4.5 V or more), an alloy, an electrically conductive compound, or a mixture thereof as an electrode material is preferably used.
  • an electrode material include metals such as Au and conductive transparent materials such as CuI, indium zinc oxide (ITO), SnO 2, and ZnO.
  • a material such as IDIXO (In 2 O 3- ZnO) which is amorphous and can produce a transparent conductive film may be used.
  • a thin film may be formed by forming a thin film of these electrode materials by a method such as thin film deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when pattern accuracy is not required so much (about 100 ⁇ m or more). ), A pattern may be formed through a mask having a desired shape during vapor deposition or sputtering of the electrode material.
  • a coatable substance such as an organic conductive compound
  • a wet film forming method such as a printing method or a coating method can also be used.
  • the transmittance is preferably made larger than 10%, and the sheet resistance as the anode is several hundred ⁇ / sq.
  • the film thickness of the anode depends on the material, but is usually selected in the range of 10 nm to 1 ⁇ m, preferably 10 to 200 nm.
  • cathode As the cathode, a metal having a small work function (5 eV or less) (referred to as an electron-injectable metal), an alloy, an electrically conductive compound, or a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, silver, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al). 2 O 3 ) Examples include mixtures, indium, lithium / aluminum mixtures, aluminum, rare earth metals and the like.
  • a mixture of an electron injectable metal and a second metal which is a stable metal having a larger work function value than this for example, magnesium / silver mixture, magnesium / Aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al 2 O 3 ) mixture, lithium / aluminum mixture, aluminum and the like are suitable.
  • the cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. Alternatively, when a coatable substance such as metal nanoparticles is used, a wet film forming method such as a printing method or a coating method can also be used. Sheet resistance as a cathode is several hundred ⁇ / sq. The following is preferable, and the film thickness is usually selected in the range of 10 nm to 5 ⁇ m, preferably 50 to 200 nm. Since the emitted light is transmitted, it is convenient that the emission brightness is improved if either the anode or the cathode of the organic EL element is transparent or translucent.
  • a transparent or translucent cathode can be produced by producing the above metal on the cathode having a thickness of 1 to 20 nm and then producing the conductive transparent material mentioned in the description of the anode on the cathode. By applying the above, it is possible to manufacture an element in which both the anode and the cathode are transparent.
  • the types of support substrates (hereinafter, also referred to as substrates, substrates, substrates, supports, etc.) that can be used for organic EL elements are not particularly limited, such as glass and plastic, and even if they are transparent, they are opaque. It may be.
  • the support substrate is preferably transparent.
  • the transparent support substrate preferably used include glass, quartz, and a transparent resin film.
  • a particularly preferable support substrate is a resin film capable of imparting flexibility to the organic EL element.
  • polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate (TAC), cellulose acetate butyrate, and cellulose acetate propionate (CAP).
  • Cellulosic acetate phthalate such as cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide, Polyether sulfone (PES), polyphenylene sulfide, polysulfones, polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylates, Arton® (registered trademark) or Examples thereof include resin films such as cycloolefin resins such as Apel (registered trademark) (manufactured by Mitsui Chemicals, Inc.).
  • a gas barrier film of an inorganic substance, an organic substance, or a hybrid gas barrier film of both of them may be formed on the surface of the resin film, and the water vapor permeability (25 ⁇ 0. 5 ° C., preferably a relative humidity (90 ⁇ 2)% RH) is the gas barrier film of 0.01g / (m 2 ⁇ 24h) or less, and further, is measured by the method based on JIS K 7126-1987 oxygen permeability, 10 -3 mL / (m 2 ⁇ 24h ⁇ atm) or less, the water vapor permeability is preferably 10 -5 g / (m 2 ⁇ 24h) or less of the high barrier film.
  • any material that causes deterioration of the element such as moisture and oxygen but has a function of suppressing infiltration can be used, and for example, silicon oxide, silicon dioxide, silicon nitride and the like can be used.
  • silicon oxide, silicon dioxide, silicon nitride and the like can be used.
  • the stacking order of the inorganic layer and the organic functional layer is not particularly limited, but it is preferable to stack the inorganic layer and the organic functional layer alternately a plurality of times.
  • the method for forming the gas barrier film is not particularly limited, for example, vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma polymerization method.
  • Plasma CVD method, laser CVD method, thermal CVD method, coating method and the like can be used, but the atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.
  • the opaque support substrate examples include a metal plate such as aluminum and stainless steel, a film or opaque resin substrate, and a ceramic substrate.
  • the external extraction quantum efficiency of the light emission of the organic EL device of the present invention at room temperature is preferably 1% or more, more preferably 5% or more.
  • the external extraction quantum efficiency (%) the number of photons emitted to the outside of the organic EL element / the number of electrons passed through the organic EL element ⁇ 100.
  • a hue improving filter such as a color filter may be used in combination, or a color conversion filter that converts the color emitted from the organic EL element into multiple colors using a phosphor may be used in combination.
  • sealing means used for sealing the organic EL element include a method of adhering the sealing member, the electrode, and the support substrate with an adhesive.
  • the sealing member may be arranged so as to cover the display area of the organic EL element, and may be intaglio-shaped or flat-plate-shaped. Further, transparency and electrical insulation are not particularly limited.
  • glass plates examples include glass plates, polymer plates / films, metal plates / films, and the like.
  • the glass plate include soda lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz.
  • the polymer plate examples include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, polysulfone and the like.
  • metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium and tantalum.
  • a polymer film or a metal film can be preferably used because the organic EL element can be thinned.
  • the polymer film is JIS K.
  • Oxygen permeability measured by a method according to 7126-1987 is 1 ⁇ 10 -3 mL / m 2 / 24h or less, and water vapor permeability (25 ⁇ 0.) Measured by a method according to JIS K 7129-1992. 5 ° C., relative humidity (90 ⁇ 2)%) is preferably 1 ⁇ 10 -3 g / (m 2 / 24h) or less.
  • Sandblasting, chemical etching, etc. are used to process the sealing member into a concave shape.
  • the adhesive include acrylic acid-based oligomers, photocurable and thermosetting adhesives having a reactive vinyl group of methacrylic acid-based oligomers, and moisture-curable adhesives such as 2-cyanoacrylic acid ester. Can be mentioned.
  • heat and chemical curing type such as epoxy type can be mentioned.
  • hot melt type polyamide, polyester and polyolefin can be mentioned.
  • a cation-curable type ultraviolet-curable epoxy resin adhesive can be mentioned.
  • the organic EL element may be deteriorated by heat treatment, it is preferable that the organic EL element can be adhesively cured from room temperature to 80 ° C. Further, the desiccant may be dispersed in the adhesive. A commercially available dispenser may be used to apply the adhesive to the sealing portion, or printing may be performed as in screen printing.
  • the electrode and the organic functional layer on the outside of the electrode on the side facing the support substrate with the organic functional layer sandwiched between them, and form an inorganic or organic layer in contact with the support substrate to form a sealing film.
  • the material for forming the film may be any material that causes deterioration of the element such as moisture and oxygen but has a function of suppressing infiltration, and for example, silicon oxide, silicon dioxide, silicon nitride and the like can be used.
  • the method for forming these films is not particularly limited, and for example, vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma polymerization method. , Plasma CVD method, laser CVD method, thermal CVD method, coating method and the like can be used.
  • an inert gas such as nitrogen or argon or an inert liquid such as fluorinated hydrocarbon or silicone oil may be injected into the gap between the sealing member and the display region of the organic EL element.
  • an inert gas such as nitrogen or argon or an inert liquid such as fluorinated hydrocarbon or silicone oil
  • an inert liquid such as fluorinated hydrocarbon or silicone oil
  • a hygroscopic compound can be enclosed inside.
  • Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide, etc.), sulfates (for example, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate, etc.), and metals.
  • metal oxides for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide, etc.
  • sulfates for example, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate, etc.
  • Halides eg calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide, etc.
  • perchlorates eg barium perchlorate, magnesium perchlorate, etc.
  • anhydrous salts are preferably used for sulfates, metal halides and perchlorates.
  • a protective film or protective plate may be provided on the outer side of the sealing film or the sealing film on the side facing the support substrate with the organic functional layer sandwiched in order to increase the mechanical strength of the device.
  • the mechanical strength thereof is not necessarily high, so it is preferable to provide such a protective film and a protective plate.
  • a glass plate, a polymer plate / film, a metal plate / film, etc. similar to those used for the sealing can be used, but the polymer film is lightweight and thin. Is preferably used.
  • the organic EL element emits light inside a layer having a refractive index higher than that of air (within a refractive index of about 1.6 to 2.1), and only about 15 to 20% of the light generated in the light emitting layer is emitted. It is generally said that it cannot be taken out. This is because light incident on the interface (intersection between the transparent substrate and air) at an angle ⁇ equal to or greater than the critical angle causes total internal reflection and cannot be taken out of the element, and the transparent electrode or light emitting layer and the transparent substrate This is because the light is totally reflected between them, the light is waveguideed through the transparent electrode or the light emitting layer, and as a result, the light escapes toward the side surface of the element.
  • a method for improving the efficiency of light extraction for example, a method of forming irregularities on the surface of a transparent substrate to prevent total reflection at the interface between the transparent substrate and the air (for example, US Pat. No. 4,774,435), condensing light on the substrate.
  • a method of improving efficiency by imparting properties for example, Japanese Patent Application Laid-Open No. 63-314795
  • a method of forming a reflective surface on a side surface of an element for example, Japanese Patent Application Laid-Open No. 1-220394
  • a substrate and a light emitter A method of introducing a flat layer having an intermediate refractive index between them to form an antireflection film (for example, Japanese Patent Application Laid-Open No.
  • a flat layer having a lower refractive index than the substrate between the substrate and the light emitter for example, Japanese Patent Application Laid-Open No. 2001-202827, a method of forming a diffraction lattice between layers (including between the substrate and the outside world) of a substrate, a transparent electrode layer or a light emitting layer (Japanese Patent Laid-Open No. 11-283751). Gazette) and the like.
  • these methods can be used in combination with the organic EL element, but a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or a substrate and a transparent electrode layer.
  • a method of forming a diffraction grating between any layer (including between the substrate and the outside world) of the light emitting layer or the light emitting layer can be preferably used.
  • the low refractive index layer examples include airgel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate is generally in the range of about 1.5 to 1.7, it is preferable that the low refractive index layer has a refractive index of about 1.5 or less. Further, it is preferably 1.35 or less. Further, it is desirable that the thickness of the low refractive index medium is at least twice the wavelength in the medium. This is because the effect of the low refractive index layer diminishes when the thickness of the low refractive index medium becomes about the wavelength of light and the electromagnetic wave exuded by evanescent enters the substrate.
  • the method of introducing a diffraction grating into an interface that causes total reflection or in any medium is characterized by a high effect of improving light extraction efficiency.
  • This method is generated from the light emitting layer by utilizing the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction such as first-order diffraction or second-order diffraction.
  • Bragg diffraction such as first-order diffraction or second-order diffraction.
  • the generated light the light that cannot go out due to total reflection between the layers is diffracted by introducing a diffraction grating in one of the layers or in the medium (inside the transparent substrate or in the transparent electrode). , Trying to get the light out.
  • the diffraction grating to be introduced has a two-dimensional periodic refractive index. This is because the light emitted by the light emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating that has a periodic refractive index distribution only in a certain direction, only the light traveling in a specific direction is diffracted. The light extraction efficiency does not increase so much. However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and the light extraction efficiency is improved.
  • the position where the diffraction grating is introduced may be in any of the layers or in the medium (inside the transparent substrate or in the transparent electrode), but it is preferably in the vicinity of the organic light emitting layer where light is generated.
  • the period of the diffraction grating is preferably in the range of about 1/2 to 3 times the wavelength of the light in the medium.
  • the arrangement of the diffraction grating it is preferable that the arrangement is repeated two-dimensionally, such as a square lattice shape, a triangular lattice shape, and a honeycomb lattice shape.
  • the organic EL element of the present invention is processed so as to provide a structure on a microlens array, for example, on the light extraction side of a support substrate (substrate), or by combining with a so-called condensing sheet, a specific direction, for example, an element By condensing light in the front direction with respect to the light emitting surface, it is possible to increase the brightness in a specific direction.
  • a microlens array a quadrangular pyramid having a side of 30 ⁇ m and an apex angle of 90 degrees is arranged two-dimensionally on the light extraction side of the substrate. One side is preferably in the range of 10 to 100 ⁇ m. If it is smaller than this, the effect of diffraction is generated and it is colored, and if it is too large, the thickness becomes thick, which is not preferable.
  • the condensing sheet for example, a sheet that has been put into practical use in an LED backlight of a liquid crystal display device can be used.
  • a sheet for example, a brightness increasing film (BEF) manufactured by Sumitomo 3M Ltd. can be used.
  • the shape of the prism sheet may be, for example, a base material having a ⁇ -shaped stripe having an apex angle of 90 degrees and a pitch of 50 ⁇ m, or a shape having a rounded apex angle and a random pitch change. Shape or other shape may be used.
  • the light diffusing plate / film may be used in combination with the condensing sheet in order to control the light emission angle from the organic EL element.
  • a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.
  • the organic EL device of the present invention may be a device having a so-called tandem structure in which a plurality of light emitting units including at least one light emitting layer are laminated.
  • a typical element configuration of the tandem structure for example, the following configuration can be mentioned.
  • the second light emitting unit and the third light emitting unit may all be the same or different. Further, the two light emitting units may be the same, and the remaining one may be different. Further, the third light emitting unit may not be provided, while a light emitting unit or an intermediate layer may be further provided between the third light emitting unit and the electrode.
  • the plurality of light emitting units may be directly laminated or may be laminated via an intermediate layer, and the intermediate layer is generally an intermediate electrode, an intermediate conductive layer, a charge generation layer, an electron extraction layer, a connection layer, or an intermediate layer.
  • a known material and structure can be used as long as it is also called an insulating layer and has a function of supplying electrons to the adjacent layer on the anode side and holes to the adjacent layer on the cathode side.
  • Examples of the material used for the intermediate layer include ITO (inorganic tin oxide), IZO ( inorganic zinc oxide), ZnO 2 , TiN, ZrN, HfN, TiOx, VOx, CuI, InN, GaN, and CuAlO 2 .
  • Conductive inorganic compound layers such as CuGaO 2 , SrCu 2 O 2 , LaB 6 , RuO 2 , Al, bilayer films such as Au / Bi 2 O 3 , SnO 2 / Ag / SnO 2 , ZnO / Ag / ZnO , Bi 2 O 3 / Au / Bi 2 O 3, TiO 2 / TiN / TiO 2, TiO 2 / ZrN / TiO 2 or the like multilayer film, also fullerenes such as C 60, conductive organic material layer such as oligothiophene, Examples thereof include conductive organic compound layers such as metallic phthalocyanines, metal-free phthalocyanines, metal porphyrins, and metal-free porphyrins, but the present invention is not limited thereto.
  • Preferred configurations in the light emitting unit include, for example, configurations in which the anode and the cathode are removed from the configurations (i) to (vii) mentioned in the above typical element configurations, but the present invention is limited thereto. Not done.
  • tandem organic EL element examples include, for example, US Pat. No. 6,337,492, US Pat. No. 7,420,203, US Pat. No. 7,473,923, US Pat. No. 6,872,472, US Patent No. 6107734, US Pat. No. 6,337,492, International Publication. 2005/09087, Japanese Patent Application Laid-Open No. 2006-228712, Japanese Patent Application Laid-Open No. 2006-24791, Japanese Patent Application Laid-Open No. 2006-49393, Japanese Patent Application Laid-Open No. 2006-49394, Japanese Patent Application Laid-Open No. 2006-49396, Japanese Patent Application Laid-Open No.
  • the organic EL element of the present invention can be used as a display device, a display, and various light emitting light sources.
  • a light source for example, a lighting device (household lighting, in-car lighting), a backlight for a clock or a liquid crystal, a signboard advertisement, a traffic light, a light source of an optical storage medium, a light source of an electrophotographic copying machine, a light source of an optical communication processor, an optical sensor.
  • the light source is not limited to this, but can be effectively used as a backlight of a liquid crystal display device or a light source for lighting.
  • the organic EL device of the present invention may be patterned by a metal mask, an inkjet printing method, or the like at the time of film formation.
  • patterning only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or all the layers of the device may be patterned.
  • a conventionally known method is used. Can be done.
  • a lighting device including the organic EL element of the present invention An aspect of a lighting device including the organic EL element of the present invention will be described.
  • the non-light emitting surface of the organic EL element is covered with a glass case, a glass substrate having a thickness of 300 ⁇ m is used as a sealing substrate, and an epoxy-based photocurable adhesive (Luxtrac LC0629B manufactured by Toa Synthetic Co., Ltd.) is used as a sealing material around the glass substrate. ) Is applied, this is placed on the cathode and brought into close contact with the transparent support substrate, UV light is irradiated from the glass substrate side, the curing is performed, and the sealing is performed. Can be formed.
  • FIG. 3 shows a schematic view of the lighting device, and the organic EL element (101) according to the present invention is covered with a glass cover (102) (note that the sealing work with the glass cover is performed by the organic EL element (101). ) was carried out in a glove box under a nitrogen atmosphere (under an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more) without contacting the air.
  • FIG. 4 shows a cross-sectional view of the lighting device, in which (105) shows a cathode, (106) shows an organic EL layer, and (107) shows a glass substrate with a transparent electrode.
  • the glass cover (102) is filled with nitrogen gas (108), and a water catching agent (109) is provided.
  • a substrate (NA45 manufactured by NH Technoglass) having a film formation of ITO (indium tin oxide) having a thickness of 100 nm was prepared on a glass substrate of 100 mm ⁇ 100 mm ⁇ 1.1 mm, and the substrate was placed on the substrate. Patterning was performed. Then, the substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and further subjected to UV ozone cleaning for 5 minutes.
  • ITO indium tin oxide
  • PEDOT / PSS polystyrene sulfonate
  • This substrate was transferred to a nitrogen atmosphere, and the following luminescent dopant layer composition 1 was formed on the hole transport layer at 500 rpm for 120 seconds by a spin coating method (thickness: about 100 nm) at 120 ° C. It was heated and dried for 90 minutes to form a light emitting layer.
  • Luminescent Dopant Layer Composition 1 4CzIPN 5.0 parts by mass Polystyrene 7.5 parts by mass Diethylene glycol 100 parts by mass
  • This substrate is fixed to the substrate holder of the vacuum vapor deposition apparatus, the vacuum chamber is depressurized to 4 ⁇ 10 -4 Pa, and then Ag is vapor-deposited to form a cathode having a thickness of 100 nm, and the organic EL element (1-1) is formed. Made.
  • a substrate (NA45 manufactured by NH Technoglass) in which ITO (indium tin oxide) is formed into a film having a thickness of 100 nm is prepared on a glass substrate of 100 mm ⁇ 100 mm ⁇ 1.1 mm, and patterning is performed on the substrate. was done. Then, the substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and further subjected to UV ozone cleaning for 5 minutes.
  • ITO indium tin oxide
  • PEDOT / PSS polystyrene sulfonate
  • This substrate was transferred to a nitrogen atmosphere, and a solution of 80 mg of polystyrene dissolved in 10 ml of diethylene glycol dimethyl ether was formed on a hole transport layer by a spin coating method at 500 rpm for 120 seconds (thickness: about 60 nm). It was heated and dried at 120 ° C. for 90 minutes to prepare a host layer.
  • the following luminescent dopant layer composition 2 was ejected and injected using an inkjet head (manufactured by Epson; MJ800C) so that the wet film thickness was 4 ⁇ m.
  • This substrate is fixed to a substrate holder of a drying box provided with upper and lower partition walls and independent drying air temperature regulators at the upper and lower portions of the partition wall, and heating is controlled to 120 ° C. on the upper surface of the substrate (light emitting layer coating surface). Dry nitrogen was circulated, and heat-dried nitrogen controlled at 80 ° C. was circulated on the back surface side of the substrate. In this state, a drying treatment was performed for 10 minutes.
  • This substrate is fixed to the substrate holder of the vacuum vapor deposition apparatus, the vacuum chamber is depressurized to 4 ⁇ 10 -4 Pa, and then Ag is vapor-deposited to form a cathode having a thickness of 100 nm, and the organic EL element (1-6) is formed. Made.
  • a substrate (NA45 manufactured by NH Technoglass) in which ITO (indium tin oxide) is formed into a film having a thickness of 100 nm is prepared on a glass substrate of 100 mm ⁇ 100 mm ⁇ 1.1 mm, and patterning is performed on the substrate. was done. Then, the substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and further subjected to UV ozone cleaning for 5 minutes.
  • ITO indium tin oxide
  • PEDOT / PSS polystyrene sulfonate
  • This substrate was transferred to a nitrogen atmosphere, and a solution of 80 mg of polystyrene dissolved in 10 ml of diethylene glycol dimethyl ether was formed on a hole transport layer by a spin coating method at 500 rpm for 120 seconds (thickness: about 60 nm). It was heated and dried at 120 ° C. for 90 minutes to prepare a host layer.
  • the following luminescent dopant layer composition 3 was ejected and injected using an inkjet head (manufactured by Epson; MJ800C) so that the wet film thickness was 4 ⁇ m.
  • This substrate is fixed to a substrate holder of a drying box provided with upper and lower partition walls and independent drying air temperature regulators at the upper and lower portions of the partition wall, and heating is controlled to 120 ° C. on the upper surface of the substrate (light emitting layer coating surface). Dry nitrogen was circulated, and heat-dried nitrogen controlled at 80 ° C. was circulated on the back surface side of the substrate. In this state, the luminescent dopant layer was dried by performing a drying treatment for 10 minutes.
  • this substrate is placed on a hot plate and heated at 170 ° C. for 1 hour to melt the host layer, and the compositions of the host compound and the luminescent dopant are continuously changed in the thickness direction on the cathode side.
  • a light emitting layer was formed in which the concentration of the light emitting dopant was continuously decreased from the to the anode side.
  • This substrate is fixed to the substrate holder of the vacuum vapor deposition apparatus, the vacuum chamber is depressurized to 4 ⁇ 10 -4 Pa, and then Ag is vapor-deposited to form a cathode having a thickness of 100 nm, and the organic EL element (1-7) is formed. Made.
  • the concentration distribution of the luminescent dopant contained in the light emitting layer of the obtained organic EL element is TOF-SIMS (time-of-flight secondary ion mass spectrometry) (measuring device: Physical Electricals 2100TRIFT2 primary ion: Ga primary ion acceleration. voltage: 25 kV primary ion current: 2 pA raster range: 20 [mu] m measured mass number: 0.5 - 1000 Da measurement temperature: - by 100 ° C.), was detected by analyzing the luminescent dopant in the layer thickness direction.
  • TOF-SIMS time-of-flight secondary ion mass spectrometry
  • Each of the above-produced organic EL elements is made to emit light at room temperature (about 25 ° C.) under a constant current condition of 0.5 mA / cm 2 , and the emission brightness is measured using a spectral radiance meter CS-2000 (manufactured by Konica Minolta). , 100 points were measured by changing the position at intervals of 0.01 m. The average of the measured values at 100 points was taken as the emission brightness of each element.
  • Table I shows the relative values of the obtained emission luminance (relative values to the emission luminance of the organic EL element (1-1)).
  • Each of the above-produced organic EL elements is made to emit light at room temperature (about 25 ° C.) under a constant current condition of 0.5 mA / cm 2 , and the emission brightness is measured using a spectral radiance meter CS-2000 (manufactured by Konica Minolta). , 100 points were measured by changing the position at intervals of 0.01 m. Of the 100 measured values, the maximum brightness value, the minimum brightness value, and the average brightness value were obtained, the variation in brightness was obtained by the following formula, and the uniformity of brightness was evaluated.
  • Luminance variation ⁇ (maximum brightness value-minimum brightness value) / average brightness ⁇ x 100
  • ⁇ The variation in brightness is less than 1.0, and the film is uniformly formed.
  • X The variation in brightness is 1.0 or more, and the film is not uniformly formed.
  • a substrate (NA45 manufactured by NH Technoglass) having a film formation of ITO (indium tin oxide) having a thickness of 100 nm was prepared on a glass substrate of 100 mm ⁇ 100 mm ⁇ 1.1 mm, and the substrate was placed on the substrate. Patterning was performed. Then, the substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and further subjected to UV ozone cleaning for 5 minutes.
  • ITO indium tin oxide
  • PEDOT / PSS polystyrene sulfonate
  • This substrate was transferred to a nitrogen atmosphere, and the following luminescent dopant layer composition 1 was formed on the hole transport layer at 500 rpm for 120 seconds by a spin coating method (thickness: about 100 nm) at 120 ° C. It was heated and dried for 90 minutes to form a light emitting layer.
  • Luminescent Dopant Layer Composition 1 4CzIPN 5.0 parts by mass Polystyrene 7.5 parts by mass Diethylene glycol 100 parts by mass
  • this substrate was fixed to a substrate holder of a commercially available vacuum vapor deposition apparatus.
  • Each of the crucibles for vapor deposition in the vacuum vapor deposition apparatus was filled with the constituent materials of each layer in the optimum amount for manufacturing the device.
  • As the crucible for vapor deposition a crucible made of molybdenum or tungsten made of a resistance heating material was used. After depressurizing to a vacuum degree of 1 ⁇ 10 -4 Pa, SF3-TRZ was vapor-deposited at a vapor deposition rate of 1.0 nm / sec to form a hole blocking layer having a layer thickness of 5 nm.
  • SF3-TRZ and LiQ (8-hydroxyquinolinolato-lithium) are co-deposited at a vapor deposition rate of 1.0 nm / sec so as to be 50% and 50% mol%, respectively, and electron transport with a layer thickness of 30 nm. A layer was formed.
  • a substrate (NA45 manufactured by NH Technoglass) in which ITO (indium tin oxide) is formed into a film having a thickness of 100 nm is prepared on a glass substrate of 100 mm ⁇ 100 mm ⁇ 1.1 mm, and patterning is performed on the substrate. was done. Then, the substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and further subjected to UV ozone cleaning for 5 minutes.
  • ITO indium tin oxide
  • PEDOT / PSS polystyrene sulfonate
  • This substrate was transferred to a nitrogen atmosphere, and a solution of 80 mg of polystyrene dissolved in 10 ml of diethylene glycol dimethyl ether was formed on a hole transport layer by a spin coating method at 500 rpm for 120 seconds (thickness: about 60 nm). It was heated and dried at 120 ° C. for 90 minutes to prepare a host layer.
  • the following luminescent dopant layer composition 2 was ejected and injected using an inkjet head (manufactured by Epson; MJ800C) so that the wet film thickness was 4 ⁇ m.
  • This substrate is fixed to a substrate holder of a drying box provided with upper and lower partition walls and independent drying air temperature regulators at the upper and lower portions of the partition wall, and heating is controlled to 120 ° C. on the upper surface of the substrate (light emitting layer coating surface). Dry nitrogen was circulated, and heat-dried nitrogen controlled at 80 ° C. was circulated on the back surface side of the substrate. In this state, a drying treatment was performed for 10 minutes.
  • this substrate was fixed to a substrate holder of a commercially available vacuum vapor deposition apparatus.
  • Each of the crucibles for vapor deposition in the vacuum vapor deposition apparatus was filled with the constituent materials of each layer in the optimum amount for manufacturing the device.
  • As the crucible for vapor deposition a crucible made of molybdenum or tungsten made of a resistance heating material was used. After depressurizing to a vacuum degree of 1 ⁇ 10 -4 Pa, SF3-TRZ was vapor-deposited at a vapor deposition rate of 1.0 nm / sec to form a hole blocking layer having a layer thickness of 5 nm.
  • SF3-TRZ and LiQ (8-hydroxyquinolinolato-lithium) are co-deposited at a vapor deposition rate of 1.0 nm / sec so as to be 50% and 50% mol%, respectively, and electron transport with a layer thickness of 30 nm. A layer was formed.
  • lithium fluoride with a film thickness of 0.5 nm
  • aluminum 100 nm was vapor-deposited to form a cathode.
  • the non-light emitting surface side of the element is covered with a can-shaped glass case in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more, and an electrode take-out wiring is installed to manufacture an organic EL element (2-6). did.
  • a substrate (NA45 manufactured by NH Technoglass) in which ITO (indium tin oxide) is formed into a film having a thickness of 100 nm is prepared on a glass substrate of 100 mm ⁇ 100 mm ⁇ 1.1 mm, and patterning is performed on the substrate. was done. Then, the substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and further subjected to UV ozone cleaning for 5 minutes.
  • ITO indium tin oxide
  • PEDOT / PSS polystyrene sulfonate
  • This substrate was transferred to a nitrogen atmosphere, and a solution of 80 mg of polystyrene dissolved in 10 ml of diethylene glycol dimethyl ether was formed on a hole transport layer by a spin coating method at 500 rpm for 120 seconds (thickness: about 60 nm). It was heated and dried at 120 ° C. for 90 minutes to prepare a host layer.
  • the following luminescent dopant layer composition 3 was ejected and injected using an inkjet head (manufactured by Epson; MJ800C) so that the wet film thickness was 4 ⁇ m.
  • This substrate is fixed to a substrate holder of a drying box provided with upper and lower partition walls and independent drying air temperature regulators at the upper and lower portions of the partition wall, and heating is controlled to 120 ° C. on the upper surface of the substrate (light emitting layer coating surface). Dry nitrogen was circulated, and heat-dried nitrogen controlled at 80 ° C. was circulated on the back surface side of the substrate. In this state, the luminescent dopant layer was dried by performing a drying treatment for 10 minutes.
  • this substrate is placed on a hot plate and heated at 170 ° C. for 1 hour to melt the host layer, and the compositions of the host compound and the luminescent dopant are continuously changed in the thickness direction from the cathode side.
  • a light emitting layer in which the concentration of the light emitting dopant was reduced was formed toward the anode side.
  • this substrate was fixed to a substrate holder of a commercially available vacuum vapor deposition apparatus.
  • Each of the crucibles for vapor deposition in the vacuum vapor deposition apparatus was filled with the constituent materials of each layer in the optimum amount for manufacturing the device.
  • As the crucible for vapor deposition a crucible made of molybdenum or tungsten made of a resistance heating material was used. After depressurizing to a vacuum degree of 1 ⁇ 10 -4 Pa, SF3-TRZ was vapor-deposited at a vapor deposition rate of 1.0 nm / sec to form a hole blocking layer having a layer thickness of 5 nm.
  • SF3-TRZ and LiQ (8-hydroxyquinolinolato-lithium) are co-deposited at a vapor deposition rate of 1.0 nm / sec so as to be 50% and 50% mol%, respectively, and electron transport with a layer thickness of 30 nm. A layer was formed.
  • lithium fluoride with a film thickness of 0.5 nm
  • aluminum 100 nm was vapor-deposited to form a cathode.
  • the non-light emitting surface side of the element is covered with a can-shaped glass case in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more, and an electrode take-out wiring is installed to manufacture an organic EL element (2-7). did.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Electroluminescent Light Sources (AREA)

Abstract

The problem to be solved by the present invention is to provide a method for manufacturing, via a simple process, an organic electroluminescent element in which brightness irregularities are ameliorated, and an organic electroluminescent element manufactured via said manufacturing method.　The organic electroluminescent element manufacturing method according to the present invention is a method for manufacturing an organic electroluminescent element comprising: an anode; an organic functional layer including at least one light-emitting layer; and a cathode on a substrate, the method being characterized by comprising a step for forming the light-emitting layer via a wet process, and a heating/melting step for continuously or discontinuously altering, in the through-thickness direction of the light-emitting layer, the compositions of a host compound and a light-emitting dopant contained in the light-emitting layer.

Description

有機エレクトロルミネッセンス素子の製造方法及び有機エレクトロルミネッセンス素子Manufacturing method of organic electroluminescence device and organic electroluminescence device
　本発明は、有機エレクトロルミネッセンス素子の製造方法及び有機エレクトロルミネッセンス素子に関する。
　より詳しくは、簡便なプロセスで輝度ムラが改善される有機エレクトロルミネッセンス素子の製造方法及び当該製造方法により製造された有機エレクトロルミネッセンス素子に関する。 The present invention relates to a method for manufacturing an organic electroluminescent device and an organic electroluminescent device.
More specifically, the present invention relates to a method for producing an organic electroluminescent device in which brightness unevenness is improved by a simple process, and an organic electroluminescent device manufactured by the manufacturing method.
　有機材料のエレクトロルミネッセンス（ｅｌｅｃｔｒｏｌｕｍｉｎｅｓｃｅｎｃｅ：以下「ＥＬ」と略記する。）を利用した有機エレクトロルミネッセンス素子（「有機電界発光素子」、「有機ＥＬ素子」ともいう。）は、平面発光を可能とする新しい発光システムとして既に実用化されている技術である。有機ＥＬ素子は、電子ディスプレイはもとより、最近では照明機器にも適用され、その発展が期待されている。 An organic electroluminescence element (also referred to as an "organic electroluminescent element" or "organic EL element") using an organic material electroluminescence (hereinafter abbreviated as "EL") is a new type that enables planar light emission. This is a technology that has already been put into practical use as a light emitting system. Organic EL elements have recently been applied not only to electronic displays but also to lighting equipment, and their development is expected.
　有機エレクトロルミネッセンス素子は、発光する化合物を含有する発光層を陰極と陽極で挟んだ構成を有し、発光層に電子及び正孔を注入して、再結合させることにより励起子（エキシトン）を生成させる。このエキシトンが失活する際の光の放出（蛍光・リン光）を利用して発光する素子であり、数～十数Ｖ程度の電圧で発光が可能である。 The organic electroluminescence element has a structure in which a light emitting layer containing a light emitting compound is sandwiched between a cathode and an anode, and excitons (excitons) are generated by injecting electrons and holes into the light emitting layer and recombining them. Let me. It is an element that emits light by utilizing the emission of light (fluorescence / phosphorescence) when the excitons are deactivated, and can emit light at a voltage of about several to several tens of volts.
　有機エレクトロルミネッセンス素子を照明用光源又はディスプレイのバックライトとして実用するための課題として発光効率や輝度ムラが挙げられる。
　発光効率の向上のためには、有機エレクトロルミネッセンス素子を構成する有機機能層の一部において、それぞれ別の機能を有する材料を混合して構成する、いわゆるホスト－ゲスト構造を組み入れることが一般的となっている。具体的には、発光層におけるホスト化合物と発光性ド一パントの組み合わせが挙げられる。
　輝度ムラは、有機機能層の厚さや組成のバラつきにより生じるため、広い面積を均一に成膜する方法が求められている。 Luminous efficiency and uneven brightness are issues for practical use of an organic electroluminescent element as a light source for illumination or a backlight for a display.
In order to improve the luminous efficiency, it is common to incorporate a so-called host-guest structure in which materials having different functions are mixed in a part of the organic functional layer constituting the organic electroluminescence element. It has become. Specific examples thereof include a combination of a host compound and a luminescent dopunt in the light emitting layer.
Since uneven brightness is caused by variations in the thickness and composition of the organic functional layer, there is a demand for a method for uniformly forming a large area.
　例えば特許文献１及び非特許文献１では、発光層における発光性ホスト化合物に対する発光性ド一パントの比率が、発光層内で連続的に変化することで効率が向上することを示している。しかし、発光性ド一パントの濃度を連続的に変化させる手段として明示しているのは真空蒸着法における蒸着レートの制御のみであり、生産性に適した手段の提案とはいえない。 For example, Patent Document 1 and Non-Patent Document 1 show that the ratio of luminescent dopants to luminescent host compounds in the light emitting layer is continuously changed in the light emitting layer to improve efficiency. However, only the control of the vapor deposition rate in the vacuum vapor deposition method is specified as a means for continuously changing the concentration of the luminescent dopant, and it cannot be said that the means suitable for productivity is proposed.
　一方、有機エレクトロルミネッセンス素子の製造方法としては、蒸着法、ウェット・プロセス（スピンコート法、ダイコート法、キャスト法、インクジェット法、スプレー法、印刷法）等があるが、真空プロセスを必要とせず、連続生産が簡便であるという理由で近年はウェット・プロセスにおける製造方法が注目されている。 On the other hand, as a method for manufacturing an organic electroluminescence element, there are a vapor deposition method, a wet process (spin coating method, die coating method, casting method, inkjet method, spray method, printing method) and the like, but the vacuum process is not required. In recent years, a manufacturing method in a wet process has attracted attention because continuous production is easy.
　特許文献２では、ウェット・プロセスにおいて、ホスト化合物と発光性ドーパントの比率が異なる溶液をあらかじめ２種以上準備し、それらを順次積層塗布し、乾燥時にホスト化合物と発光性ドーパントが相互に拡散して連続的な濃度変化を生じさせる方法が開示されている。 In Patent Document 2, in the wet process, two or more kinds of solutions having different ratios of the host compound and the luminescent dopant are prepared in advance, and they are sequentially laminated and coated, and the host compound and the luminescent dopant are diffused to each other during drying. A method for producing a continuous change in concentration is disclosed.
　また、非特許文献２では、ホスト層の上にインクジェットにより発光性ドーパントの液を滴下し、ホスト層が発光性ドーパント液に溶けることで、発光層を形成する方法が開示されている。
　しかし、特許文献２及び非特許文献２には、生産性に優れるウェット・プロセスによる有機ＥＬ素子の製造方法が開示されているが、本発明者が検討したところ、膜厚や組成の不均一性に起因すると考えられる輝度ムラが生じることが分かった。 Further, Non-Patent Document 2 discloses a method of forming a light emitting layer by dropping a liquid of a light emitting dopant onto a host layer by inkjet and dissolving the host layer in the liquid of light emitting dopant.
However, Patent Document 2 and Non-Patent Document 2 disclose a method for producing an organic EL element by a wet process having excellent productivity, but as a result of examination by the present inventor, non-uniformity in film thickness and composition is disclosed. It was found that uneven brightness, which is considered to be caused by the above, occurs.
特開２００４－６１０２号公報Japanese Unexamined Patent Publication No. 2004-6102 国際公開第２００９／０８４４１３号International Publication No. 2009/0844113
　本発明は、上記問題・状況に鑑みてなされたものであり、その解決課題は、簡便なプロセスで輝度ムラが改善される有機エレクトロルミネッセンス素子の製造方法及び当該製造方法により製造された有機エレクトロルミネッセンス素子を提供することである。 The present invention has been made in view of the above problems and situations, and the problem to be solved is a method for manufacturing an organic electroluminescence element in which brightness unevenness is improved by a simple process, and an organic electroluminescence manufactured by the manufacturing method. It is to provide an element.
　本発明者は、上記課題を解決すべく、上記問題の原因等について検討する過程において、ある特定の有機機能層を加熱・融解させたとき、当該有機機能層を構成する化合物が、隣接層を構成する化合物と混合する挙動を見出し本発明に至った。
　すなわち、本発明に係る上記課題は、以下の手段により解決される。 In the process of investigating the cause of the above problem in order to solve the above-mentioned problems, the present inventor, when a specific organic functional layer is heated and melted, the compounds constituting the organic functional layer form an adjacent layer. We have found the behavior of mixing with the constituent compounds and arrived at the present invention.
That is, the above problem according to the present invention is solved by the following means.
１．基板上に、陽極と、少なくとも一層の発光層を含む有機機能層と、陰極とを有する有機エレクトロルミネッセンス素子の製造方法であって、
　前記発光層をウェット・プロセスで形成する工程を有し、かつ、
　当該発光層に含有させるホスト化合物と発光性ドーパントの組成を、当該発光層の厚さ方向において、連続的又は断続的に変化させる加熱・融解工程を有する、
　ことを特徴とする有機エレクトロルミネッセンス素子の製造方法。 1. 1. A method for manufacturing an organic electroluminescence device having an anode, an organic functional layer including at least one light emitting layer, and a cathode on a substrate.
It has a step of forming the light emitting layer by a wet process, and
It has a heating / melting step of continuously or intermittently changing the composition of the host compound and the luminescent dopant contained in the light emitting layer in the thickness direction of the light emitting layer.
A method for manufacturing an organic electroluminescent device.
２．前記発光層の形成において、前記基板側から、前記ホスト化合物を含有するホスト層と前記発光性ドーパントを含有するドーパント層をこの順に形成し、その後、
　前記加熱・融解工程において、少なくとも前記ホスト層を融解させることで、当該ホスト層と前記ドーパント層のそれぞれの構成成分を混合させ、かつ、
　前記発光層の厚さ方向において、前記ホスト化合物と前記発光性ドーパントの組成を連続的又は断続的に変化させる、
　ことを特徴とする第１項に記載の有機エレクトロルミネッセンス素子の製造方法。 2. In the formation of the light emitting layer, the host layer containing the host compound and the dopant layer containing the light emitting dopant are formed in this order from the substrate side, and then the light emitting layer is formed.
In the heating / melting step, at least the host layer is melted to mix the respective constituent components of the host layer and the dopant layer, and
The composition of the host compound and the luminescent dopant is continuously or intermittently changed in the thickness direction of the light emitting layer.
The method for manufacturing an organic electroluminescent device according to the first item.
３．前記加熱・融解工程において、前記発光層の前記陰極側から前記陽極側に向かう厚さ方向において、前記発光性ドーパントの濃度が連続的又は断続的に減少する領域を形成する、
　ことを特徴とする第１項又は第２項に記載の有機エレクトロルミネッセンス素子の製造方法。 3. 3. In the heating / melting step, a region is formed in which the concentration of the luminescent dopant is continuously or intermittently decreased in the thickness direction of the light emitting layer from the cathode side to the anode side.
The method for producing an organic electroluminescent device according to the first or second paragraph.
４．前記発光性ドーパントが、熱活性型遅延蛍光性化合物である、
　ことを特徴とする第１項から第３項までのいずれか一項に記載の有機エレクトロルミネッセンス素子の製造方法。 4. The luminescent dopant is a thermally activated delayed fluorescent compound.
The method for manufacturing an organic electroluminescent device according to any one of the items 1 to 3, wherein the method comprises the above.
５．前記ホスト化合物が、絶縁性の高分子化合物である、
　ことを特徴とする第１項から第４項までのいずれか一項に記載の有機エレクトロルミネッセンス素子の製造方法。 5. The host compound is an insulating polymer compound.
The method for manufacturing an organic electroluminescent device according to any one of the items 1 to 4, wherein the method comprises the above.
６．前記ホスト化合物が、ポリスチレンである、
　ことを特徴とする第１項から第５項までのいずれか一項に記載の有機エレクトロルミネッセンス素子の製造方法 6. The host compound is polystyrene.
The method for manufacturing an organic electroluminescent device according to any one of the items 1 to 5, wherein the organic electroluminescence device is characterized by the above.
７．基板上に、陽極と、少なくとも一層の発光層を含む有機機能層と、陰極とを有する有機エレクトロルミネッセンス素子であって、
　前記発光層が、前記基板側から前記ホスト化合物を含有するホスト層と前記発光性ドーパントを含有するドーパント層の塗布膜からなり、
　当該ホスト層と当該ドーパント層とが融解接合されており、かつ、
　前記発光層の厚さ方向において、前記ホスト化合物と前記発光性ドーパントの組成が連続的又は断続的に変化している、
　ことを特徴とする有機エレクトロルミネッセンス素子。 7. An organic electroluminescence device having an anode, an organic functional layer including at least one light emitting layer, and a cathode on a substrate.
The light emitting layer is composed of a coating film of a host layer containing the host compound and a dopant layer containing the light emitting dopant from the substrate side.
The host layer and the dopant layer are melt-bonded and
The composition of the host compound and the luminescent dopant changes continuously or intermittently in the thickness direction of the light emitting layer.
An organic electroluminescence device characterized by this.
８．前記発光性ドーパントが、熱活性型遅延蛍光性化合物である、
　ことを特徴とする第７項に記載の有機エレクトロルミネッセンス素子。 8. The luminescent dopant is a thermally activated delayed fluorescent compound.
The organic electroluminescence device according to item 7, wherein the organic electroluminescence device is characterized.
９．前記ホスト化合物が、絶縁性の高分子化合物である、
　ことを特徴とする第７項又は第８項に記載の有機エレクトロルミネッセンス素子。 9. The host compound is an insulating polymer compound.
8. The organic electroluminescence device according to item 7 or 8.
　本発明の上記手段により、簡便なプロセスで輝度ムラが改善される有機エレクトロルミネッセンス素子の製造方法及び当該製造方法により製造された有機エレクトロルミネッセンス素子を提供することができる。 According to the above means of the present invention, it is possible to provide a method for producing an organic electroluminescent device in which brightness unevenness is improved by a simple process, and an organic electroluminescent device manufactured by the manufacturing method.
インクジェット印刷方式を用いた有機ＥＬ素子の製造方法の一例を示す概略図Schematic diagram showing an example of a method for manufacturing an organic EL element using an inkjet printing method. インクジェット印刷方式に適用可能なインクジェットヘッドの構造の一例を示す概略外観図Schematic external view showing an example of the structure of an inkjet head applicable to an inkjet printing method. インクジェット印刷方式に適用可能なインクジェットヘッドの構造の一例を示す概略外観図Schematic external view showing an example of the structure of an inkjet head applicable to an inkjet printing method. 照明装置の概略図Schematic diagram of lighting equipment 照明装置の模式図Schematic diagram of lighting equipment
　本発明の有機エレクトロルミネッセンス素子の製造方法は、基板上に、陽極と、少なくとも一層の発光層を含む有機機能層と、陰極とを有する有機エレクトロルミネッセンス素子の製造方法であって、前記発光層をウェット・プロセスで形成する工程を有し、かつ、当該発光層に含有させるホスト化合物と発光性ドーパントの組成を、当該発光層の厚さ方向において、連続的又は断続的に変化させる加熱・融解工程を有することを特徴とする。
　この特徴は、下記各実施形態に共通する又は対応する技術的特徴である。 The method for manufacturing an organic electroluminescence device of the present invention is a method for manufacturing an organic electroluminescence device having an anode, an organic functional layer including at least one light emitting layer, and a cathode on a substrate, wherein the light emitting layer is formed. A heating / melting step that has a step of forming by a wet process and continuously or intermittently changes the composition of the host compound and the luminescent dopant contained in the light emitting layer in the thickness direction of the light emitting layer. It is characterized by having.
This feature is a technical feature common to or corresponding to each of the following embodiments.
　本発明の実施形態としては、本発明の効果発現の観点から、前記発光層の形成において、前記基板側から、前記ホスト化合物を含有するホスト層と前記発光性ドーパントを含有するドーパント層をこの順に形成し、その後、前記加熱・融解工程において、少なくとも前記ホスト層を融解させることで、当該ホスト層と前記ドーパント層のそれぞれの構成成分を混合させ、かつ、前記発光層の厚さ方向において、前記ホスト化合物と前記発光性ドーパントの組成を連続的又は断続的に変化させる形態であることが好ましい。 In the embodiment of the present invention, from the viewpoint of exhibiting the effect of the present invention, in the formation of the light emitting layer, the host layer containing the host compound and the dopant layer containing the light emitting dopant are arranged in this order from the substrate side. After the formation, in the heating / melting step, at least the host layer is melted to mix the respective components of the host layer and the dopant layer, and in the thickness direction of the light emitting layer, the said It is preferable that the composition of the host compound and the luminescent dopant is continuously or intermittently changed.
　また、前記加熱・融解工程において、前記発光層の前記陰極側から前記陽極側に向かう厚さ方向において、前記発光性ドーパントの濃度が連続的又は断続的に減少する領域を形成することが、発光効率の向上及び発光輝度ムラ防止等の観点から好ましい。 Further, in the heating / melting step, forming a region in which the concentration of the luminescent dopant continuously or intermittently decreases in the thickness direction from the cathode side to the anode side of the light emitting layer causes light emission. It is preferable from the viewpoint of improving efficiency and preventing uneven emission brightness.
　本発明においては、発光効率の観点から、前記発光性ドーパントが、熱活性型遅延蛍光性化合物であることが好ましい。また、前記ホスト化合物が、絶縁性の高分子化合物であることが好ましい。さらに、前記ホスト化合物が、ポリスチレンであることが好ましい。 In the present invention, the luminous dopant is preferably a thermally activated delayed fluorescent compound from the viewpoint of luminous efficiency. Further, it is preferable that the host compound is an insulating polymer compound. Further, the host compound is preferably polystyrene.
　本発明の有機エレクトロルミネッセンス素子は、基板上に、陽極と、少なくとも一層の発光層を含む有機機能層と、陰極とを有する有機エレクトロルミネッセンス素子であって、前記発光層が、前記基板側から前記ホスト化合物を含有するホスト層と前記発光性ドーパントを含有するドーパント層の塗布膜からなり、当該ホスト層と当該ドーパント層とが融解接合されており、かつ、前記発光層の厚さ方向において、前記ホスト化合物と前記発光性ドーパントの組成が連続的又は断続的に変化していることを特徴とする。 The organic electroluminescence element of the present invention is an organic electroluminescence element having an anode, an organic functional layer including at least one light emitting layer, and a cathode on a substrate, and the light emitting layer is said to be from the substrate side. It is composed of a coating film of a host layer containing a host compound and a dopant layer containing the light emitting dopant, and the host layer and the dopant layer are melt-bonded, and in the thickness direction of the light emitting layer, the said It is characterized in that the composition of the host compound and the luminescent dopant is continuously or intermittently changed.
　以下、本発明とその構成要素及び本発明を実施するための形態・態様について説明をする。なお、本願において、「～」は、その前後に記載される数値を下限値及び上限値として含む意味で使用する。 Hereinafter, the present invention, its constituent elements, and modes and modes for carrying out the present invention will be described. In the present application, "-" is used to mean that the numerical values described before and after the value are included as the lower limit value and the upper limit value.
　（有機エレクトロルミネッセンス素子の製造方法の概要）
　本発明の有機エレクトロルミネッセンス素子の製造方法（以下、「有機ＥＬ素子」という。）は、基板上に、陽極と、少なくとも一層の発光層を含む有機機能層と、陰極とを有する有機エレクトロルミネッセンス素子の製造方法であって、前記発光層をウェット・プロセスで形成する工程を有し、かつ、当該発光層に含有させるホスト化合物と発光性ドーパントの組成を、当該発光層の厚さ方向において、連続的又は断続的に変化させる加熱・融解工程を有することを特徴とする。 (Outline of manufacturing method of organic electroluminescence device)
The method for manufacturing an organic electroluminescent device of the present invention (hereinafter, referred to as "organic EL device") is an organic electroluminescent device having an anode, an organic functional layer including at least one light emitting layer, and a cathode on a substrate. The method for producing the above, which comprises a step of forming the light emitting layer by a wet process, and the composition of the host compound and the luminescent dopant contained in the light emitting layer is continuously formed in the thickness direction of the light emitting layer. It is characterized by having a heating / melting step that changes the target or intermittently.
　なお、本願でいう「ホスト化合物と発光性ドーパントの組成を、発光層の厚さ方向において、連続的又は断続的に変化させる」とは、発光層の厚さ方向において、一定間隔で、当該ホスト化合物と発光性ドーパントのそれぞれの濃度の変化状態を測定したとき、連続的若しくは断続的に濃度が減少している状態、又は連続的若しくは断続的に濃度が増加している状態になっているように変化させることをいう。 In addition, "the composition of the host compound and the luminescent dopant is continuously or intermittently changed in the thickness direction of the light emitting layer" in the present application means that the host concerned at regular intervals in the thickness direction of the light emitting layer. When the change state of each concentration of the compound and the luminescent dopant is measured, it seems that the concentration is continuously or intermittently decreasing, or the concentration is continuously or intermittently increasing. It means to change to.
　ここで、「連続的」とは、一定間隔で測定して得られた濃度の値を発光層の厚さ方向の表面からの距離に対してプロットしたとき、略一定の傾きの直線又は略一定の曲率の曲線が描けるような変化状態をいう。また、「断続的」とは、上記と同様のプロットをしたとき、おおよそ上記のような直線又は曲線が描けるが、当該直線や曲線上に載らない濃度値が前記厚さ方向においてところどころ観測されるような変化状態をいう。 Here, "continuous" means a straight line having a substantially constant slope or a substantially constant value when plotting the value of the concentration obtained by measuring at regular intervals with respect to the distance from the surface in the thickness direction of the light emitting layer. A changing state in which a curve of curvature can be drawn. In addition, "intermittent" means that when a plot similar to the above is made, a straight line or a curve as described above can be drawn, but a concentration value that does not appear on the straight line or the curve is observed in some places in the thickness direction. Such a changing state.
　なお、当該濃度の変化状態の測定は、例えば飛行時間型二次イオン質量分析法（ＴＯＦ－ＳＩＭＳ：Ｔｉｍｅ－ｏｆ－Ｆｌｉｇｈｔ　Ｓｅｃｏｎｄａｒｙ　Ｉｏｎ　Ｍａｓｓ　Ｓｐｅｃｔｒｏｍｅｔｒｙ）を用い、かつイオンスパッタリングを利用して表面エッチングを行いながら、スパッタと測定を交互に繰り返して得られたスペクトル情報から元素の組成又は分子構造について深さ方向プロファイルを得ることによりできる。
　以下において、各構成要素等について詳細な説明をする。 The change state of the concentration is measured by, for example, surface etching using time-of-flight secondary ion mass spectrometry (TOF-SIMS: Time-of-Flight Second Element Mass Spectrometry) and ion sputtering. However, it can be obtained by obtaining a depth direction profile for the composition or molecular structure of an element from the spectral information obtained by alternately repeating sputtering and measurement.
Hereinafter, each component and the like will be described in detail.
　（有機ＥＬ素子の構成）
　本発明の製造方法を用いることができる有機ＥＬ素子の代表的な構成例としては、以下の構成例を挙げることができるが、これらに限定されるものではない。
（ｉ）陽極／発光層／陰極
（ｉｉ）陽極／発光層／電子輸送層／陰極
（ｉｉｉ）陽極／正孔輸送層／発光層／陰極
（ｉｖ）陽極／正孔輸送層／発光層／電子輸送層／陰極
（ｖ）陽極／正孔輸送層／発光層／電子輸送層／電子注入層／陰極
（ｖｉ）陽極／正孔注入層／正孔輸送層／発光層／電子輸送層／陰極
（ｖｉｉ）陽極／正孔注入層／正孔輸送層／（電子阻止層／）発光層／（正孔阻止層／）電子輸送層／電子注入層／陰極
　上記の中で（ｖｉｉ）の構成が好ましく用いられるが、これに限定されるものではない。 (Structure of organic EL element)
Typical configuration examples of the organic EL device to which the production method of the present invention can be used include, but are not limited to, the following configuration examples.
(I) Anode / light emitting layer / cathode (ii) anode / light emitting layer / electron transport layer / cathode (iii) anode / hole transport layer / light emitting layer / cathode (iv) anode / hole transport layer / light emitting layer / electron Transport layer / cathode (v) anode / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode (vi) anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / cathode ( vi) Anophode / hole injection layer / hole transport layer / (electron blocking layer /) light emitting layer / (hole blocking layer /) electron transport layer / electron injection layer / cathode Among the above, the configuration of (vii) is preferable. Used, but not limited to.
　本発明に係る発光層は、単層又は複数層で構成されており、発光層が複数の場合は各発光層の間に非発光性の中間層を設けてもよい。必要に応じて、発光層と陰極との間に正孔阻止層（正孔障壁層ともいう）や電子注入層（陰極バッファー層ともいう）を設けてもよく、また、発光層と陽極との間に電子阻止層（電子障壁層ともいう）や正孔注入層（陽極バッファー層ともいう）を設けてもよい。
　本発明に係る「電子輸送層」とは、電子を輸送する機能を有する層であり、広い意味で電子注入層、正孔阻止層も電子輸送層に含まれる。また、複数層で構成されていてもよい。
　本発明に係る「正孔輸送層」とは、正孔を輸送する機能を有する層であり、広い意味で正孔注入層、電子阻止層も正孔輸送層に含まれる。また、複数層で構成されていてもよい。
　上記の代表的な素子構成において、陽極と陰極を除いた層を「有機機能層」ともいう。 The light emitting layer according to the present invention is composed of a single layer or a plurality of layers, and when there are a plurality of light emitting layers, a non-light emitting intermediate layer may be provided between the light emitting layers. If necessary, a hole blocking layer (also referred to as a hole barrier layer) or an electron injection layer (also referred to as a cathode buffer layer) may be provided between the light emitting layer and the cathode, and the light emitting layer and the anode may be provided. An electron blocking layer (also referred to as an electron barrier layer) or a hole injection layer (also referred to as an anode buffer layer) may be provided between them.
The "electron transport layer" according to the present invention is a layer having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. Further, it may be composed of a plurality of layers.
The "hole transport layer" according to the present invention is a layer having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. Further, it may be composed of a plurality of layers.
In the above typical device configuration, the layer excluding the anode and the cathode is also referred to as an "organic functional layer".
　（発光層の形成方法）
　本発明に係る発光層の形成方法については、当該発光層をウェット・プロセスで形成する工程を有し、かつ、当該発光層に含有させるホスト化合物と発光性ドーパントの組成を、当該発光層の厚さ方向において、連続的又は断続的に変化させる加熱・融解工程を有することを特徴とする。
　また、前記発光層の形成において、前記基板側から、前記ホスト化合物を含有するホスト層と前記発光性ドーパントを含有するドーパント層をこの順に形成し、その後、前記加熱・融解工程において、少なくとも前記ホスト層を融解させることで、当該ホスト層と前記ドーパント層のそれぞれの構成成分を混合させ、かつ、前記発光層の厚さ方向において、前記ホスト化合物と前記発光性ドーパントの組成を連続的又は断続的に変化させることが好ましい。 (Method of forming the light emitting layer)
The method for forming a light emitting layer according to the present invention includes a step of forming the light emitting layer by a wet process, and the composition of the host compound and the light emitting dopant contained in the light emitting layer is determined by the thickness of the light emitting layer. It is characterized by having a heating / melting step that changes continuously or intermittently in the longitudinal direction.
Further, in the formation of the light emitting layer, the host layer containing the host compound and the dopant layer containing the light emitting dopant are formed in this order from the substrate side, and then at least in the heating / melting step, at least the host. By melting the layer, the respective constituent components of the host layer and the dopant layer are mixed, and the composition of the host compound and the luminescent dopant is continuously or intermittently formed in the thickness direction of the light emitting layer. It is preferable to change to.
　《ウェット・プロセス》
　本発明に係る発光層は、ウェット・プロセスで形成することを特徴とする。
　本発明で用いられるウェット・プロセス（「湿式法」ともいう。）としては、スピンコート法、キャスト法、インクジェット印刷法、ダイコート法、ブレードコート法、ロールコート法、スプレーコート法、カーテンコート法、ＬＢ法（ラングミュア－ブロジェット法）等があるが、均質な薄膜が得られやすく、かつ高生産性の点から、ダイコート法、ロールコート法、インクジェット印刷法、スプレーコート法などのロール・ｔｏ・ロール方式適性の高い方法が好ましい。 《Wet process》
The light emitting layer according to the present invention is characterized by being formed by a wet process.
The wet process (also referred to as "wet method") used in the present invention includes a spin coating method, a casting method, an inkjet printing method, a die coating method, a blade coating method, a roll coating method, a spray coating method, and a curtain coating method. There are LB method (Langmuir-Brojet method), etc., but from the viewpoint of easy acquisition of a uniform thin film and high productivity, roll-to-roll method such as die coating method, roll coating method, inkjet printing method, spray coating method, etc. A method with high suitability for the roll method is preferable.
　本発明に係る有機ＥＬ材料（化合物又は混合物）を溶解又は分散する液媒体としては特に制限はなく、例えばクロロホルム、四塩化炭素、ジクロロメタン、１，２－ジクロロエタン、ジクロロベンゼン、ジクロロヘキサノン等のハロゲン系溶媒、アセトン、メチルエチルケトン、ジエチルケトン、メチルイソブチルケトン、ｎ－プロピルメチルケトン、シクロヘキサノン等のケトン系溶媒、ベンゼン、トルエン、キシレン、メシチレン、シクロヘキシルベンゼン等の芳香族系溶媒、シクロヘキサン、デカリン、ドデカン等の脂肪族系溶媒、酢酸エチル、酢酸ｎ－プロピル、酢酸ｎ－ブチル、プロピオン酸メチル、プロピオン酸エチル、γ－ブチロラクトン、炭酸ジエチル等のエステル系溶媒、テトラヒドロフラン、ジオキサン等のエーテル系溶媒、ジメチルホルムアミド、ジメチルアセトアミド等のアミド系溶媒、メタノール、エタノール、１－ブタノール、エチレングリコール等のアルコール系溶媒、アセトニトリル、プロピオニトリル等のニトリル系溶媒、ジメチルスルホキシド、水又はこれらの混合液媒体等が挙げられる。 The liquid medium for dissolving or dispersing the organic EL material (compound or mixture) according to the present invention is not particularly limited, and for example, halogen-based solvents such as chloroform, carbon tetrachloride, dichloromethane, 1,2-dichloroethane, dichlorobenzene, and dichlorohexanone. Solvents, ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, n-propyl methyl ketone, cyclohexanone, aromatic solvents such as benzene, toluene, xylene, mesitylen, cyclohexylbenzene, cyclohexane, decalin, dodecane and the like. Aliper solvent, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl propionate, ethyl propionate, γ-butyrolactone, diethyl carbonate and other ester solvents, tetrahydrofuran, dioxane and other ether solvents, dimethylformamide, Examples thereof include amide solvents such as dimethylacetamide, alcohol solvents such as methanol, ethanol, 1-butanol and ethylene glycol, nitrile solvents such as acetonitrile and propionitrile, dimethyl sulfoxide, water or a mixed solution medium thereof.
　これらの液媒体の沸点としては、迅速に液媒体を乾燥させる観点から乾燥処理の温度未満の沸点が好ましく、具体的には６０～２００℃の範囲内が好ましく、さらに好ましくは、８０～１８０℃の範囲内である。 The boiling point of these liquid media is preferably a boiling point lower than the temperature of the drying treatment from the viewpoint of quickly drying the liquid medium, specifically in the range of 60 to 200 ° C, more preferably 80 to 180 ° C. Is within the range of.
　塗布液は、塗布範囲を制御する目的や、塗布後の表面張力勾配に伴う液流動（例えばコーヒーリングと呼ばれる現象を引き起こす液流動）を抑制する目的に応じて、界面活性剤を含有することができる。
　界面活性剤としては、溶媒に含まれる水分の影響、レベリング性、基板への濡れ性等の観点から、例えばアニオン性又はノニオン性の界面活性剤等が挙げられる。具体的には、含フッ素系活性剤等、国際公開第０８／１４６６８１号、特開平２－４１３０８号公報等に挙げられた界面活性剤を用いることができる。 The coating liquid may contain a surfactant depending on the purpose of controlling the coating range and suppressing the liquid flow (for example, the liquid flow that causes a phenomenon called coffee ring) associated with the surface tension gradient after coating. it can.
Examples of the surfactant include anionic or nonionic surfactants from the viewpoint of the influence of water contained in the solvent, leveling property, wettability to the substrate and the like. Specifically, the surfactants listed in International Publication No. 08/146681, JP-A-2-41308, etc., such as fluorine-containing activators, can be used.
　湿式法に用いる塗布液は、有機機能層を形成する材料が液媒体に均一に溶解される溶液でも、材料が固形分として液媒体に分散される分散液でもよい。分散方法としては、超音波、高剪断力分散やメディア分散等の分散方法により分散することができる。 The coating liquid used in the wet method may be a solution in which the material forming the organic functional layer is uniformly dissolved in the liquid medium, or a dispersion liquid in which the material is dispersed in the liquid medium as a solid content. As a dispersion method, dispersion can be performed by a dispersion method such as ultrasonic waves, high shear force dispersion, or media dispersion.
　塗布膜の粘度についても、膜厚と同様に、有機機能層として必要とされる機能と有機材料の溶解度又は分散性により、適宜選択することが可能で、具体的には例えば０．３～１００ｍＰａ・ｓの範囲内で選択することができる。
　塗布膜の膜厚は、有機機能層として必要とされる機能と有機材料の溶解度又は分散性により適宜選択することが可能で、具体的には例えば１～９０μｍの範囲内で選択することができる。 Similar to the film thickness, the viscosity of the coating film can be appropriately selected depending on the function required as the organic functional layer and the solubility or dispersibility of the organic material. Specifically, for example, 0.3 to 100 mPa. -Can be selected within the range of s.
The film thickness of the coating film can be appropriately selected depending on the function required as the organic functional layer and the solubility or dispersibility of the organic material, and specifically, can be selected in the range of, for example, 1 to 90 μm. ..
　湿式法により塗布膜を形成した後、上述した液媒体を除去する乾燥工程を有することができる。乾燥工程の温度は特に制限されないが、有機機能層や透明電極や基材が損傷しない程度の温度で乾燥処理することが好ましい。具体的には、塗布液の組成等によって異なるため一概にはいえないが、例えば８０℃以上の温度とすることができ、上限は３００℃程度までは可能な領域と考えられる。時間は１０秒以上１０分以下程度とすることが好ましい。このような条件とすることにより、乾燥を迅速に行うことができる。 After forming the coating film by the wet method, it is possible to have a drying step of removing the above-mentioned liquid medium. The temperature of the drying step is not particularly limited, but it is preferable to perform the drying treatment at a temperature that does not damage the organic functional layer, the transparent electrode, or the base material. Specifically, it cannot be said unconditionally because it differs depending on the composition of the coating liquid and the like, but for example, the temperature can be set to 80 ° C. or higher, and the upper limit is considered to be a possible range up to about 300 ° C. The time is preferably about 10 seconds or more and 10 minutes or less. Under such conditions, drying can be performed quickly.
　《インクジェット印刷法》
　以下、インクジェット印刷法による有機層の形成方法について、その一例を、図を参照して説明する。 《Inkjet printing method》
Hereinafter, an example of the method for forming the organic layer by the inkjet printing method will be described with reference to the drawings.
　図１は、インクジェット印刷方式を用いた有機ＥＬ素子の製造方法の一例を示す概略図である。 FIG. 1 is a schematic view showing an example of a method for manufacturing an organic EL element using an inkjet printing method.
　図１には、インクジェットヘッド（３０）を具備したインクジェット印刷装置を用いて、基材（２）上に、有機ＥＬ素子の有機層を形成する有機機能性材料等（必要に応じて本発明のπ共役系化合物を含む）を吐出する方法の一例を示してある。 In FIG. 1, an inkjet printing apparatus provided with an inkjet head (30) is used to form an organic functional material or the like for forming an organic layer of an organic EL element on a base material (2) (if necessary, the present invention). An example of a method of discharging (including a π-conjugated compound) is shown.
　図１に示すように、一例として、基材（２）を連続的に搬送しながら、インクジェットヘッド（３０）により、前記有機機能性材料等をインク液滴として順次、基材（２）上に射出して、有機ＥＬ素子（１）の有機機能層を形成する。 As shown in FIG. 1, as an example, while continuously transporting the base material (2), the organic functional material or the like is sequentially transferred onto the base material (2) as ink droplets by the inkjet head (30). It is injected to form an organic functional layer of the organic EL element (1).
　本発明に係る有機ＥＬ素子の製造方法に適用可能なインクジェットヘッド（３０）としては、特に限定はなく、例えばインク圧力室に圧電素子を備えた振動板を有し、この振動板によるインク圧力室の圧力変化でインク組成物を吐出させる剪断モード型（ピエゾ型）のヘッドでもよいし、発熱素子を有し、この発熱素子からの熱エネルギーによりインク組成物の膜沸騰による急激な体積変化によりノズルからインク組成物を吐出させるサーマルタイプのヘッドであってもよい。 The inkjet head (30) applicable to the method for manufacturing an organic EL element according to the present invention is not particularly limited. For example, an ink pressure chamber has a diaphragm provided with a piezoelectric element, and the ink pressure chamber using the diaphragm. It may be a shear mode type (piezo type) head that ejects the ink composition by the pressure change of the above, or it has a heat generating element, and the nozzle due to a sudden volume change due to the film boiling of the ink composition due to the heat energy from the heat generating element. It may be a thermal type head that ejects the ink composition from the ink composition.
　インクジェットヘッド（３０）には、射出用のインク組成物の供給機構などが接続されている。インク組成物のインクジェットヘッド（３０）への供給は、タンク（３８Ａ）により行われる。インクジェットヘッド（３０）内のインク組成物の圧力を常に一定に保つように、この例ではタンク液面を一定にする。その方法としては、インク組成物をタンク（３８Ａ）からオーバーフローさせてタンク（３８Ｂ）に自然流下で戻している。タンク（３８Ｂ）からタンク（３８Ａ）へのインク組成物の供給は、ポンプ（３１）により行われており、射出条件に合わせて安定的にタンク（３８Ａ）の液面が一定となるように制御されている。 An ink composition supply mechanism for injection is connected to the inkjet head (30). The ink composition is supplied to the inkjet head (30) by a tank (38A). In this example, the liquid level in the tank is kept constant so that the pressure of the ink composition in the inkjet head (30) is always kept constant. As a method, the ink composition is overflowed from the tank (38A) and returned to the tank (38B) by natural flow. The ink composition is supplied from the tank (38B) to the tank (38A) by the pump (31), and the liquid level of the tank (38A) is controlled to be stable according to the injection conditions. Has been done.
　なお、ポンプ（３１）によりタンク（３８Ａ）へインク組成物を戻す際には、フィルター（３２）を通してから行われている。このように、インク組成物はインクジェットヘッド（３０）へ供給される前に絶対濾過精度又は準絶対濾過精度が０．０５～５０μｍの濾材を少なくとも１回は通過させることが好ましい。 When returning the ink composition to the tank (38A) by the pump (31), it is performed after passing through the filter (32). As described above, it is preferable that the ink composition is passed through a filter medium having an absolute filtration accuracy or a quasi-absolute filtration accuracy of 0.05 to 50 μm at least once before being supplied to the inkjet head (30).
　また、インクジェットヘッド（３０）の洗浄作業や液体充填作業などを実施するためにタンク（３６）よりインク組成物が、タンク（３７）より洗浄溶媒がポンプ（３９）によりインクジェットヘッド（３０）へ強制的に供給可能となっている。インクジェットヘッド（３０）に対してこうしたタンクポンプ類は複数に分けても良いし、配管の分岐を使用してもよい、またそれらの組み合わせでもかまわない。 Further, in order to perform cleaning work and liquid filling work of the inkjet head (30), the ink composition is forced from the tank (36) and the cleaning solvent is forced from the tank (37) to the inkjet head (30) by the pump (39). Can be supplied. Such tank pumps may be divided into a plurality of such tank pumps with respect to the inkjet head (30), a branch of a pipe may be used, or a combination thereof may be used.
　図１では配管分岐（３３）を使用している。さらにインクジェットヘッド（３０）内のエアーを十分に除去するためにタンク（３６）よりポンプ（３９）にてインクジェットヘッド（３０）へインク組成物を強制的に送液しながらエアー抜き配管からインク組成物を抜き出して廃液タンク（３４）に送ることもある。 In FIG. 1, the piping branch (33) is used. Further, in order to sufficiently remove the air in the inkjet head (30), the ink composition is forcibly sent from the tank (36) to the inkjet head (30) by the pump (39) while the ink composition is discharged from the air bleeding pipe. In some cases, an object is taken out and sent to a waste liquid tank (34).
　《インクジェットヘッド》
　図２Ａ及び図２Ｂは、インクジェット印刷方式に適用可能なインクジェットヘッドの構造の一例を示す概略外観図である。 《Inkjet head》
2A and 2B are schematic external views showing an example of an inkjet head structure applicable to an inkjet printing method.
　図２Ａは、本発明に適用可能なインクジェットヘッド（１００）を示す概略斜視図であり、図２Ｂは、インクジェットヘッド（１００）の底面図である。 FIG. 2A is a schematic perspective view showing an inkjet head (100) applicable to the present invention, and FIG. 2B is a bottom view of the inkjet head (100).
　本発明に適用可能なインクジェットヘッド（１００）は、インクジェット記録装置（図示略）に搭載されるものであり、インクをノズルから吐出させるヘッドチップと、このヘッドチップが配設された配線基板と、この配線基板とフレキシブル基板を介して接続された駆動回路基板と、ヘッドチップのチャネルにフィルターを介してインクを導入するマニホールドと、内側にマニホールドが収納された筐体（５６）と、この筐体（５６）の底面開口を塞ぐように取り付けられたキャップ受板（５７）と、マニホールドの第１インクポート及び第２インクポートに取り付けられた第１及び第２ジョイント（８１ａ、８１ｂ）と、マニホールドの第３インクポートに取り付けられた第３ジョイント（８２）と、筐体（５６）に取り付けられたカバー部材（５９）とを備えている。また、筐体（５６）をプリンタ本体側に取り付けるための取り付け用孔（６８）がそれぞれ形成されている。 The inkjet head (100) applicable to the present invention is mounted on an inkjet recording device (not shown), and includes a head chip that ejects ink from a nozzle, a wiring board on which the head chip is arranged, and a wiring board. A drive circuit board connected to the wiring board via a flexible board, a manifold for introducing ink into the channel of the head chip via a filter, a housing (56) in which the manifold is housed, and this housing. The cap receiving plate (57) attached so as to close the bottom opening of (56), the first and second joints (81a, 81b) attached to the first ink port and the second ink port of the manifold, and the manifold. A third joint (82) attached to the third ink port of No. 1 and a cover member (59) attached to the housing (56) are provided. Further, mounting holes (68) for mounting the housing (56) on the printer main body side are formed.
　また、図２Ｂで示すキャップ受板（５７）は、キャップ受板取り付け部（６２）の形状に対応して、外形が左右方向に長尺な略矩形板状として形成され、その略中央部に複数のノズルが配置されているノズルプレート（６１）を露出させるため、左右方向に長尺なノズル用開口部（７１）が設けられている。また、図２Ａで示すインクジェットヘッド内部の具体的な構造に関しては、例えば特開２０１２－１４００１７号公報に記載されている図２等を参照することができる。 Further, the cap receiving plate (57) shown in FIG. 2B is formed as a substantially rectangular plate whose outer shape is elongated in the left-right direction corresponding to the shape of the cap receiving plate mounting portion (62), and is formed at a substantially central portion thereof. In order to expose the nozzle plate (61) in which a plurality of nozzles are arranged, a long nozzle opening (71) is provided in the left-right direction. Further, regarding the specific structure inside the inkjet head shown in FIG. 2A, for example, FIG. 2 and the like described in Japanese Patent Application Laid-Open No. 2012-140017 can be referred to.
　図２Ａ及び図２Ｂにはインクジェットヘッドの代表例を示したが、その他にも、例えば特開２０１２－１４００１７号公報、特開２０１３－０１０２２７号公報、特開２０１４－０５８１７１号公報、特開２０１４－０９７６４４号公報、特開２０１５－１４２９７９号公報、特開２０１５－１４２９８０号公報、特開２０１６－００２６７５号公報、特開２０１６－００２６８２号公報、特開２０１６－１０７４０１号公報、特開２０１７－１０９４７６号公報、特開２０１７－１７７６２６号公報等に記載されている構成からなるインクジェットヘッドを適宜選択して適用することができる。 Representative examples of the inkjet head are shown in FIGS. 2A and 2B, but in addition, for example, Japanese Patent Application Laid-Open No. 2012-140017, Japanese Patent Application Laid-Open No. 2013-010227, Japanese Patent Application Laid-Open No. 2014-058171 and JP-A-2014- 097644, 2015-142979, 2015-142980, 2016-002675, 2016-002682, 2016-107401, 2017-109476 An inkjet head having the configuration described in Japanese Patent Application Laid-Open No. 2017-177626 can be appropriately selected and applied.
　本発明に適用可能なインクジェットヘッドは、例えば特開２０１２－１４００１７号公報、特開２０１３－０１０２２７号公報、特開２０１４－０５８１７１号公報、特開２０１４－０９７６４４号公報、特開２０１５－１４２９７９号公報、特開２０１５－１４２９８０号公報、特開２０１６－００２６７５号公報、特開２０１６－００２６８２号公報、特開２０１６－１０７４０１号公報、特開２０１７－１０９４７６号公報、特開２０１７－１７７６２６号公報等に記載されている構成からなるインクジェットヘッドを適宜選択して適用することができる。 Inkjet heads applicable to the present invention are, for example, JP-A-2012-140017, JP-A-2013-010227, JP-A-2014-058171, JP-A-2014-097644, JP-A-2015-142979. , JP-A-2015-142980, JP-A-2016-002675, JP-A-2016-002682, JP-A-2016-107401, JP-A-2017-109476, JP-A-2017-177626, etc. An inkjet head having the described configuration can be appropriately selected and applied.
　《加熱・融解工程》
　本発明に係る発光層の形成方法については、当該発光層をウェット・プロセスで形成する工程を有し、かつ、当該発光層に含有させるホスト化合物と発光性ドーパントの組成を、当該発光層の厚さ方向において、連続的又は断続的に変化させる加熱・融解工程を有することを特徴とする。
　ここで、「加熱・融解」とは、固体状の物質を加熱して融解させること、すなわち、固体状物質を加熱して液体状に変化させることをいう。 《Heating / melting process》
The method for forming a light emitting layer according to the present invention includes a step of forming the light emitting layer by a wet process, and the composition of the host compound and the light emitting dopant contained in the light emitting layer is determined by the thickness of the light emitting layer. It is characterized by having a heating / melting step that changes continuously or intermittently in the longitudinal direction.
Here, "heating / melting" means heating and melting a solid substance, that is, heating a solid substance to change it into a liquid state.
　加熱・融解工程における加熱温度は、ホスト層を構成する化合物及び組成等に依存して異なるが、少なくともホスト層の一部が融解しホスト層の構成成分（化合物）がドーパント層に浸透・拡散させて、両層の構成成分を混合させ、かつ、前記ホスト化合物と前記発光性ドーパントの組成を厚さ方向で連続的に変化させることができる温度にすることが好ましい。具体的には、ホスト層を構成するホスト化合物の融解温度以上、昇華温度以下の範囲内の温度で加熱することが好ましい。
　加熱手段としては、ホットプレートによる加熱、加熱乾燥した気体（例えば窒素ガス、ヘリウムガス等の不活性気体）による加熱や赤外線照射による加熱等を挙げることができる。 The heating temperature in the heating / melting step differs depending on the compound and composition constituting the host layer, but at least a part of the host layer is melted and the constituent components (compounds) of the host layer permeate and diffuse into the dopant layer. It is preferable that the constituent components of both layers are mixed and the temperature is such that the composition of the host compound and the luminescent dopant can be continuously changed in the thickness direction. Specifically, it is preferable to heat at a temperature within the range of the melting temperature or higher and the sublimation temperature or lower of the host compound constituting the host layer.
Examples of the heating means include heating with a hot plate, heating with a heat-dried gas (for example, an inert gas such as nitrogen gas or helium gas), heating with infrared irradiation, and the like.
　《その他の有機機能層の形成方法》
　本発明に係る発光層以外の有機機能層、例えば正孔注入層、正孔輸送層、正孔阻止層、電子輸送層、電子注入層等の形成方法について、特に制限はなく、従来公知の例えば真空蒸着法、ウェット・プロセス等による形成方法を用いることができる。
　ウェット・プロセスについては、発光層の形成方法と同様の方法を採用できる。 << Method of forming other organic functional layers >>
There is no particular limitation on the method for forming an organic functional layer other than the light emitting layer according to the present invention, for example, a hole injection layer, a hole transport layer, a hole blocking layer, an electron transport layer, an electron injection layer, etc. A forming method such as a vacuum deposition method or a wet process can be used.
For the wet process, a method similar to the method for forming the light emitting layer can be adopted.
　なお、各有機機能層ごとに異なる成膜法を適用してもよい。成膜に蒸着法を採用する場合、その蒸着条件は使用する化合物の種類等により異なるが、一般にボート加熱温度５０～４５０℃、真空度１０－６～１０－２Ｐａ、蒸着速度０．０１～５０ｎｍ／秒、基板温度－５０～３００℃、膜厚０．１ｎｍ～５μｍ、好ましくは５～２００ｎｍの範囲内で適宜選ぶことが望ましい。 A different film forming method may be applied to each organic functional layer. When the vapor deposition method is adopted for film formation, the vapor deposition conditions differ depending on the type of compound used, etc., but generally, the boat heating temperature is 50 to 450 ° C., the degree of vacuum is 10-6 to 10-2 Pa, and the vapor deposition rate is 0.01 to. It is desirable to appropriately select within the range of 50 nm / sec, substrate temperature -50 to 300 ° C., film thickness 0.1 nm to 5 μm, preferably 5 to 200 nm.
（有機ＥＬ素子の構成する有機機能層及び電極）
　以下において、本発明の有機ＥＬ素子を構成する主要な有機機能層等について順次説明する。
　《発光層》
　本発明に係る発光層は、基板側からホスト化合物（単に「ホスト」ともいう。）を含有するホスト層と発光性ドーパント（単に「ドーパント」ともいう。）を含有するドーパント層の塗布膜からなり、当該ホスト層と当該ドーパント層が融解接合されており、かつ、当該発光層に含有されるホスト化合物及び発光性ドーパントの組成が厚さ方向において、連続的又は断続的に変化していることを特徴とする。 (Organic functional layer and electrode constituting the organic EL element)
Hereinafter, the main organic functional layers and the like constituting the organic EL device of the present invention will be sequentially described.
《Light emitting layer》
The light emitting layer according to the present invention comprises a coating film of a host layer containing a host compound (also simply referred to as “host”) and a dopant layer containing a light emitting dopant (also simply referred to as “dopant”) from the substrate side. , The host layer and the dopant layer are melt-bonded, and the composition of the host compound and the light emitting dopant contained in the light emitting layer is continuously or intermittently changed in the thickness direction. It is a feature.
　本発明に係る発光層は、電極又は隣接層から注入されてくる電子及び正孔が再結合し、励起子を経由して発光する場を提供する層であり、発光する部分は発光層の層内であっても、発光層と隣接層との境界面であってもよい。
　発光層の厚さの総和は、特に制限はないが、形成する層の均質性や、発光時に不必要な高電圧を印加するのを防止し、かつ、駆動電流に対する発光色の安定性向上の観点から、２ｎｍ～５μｍの範囲内に調整することが好ましく、より好ましくは２～５００ｎｍの範囲内に調整され、さらに好ましくは５～２００ｎｍの範囲内に調整される。
　また、個々の発光層の厚さとしては、２ｎｍ～１μｍの範囲内に調整することが好ましく、より好ましくは２～２００ｎｍの範囲内に調整され、さらに好ましくは３～１５０ｎｍの範囲内に調整される。 The light emitting layer according to the present invention is a layer that provides a place where electrons and holes injected from an electrode or an adjacent layer are recombined and emit light via excitons, and the light emitting portion is a layer of the light emitting layer. It may be inside or at the interface between the light emitting layer and the adjacent layer.
The total thickness of the light emitting layer is not particularly limited, but the homogeneity of the formed layer, prevention of applying an unnecessary high voltage at the time of light emission, and improvement of the stability of the light emitting color with respect to the driving current are improved. From the viewpoint, it is preferably adjusted within the range of 2 nm to 5 μm, more preferably adjusted within the range of 2 to 500 nm, and further preferably adjusted within the range of 5 to 200 nm.
The thickness of each light emitting layer is preferably adjusted within the range of 2 nm to 1 μm, more preferably adjusted within the range of 2 to 200 nm, and further preferably adjusted within the range of 3 to 150 nm. To.
　発光層についての更に詳細な説明に入る前に、本発明の基礎となる技術的思想と関連する有機ＥＬの発光方式及び発光材料について述べる。 Before going into a more detailed explanation of the light emitting layer, the light emitting method and the light emitting material of the organic EL related to the technical idea underlying the present invention will be described.
　《有機ＥＬの発光方式》
　有機ＥＬの発光方式としては三重項励起状態から基底状態に戻る際に光を発する「リン光発光」と、一重項励起状態から基底状態に戻る際に光を発する「蛍光発光」の二通りがある。
　有機ＥＬ素子のような電界で励起する場合には、三重項励起子が７５％の確率で、一重項励起子が２５％の確率で生成するため、リン光発光の方が蛍光発光に比べ発光効率を高くすることが可能で、低消費電力化を実現するには優れた方式である。 << Organic EL light emission method >>
There are two types of light emission methods for organic EL: "phosphorescence emission" that emits light when returning from the triplet excited state to the ground state, and "fluorescence emission" that emits light when returning from the singlet excited state to the ground state. is there.
When excited by an electric field such as an organic EL element, triplet excitons are generated with a 75% probability and singlet excitons are generated with a 25% probability. It is possible to increase the efficiency and it is an excellent method to realize low power consumption.
　さらに、近年では、安達らの発見により一重項励起状態と三重項励起状態のエネルギーギャップを小さくすることで、発光中のジュール熱及び／又は発光素子が置かれる環境温度によりエネルギー準位の低い三重項励起状態から一重項励起状態に逆項間交差がおこり、結果としてほぼ１００％に近い蛍光発光を可能とする現象（熱活性型遅延蛍光又は熱励起型遅延蛍光ともいう：「ＴＡＤＦ」：ｔｈｅｒｍａｌｌｙ　ａｃｔｉｖａｔｅｄ　ｄｅｌａｙｅｄ　ｆｌｕｏｒｅｓｃｅｎｃｅ）と、それを可能にする蛍光発光性化合物が見いだされている（例えば非特許文献Ｈ．Ｕｏｙａｍａ，ｅｔ　ａｌ．，Ｎａｔｕｒｅ，２０１２，４９２，２３４－２３８、Ｈ．Ｎａｋａｎоｔａｎｉ，ｅｔ　ａｌ．，Ｎａｔｕｒｅ　Ｃｏｍｍｕｎｉｃａｉｏｎ，２０１４，５，４０１６－４０２２等参照。）。 Furthermore, in recent years, Adachi et al. Have discovered that by reducing the energy gap between the single-term excited state and the triple-term excited state, triples with lower energy levels due to Joule heat during light emission and / or the environmental temperature at which the light-emitting element is placed. A phenomenon in which inverse intertermic intersection occurs from the term-excited state to the single-term excited state, resulting in nearly 100% fluorescent emission (also referred to as thermally activated delayed fluorescence or thermally excited delayed fluorescence: "TADF": thermally. Activated delayed fluorescence) and fluorescent compounds that enable it have been found (eg, Non-Patent Documents H. Uoyama, et al., Nature, 2012, 492, 234-238, H. Nakanоtani, et al. , Nature Communication, 2014, 5, 4016-4022, etc.).
　《リン光発光性化合物》
　前述のとおり、リン光発光は発光効率的には蛍光発光よりも理論的には３倍有利であるが、三重項励起状態から一重項基底状態へのエネルギー失活（＝リン光発光）は禁制遷移であり、また同様に一重項励起状態から三重項励起状態への項間交差も禁制遷移であるため、通常その速度定数は小さい。すなわち、遷移が起こりにくいため、リン光寿命はミリ秒から秒オーダーと長くなり、所望の発光を得ることが困難である。
　ただし、イリジウムやプラチナなどの重金属を用いた錯体が発光する場合には、中心金属の重原子効果によって、前記の禁制遷移の速度定数が三桁以上増大し、配位子の選択によっては、１００％のリン光量子収率を得ることも可能となる。 << Phosphorescent compound >>
As mentioned above, phosphorescence emission is theoretically three times more advantageous than fluorescence emission in terms of emission efficiency, but energy deactivation (= phosphorescence emission) from the triplet excited state to the singlet ground state is prohibited. Since it is a transition and the intersystem crossing from the singlet excited state to the triplet excited state is also a forbidden transition, its velocity constant is usually small. That is, since the transition is unlikely to occur, the phosphorescence lifetime is extended to the order of milliseconds to seconds, and it is difficult to obtain desired light emission.
However, when a complex using a heavy metal such as iridium or platinum emits light, the rate constant of the forbidden transition increases by three orders of magnitude or more due to the heavy atom effect of the central metal, and depending on the selection of the ligand, 100 It is also possible to obtain a phosphorus photon yield of%.
　《蛍光発光性化合物》
　一般的な蛍光発光性材料は、リン光発光性材料のような重金属錯体である必要性は特になく、炭素、酸素、窒素及び水素などの一般的な元素の組み合わせから構成される、いわゆる有機化合物が適用でき、さらに、リンや硫黄、ケイ素などその他の非金属元素を用いることも可能で、また、アルミニウムや亜鉛などの典型金属の錯体も活用できるなど、その多様性はほぼ無限といえる。
　ただし、従来の蛍光化合物では前記のように励起子の２５％しか発光に適用できないために、リン光発光のような高効率発光は望めない。 《Fluorescent compound》
A general fluorescent material does not need to be a heavy metal complex like a phosphorescent material, and is a so-called organic compound composed of a combination of general elements such as carbon, oxygen, nitrogen and hydrogen. In addition, other non-metal elements such as phosphorus, sulfur, and silicon can be used, and complexes of typical metals such as aluminum and zinc can also be used, so that the variety can be said to be almost infinite.
However, since only 25% of excitons can be applied to light emission with a conventional fluorescent compound as described above, high-efficiency light emission such as phosphorescence light emission cannot be expected.
　《遅延蛍光化合物》
　［励起三重項－三重項消滅（ＴＴＡ）遅延蛍光化合物］
　蛍光発光性化合物の問題点を解決すべく登場したのが遅延蛍光を利用した発光方式である。三重項励起子同士の衝突を起源とするＴＴＡ方式は、下記のような一般式で記述できる。すなわち、従来、励起子のエネルギーが、無輻射失活により、熱にしか変換されなかった三重項励起子の一部が、発光に寄与しうる一重項励起子に逆項間交差できるメリットがあり、実際の有機ＥＬ素子においても従来の蛍光発光素子の約２倍の外部取り出し量子効率を得ることができている。
　一般式：　Ｔ＊　＋　Ｔ＊　→　Ｓ＊　＋　Ｓ（式中、Ｔ＊は三重項励起子、Ｓ＊は一重項励起子、Ｓは基底状態分子を表す。）
　しかしながら、上式からもわかるように、二つの三重項励起子から発光に利用できる一重項励起子は一つしか生成しないため、この方式で１００％の内部量子効率を得ることは原理上できない。 << Delayed fluorescent compound >>
[Excited triplet-triplet annihilation (TTA) delayed fluorescent compound]
An emission method using delayed fluorescence has emerged to solve the problems of fluorescent compounds. The TTA method originating from the collision between triplet excitons can be described by the following general formula. That is, there is an advantage that a part of triplet excitons, in which exciton energy is conventionally converted only into heat by non-radiation deactivation, can cross the singlet excitons that can contribute to light emission. Even in an actual organic EL element, it is possible to obtain an external extraction quantum efficiency about twice that of a conventional fluorescent light emitting element.
General formula: T * + T * → S * + S (In the formula, T * represents a triplet exciton, S * represents a singlet exciton, and S represents a ground state molecule.)
However, as can be seen from the above equation, since only one singlet exciton that can be used for light emission is generated from the two triplet excitons, it is not possible in principle to obtain 100% internal quantum efficiency by this method.
　《熱活性型遅延蛍光（ＴＡＤＦ）化合物》
　もう一つの高効率蛍光発光であるＴＡＤＦ方式は、ＴＴＡの問題点を解決できる方式である。
　蛍光発光性化合物は、前記のごとく無限に分子設計できる利点を持っている。すなわち、分子設計された化合物の中で、特異的に三重項励起状態と一重項励起状態のエネルギー準位差（以下において、適宜、「ΔＥＳＴ」と略記する。）が極めて近接する化合物が存在する。
　このような化合物は、分子内に重原子を持っていないにもかかわらず、ΔＥＳＴが小さいために通常では起こりえない三重項励起状態から一重項励起状態への逆項間交差が起こる。さらに、一重項励起状態から基底状態への失活（＝蛍光発光）の速度定数が極めて大きいことから、三重項励起子はそれ自体が基底状態に熱的に失活（無輻射失活）するよりも、一重項励起状態経由で蛍光を発しながら基底状態に戻る方が速度論的に有利である。そのため、ＴＡＤＦでは理論的には１００％の蛍光発光が可能となる。 << Thermally Activated Delayed Fluorescence (TADF) Compound >>
The TADF method, which is another high-efficiency fluorescent emission, is a method that can solve the problems of TTA.
Fluorescent compounds have the advantage of being able to design an infinite number of molecules as described above. That is, in the molecular design compounds, specifically triplet excited state and the energy level difference between the singlet excited state (hereinafter, appropriately abbreviated as "Delta] E ST".) Is very close compound present To do.
Such compounds, even though in the molecule does not have a heavy atom, reverse intersystem crossing from a triplet excited state is usually not occur because Delta] E ST is smaller to the singlet excited state occurs. Furthermore, since the rate constant of deactivation (= fluorescence emission) from the singlet excited state to the ground state is extremely large, the triplet excited state itself is thermally deactivated to the ground state (non-radiation deactivation). It is more rhythmically advantageous to return to the ground state while emitting fluorescence via the singlet excited state. Therefore, TADF can theoretically emit 100% fluorescent light.
　＜ΔＥＳＴに関する分子設計思想＞
　上記ΔＥＳＴを小さくするための分子設計について説明する。
　ΔＥＳＴを小さくするためには、原理上分子内の最高被占軌道（ｈｉｇｈｅｓｔ　ｏｃｃｕｐｉｅｄ　ｍｏｌｅｃｕｌａｒ　ｏｒｂｉｔａｌ：ＨＯＭＯ）と最低空軌道（ｌｏｗｅｓｔ　ｕｎｏｃｃｕｐｉｅｄ　ｍｏｌｅｃｕｌａｒ　ｏｒｂｉｔａｌ：ＬＵＭＯ）の空間的な重なりを小さくすることが最も効果的である。
　一般に分子の電子軌道において、ＨＯＭＯは電子供与性部位に、ＬＵＭＯは電子吸引性部位に分布することが知られており、分子内に電子供与性と電子吸引性の骨格を導入することによって、ＨＯＭＯとＬＵＭＯが存在する位置を遠ざけることが可能である。 <Molecular design concepts related to ΔE ST>
It explained molecular design for reducing the Delta] E ST.
ΔE in order to reduce the ST is highest occupied molecular orbital in principle molecules (highest occupied molecular orbital: HOMO) and lowest unoccupied molecular orbital (lowest unoccupied molecular orbital: LUMO) spatial overlap the small to most effects of Is the target.
It is generally known that HOMO is distributed in the electron donating site and LUMO is distributed in the electron attracting site in the electron orbit of the molecule. By introducing an electron donating and electron attracting skeleton into the molecule, HOMO is distributed. And the position where LUMO exists can be moved away.
　例えば「実用化ステージを迎えた有機光エレクトロニクス」応用物理　第８２巻、第６号、２０１３年においては、シアノ基やトリアジンなどの電子吸引性の骨格と、カルバゾールやジフェニルアミノ基等の電子供与性の骨格とを導入することで、ＬＵＭＯとＨＯＭＯとをそれぞれ局在化させている。
　また、化合物の基底状態と三重項励起状態との分子構造変化を小さくすることも効果的である。構造変化を小さくするための方法としては、例えば化合物を剛直にすることなどが効果的である。ここで述べる剛直とは、例えば分子内の環と環との結合における自由回転を抑制することや、π共役面の大きい縮合環を導入するなど、分子内において自由に動ける部位が少ないことを意味する。特に、発光に関与する部位を剛直にすることによって、励起状態における構造変化を小さくすることが可能である。 For example, in Applied Physics Vol. 82, No. 6, 2013 of "Organic Optoelectronics Reaching the Practical Use Stage", an electron-withdrawing skeleton such as a cyano group or triazine and an electron-donating property such as a carbazole or a diphenylamino group. LUMO and HOMO are localized by introducing the skeleton of.
It is also effective to reduce the change in molecular structure between the ground state and triplet excited state of the compound. As a method for reducing the structural change, for example, making the compound rigid is effective. Rigidity described here means that there are few parts in the molecule that can move freely, such as suppressing free rotation in the bond between rings in the molecule and introducing a fused ring with a large π-conjugated surface. To do. In particular, it is possible to reduce the structural change in the excited state by making the portion involved in light emission rigid.
　（１）発光性ドーパント
　本発明の発光性ドーパントとしては、蛍光発光性化合物とリン光発光性化合物が好ましく用いられる。本発明においては、発光性ドーパントが発光層中に、５～８０質量％の範囲内で含有し、特に、２０～４０質量％の範囲内で含有することが好ましい。 (1) Luminescent Dopant As the luminescent dopant of the present invention, a fluorescent luminescent compound and a phosphorescent luminescent compound are preferably used. In the present invention, the luminescent dopant is contained in the light emitting layer in the range of 5 to 80% by mass, and particularly preferably in the range of 20 to 40% by mass.
　発光層中の発光性化合物の濃度については、使用される特定の発光性化合物及びデバイスの必要条件に基づいて、任意に決定することができる。
　また、本発明で用いられる発光性化合物は、複数種を併用して用いてもよく、構造の異なる蛍光発光性化合物同士の組み合わせや、蛍光発光性化合物とリン光発光性化合物とを組み合わせて用いてもよい。これにより、任意の発光色を得ることができる。 The concentration of the luminescent compound in the light emitting layer can be arbitrarily determined based on the specific luminescent compound used and the requirements of the device.
Further, the luminescent compound used in the present invention may be used in combination of a plurality of types, and may be used in combination of fluorescent compounds having different structures or in combination of a fluorescent compound and a phosphorescent compound. You may. Thereby, an arbitrary emission color can be obtained.
　本発明の有機ＥＬ素子や本発明に用いられる化合物の発光する色は、「新編色彩科学ハンドブック」（日本色彩学会編、東京大学出版会、１９８５）の１０８頁の図３．１６において、分光放射輝度計ＣＳ－１０００（コニカミノルタ（株）製）で測定した結果をＣＩＥ色度座標に当てはめたときの色で決定される。
　本発明においては、１層又は複数層の発光層が、発光色の異なる複数の発光性化合物を含有し、白色発光を示すことも好ましい。
　白色を示す発光性化合物の組み合わせについては特に限定はないが、例えば青と橙や、青と緑と赤の組合わせ等が挙げられる。
　本発明の有機ＥＬ素子における白色とは、２度視野角正面輝度を前述の方法により測定した際に、１０００ｃｄ／ｍ２でのＣＩＥ１９３１表色系における色度がｘ＝０．３９±０．０９、ｙ＝０．３８±０．０８の領域内にあることが好ましい。 The emission colors of the organic EL element of the present invention and the compound used in the present invention are shown in FIG. 3.16 on page 108 of the "New Color Science Handbook" (edited by the Color Society of Japan, The University of Tokyo Press, 1985). It is determined by the color when the result measured by the luminometer CS-1000 (manufactured by Konica Minolta Co., Ltd.) is applied to the CIE chromaticity coordinates.
In the present invention, it is also preferable that the light emitting layer of one layer or a plurality of layers contains a plurality of light emitting compounds having different light emitting colors and exhibits white light emission.
The combination of luminescent compounds showing white color is not particularly limited, and examples thereof include a combination of blue and orange and a combination of blue and green and red.
The white color in the organic EL element of the present invention means that the chromaticity in the CIE 1931 color system at 1000 cd / m 2 is x = 0.39 ± 0.09 when the 2 degree viewing angle front luminance is measured by the above method. , Y = 0.38 ± 0.08, preferably within the region.
　（１．１）蛍光発光性化合物
　蛍光発光性化合物は、上述の特定の有機化合物を用いてもよいし、有機ＥＬ素子の発光層に使用される公知の蛍光発光性化合物や遅延蛍光を発する化合物（遅延蛍光発光性化合物）の中から適宜選択して用いてもよい。 (1.1) Fluorescent Luminescent Compound As the fluorescent luminescent compound, the above-mentioned specific organic compound may be used, a known fluorescent luminescent compound used in the light emitting layer of an organic EL element, or a compound that emits delayed fluorescence. (Delayed fluorescent luminescent compound) may be appropriately selected and used.
　本発明に使用できる公知の蛍光性化合物の例としては、アントラセン誘導体、ピレン誘導体、クリセン誘導体、フルオランテン誘導体、ペリレン誘導体、フルオレン誘導体、アリールアセチレン誘導体、スチリルアリーレン誘導体、スチリルアミン誘導体、アリールアミン誘導体、ホウ素錯体、クマリン誘導体、ピラン誘導体、シアニン誘導体、クロコニウム誘導体、スクアリウム誘導体、オキソベンツアントラセン誘導体、フルオレセイン誘導体、ローダミン誘導体、ピリリウム誘導体、ペリレン誘導体、ポリチオフェン誘導体、又は希土類錯体系化合物等が挙げられる。 Examples of known fluorescent compounds that can be used in the present invention include anthracene derivatives, pyrene derivatives, chrysene derivatives, fluorantene derivatives, perylene derivatives, fluorene derivatives, arylacetylene derivatives, styrylarylene derivatives, styrylamine derivatives, arylamine derivatives, boron. Examples thereof include complexes, coumarin derivatives, pyran derivatives, cyanine derivatives, croconium derivatives, squalium derivatives, oxobenzanthracene derivatives, fluorescein derivatives, rhodamine derivatives, pyrylium derivatives, perylene derivatives, polythiophene derivatives, and rare earth complex compounds.
　遅延蛍光を発する化合物（遅延蛍光発光性化合物及び熱活性型遅延蛍光化合物）の例としては、国際公開第２０１１／１５６７９３号、特開２０１１－２１３６４３号公報、特開２０１０－９３１８１号公報、特許５３６６１０６号、国際公開第２０１３／１６１４３７号、国際公開第２０１６／１５８５４０号等に記載の化合物が挙げられるが、本発明はこれらに限定されない。 Examples of compounds that emit delayed fluorescence (delayed fluorescent compounds and thermally activated delayed fluorescence compounds) are International Publication No. 2011/156793, JP-A-2011-21364, JP-A-2010-93181, and Patent No. 5366106. No., International Publication No. 2013/161437, International Publication No. 2016/158540, and the like can be mentioned, but the present invention is not limited thereto.
　上記の熱活性型遅延蛍光化合物として、下記一般式（１）～（６）で表される構造を有する化合物が好ましい。 As the above-mentioned thermally activated delayed fluorescent compound, compounds having structures represented by the following general formulas (1) to (6) are preferable.
Figure JPOXMLDOC01-appb-C000001
Figure JPOXMLDOC01-appb-C000001
［一般式（１）において、Ａｒ１～Ａｒ３は、各々独立に、置換又は無置換のアリール基を表し、少なくとも１つは下記一般式（２）で表される構造を有する基で置換されたアリール基を表す。］ [In the general formula (1), Ar 1 to Ar 3 each independently represent a substituted or unsubstituted aryl group, and at least one is substituted with a group having a structure represented by the following general formula (2). Represents an aryl group. ]
Figure JPOXMLDOC01-appb-C000002
Figure JPOXMLDOC01-appb-C000002
［一般式（２）において、Ｒ１～Ｒ８は、各々独立に、水素原子又は置換基を表す。Ｚは、Ｏ、Ｓ、Ｏ＝Ｃ、Ａｒ４－Ｎ、又は化学結合を表す。Ａｒ４は、置換又は無置換のアリール基を表す。Ｒ１～Ｒ８のうち隣り合う基同士は、互いに結合を形成、又は、連結基を介して環を形成してもよい。］ [In the general formula (2), R 1 to R 8 each independently represent a hydrogen atom or a substituent. Z represents O, S, O = C, Ar 4- N, or a chemical bond. Ar 4 represents a substituted or unsubstituted aryl group. Adjacent groups of R 1 to R 8 may form a bond with each other or form a ring via a linking group. ]
Figure JPOXMLDOC01-appb-C000003
Figure JPOXMLDOC01-appb-C000003
［一般式（３）において、Ｒ１～Ｒ５の少なくとも１つは、シアノ基を表し、Ｒ１～Ｒ５の少なくとも１つは下記一般式（４）で表される構造を有する基を表し、残りのＲ１～Ｒ５は水素原子又は置換基を表す。］ [In the general formula (3), at least one of R 1 ~ R 5 represents a cyano group, at least one of R 1 ~ R 5 is a group having the structure represented by the following general formula (4) , The remaining R 1 to R 5 represent hydrogen atoms or substituents. ]
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000004
［一般式（４）において、Ｒ２１～Ｒ２８は、各々独立に、水素原子又は置換基を表す。ただし、下記要件（Ａ）又は（Ｂ）の少なくとも一方を満たす。
要件（Ａ）：Ｒ２５及びＲ２６は、単結合を形成する。
要件（Ｂ）：Ｒ２７及びＲ２８は、置換又は無置換のベンゼン環を形成するのに必要な原子団を表す。］ [In the general formula (4), R 21 to R 28 each independently represent a hydrogen atom or a substituent. However, at least one of the following requirements (A) or (B) is satisfied.
Requirement (A): R 25 and R 26 form a single bond.
Requirement (B): R 27 and R 28 represent the atomic groups required to form a substituted or unsubstituted benzene ring. ]
Figure JPOXMLDOC01-appb-C000005
Figure JPOXMLDOC01-appb-C000005
［一般式（５）において、Ｒ１及びＲ２は、各々独立に、下記一般式（６）で表される構造を有する基を表す。］ [In the general formula (5), R 1 and R 2 each independently represent a group having a structure represented by the following general formula (6). ]
Figure JPOXMLDOC01-appb-C000006
Figure JPOXMLDOC01-appb-C000006
［一般式（６）において、Ｒ１～Ｒ８は、各々独立に、水素原子又は置換基を表す。Ｚは、Ｏ、Ｓ、Ｏ＝Ｃ、Ａｒ４－Ｎ、又は結合を表す。Ａｒ４は、置換又は無置換のアリール基を表す。Ｒ１～Ｒ８のうち隣り合う基同士は、互いに結合を形成、又は、連結基を介して環を形成してもよい。］ [In the general formula (6), R 1 to R 8 each independently represent a hydrogen atom or a substituent. Z represents O, S, O = C, Ar 4- N, or a bond. Ar 4 represents a substituted or unsubstituted aryl group. Adjacent groups of R 1 to R 8 may form a bond with each other or form a ring via a linking group. ]
　以下にＴＡＤＦ性化合物を例に挙げるが、本発明はこれに限定されない。 The TADF compound is given as an example below, but the present invention is not limited to this.
Figure JPOXMLDOC01-appb-C000007
Figure JPOXMLDOC01-appb-C000007
Figure JPOXMLDOC01-appb-C000008
Figure JPOXMLDOC01-appb-C000008
Figure JPOXMLDOC01-appb-C000009
Figure JPOXMLDOC01-appb-C000009
　以下に、本発明に係るＴＡＤＦ性化合物に関する種々の測定方法について記載する。 The various measuring methods for the TADF compound according to the present invention will be described below.
　（電子密度分布）
　本発明に係る発光性化合物は、ΔＥｓｔを小さくするという観点から、分子内においてＨＯＭＯとＬＵＭＯが実質的に分離していることが好ましい。これらＨＯＭＯ及びＬＵＭＯの分布状態については、分子軌道計算により得られる構造最適化した際の電子密度分布から求めることができる。
　本発明に係る発光性化合物の分子軌道計算による構造最適化及び電子密度分布の算出は、計算手法として、汎関数としてＢ３ＬＹＰ、基底関数として６－３１Ｇ（ｄ）を用いた分子軌道計算用ソフトウェアを用いて算出することができ、ソフトウェアに特に限定はなく、いずれを用いても同様に求めることができる。 (Electronic density distribution)
In the luminescent compound according to the present invention, it is preferable that HOMO and LUMO are substantially separated in the molecule from the viewpoint of reducing ΔEst. The distribution state of these HOMO and LUMO can be obtained from the electron density distribution when the structure is optimized obtained by the calculation of the molecular orbital.
For the structural optimization and the calculation of the electron density distribution by the molecular orbital calculation of the luminescent compound according to the present invention, a molecular orbital calculation software using B3LYP as a functional and 6-31G (d) as a basis function is used as a calculation method. It can be calculated by using it, and the software is not particularly limited, and it can be calculated in the same manner by using any of them.
　本発明においては、分子軌道計算用ソフトウェアとして、米国Ｇａｕｓｓｉａｎ社製のＧａｕｓｓｉａｎ０９（Ｒｅｖｉｓｉｏｎ　Ｃ．０１，Ｍ．Ｊ．Ｆｒｉｓｃｈ，ｅｔ　ａｌ，Ｇａｕｓｓｉａｎ，Ｉｎｃ．，２０１０．）を用いた。
　また、「ＨＯＭＯとＬＵＭＯが実質的に分離している」とは、上記分子計算により算出されたＨＯＭＯ軌道分布及びＬＵＭＯ軌道分布の中心部位が離れており、より好ましくはＨＯＭＯ軌道の分布とＬＵＭＯ軌道の分布がほぼ重なっていないことを意味する。 In the present invention, Gaussian 09 (Revision C.01, MJ Frisch, et al, Gaussian, Inc., 2010.) manufactured by Gaussian, USA was used as the software for calculating the molecular orbital.
Further, "HOMO and LUMO are substantially separated" means that the central parts of the HOMO orbital distribution and the LUMO orbital distribution calculated by the above molecular calculation are separated, and more preferably, the HOMO orbital distribution and the LUMO orbital are separated. It means that the distributions of are almost non-overlapping.
　また、ＨＯＭＯとＬＵＭＯの分離状態については、前述の汎関数としてＢ３ＬＹＰ、基底関数として６－３１Ｇ（ｄ）を用いた構造最適化計算から、さらに時間依存密度汎関数法（Ｔｉｍｅ－Ｄｅｐｅｎｄｅｎｔ　ＤＦＴ）による励起状態計算を実施してＳ１、Ｔ１のエネルギー（それぞれＥ（Ｓ１）、Ｅ（Ｔ１））を求めてΔＥｓｔ＝Ｅ（Ｓ１）－Ｅ（Ｔ１）として算出することも可能である。算出されたΔＥｓｔが小さいほど、ＨＯＭＯとＬＵＭＯがより分離していることを示す。本発明においては、前述と同様の計算手法を用いて算出されたΔＥｓｔが０．５ｅＶ以下であることが好ましく、より好ましくは０．２ｅＶ以下であり、さらに好ましくは０．１ｅＶ以下である。 Regarding the separated state of HOMO and LUMO, the time-dependent density functional theory (Time-Dependent DFT) is applied from the structural optimization calculation using B3LYP as the functional and 6-31G (d) as the basis function. It is also possible to calculate the excited state to obtain the energies of S 1 and T 1 (E (S 1 ) and E (T 1 ), respectively) and calculate as ΔEst = E (S 1 ) -E (T 1). Is. The smaller the calculated ΔEst, the more separated HOMO and LUMO are. In the present invention, ΔEst calculated by using the same calculation method as described above is preferably 0.5 eV or less, more preferably 0.2 eV or less, and further preferably 0.1 eV or less.
　（最低励起一重項エネルギーＳ１）
　本発明に係る発光性化合物の最低励起一重項エネルギーＳ１については、本発明においても通常の手法と同様にして算出されるもので定義される。すなわち、測定対象となる化合物を石英基板上に蒸着して試料を作製し、室温（２５℃）でこの試料の吸収スペクトル（縦軸：吸光度、横軸：波長とする。）を測定する。この吸収スペクトルの長波長側の立ち上がりに対して接線を引き、その接線と横軸との交点の波長値に基づいて、所定の換算式から算出される。 (Minimum excitation singlet energy S 1 )
For the lowest excited singlet energy S 1 luminescent compound according to the present invention is defined by what is calculated in the same manner as the conventional method in the present invention. That is, a compound to be measured is vapor-deposited on a quartz substrate to prepare a sample, and the absorption spectrum (vertical axis: absorbance, horizontal axis: wavelength) of this sample is measured at room temperature (25 ° C.). A tangent line is drawn with respect to the rising edge of the absorption spectrum on the long wavelength side, and the calculation is performed from a predetermined conversion formula based on the wavelength value at the intersection of the tangent line and the horizontal axis.
　ただし、本発明において使用する発光性化合物の、分子自体の凝集性が比較的高い場合においては、薄膜の測定においては凝集による誤差を生じる可能性がある。本発明における発光性化合物はストークスシフトが比較的小さいこと、さらに励起状態と基底状態の構造変化が小さいことを考慮し、本発明に係る最低励起一重項エネルギーＳ１は、室温（２５℃）における発光性化合物の溶液状態の最大発光波長のピーク値を近似値として用いた。ここで、使用する溶媒は、発光性化合物の凝集状態に影響を与えない、すなわち溶媒効果の影響が小さい溶媒、例えばシクロヘキサンやトルエン等の非極性溶媒等を用いることができる。 However, when the luminescent compound used in the present invention has a relatively high cohesiveness of the molecule itself, an error may occur due to the cohesiveness in the measurement of the thin film. Luminescent compound in the present invention that the Stokes shift is relatively small, considering that further structural changes in the excited state and the ground state is small, the lowest excited singlet energy S 1 according to the present invention, at room temperature (25 ° C.) The peak value of the maximum emission wavelength in the solution state of the luminescent compound was used as an approximate value. Here, as the solvent used, a solvent that does not affect the aggregated state of the luminescent compound, that is, a solvent that is less affected by the solvent effect, for example, a non-polar solvent such as cyclohexane or toluene can be used.
　（ストークスシフトの測定）
　発光性化合物の溶液（ジクロロメタン、クロロホルム等の適切な溶媒を使用）の励起（吸収）スペクトルと発光スペクトルとを、蛍光分光光度計（例えば島津製作所製ＲＦ－５３００型蛍光分光計、日立社製Ｆ－４５００型蛍光分光計等）を用いて測定し、蛍光極大波長と励起（吸収）極大波長との差を「ストークスシフト」として求めることができる。 (Measurement of Stokes shift)
The excitation (absorption) spectrum and the emission spectrum of the solution of the luminescent compound (using an appropriate solvent such as dichloromethane or chloroform) are measured with a fluorescence spectrophotometer (for example, RF-5300 type fluorescence spectrometer manufactured by Shimadzu Corporation, F manufactured by Hitachi, Ltd.). It can be measured using a -4500 type fluorescence spectrometer or the like), and the difference between the fluorescence maximum wavelength and the excitation (absorption) maximum wavelength can be obtained as a “Stokes shift”.
　（１．２）リン光発光性ドーパント
　本発明に用いられるリン光発光性ドーパントは、励起三重項からの発光が観測される化合物であり、具体的には、室温（２５℃）にてリン光発光する化合物であり、リン光量子収率が、２５℃において０．０１以上の化合物であると定義されるが、好ましいリン光量子収率は０．１以上である。
　上記リン光量子収率は、第４版実験化学講座７の分光IIの３９８頁（１９９２年版、丸善）に記載の方法により測定できる。溶液中でのリン光量子収率は種々の溶媒を用いて測定できるが、本発明に用いられるリン光発光性ドーパントは、任意の溶媒のいずれかにおいて上記リン光量子収率（０．０１以上）が達成されればよい。 (1.2) Phosphorescent Dopant The phosphorescent dopant used in the present invention is a compound in which light emission from an excited triplet is observed. Specifically, phosphorescence is performed at room temperature (25 ° C.). It is a compound that emits light and is defined as a compound having a phosphorescence quantum yield of 0.01 or more at 25 ° C., but a preferable phosphorescence quantum yield is 0.1 or more.
The phosphorus photon yield can be measured by the method described on page 398 (1992 edition, Maruzen) of Spectroscopy II of the 4th edition Experimental Chemistry Course 7. The phosphorescence quantum yield in a solution can be measured using various solvents, but the phosphorescence-emitting dopant used in the present invention has the above-mentioned phosphorescence quantum yield (0.01 or more) in any of the solvents. It should be achieved.
　リン光発光性ドーパントは、有機ＥＬ素子の発光層に使用される公知のものの中から適宜選択して用いることができる。本発明に使用できる公知のリン光発光性ドーパントの具体例としては、以下の文献に記載されている化合物等が挙げられる。
　Ｎａｔｕｒｅ　３９５，１５１（１９９８）、Ａｐｐｌ．Ｐｈｙｓ．Ｌｅｔｔ．７８，１６２２（２００１）、Ａｄｖ．Ｍａｔｅｒ．１９，７３９（２００７）、Ｃｈｅｍ．Ｍａｔｅｒ．１７，３５３２（２００５）、Ａｄｖ．Ｍａｔｅｒ．１７，１０５９（２００５）、国際公開第２００９／１００９９１号、国際公開第２００８／１０１８４２号、国際公開第２００３／０４０２５７号、米国特許出願公開第２００６／８３５４６９号明細書、米国特許出願公開第２００６／０２０２１９４号明細書、米国特許出願公開第２００７／００８７３２１号明細書、米国特許出願公開第２００５／０２４４６７３号明細書、Ｉｎｏｒｇ．Ｃｈｅｍ．４０，１７０４（２００１）、Ｃｈｅｍ．Ｍａｔｅｒ．１６，２４８０（２００４）、Ａｄｖ．Ｍａｔｅｒ．１６，２００３（２００４）、Ａｎｇｅｗ．Ｃｈｅｍ．ｌｎｔ．Ｅｄ．２００６，４５，７８００、Ａｐｐｌ．Ｐｈｙｓ．Ｌｅｔｔ．８６，１５３５０５（２００５）、Ｃｈｅｍ．Ｌｅｔｔ．３４，５９２（２００５）、Ｃｈｅｍ．Ｃｏｍｍｕｎ．２９０６（２００５）、Ｉｎｏｒｇ．Ｃｈｅｍ．４２，１２４８（２００３）、国際公開第２００９／０５０２９０号、国際公開第２００２／０１５６４５号、国際公開第２００９／０００６７３号、米国特許出願公開第２００２／００３４６５６号明細書、米国特許第７３３２２３２号、米国特許出願公開第２００９／０１０８７３７号明細書、米国特許出願公開第２００９／００３９７７６号明細書、米国特許第６９２１９１５号、米国特許第６６８７２６６号、米国特許出願公開第２００７／０１９０３５９号明細書、米国特許出願公開第２００６／０００８６７０号明細書、米国特許出願公開第２００９／０１６５８４６号明細書、米国特許出願公開第２００８／００１５３５５号明細書、米国特許第７２５０２２６号、米国特許第７３９６５９８号、米国特許出願公開第２００６／０２６３６３５号明細書、米国特許出願公開第２００３／０１３８６５７号明細書、米国特許出願公開第２００３／０１５２８０２号明細書、米国特許第７０９０９２８号、Ａｎｇｅｗ．Ｃｈｅｍ．ｌｎｔ．Ｅｄ．４７，１（２００８）、Ｃｈｅｍ．Ｍａｔｅｒ．１８，５１１９（２００６）、Ｉｎｏｒｇ．Ｃｈｅｍ．４６，４３０８（２００７）、Ｏｒｇａｎｏｍｅｔａｌｌｉｃｓ　２３，３７４５（２００４）、Ａｐｐｌ．Ｐｈｙｓ．Ｌｅｔｔ．７４，１３６１（１９９９）、国際公開第２００２／００２７１４号、国際公開第２００６／００９０２４号、国際公開第２００６／０５６４１８号、国際公開第２００５／０１９３７３号、国際公開第２００５／１２３８７３号、国際公開第２００５／１２３８７３号、国際公開第２００７／００４３８０号、国際公開第２００６／０８２７４２号、米国特許出願公開第２００６／０２５１９２３号明細書、米国特許出願公開第２００５／０２６０４４１号明細書、米国特許第７３９３５９９号、米国特許第７５３４５０５号、米国特許第７４４５８５５号、米国特許出願公開第２００７／０１９０３５９号明細書、米国特許出願公開第２００８／０２９７０３３号明細書、米国特許第７３３８７２２号、米国特許出願公開第２００２／０１３４９８４号明細書、米国特許第７２７９７０４号、米国特許出願公開第２００６／０９８１２０号明細書、米国特許出願公開第２００６／１０３８７４号明細書、国際公開第２００５／０７６３８０号、国際公開第２０１０／０３２６６３号、国際公開第２００８１４０１１５号、国際公開第２００７／０５２４３１号、国際公開第２０１１／１３４０１３号、国際公開第２０１１／１５７３３９号、国際公開第２０１０／０８６０８９号、国際公開第２００９／１１３６４６号、国際公開第２０１２／０２０３２７号、国際公開第２０１１／０５１４０４号、国際公開第２０１１／００４６３９号、国際公開第２０１１／０７３１４９号、米国特許出願公開第２０１２／２２８５８３号明細書、米国特許出願公開第２０１２／２１２１２６号明細書、特開２０１２－０６９７３７号公報、特願２０１１－１８１３０３号公報、特開２００９－１１４０８６号公報、特開２００３－８１９８８号公報、特開２００２－３０２６７１号公報、特開２００２－３６３５５２号公報等である。
　中でも、好ましいリン光発光性ドーパントとしては、Ｉｒを中心金属に有する有機金属錯体が挙げられる。さらに好ましくは、金属－炭素結合、金属－窒素結合、金属－酸素結合、金属－硫黄結合の少なくとも一つの配位様式を含む錯体が好ましい。 The phosphorescent dopant can be appropriately selected from known ones used for the light emitting layer of the organic EL device. Specific examples of known phosphorescent dopants that can be used in the present invention include compounds described in the following documents.
Nature 395, 151 (1998), Appl. Phys. Lett. 78, 1622 (2001), Adv. Mater. 19,739 (2007), Chem. Mater. 17, 3532 (2005), Adv. Mater. 17,1059 (2005), International Publication No. 2009/10991, International Publication No. 2008/101842, International Publication No. 2003/040257, US Patent Application Publication No. 2006/835469, US Patent Application Publication No. 2006 / 0202194, US Patent Application Publication No. 2007/0087321, US Patent Application Publication No. 2005/0244673, Inorg. Chem. 40,1704 (2001), Chem. Mater. 16,2480 (2004), Adv. Mater. 16, 2003 (2004), Angew. Chem. lnt. Ed. 2006, 45, 7800, Appl. Phys. Lett. 86,153505 (2005), Chem. Lett. 34,592 (2005), Chem. Commun. 2906 (2005), Inorg. Chem. 42,1248 (2003), International Publication No. 2009/050290, International Publication No. 2002/015645, International Publication No. 2009/000673, US Patent Application Publication No. 2002/0034656, US Pat. No. 7,332,232, USA Publication of Patent Application No. 2009/01087737, Publication of US Patent Application No. 2009/00397776, US Patent No. 6921915, US Patent No. 6687266, US Patent Application Publication No. 2007/0190359, US Patent Application Publication No. 2006/0008670, US Patent Application Publication No. 2009/0158464, US Patent Application Publication No. 2008/0015355, US Patent No. 7250226, US Patent No. 7396598, US Patent Application Publication No. 2006/0263635, US Patent Application Publication No. 2003/0138657, US Patent Application Publication No. 2003/0152802, US Patent No. 70090928, Angew. Chem. lnt. Ed. 47, 1 (2008), Chem. Mater. 18,5119 (2006), Inorg. Chem. 46,4308 (2007), Organometallics 23,3745 (2004), Appl. Phys. Lett. 74,1361 (1999), International Publication No. 2002/002714, International Publication No. 2006/090024, International Publication No. 2006/056418, International Publication No. 2005/019373, International Publication No. 2005/123873, International Publication No. 2005/123873, International Publication No. 2007/004380, International Publication No. 2006/082742, US Patent Application Publication No. 2006/0251923, US Patent Application Publication No. 2005/02060441, US Patent No. 73935999 , US Patent No. 7534505, US Patent No. 7445855, US Patent Application Publication No. 2007/0190359, US Patent Application Publication No. 2008/0297033, US Patent No. 7338722, US Patent Application Publication No. 2002 / 0134984, US Patent No. 7279704, US Patent Application Publication No. 2006/098120, US Patent Application Publication No. 2006/103874, International Publication No. 2005/076380, International Publication No. 2010/032663 , International Publication No. 2008140115, International Publication No. 2007/052431, International Publication No. 2011/134013, International Publication No. 2011/157339, International Publication No. 2010/086089, International Publication No. 2009/1163646, International Publication No. 2012/20327, International Publication No. 2011/051404, International Publication No. 2011/004639, International Publication No. 2011/073149, US Patent Application Publication No. 2012/228583, US Patent Application Publication No. 2012/212126 Japanese Patent Application Laid-Open No. 2012-069737, Japanese Patent Application Laid-Open No. 2011-181303, Japanese Patent Application Laid-Open No. 2009-114086, Japanese Patent Application Laid-Open No. 2003-81988, Japanese Patent Application Laid-Open No. 2002-302671 and Japanese Patent Application Laid-Open No. 2002-363552 And so on.
Among them, preferred phosphorescent dopants include organometallic complexes having Ir as the central metal. More preferably, a complex containing at least one coordination mode of metal-carbon bond, metal-nitrogen bond, metal-oxygen bond and metal-sulfur bond is preferable.
　（２）ホスト化合物
　本発明に用いられるホスト化合物は、発光層において主に発光性化合物の分散を担う化合物であり、有機ＥＬ素子においてそれ自体の発光は実質的に観測されない。
　ホスト化合物は、単独で用いてもよく、又は複数種併用して用いてもよい。ホスト化合物を複数種用いることで、電荷の移動を調整することが可能であり、有機エレクトロルミネッセンス素子を高効率化することができる。 (2) Host Compound The host compound used in the present invention is a compound mainly responsible for the dispersion of the luminescent compound in the light emitting layer, and its own luminescence is not substantially observed in the organic EL element.
The host compound may be used alone or in combination of two or more. By using a plurality of types of host compounds, it is possible to adjust the charge transfer, and it is possible to improve the efficiency of the organic electroluminescence element.
　ホスト化合物としては、逆エネルギー移動の観点から、発光性ドーパントの励起一重項エネルギーより大きな励起エネルギーをもつものが好ましく、さらに発光性ドーパントの励起三重項エネルギーより大きな励起三重項エネルギーをもつものがより好ましい。 From the viewpoint of reverse energy transfer, the host compound is preferably one having an excitation energy larger than the excitation triplet energy of the luminescent dopant, and more preferably one having an excitation triplet energy larger than the excitation triplet energy of the luminescent dopant. preferable.
　ホスト化合物は、駆動安定性の観点から、カチオンラジカル状態、アニオンラジカル状態、及び励起状態の全ての活性種の状態において安定に存在でき、分解や付加反応などの化学変化を起こさないこと、さらに、層中において通電経時でホスト分子がオングストロームレベルで移動しないことが好ましい。 From the viewpoint of drive stability, the host compound can exist stably in all active species states such as cation radical state, anion radical state, and excited state, and does not cause chemical changes such as decomposition and addition reaction. It is preferable that the host molecules do not move at the angstrom level in the layer over time of energization.
　本発明の有機ＥＬ素子に公知のホスト化合物を用いる場合、その具体例としては、以下の文献に記載の化合物等が挙げられるが、本発明はこれらに限定されない。
　特開２００１－２５７０７６号公報、同２００２－３０８８５５号公報、同２００１－３１３１７９号公報、同２００２－３１９４９１号公報、同２００１－３５７９７７号公報、同２００２－３３４７８６号公報、同２００２－８８６０号公報、同２００２－３３４７８７号公報、同２００２－１５８７１号公報、同２００２－３３４７８８号公報、同２００２－４３０５６号公報、同２００２－３３４７８９号公報、同２００２－７５６４５号公報、同２００２－３３８５７９号公報、同２００２－１０５４４５号公報、同２００２－３４３５６８号公報、同２００２－１４１１７３号公報、同２００２－３５２９５７号公報、同２００２－２０３６８３号公報、同２００２－３６３２２７号公報、同２００２－２３１４５３号公報、同２００３－３１６５号公報、同２００２－２３４８８８号公報、同２００３－２７０４８号公報、同２００２－２５５９３４号公報、同２００２－２６０８６１号公報、同２００２－２８０１８３号公報、同２００２－２９９０６０号公報、同２００２－３０２５１６号公報、同２００２－３０５０８３号公報、同２００２－３０５０８４号公報、同２００２－３０８８３７号公報、同２０１６－１７８２７４号公報、米国特許出願公開第２００３／０１７５５５３号、米国特許出願公開第２００６／０２８０９６５号、米国特許出願公開第２００５／０１１２４０７号、米国特許出願公開第２００９／００１７３３０号、米国特許出願公開第２００９／００３０２０２号、米国特許出願公開第２００５／０２３８９１９号、国際公開第２００１／０３９２３４号、国際公開第２００９／０２１１２６号、国際公開第２００８／０５６７４６号、国際公開第２００４／０９３２０７号、国際公開第２００５／０８９０２５号、国際公開第２００７／０６３７９６号、国際公開第２００７／０６３７５４号、国際公開第２００４／１０７８２２号、国際公開第２００５／０３０９００号、国際公開第２００６／１１４９６６号、国際公開第２００９／０８６０２８号、国際公開第２００９／００３８９８号、国際公開第２０１２／０２３９４７号、特開２００８－０７４９３９号公報、特開２００７－２５４２９７号公報、欧州特許第２０３４５３８号明細書、国際公開第２０１１／０５５９３３号、国際公開第２０１２／０３５８５３号、特開２０１５－３８９４１号公報、米国特許出願公開第２０１７／０５６８１４号である。 When a known host compound is used for the organic EL device of the present invention, specific examples thereof include the compounds described in the following documents, but the present invention is not limited thereto.
JP 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357977, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002. 2002-105445, 2002-343568, 2002-141173, 2002-352957, 2002-203683, 2002-363227, 2002-231453, 2003 -3165, 2002-234888, 2003-27048, 2002-255934, 2002-260861, 2002-280183, 2002-299060, 2002- 302516, 2002-305083, 2002-305084, 2002-308837, 2016-178274, US Patent Application Publication No. 2003/01755553, US Patent Application Publication No. 2006/0280965 No., US Patent Application Publication No. 2005/0112407, US Patent Application Publication No. 2009/0017330, US Patent Application Publication No. 2009/0030202, US Patent Application Publication No. 2005/0238919, International Publication No. 2001/039234, International Publication No. 2009/021126, International Publication No. 2008/056746, International Publication No. 2004/093207, International Publication No. 2005/089025, International Publication No. 2007/0637996, International Publication No. 2007/0637554, International Publication No. 2004/107822, International Publication No. 2005/030900, International Publication No. 2006/114966, International Publication No. 2009/086028, International Publication No. 2009/003898, International Publication No. 2012/0293947, Japanese Patent Application Laid-Open No. 2008- 074939, 2007-254297, European Patent No. 2034538, International Publication No. 2011/055933, International Publication No. 2012/035853, Japanese Patent Application Laid-Open No. 2015-38941, US Patent Application Publication No. 2017/056814.
　（２．１）絶縁性ポリマー
　本発明に用いられる絶縁性ポリマーの「絶縁性」とは、電気抵抗率が１×１０６Ω・ｍ以上であり、好ましくは１×１０８Ω・ｍ以上であり、さらに好ましくは１×１０１０Ω・ｍ以上である。
　絶縁性ポリマー単体の電気抵抗率が１×１０６Ω・ｍ以上であることにより、発光層中を流れるリーク電流を抑えることができると考えられる。 (2.1) Insulating Polymer The "insulating property" of the insulating polymer used in the present invention means that the electrical resistivity is 1 × 10 6 Ω · m or more, preferably 1 × 10 8 Ω · m or more. Yes, more preferably 1 × 10 10 Ω · m or more.
It is considered that the leakage current flowing through the light emitting layer can be suppressed when the electrical resistivity of the insulating polymer alone is 1 × 10 6 Ω · m or more.
　絶縁性ポリマーの種類は、発光性ドーパント化合物とともに発光層を形成可能であれば特に限定されない。一実施形態において、絶縁性ポリマーとしては、安定性がより高い、主鎖が炭素原子で構成されているポリマーが用いられる。 The type of insulating polymer is not particularly limited as long as a light emitting layer can be formed together with the light emitting dopant compound. In one embodiment, as the insulating polymer, a polymer having a higher stability and whose main chain is composed of carbon atoms is used.
　絶縁性ポリマーを含む発光層を塗布法により形成できるように、絶縁性ポリマーは可溶性のポリマーであることが好ましく、非プロトン性極性溶媒への溶解性を示すことが好ましい。具体的には、１ｇのＮ，Ｎ－ジメチルホルムアミドに対する絶縁性ポリマーの２５℃における溶解度は、０．５ｍｇ以上であることが好ましく、１．０ｍｇ以上であることがさらに好ましく、２．０ｍｇ以上であることがより好ましい。 The insulating polymer is preferably a soluble polymer and preferably exhibits solubility in an aprotic polar solvent so that a light emitting layer containing the insulating polymer can be formed by a coating method. Specifically, the solubility of the insulating polymer in 1 g of N, N-dimethylformamide at 25 ° C. is preferably 0.5 mg or more, more preferably 1.0 mg or more, and more preferably 2.0 mg or more. More preferably.
　絶縁性ポリマーの種類に特段の制限はなく、例えばポリスチレン、ポリメタクリル酸メチル、ポリビニルアルコール、ポリアクリルアミド、ポリビニルピロリドン、ポリビニルポリピロリドン、ポリエチレングリコール、ポリメチルビニルエーテル、ポリイソプロピルアクリルアミド等の非イオン性ポリマー；ポリアクリル酸ナトリウム、ポリスチレンスルホン酸ナトリウム、ポリイソプロピレンスルホン酸ナトリウム、ポリナフタレンスルホン酸縮合体塩、ポリエチレンイミンザンテート塩等のカチオン性ポリマー；ジメチルアミノメチル（メタ）アクリレート四級塩、ジメチルジアリルアンモニウムクロライド、ポリアミジン、ポリビニルイミダゾリン、ジシアンジアミド系縮合体、エピクロルヒドリンジメチルアミン縮合体、ポリエチレンイミン等のアニオン性ポリマー；ジメチルアミノエチル（メタ）アクリレート四級塩アクリル酸共重合体、ポリアクリルアミドのホフマン分解物等の両性ポリマーが挙げられる。好ましくは、ポリスチレン、ポリメタクリル酸メチルである。
　絶縁性ポリマーは、２以上の互いに異なる繰り返し単位を含んでいてもよい。 There are no particular restrictions on the type of insulating polymer, and nonionic polymers such as polystyrene, polymethylmethacrylate, polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, polyvinylpolypyrrolidone, polyethylene glycol, polymethylvinyl ether, and polyisopropylacrylamide; Cationic polymers such as sodium polyacrylate, sodium polystyrene sulfonate, sodium polyisopropylene sulfonate, polynaphthalene sulfonic acid condensate salt, polyethylene iminsantate salt; dimethylaminomethyl (meth) acrylate quaternary salt, dimethyldialylammonium Anionic polymers such as chloride, polyamidine, polyvinyl imidazoline, dicyandiamide-based condensate, epichlorohydrin dimethylamine condensate, polyethyleneimine; dimethylaminoethyl (meth) acrylate quaternary salt acrylic acid copolymer, Hoffman decomposition product of polyacrylamide, etc. Amphoteric polymers can be mentioned. Preferred are polystyrene and polymethyl methacrylate.
The insulating polymer may contain two or more different repeating units.
　絶縁性ポリマーの重量平均分子量は、特に限定されないが、好ましくは５×１０３以上であり、より好ましくは１０×１０３以上である。また、好ましくは１０００×１０３以下であり、より好ましくは４００×１０３以下である。重量平均分子量がこの範囲にあることにより、発光性ドーパントの拡散を適切に制御できるものと考えられる。 The weight average molecular weight of the insulating polymer is not particularly limited, but is preferably 5 × 10 3 or more, and more preferably 10 × 10 3 or more. Also, preferably at 1000 × 10 3 or less, more preferably 400 × 10 3 or less. It is considered that when the weight average molecular weight is in this range, the diffusion of the luminescent dopant can be appropriately controlled.
　《電子輸送層》
　電子輸送層とは、電子を輸送する機能を有する材料からなり、陰極より注入された電子を発光層に伝達する機能を有する層をいう。
　電子輸送層の総膜厚については、特に制限はないが、通常は２ｎｍ～５μｍの範囲内であり、より好ましくは２～５００ｎｍの範囲内であり、さらに好ましくは５～２００ｎｍの範囲内である。 《Electron transport layer》
The electron transport layer is a layer made of a material having a function of transporting electrons and having a function of transmitting electrons injected from a cathode to a light emitting layer.
The total film thickness of the electron transport layer is not particularly limited, but is usually in the range of 2 nm to 5 μm, more preferably in the range of 2 to 500 nm, and further preferably in the range of 5 to 200 nm. ..
　電子輸送層に用いられる材料（以下、「電子輸送材料」ともいう。）としては、電子の注入性又は輸送性、正孔の障壁性のいずれかを有していればよく、従来公知の化合物の中から任意のものを選択して用いることができる。
　従来公知の化合物としては、例えば含窒素芳香族複素環誘導体（カルバゾール誘導体、アザカルバゾール誘導体（カルバゾール環を構成する炭素原子の一つ以上が窒素原子に置換されたもの）、ピリジン誘導体、ピリミジン誘導体、ピラジン誘導体、ピリダジン誘導体、トリアジン誘導体、キノリン誘導体、キノキサリン誘導体、フェナントロリン誘導体、アザトリフェニレン誘導体、オキサゾール誘導体、チアゾール誘導体、オキサジアゾール誘導体、チアジアゾール誘導体、トリアゾール誘導体、ベンズイミダゾール誘導体、ベンズオキサゾール誘導体、ベンズチアゾール誘導体等）、ジベンゾフラン誘導体、ジベンゾチオフェン誘導体、シロール誘導体、芳香族炭化水素環誘導体（ナフタレン誘導体、アントラセン誘導体、トリフェニレン等）等が挙げられる。 The material used for the electron transport layer (hereinafter, also referred to as “electron transport material”) may have any of electron injection property, transport property, and hole barrier property, and is a conventionally known compound. Any one can be selected and used from the above.
Conventionally known compounds include, for example, nitrogen-containing aromatic heterocyclic derivatives (carbazole derivatives, azacarbazole derivatives (one or more carbon atoms constituting the carbazole ring substituted with nitrogen atoms), pyridine derivatives, pyrimidine derivatives, etc. Pyrazine derivative, pyridazine derivative, triazine derivative, quinoline derivative, quinoxalin derivative, phenanthroline derivative, azatriphenylene derivative, oxazole derivative, thiazole derivative, oxadiazole derivative, thiadiazol derivative, triazole derivative, benzimidazole derivative, benzoxazole derivative, benzthiazole derivative Etc.), dibenzofuran derivatives, dibenzothiophene derivatives, silol derivatives, aromatic hydrocarbon ring derivatives (naphthalene derivatives, anthracene derivatives, triphenylene, etc.) and the like.
　また、配位子にキノリノール骨格やジベンゾキノリノール骨格を有する金属錯体、例えばトリス（８－キノリノール）アルミニウム（Ａｌｑ３）、トリス（５，７－ジクロロ－８－キノリノール）アルミニウム、トリス（５，７－ジブロモ－８－キノリノール）アルミニウム、トリス（２－メチル－８－キノリノール）アルミニウム、トリス（５－メチル－８－キノリノール）アルミニウム、ビス（８－キノリノール）亜鉛（Ｚｎｑ）等、及びこれらの金属錯体の中心金属がＩｎ、Ｍｇ、Ｃｕ、Ｃａ、Ｓｎ、Ｇａ又はＰｂに置き替わった金属錯体も、電子輸送材料として用いることができる。 Further, metal complexes having a quinolinol skeleton or a dibenzoquinolinol skeleton as ligands, for example, tris (8-quinolinol) aluminum (Alq 3 ), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-) Dibromo-8-quinolinol) aluminum, tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and metal complexes thereof. A metal complex in which the central metal is replaced with In, Mg, Cu, Ca, Sn, Ga or Pb can also be used as an electron transport material.
　その他、メタルフリー若しくはメタルフタロシアニン、又はそれらの末端がアルキル基やスルホン酸基等で置換されているものも、電子輸送材料として好ましく用いることができる。また、発光層の材料として例示したジスチリルピラジン誘導体も、電子輸送材料として用いることができるし、正孔注入層、正孔輸送層と同様にｎ型－Ｓｉ、ｎ型－ＳｉＣ等の無機半導体も電子輸送材料として用いることができる。
　また、これらの材料を高分子鎖に導入した、又はこれらの材料を高分子の主鎖とした高分子材料を用いることもできる。 In addition, metal-free or metal phthalocyanine, or those whose terminals are substituted with an alkyl group, a sulfonic acid group, or the like can also be preferably used as an electron transport material. Further, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and an inorganic semiconductor such as n-type-Si or n-type-SiC is used like the hole injection layer and the hole transport layer. Can also be used as an electron transport material.
Further, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.
　本発明に係る電子輸送層においては、電子輸送層にドープ材をゲスト材料としてドープして、ｎ性の高い（電子リッチ）電子輸送層を形成してもよい。ドープ材としては、金属錯体やハロゲン化金属など金属化合物等のｎ型ドーパントが挙げられる。このような構成の電子輸送層の具体例としては、例えば特開平４－２９７０７６号公報、同１０－２７０１７２号公報、特開２０００－１９６１４０号公報、同２００１－１０２１７５号公報、Ｊ．Ａｐｐｌ．Ｐｈｙｓ．，９５，５７７３（２００４）等の文献に記載されたものが挙げられる。 In the electron transport layer according to the present invention, the electron transport layer may be doped with a doping material as a guest material to form a highly n-type (electron-rich) electron transport layer. Examples of the doping material include n-type dopants such as metal complexes and metal compounds such as metal halides. Specific examples of the electron transport layer having such a structure include, for example, JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, JP-A-2001-102175, J. Mol. Apple. Phys. , 95, 5773 (2004) and the like.
　本発明の有機ＥＬ素子に用いられる、公知の好ましい電子輸送材料の具体例としては、以下の文献に記載の化合物等が挙げられるが、本発明はこれらに限定されない。
　米国特許第６５２８１８７号、米国特許第７２３０１０７号、米国特許公開第２００５／００２５９９３号、米国特許公開第２００４／００３６０７７号、米国特許公開第２００９／０１１５３１６号、米国特許公開第２００９／０１０１８７０号、米国特許公開第２００９／０１７９５５４号、国際公開第２００３／０６０９５６号、国際公開第２００８／１３２０８５号、Ａｐｐｌ．　Ｐｈｙｓ．　Ｌｅｔｔ．　７５，　４　（１９９９）、Ａｐｐｌ．　Ｐｈｙｓ．　Ｌｅｔｔ．　７９，　４４９　（２００１）、Ａｐｐｌ．　Ｐｈｙｓ．Ｌｅｔｔ．　８１，　１６２　（２００２）、Ａｐｐｌ．　Ｐｈｙｓ．　Ｌｅｔｔ．　８１，　１６２　（２００２）、Ａｐｐｌ．　Ｐｈｙｓ．　Ｌｅｔｔ．　７９，
　１５６　（２００１）、米国特許第７９６４２９３号、米国特許公開第２００９／０３０２０２号、国際公開第２００４／０８０９７５号、国際公開第２００４／０６３１５９号、国際公開第２００５／０８５３８７号、国際公開第２００６／０６７９３１号、国際公開第２００７／０８６５５２号、国際公開第２００８／１１４６９０号、国際公開第２００９／０６９４４２号、国際公開第２００９／０６６７７９号、国際公開第２００９／０５４２５３号、国際公開第２０１１／０８６９３５号、国際公開第２０１０／１５０５９３号、国際公開第２０１０／０４７７０７号、ＥＰ２３１１８２６号、特開２０１０－２５１６７５号公報、特開２００９－２０９１３３号公報、特開２００９－１２４１１４号公報、特開２００８－２７７８１０号公報、特開２００６－１５６４４５号公報、特開２００５－３４０１２２号公報、特開２００３－４５６６２号公報、特開２００３－３１３６７号公報、特開２００３－２８２２７０号公報、国際公開第２０１２／１１５０３４号、等である。 Specific examples of known and preferable electron transporting materials used in the organic EL device of the present invention include, but are not limited to, the compounds described in the following documents.
U.S. Patent No. 6528187, U.S. Patent No. 7230107, U.S. Patent Publication No. 2005/0025993, U.S. Patent Publication No. 2004/0036077, U.S. Patent Publication No. 2009/0115316, U.S. Patent Publication No. 2009/0101870, U.S. Patent Publication No. 2009/0179554, International Publication No. 2003/060956, International Publication No. 2008/132805, Appl. Phys. Lett. 75, 4 (1999), Appl. Phys. Lett. 79, 449 (2001), Appl. Phys. Lett. 81, 162 (2002), Appl. Phys. Lett. 81, 162 (2002), Appl. Phys. Lett. 79,
156 (2001), US Patent No. 7964293, US Patent Publication No. 2009/030202, International Publication No. 2004/080975, International Publication No. 2004/063159, International Publication No. 2005/085387, International Publication No. 2006/067931 No., International Publication No. 2007/0865552, International Publication No. 2008/114690, International Publication No. 2009/0694242, International Publication No. 2009/066797, International Publication No. 2009/054253, International Publication No. 2011/086935, International Publication No. 2010/150593, International Publication No. 2010/047707, EP23111826, JP-A-2010-251675, JP-A-2009-209133, JP-A-2009-124114, JP-A-2008-277810 , JP-A-2006-156445, JP-A-2005-340122, JP-A-2003-456662, JP-A-2003-31367, JP-A-2003-282270, International Publication No. 2012/115034, etc. Is.
　より好ましい電子輸送材料としては、ピリジン誘導体、ピリミジン誘導体、ピラジン誘導体、トリアジン誘導体、ジベンゾフラン誘導体、ジベンゾチオフェン誘導体、カルバゾール誘導体、アザカルバゾール誘導体、ベンズイミダゾール誘導体が挙げられる。
　電子輸送材料は単独で用いてもよく、また複数種を併用して用いてもよい。 More preferable electron transporting materials include pyridine derivatives, pyrimidine derivatives, pyrazine derivatives, triazine derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, carbazole derivatives, azacarbazole derivatives, and benzimidazole derivatives.
The electron transport material may be used alone or in combination of two or more.
　《正孔阻止層》
　正孔阻止層とは、広い意味では、電子輸送層の機能を有する層であり、好ましくは電子を輸送する機能を有しつつ正孔を輸送する能力が小さい材料からなり、電子を輸送しつつ正孔を阻止することで電子と正孔の再結合確率を向上させることができる層をいう。
　また、前述の電子輸送層の構成を必要に応じて、正孔阻止層として用いることができる。 《Hole blocking layer》
The hole blocking layer is, in a broad sense, a layer having a function of an electron transporting layer, preferably made of a material having a function of transporting electrons and a small ability to transport holes, while transporting electrons. A layer that can improve the recombination probability of electrons and holes by blocking holes.
In addition, the above-mentioned structure of the electron transport layer can be used as a hole blocking layer, if necessary.
　前記正孔阻止層は、発光層の陰極側に隣接して設けられることが好ましい。
　また、正孔阻止層の層厚としては、好ましくは３～１００ｎｍの範囲内であり、さらに好ましくは５～３０ｎｍの範囲内である。
　正孔阻止層に用いられる材料としては、前述の電子輸送層に用いられる材料が好ましく用いられ、また、前述のホスト化合物として用いられる材料も正孔阻止層に好ましく用いられる。 The hole blocking layer is preferably provided adjacent to the cathode side of the light emitting layer.
The thickness of the hole blocking layer is preferably in the range of 3 to 100 nm, and more preferably in the range of 5 to 30 nm.
As the material used for the hole blocking layer, the material used for the electron transporting layer described above is preferably used, and the material used as the host compound described above is also preferably used for the hole blocking layer.
　《電子注入層》
　電子注入層（「陰極バッファー層」ともいう。）とは、駆動電圧低下や発光輝度向上のために陰極と発光層との間に設けられる層をいい、「有機ＥＬ素子とその工業化最前線（１９９８年１１月３０日エヌ・ティー・エス社発行）」の第２編第２章「電極材料」（１２３～１６６頁）に詳細に記載されている。
　電子注入層は、必要に応じて設け、上記のように陰極と発光層との間、又は陰極と電子輸送層との間に存在させてもよい。
　電子注入層はごく薄い膜であることが好ましく、素材にもよるが、その層厚は０．１～５ｎｍの範囲内が好ましい。また構成材料が断続的に存在する不均一な膜であってもよい。 《Electron injection layer》
The electron injection layer (also referred to as "cathode buffer layer") refers to a layer provided between the cathode and the light emitting layer in order to reduce the driving voltage and improve the emission brightness, and refers to "organic EL element and its forefront of industrialization (also referred to as" cathode buffer layer "). It is described in detail in Volume 2, Chapter 2, "Electrode Materials" (pages 123-166) of "November 30, 1998, published by NTS Co., Ltd.).
The electron injection layer may be provided as needed and may be present between the cathode and the light emitting layer or between the cathode and the electron transport layer as described above.
The electron injection layer is preferably a very thin film, and the layer thickness is preferably in the range of 0.1 to 5 nm, although it depends on the material. Further, it may be a non-uniform film in which the constituent material is intermittently present.
　電子注入層は、特開平６－３２５８７１号公報、同９－１７５７４号公報、同１０－７４５８６号公報等にもその詳細が記載されており、電子注入層に好ましく用いられる材料の具体例としては、ストロンチウムやアルミニウム等に代表される金属、フッ化リチウム、フッ化ナトリウム、フッ化カリウム等に代表されるアルカリ金属化合物、フッ化マグネシウム、フッ化カルシウム等に代表されるアルカリ土類金属化合物、酸化アルミニウムに代表される金属酸化物、リチウム８－ヒドロキシキノレート（Ｌｉｑ）等に代表される金属錯体等が挙げられる。また、前述の電子輸送材料を用いることも可能である。
　また、上記の電子注入層に用いられる材料は単独で用いてもよく、複数種を併用して用いてもよい。 The details of the electron-injected layer are also described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like, and specific examples of materials preferably used for the electron-injected layer include , Metals such as strontium and aluminum, alkali metal compounds such as lithium fluoride, sodium fluoride and potassium fluoride, alkaline earth metal compounds such as magnesium fluoride and calcium fluoride, oxidation Examples thereof include metal oxides typified by aluminum, metal complexes typified by lithium 8-hydroxyquinolate (Liq) and the like. It is also possible to use the above-mentioned electron transport material.
Further, the material used for the above-mentioned electron injection layer may be used alone or in combination of two or more.
　《正孔輸送層》
　正孔輸送層とは、正孔を輸送する機能を有する材料からなり、陽極より注入された正孔を発光層に伝達する機能を有する層をいう。
　前記正孔輸送層の総膜厚については、特に制限はないが、通常は５ｎｍ～５μｍの範囲内であり、より好ましくは２～５００ｎｍの範囲内であり、さらに好ましくは５～２００ｎｍの範囲内である。 《Hole transport layer》
The hole transport layer is a layer made of a material having a function of transporting holes and having a function of transmitting holes injected from an anode to a light emitting layer.
The total film thickness of the hole transport layer is not particularly limited, but is usually in the range of 5 nm to 5 μm, more preferably in the range of 2 to 500 nm, and further preferably in the range of 5 to 200 nm. Is.
　正孔輸送層に用いられる材料（以下、「正孔輸送材料」という。）としては、正孔の注入性又は輸送性、電子の障壁性のいずれかを有していればよく、従来公知の化合物の中から任意のものを選択して用いることができる。 The material used for the hole transport layer (hereinafter referred to as “hole transport material”) may have any of hole injection property, transport property, and electron barrier property, and is conventionally known. Any compound can be selected and used.
　例えばポルフィリン誘導体、フタロシアニン誘導体、オキサゾール誘導体、オキサジアゾール誘導体、トリアゾール誘導体、イミダゾール誘導体、ピラゾリン誘導体、ピラゾロン誘導体、フェニレンジアミン誘導体、ヒドラゾン誘導体、スチルベン誘導体、ポリアリールアルカン誘導体、トリアリールアミン誘導体、カルバゾール誘導体、インドロカルバゾール誘導体、イソインドール誘導体、アントラセンやナフタレン等のアセン系誘導体、フルオレン誘導体、フルオレノン誘導体、及びポリビニルカルバゾール、芳香族アミンを主鎖又は側鎖に導入した高分子材料又はオリゴマー、ポリシラン、導電性ポリマー又はオリゴマー（例えばＰＥＤＯＴ：ＰＳＳ、アニリン系共重合体、ポリアニリン、ポリチオフェン等）等が挙げられる。 For example, porphyrin derivatives, phthalocyanine derivatives, oxazole derivatives, oxadiazole derivatives, triazole derivatives, imidazole derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, hydrazone derivatives, stillben derivatives, polyarylalkane derivatives, triarylamine derivatives, carbazole derivatives, Indrocarbazole derivatives, isoindole derivatives, acene derivatives such as anthracene and naphthalene, fluorene derivatives, fluorenone derivatives, and polymer materials or oligomers with polyvinylcarbazole and aromatic amines introduced into the main and side chains, polysilanes, and conductivity. Examples thereof include polymers or oligomers (for example, PEDOT: PSS, aniline-based copolymers, polyaniline, polythiophene, etc.).
　トリアリールアミン誘導体としては、α－ＮＰＤに代表されるベンジジン型や、ＭＴＤＡＴＡに代表されるスターバースト型、トリアリールアミン連結コア部にフルオレンやアントラセンを有する化合物等が挙げられる。
　また、特表２００３－５１９４３２号公報や特開２００６－１３５１４５号公報等に記載されているようなヘキサアザトリフェニレン誘導体も同様に正孔輸送材料として用いることができる。
　さらに、不純物をドープしたｐ性の高い正孔輸送層を用いることもできる。その例としては、特開平４－２９７０７６号公報、特開２０００－１９６１４０号公報、同２００１－１０２１７５号公報の各公報、Ｊ．Ａｐｐｌ．Ｐｈｙｓ．，９５，５７７３（２００４）等に記載されたものが挙げられる。 Examples of the triarylamine derivative include a benzidine type represented by α-NPD, a starburst type represented by MTDATA, and a compound having fluorene or anthracene in the triarylamine connecting core portion.
Hexaazatriphenylene derivatives as described in JP-A-2003-591432 and JP-A-2006-135145 can also be used as the hole transport material in the same manner.
Further, a hole transport layer having a high p property doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, and JP-A-2001-102175. Apple. Phys. , 95, 5773 (2004) and the like.
　また、特開平１１－２５１０６７号公報、Ｊ．Ｈｕａｎｇ　ｅｔ．ａｌ．著文献（Ａｐｐｌｉｅｄ　Ｐｈｙｓｉｃｓ　Ｌｅｔｔｅｒｓ　８０（２００２），ｐ．１３９）に記載されているような、いわゆるｐ型正孔輸送材料やｐ型－Ｓｉ、ｐ型－ＳｉＣ等の無機化合物を用いることもできる。さらにＩｒ（ｐｐｙ）３に代表されるような中心金属にＩｒやＰｔを有するオルトメタル化有機金属錯体も好ましく用いられる。
　正孔輸送材料としては、上記のものを使用することができるが、トリアリールアミン誘導体、カルバゾール誘導体、インドロカルバゾール誘導体、アザトリフェニレン誘導体、有機金属錯体、芳香族アミンを主鎖又は側鎖に導入した高分子材料又はオリゴマー等が好ましく用いられる。 In addition, Japanese Patent Application Laid-Open No. 11-251067, J. Am. Hung et. al. So-called p-type hole transport materials and inorganic compounds such as p-type-Si and p-type-SiC as described in the authored literature (Applied Physics Letters 80 (2002), p.139) can also be used. Further, an orthometalated organometallic complex having Ir or Pt in the central metal as represented by Ir (ppy) 3 is also preferably used.
As the hole transporting material, the above-mentioned materials can be used, but a triarylamine derivative, a carbazole derivative, an indolocarbazole derivative, an azatriphenylene derivative, an organic metal complex, and an aromatic amine are introduced into the main chain or side chain. High molecular weight materials or oligomers are preferably used.
　本発明の有機ＥＬ素子に用いられる、公知の好ましい正孔輸送材料の具体例としては、上記で挙げた文献の他、以下の文献に記載の化合物等が挙げられるが、本発明はこれらに限定されない。 Specific examples of known and preferable hole transporting materials used in the organic EL device of the present invention include the compounds described in the following documents in addition to the above-mentioned documents, but the present invention is limited thereto. Not done.
　例えばＡｐｐｌ．　Ｐｈｙｓ．　Ｌｅｔｔ．　６９，　２１６０　（１９９６）、Ｊ．　Ｌｕｍｉｎ．　７２－７４，　９８５　（１９９７）、Ａｐｐｌ．　Ｐｈｙｓ．　Ｌｅｔｔ．　７８，　６７３　（２００１）、Ａｐｐｌ．　Ｐｈｙｓ．　Ｌｅｔｔ．　９０，　１８３５０３（２００７）、Ａｐｐｌ．　Ｐｈｙｓ．　Ｌｅｔｔ．　９０，　１８３５０３　（２００７）、Ａｐｐｌ．　Ｐｈｙｓ．　Ｌｅｔｔ．　５１，　９１３　（１９８７）、Ｓｙｎｔｈ．　Ｍｅｔ．　８７，　１７１　（１９９７）、Ｓｙｎｔｈ．　Ｍｅｔ．　９１，　２０９　（１９９７）、Ｓｙｎｔｈ．　Ｍｅｔ．　１１１，４２１　（２０００）、ＳＩＤ　ＳｙｍｐｏｓｉｕｍＤｉｇｅｓｔ，　３７，　９２３　（２００６）、Ｊ．　Ｍａｔｅｒ．　Ｃｈｅｍ．　３，　３１９　（１９９３）、Ａｄｖ．　Ｍａｔｅｒ．　６，　６７７　（１９９４）、Ｃｈｅｍ．　Ｍａｔｅｒ．　１５，３１４８　（２００３）、米国特許公開第２００３／０１６２０５３号、米国特許公開第２００２／０１５８２４２号、米国特許公開第２００６／０２４０２７９号、米国特許公開第２００８／０２２０２６５号、米国特許第５０６１５６９号、国際公開第２００７／００２６８３号、国際公開第２００９／０１８００９号、ＥＰ６５０９５５、米国特許公開第２００８／０１２４５７２号、米国特許公開第２００７／０２７８９３８号、米国特許公開第２００８／０１０６１９０号、米国特許公開第２００８／００１８２２１号、国際公開第２０１２／１１５０３４号、特表２００３－５１９４３２号公報、特開２００６－１３５１４５号公報、米国特許出願番号１３／５８５９８１号等である。
　正孔輸送材料は単独で用いてもよく、また複数種を併用して用いてもよい。 For example, Appl. Phys. Lett. 69, 2160 (1996), J. Mol. Lumin. 72-74, 985 (1997), Appl. Phys. Lett. 78, 673 (2001), Appl. Phys. Lett. 90, 183503 (2007), Appl. Phys. Lett. 90, 183503 (2007), Appl. Phys. Lett. 51, 913 (1987), Synth. Met. 87, 171 (1997), Synth. Met. 91, 209 (1997), Synth. Met. 111,421 (2000), SID SymposiumDigest, 37, 923 (2006), J. Mol. Mater. Chem. 3, 319 (1993), Adv. Mater. 6, 677 (1994), Chem. Mater. 15,3148 (2003), U.S. Patent Publication No. 2003/0162053, U.S. Patent Publication No. 2002/0158242, U.S. Patent Publication No. 2006/0240279, U.S. Patent Publication No. 2008/0220265, U.S. Patent No. 5061569, International Publication No. 2007/002683, International Publication No. 2009/01809, EP650955, US Patent Publication No. 2008/01245772, US Patent Publication No. 2007/0278938, US Patent Publication No. 2008/0106190, US Patent Publication No. 2008 / 0018221, International Publication No. 2012/115344, Japanese Patent Application Laid-Open No. 2003-591432, Japanese Patent Application Laid-Open No. 2006-135145, US Patent Application No. 13/585981, and the like.
The hole transporting material may be used alone or in combination of two or more.
　《電子阻止層》
　電子阻止層とは、広い意味では正孔輸送層の機能を有する層であり、好ましくは正孔を輸送する機能を有しつつ電子を輸送する能力が小さい材料からなり、正孔を輸送しつつ電子を阻止することで電子と正孔の再結合確率を向上させることができる層をいう。
　また、前述の正孔輸送層の構成を必要に応じて、電子阻止層として用いることができる。
　前記電子阻止層は、発光層の陽極側に隣接して設けられることが好ましい。
　また、電子阻止層の層厚としては、好ましくは３～１００ｎｍの範囲内であり、さらに好ましくは５～３０ｎｍの範囲内である。
　電子阻止層に用いられる材料としては、前述の正孔輸送層に用いられる材料が好ましく用いられ、また、前述のホスト化合物として用いられる材料も電子阻止層に好ましく用いられる。 《Electronic blocking layer》
The electron blocking layer is a layer having a function of a hole transporting layer in a broad sense, and is preferably made of a material having a function of transporting holes and a small ability to transport electrons, while transporting holes. A layer that can improve the recombination probability of electrons and holes by blocking electrons.
In addition, the structure of the hole transport layer described above can be used as an electron blocking layer, if necessary.
The electron blocking layer is preferably provided adjacent to the anode side of the light emitting layer.
The thickness of the electron blocking layer is preferably in the range of 3 to 100 nm, and more preferably in the range of 5 to 30 nm.
As the material used for the electron blocking layer, the material used for the hole transporting layer described above is preferably used, and the material used as the host compound described above is also preferably used for the electron blocking layer.
　《正孔注入層》
　正孔注入層（「陽極バッファー層」ともいう。）とは、駆動電圧低下や発光輝度向上のために陽極と発光層との間に設けられる層をいう。例えば「有機ＥＬ素子とその工業化最前線（１９９８年１１月３０日エヌ・ティー・エス社発行）」の第２編第２章「電極材料」（１２３～１６６頁）に詳細に記載されている。
　正孔注入層は必要に応じて設け、上記のように陽極と発光層又は陽極と正孔輸送層との間に存在させてもよい。 《Hole injection layer》
The hole injection layer (also referred to as “anode buffer layer”) is a layer provided between the anode and the light emitting layer in order to reduce the driving voltage and improve the emission brightness. For example, it is described in detail in Volume 2, Chapter 2, "Electrode Materials" (pages 123-166) of "Organic EL Devices and Their Industrialization Frontline (November 30, 1998, published by NTS)". ..
The hole injection layer may be provided as needed and may be present between the anode and the light emitting layer or between the anode and the hole transport layer as described above.
　正孔注入層は、特開平９－４５４７９号公報、同９－２６００６２号公報、同８－２８８０６９号公報等にもその詳細が記載されており、正孔注入層に用いられる材料としては、例えば前述の正孔輸送層に用いられる材料等が挙げられる。 The details of the hole injection layer are also described in JP-A-9-45479, 9-2660062, 8-288609, etc., and examples of the material used for the hole injection layer include. Examples thereof include materials used for the hole transport layer described above.
　中でも銅フタロシアニンに代表されるフタロシアニン誘導体、特表２００３－５１９４３２号公報や特開２００６－１３５１４５号公報等に記載されているようなヘキサアザトリフェニレン誘導体、酸化バナジウムに代表される金属酸化物、アモルファスカーボン、ポリアニリン（エメラルディン）やポリチオフェン等の導電性高分子、トリス（２－フェニルピリジン）イリジウム錯体等に代表されるオルトメタル化錯体、トリアリールアミン誘導体等が好ましい。
　前述の正孔注入層に用いられる材料は単独で用いてもよく、また複数種を併用して用いてもよい。 Among them, phthalocyanine derivatives typified by copper phthalocyanine, hexaazatriphenylene derivatives as described in JP-A-2003-591432 and JP-A-2006-135145, metal oxides typified by vanadium oxide, amorphous carbon. , Polyaniline (emeraldine), polythiophene and other conductive polymers, tris (2-phenylpyridine) iridium complexes and the like, orthometallated complexes, triarylamine derivatives and the like are preferable.
The material used for the hole injection layer described above may be used alone or in combination of two or more.
　《その他添加剤》
　前述した本発明に係る有機機能層は、さらに他の添加剤が含まれていてもよい。
　添加剤としては、例えば臭素、ヨウ素及び塩素等のハロゲン元素やハロゲン化化合物、Ｐｄ、Ｃａ、Ｎａ等のアルカリ金属やアルカリ土類金属、遷移金属の化合物や錯体、塩等が挙げられる。
　添加剤の含有量は、任意に決定することができるが、含有される層の全質量％に対して１０００ｐｐｍ以下であることが好ましく、より好ましくは５００ｐｐｍ以下であり、さらに好ましくは５０ｐｐｍ以下である。
　ただし、電子や正孔の輸送性を向上させる目的や、励起子のエネルギー移動を有利にするための目的などによってはこの範囲内ではない。 << Other additives >>
The organic functional layer according to the present invention described above may further contain other additives.
Examples of the additive include halogen elements such as bromine, iodine and chlorine, halogenated compounds, alkali metals and alkaline earth metals such as Pd, Ca and Na, compounds and complexes of transition metals, salts and the like.
The content of the additive can be arbitrarily determined, but is preferably 1000 ppm or less, more preferably 500 ppm or less, still more preferably 50 ppm or less, based on the total mass% of the contained layer. ..
However, it is not within this range depending on the purpose of improving the transportability of electrons and holes and the purpose of favoring the energy transfer of excitons.
　《陽極》
　有機ＥＬ素子における陽極としては、仕事関数の大きい（４ｅＶ以上、好ましくは４．５Ｖ以上）金属、合金、電気伝導性化合物及びこれらの混合物を電極物質とするものが好ましく用いられる。このような電極物質の具体例としては、Ａｕ等の金属、ＣｕＩ、インジウムチンオキシド（ＩＴＯ）、ＳｎＯ２、ＺｎＯ等の導電性透明材料が挙げられる。また、ＩＤＩＸＯ（Ｉｎ２Ｏ３－ＺｎＯ）等非晶質で透明導電膜を作製可能な材料を用いてもよい。 "anode"
As the anode in the organic EL element, a metal having a large work function (4 eV or more, preferably 4.5 V or more), an alloy, an electrically conductive compound, or a mixture thereof as an electrode material is preferably used. Specific examples of such an electrode material include metals such as Au and conductive transparent materials such as CuI, indium zinc oxide (ITO), SnO 2, and ZnO. Further, a material such as IDIXO (In 2 O 3- ZnO) which is amorphous and can produce a transparent conductive film may be used.
　陽極は、これらの電極物質を蒸着やスパッタリング等の方法により薄膜を形成させ、フォトリソグラフィー法で所望の形状のパターンを形成してもよく、又はパターン精度を余り必要としない場合は（１００μｍ以上程度）、上記電極物質の蒸着やスパッタリング時に所望の形状のマスクを介してパターンを形成してもよい。
　又は、有機導電性化合物のように塗布可能な物質を用いる場合には、印刷方式、コーティング方式等湿式成膜法を用いることもできる。この陽極より発光を取り出す場合には、透過率を１０％より大きくすることが好ましく、また陽極としてのシート抵抗は数百Ω／ｓｑ．以下が好ましい。
　陽極の膜厚は材料にもよるが、通常１０ｎｍ～１μｍ、好ましくは１０～２００ｎｍの範囲で選ばれる。 For the anode, a thin film may be formed by forming a thin film of these electrode materials by a method such as thin film deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when pattern accuracy is not required so much (about 100 μm or more). ), A pattern may be formed through a mask having a desired shape during vapor deposition or sputtering of the electrode material.
Alternatively, when a coatable substance such as an organic conductive compound is used, a wet film forming method such as a printing method or a coating method can also be used. When light emission is taken out from this anode, the transmittance is preferably made larger than 10%, and the sheet resistance as the anode is several hundred Ω / sq. The following is preferable.
The film thickness of the anode depends on the material, but is usually selected in the range of 10 nm to 1 μm, preferably 10 to 200 nm.
　《陰極》
　陰極としては、仕事関数の小さい（５ｅＶ以下）金属（電子注入性金属と称する。）、合金、電気伝導性化合物及びこれらの混合物を電極物質とするものが用いられる。このような電極物質の具体例としては、ナトリウム、ナトリウム－カリウム合金、マグネシウム、リチウム、銀、マグネシウム／銅混合物、マグネシウム／銀混合物、マグネシウム／アルミニウム混合物、マグネシウム／インジウム混合物、アルミニウム／酸化アルミニウム（Ａｌ２Ｏ３）混合物、インジウム、リチウム／アルミニウム混合物、アルミニウム、希土類金属等が挙げられる。 "cathode"
As the cathode, a metal having a small work function (5 eV or less) (referred to as an electron-injectable metal), an alloy, an electrically conductive compound, or a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, silver, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al). 2 O 3 ) Examples include mixtures, indium, lithium / aluminum mixtures, aluminum, rare earth metals and the like.
　これらの中で、電子注入性及び酸化等に対する耐久性の点から、電子注入性金属とこれより仕事関数の値が大きく安定な金属である第二金属との混合物、例えばマグネシウム／銀混合物、マグネシウム／アルミニウム混合物、マグネシウム／インジウム混合物、アルミニウム／酸化アルミニウム（Ａｌ２Ｏ３）混合物、リチウム／アルミニウム混合物、アルミニウム等が好適である。 Among these, from the viewpoint of electron injectability and durability against oxidation, etc., a mixture of an electron injectable metal and a second metal which is a stable metal having a larger work function value than this, for example, magnesium / silver mixture, magnesium / Aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al 2 O 3 ) mixture, lithium / aluminum mixture, aluminum and the like are suitable.
　陰極は、これらの電極物質を蒸着やスパッタリング等の方法により薄膜を形成させることにより、作製することができる。又は、金属ナノ粒子のように塗布可能な物質を用いる場合には、印刷方式、コーティング方式等湿式成膜法を用いることもできる。陰極としてのシート抵抗は数百Ω／ｓｑ．以下が好ましく、膜厚は通常１０ｎｍ～５μｍ、好ましくは５０～２００ｎｍの範囲で選ばれる。
　なお、発光した光を透過させるため、有機ＥＬ素子の陽極又は陰極のいずれか一方が透明又は半透明であれば発光輝度が向上し好都合である。
　また、陰極に上記金属を１～２０ｎｍの膜厚で作製した後に、陽極の説明で挙げる導電性透明材料をその上に作製することで、透明又は半透明の陰極を作製することができ、これを応用することで陽極と陰極の両方が透過性を有する素子を作製することができる。 The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. Alternatively, when a coatable substance such as metal nanoparticles is used, a wet film forming method such as a printing method or a coating method can also be used. Sheet resistance as a cathode is several hundred Ω / sq. The following is preferable, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm.
Since the emitted light is transmitted, it is convenient that the emission brightness is improved if either the anode or the cathode of the organic EL element is transparent or translucent.
Further, a transparent or translucent cathode can be produced by producing the above metal on the cathode having a thickness of 1 to 20 nm and then producing the conductive transparent material mentioned in the description of the anode on the cathode. By applying the above, it is possible to manufacture an element in which both the anode and the cathode are transparent.
　《支持基板》
　有機ＥＬ素子に用いることのできる支持基板（以下、基体、基板、基材、支持体等ともいう。）としては、ガラス、プラスチック等の種類には特に限定はなく、また透明であっても不透明であってもよい。支持基板側から光を取り出す場合には、支持基板は透明であることが好ましい。好ましく用いられる透明な支持基板としては、ガラス、石英、透明樹脂フィルムを挙げることができる。特に好ましい支持基板は、有機ＥＬ素子にフレキシブル性を与えることが可能な樹脂フィルムである。 《Support board》
The types of support substrates (hereinafter, also referred to as substrates, substrates, substrates, supports, etc.) that can be used for organic EL elements are not particularly limited, such as glass and plastic, and even if they are transparent, they are opaque. It may be. When light is taken out from the support substrate side, the support substrate is preferably transparent. Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable support substrate is a resin film capable of imparting flexibility to the organic EL element.
　樹脂フィルムとしては、例えばポリエチレンテレフタレート（ＰＥＴ）、ポリエチレンナフタレート（ＰＥＮ）等のポリエステル、ポリエチレン、ポリプロピレン、セロファン、セルロースジアセテート、セルローストリアセテート（ＴＡＣ）、セルロースアセテートブチレート、セルロースアセテートプロピオネート（ＣＡＰ）、セルロースアセテートフタレート、セルロースナイトレート等のセルロースエステル類又はそれらの誘導体、ポリ塩化ビニリデン、ポリビニルアルコール、ポリエチレンビニルアルコール、シンジオタクティックポリスチレン、ポリカーボネート、ノルボルネン樹脂、ポリメチルペンテン、ポリエーテルケトン、ポリイミド、ポリエーテルスルホン（ＰＥＳ）、ポリフェニレンスルフィド、ポリスルホン類、ポリエーテルイミド、ポリエーテルケトンイミド、ポリアミド、フッ素樹脂、ナイロン、ポリメチルメタクリレート、アクリル又はポリアリレート類、アートン（登録商標）（ＪＳＲ社製）又はアペル（登録商標）（三井化学社製）といったシクロオレフィン系樹脂等の樹脂フィルムを挙げられる。 Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate (TAC), cellulose acetate butyrate, and cellulose acetate propionate (CAP). ), Cellulosic acetate phthalate, cellulose esters such as cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide, Polyether sulfone (PES), polyphenylene sulfide, polysulfones, polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylates, Arton® (registered trademark) or Examples thereof include resin films such as cycloolefin resins such as Apel (registered trademark) (manufactured by Mitsui Chemicals, Inc.).
　樹脂フィルムの表面には、無機物、有機物のガスバリア膜又はその両者のハイブリッドガスバリア膜が形成されていてもよく、ＪＩＳ　Ｋ　７１２９－１９９２に準拠した方法で測定された、水蒸気透過度（２５±０．５℃、相対湿度（９０±２）％ＲＨ）が０．０１ｇ／（ｍ２・２４ｈ）以下のガスバリア性フィルムであることが好ましく、さらには、ＪＩＳ　Ｋ　７１２６－１９８７に準拠した方法で測定された酸素透過度が、１０－３ｍＬ／（ｍ２・２４ｈ・ａｔｍ）以下、水蒸気透過度が、１０－５ｇ／（ｍ２・２４ｈ）以下の高バリア性フィルムであることが好ましい。 A gas barrier film of an inorganic substance, an organic substance, or a hybrid gas barrier film of both of them may be formed on the surface of the resin film, and the water vapor permeability (25 ± 0. 5 ° C., preferably a relative humidity (90 ± 2)% RH) is the gas barrier film of 0.01g / (m 2 · 24h) or less, and further, is measured by the method based on JIS K 7126-1987 oxygen permeability, 10 -3 mL / (m 2 · 24h · atm) or less, the water vapor permeability is preferably 10 -5 g / (m 2 · 24h) or less of the high barrier film.
　ガスバリア膜を形成する材料としては、水分や酸素等素子の劣化をもたらすものの浸入を抑制する機能を有する材料であればよく、例えば酸化ケイ素、二酸化ケイ素、窒化ケイ素等を用いることができる。さらに膜の脆弱性を改良するために、これら無機層と有機材料からなる層の積層構造を持たせることがより好ましい。無機層と有機機能層の積層順については特に制限はないが、両者を交互に複数回積層させることが好ましい。 As the material for forming the gas barrier film, any material that causes deterioration of the element such as moisture and oxygen but has a function of suppressing infiltration can be used, and for example, silicon oxide, silicon dioxide, silicon nitride and the like can be used. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and layers made of an organic material. The stacking order of the inorganic layer and the organic functional layer is not particularly limited, but it is preferable to stack the inorganic layer and the organic functional layer alternately a plurality of times.
　ガスバリア膜の形成方法については、特に限定はなく、例えば真空蒸着法、スパッタリング法、反応性スパッタリング法、分子線エピタキシー法、クラスターイオンビーム法、イオンプレーティング法、プラズマ重合法、大気圧プラズマ重合法、プラズマＣＶＤ法、レーザーＣＶＤ法、熱ＣＶＤ法、コーティング法等を用いることができるが、特開２００４－６８１４３号公報に記載されているような大気圧プラズマ重合法によるものが特に好ましい。 The method for forming the gas barrier film is not particularly limited, for example, vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma polymerization method. , Plasma CVD method, laser CVD method, thermal CVD method, coating method and the like can be used, but the atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.
　不透明な支持基板としては、例えばアルミ、ステンレス等の金属板、フィルムや不透明樹脂基板、セラミック製の基板等が挙げられる。
　本発明の有機ＥＬ素子の発光の室温における外部取り出し量子効率は、１％以上であることが好ましく、５％以上であるとより好ましい。
　ここで、外部取り出し量子効率（％）＝有機ＥＬ素子外部に発光した光子数／有機ＥＬ素子に流した電子数×１００である。
　また、カラーフィルター等の色相改良フィルター等を併用しても、有機ＥＬ素子からの発光色を蛍光体を用いて多色へ変換する色変換フィルターを併用してもよい。 Examples of the opaque support substrate include a metal plate such as aluminum and stainless steel, a film or opaque resin substrate, and a ceramic substrate.
The external extraction quantum efficiency of the light emission of the organic EL device of the present invention at room temperature is preferably 1% or more, more preferably 5% or more.
Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons passed through the organic EL element × 100.
Further, a hue improving filter such as a color filter may be used in combination, or a color conversion filter that converts the color emitted from the organic EL element into multiple colors using a phosphor may be used in combination.
　《封止》
　有機ＥＬ素子の封止に用いられる封止手段としては、例えば封止部材と、電極、支持基板とを接着剤で接着する方法を挙げることができる。封止部材としては、有機ＥＬ素子の表示領域を覆うように配置されていればよく、凹板状でも、平板状でもよい。また、透明性、電気絶縁性は特に限定されない。 《Seal》
Examples of the sealing means used for sealing the organic EL element include a method of adhering the sealing member, the electrode, and the support substrate with an adhesive. The sealing member may be arranged so as to cover the display area of the organic EL element, and may be intaglio-shaped or flat-plate-shaped. Further, transparency and electrical insulation are not particularly limited.
　具体的には、ガラス板、ポリマー板・フィルム、金属板・フィルム等が挙げられる。ガラス板としては、特にソーダ石灰ガラス、バリウム・ストロンチウム含有ガラス、鉛ガラス、アルミノケイ酸ガラス、ホウケイ酸ガラス、バリウムホウケイ酸ガラス、石英等を挙げることができる。また、ポリマー板としては、ポリカーボネート、アクリル、ポリエチレンテレフタレート、ポリエーテルサルファイド、ポリサルフォン等を挙げることができる。金属板としては、ステンレス、鉄、銅、アルミニウム、マグネシウム、ニッケル、亜鉛、クロム、チタン、モリブテン、シリコン、ゲルマニウム及びタンタルからなる群から選ばれる１種以上の金属又は合金からなるものが挙げられる。 Specific examples include glass plates, polymer plates / films, metal plates / films, and the like. Examples of the glass plate include soda lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, polysulfone and the like. Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium and tantalum.
　本発明においては、有機ＥＬ素子を薄膜化できるということからポリマーフィルム、金属フィルムを好ましく使用することができる。さらには、ポリマーフィルムはＪＩＳ　Ｋ
　７１２６－１９８７に準拠した方法で測定された酸素透過度が１×１０－３ｍＬ／ｍ２／２４ｈ以下、ＪＩＳ　Ｋ　７１２９－１９９２に準拠した方法で測定された、水蒸気透過度（２５±０．５℃、相対湿度（９０±２）％）が、１×１０－３ｇ／（ｍ２／２４ｈ）以下のものであることが好ましい。 In the present invention, a polymer film or a metal film can be preferably used because the organic EL element can be thinned. Furthermore, the polymer film is JIS K.
Oxygen permeability measured by a method according to 7126-1987 is 1 × 10 -3 mL / m 2 / 24h or less, and water vapor permeability (25 ± 0.) Measured by a method according to JIS K 7129-1992. 5 ° C., relative humidity (90 ± 2)%) is preferably 1 × 10 -3 g / (m 2 / 24h) or less.
　封止部材を凹状に加工するのは、サンドブラスト加工、化学エッチング加工等が使われる。
　接着剤としては、具体的には、アクリル酸系オリゴマー、メタクリル酸系オリゴマーの反応性ビニル基を有する光硬化及び熱硬化型接着剤、２－シアノアクリル酸エステル等の湿気硬化型等の接着剤を挙げることができる。また、エポキシ系等の熱及び化学硬化型（二液混合）を挙げることができる。また、ホットメルト型のポリアミド、ポリエステル、ポリオレフィンを挙げることができる。また、カチオン硬化タイプの紫外線硬化型エポキシ樹脂接着剤を挙げることができる。
　なお、有機ＥＬ素子が熱処理により劣化する場合があるので、室温から８０℃までに接着硬化できるものが好ましい。また、前記接着剤中に乾燥剤を分散させておいてもよい。封止部分への接着剤の塗布は市販のディスペンサーを使ってもよいし、スクリーン印刷のように印刷してもよい。 Sandblasting, chemical etching, etc. are used to process the sealing member into a concave shape.
Specific examples of the adhesive include acrylic acid-based oligomers, photocurable and thermosetting adhesives having a reactive vinyl group of methacrylic acid-based oligomers, and moisture-curable adhesives such as 2-cyanoacrylic acid ester. Can be mentioned. In addition, heat and chemical curing type (two-component mixture) such as epoxy type can be mentioned. Further, hot melt type polyamide, polyester and polyolefin can be mentioned. In addition, a cation-curable type ultraviolet-curable epoxy resin adhesive can be mentioned.
Since the organic EL element may be deteriorated by heat treatment, it is preferable that the organic EL element can be adhesively cured from room temperature to 80 ° C. Further, the desiccant may be dispersed in the adhesive. A commercially available dispenser may be used to apply the adhesive to the sealing portion, or printing may be performed as in screen printing.
　また、有機機能層を挟み支持基板と対向する側の電極の外側に電極と有機機能層を被覆し、支持基板と接する形で無機物、有機物の層を形成し封止膜とすることも好適にできる。この場合、膜を形成する材料としては、水分や酸素等素子の劣化をもたらすものの浸入を抑制する機能を有する材料であればよく、例えば酸化ケイ素、二酸化ケイ素、窒化ケイ素等を用いることができる。 It is also preferable to coat the electrode and the organic functional layer on the outside of the electrode on the side facing the support substrate with the organic functional layer sandwiched between them, and form an inorganic or organic layer in contact with the support substrate to form a sealing film. it can. In this case, the material for forming the film may be any material that causes deterioration of the element such as moisture and oxygen but has a function of suppressing infiltration, and for example, silicon oxide, silicon dioxide, silicon nitride and the like can be used.
　さらに膜の脆弱性を改良するために、これら無機層と有機材料からなる層の積層構造を持たせることが好ましい。これらの膜の形成方法については特に限定はなく、例えば真空蒸着法、スパッタリング法、反応性スパッタリング法、分子線エピタキシー法、クラスターイオンビーム法、イオンプレーティング法、プラズマ重合法、大気圧プラズマ重合法、プラズマＣＶＤ法、レーザーＣＶＤ法、熱ＣＶＤ法、コーティング法等を用いることができる。 In order to further improve the fragility of the membrane, it is preferable to have a laminated structure of these inorganic layers and layers made of an organic material. The method for forming these films is not particularly limited, and for example, vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma polymerization method. , Plasma CVD method, laser CVD method, thermal CVD method, coating method and the like can be used.
　封止部材と有機ＥＬ素子の表示領域との間隙には、気相及び液相では、窒素、アルゴン等の不活性気体やフッ化炭化水素、シリコーンオイルのような不活性液体を注入することが好ましい。また、真空とすることも可能である。また、内部に吸湿性化合物を封入することもできる。 In the gas phase and liquid phase, an inert gas such as nitrogen or argon or an inert liquid such as fluorinated hydrocarbon or silicone oil may be injected into the gap between the sealing member and the display region of the organic EL element. preferable. It is also possible to create a vacuum. Further, a hygroscopic compound can be enclosed inside.
　吸湿性化合物としては、金属酸化物（例えば酸化ナトリウム、酸化カリウム、酸化カルシウム、酸化バリウム、酸化マグネシウム、酸化アルミニウム等）、硫酸塩（例えば硫酸ナトリウム、硫酸カルシウム、硫酸マグネシウム、硫酸コバルト等）、金属ハロゲン化物（例えば塩化カルシウム、塩化マグネシウム、フッ化セシウム、フッ化タンタル、臭化セリウム、臭化マグネシウム、ヨウ化バリウム、ヨウ化マグネシウム等）、過塩素酸類（例えば過塩素酸バリウム、過塩素酸マグネシウム等）等が挙げられ、硫酸塩、金属ハロゲン化物及び過塩素酸類においては無水塩が好適に用いられる。 Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide, etc.), sulfates (for example, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate, etc.), and metals. Halides (eg calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide, etc.), perchlorates (eg barium perchlorate, magnesium perchlorate, etc.) Etc.), etc., and anhydrous salts are preferably used for sulfates, metal halides and perchlorates.
　《保護膜、保護板》
　有機機能層を挟み支持基板と対向する側の前記封止膜又は前記封止用フィルムの外側に、素子の機械的強度を高めるために、保護膜又は保護板を設けてもよい。特に、封止が前記封止膜により行われている場合には、その機械的強度は必ずしも高くないため、このような保護膜、保護板を設けることが好ましい。これに使用することができる材料としては、前記封止に用いたのと同様なガラス板、ポリマー板・フィルム、金属板・フィルム等を用いることができるが、軽量かつ薄膜化ということからポリマーフィルムを用いることが好ましい。 《Protective film, protective plate》
A protective film or protective plate may be provided on the outer side of the sealing film or the sealing film on the side facing the support substrate with the organic functional layer sandwiched in order to increase the mechanical strength of the device. In particular, when the sealing is performed by the sealing film, the mechanical strength thereof is not necessarily high, so it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, a glass plate, a polymer plate / film, a metal plate / film, etc. similar to those used for the sealing can be used, but the polymer film is lightweight and thin. Is preferably used.
　《光取り出し向上技術》
　有機ＥＬ素子は、空気よりも屈折率の高い（屈折率１．６～２．１程度の範囲内）層の内部で発光し、発光層で発生した光のうち１５～２０％程度の光しか取り出せないことが一般的にいわれている。
　これは、臨界角以上の角度θで界面（透明基板と空気との界面）に入射する光は、全反射を起こし素子外部に取り出すことができないことや、透明電極又は発光層と透明基板との間で光が全反射を起こし、光が透明電極又は発光層を導波し、結果として、光が素子側面方向に逃げるためである。 << Technology for improving light extraction >>
The organic EL element emits light inside a layer having a refractive index higher than that of air (within a refractive index of about 1.6 to 2.1), and only about 15 to 20% of the light generated in the light emitting layer is emitted. It is generally said that it cannot be taken out.
This is because light incident on the interface (intersection between the transparent substrate and air) at an angle θ equal to or greater than the critical angle causes total internal reflection and cannot be taken out of the element, and the transparent electrode or light emitting layer and the transparent substrate This is because the light is totally reflected between them, the light is waveguideed through the transparent electrode or the light emitting layer, and as a result, the light escapes toward the side surface of the element.
　この光の取り出しの効率を向上させる手法としては、例えば透明基板表面に凹凸を形成し、透明基板と空気界面での全反射を防ぐ方法（例えば米国特許第４７７４４３５号明細書）、基板に集光性を持たせることにより効率を向上させる方法（例えば特開昭６３－３１４７９５号公報）、素子の側面等に反射面を形成する方法（例えば特開平１－２２０３９４号公報）、基板と発光体の間に中間の屈折率を持つ平坦層を導入し、反射防止膜を形成する方法（例えば特開昭６２－１７２６９１号公報）、基板と発光体の間に基板よりも低屈折率を持つ平坦層を導入する方法（例えば特開２００１－２０２８２７号公報）、基板、透明電極層や発光層のいずれかの層間（含む、基板と外界間）に回折格子を形成する方法（特開平１１－２８３７５１号公報）などが挙げられる。 As a method for improving the efficiency of light extraction, for example, a method of forming irregularities on the surface of a transparent substrate to prevent total reflection at the interface between the transparent substrate and the air (for example, US Pat. No. 4,774,435), condensing light on the substrate. A method of improving efficiency by imparting properties (for example, Japanese Patent Application Laid-Open No. 63-314795), a method of forming a reflective surface on a side surface of an element (for example, Japanese Patent Application Laid-Open No. 1-220394), a substrate and a light emitter A method of introducing a flat layer having an intermediate refractive index between them to form an antireflection film (for example, Japanese Patent Application Laid-Open No. 62-172691), a flat layer having a lower refractive index than the substrate between the substrate and the light emitter. (For example, Japanese Patent Application Laid-Open No. 2001-202827), a method of forming a diffraction lattice between layers (including between the substrate and the outside world) of a substrate, a transparent electrode layer or a light emitting layer (Japanese Patent Laid-Open No. 11-283751). Gazette) and the like.
　本発明においては、これらの方法を前記有機ＥＬ素子と組み合わせて用いることができるが、基板と発光体の間に基板よりも低屈折率を持つ平坦層を導入する方法、又は基板、透明電極層や発光層のいずれかの層間（含む、基板と外界間）に回折格子を形成する方法を好適に用いることができる。
　透明電極と透明基板の間に低屈折率の媒質を光の波長よりも長い厚さで形成すると、透明電極から出てきた光は、媒質の屈折率が低いほど、外部への取り出し効率が高くなる。
　本発明は、これらの手段を組み合わせることにより、さらに高輝度又は耐久性に優れた素子を得ることができる。 In the present invention, these methods can be used in combination with the organic EL element, but a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or a substrate and a transparent electrode layer. A method of forming a diffraction grating between any layer (including between the substrate and the outside world) of the light emitting layer or the light emitting layer can be preferably used.
When a medium having a low refractive index is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the lower the refractive index of the medium, the higher the efficiency of extracting the light emitted from the transparent electrode to the outside. Become.
In the present invention, by combining these means, it is possible to obtain an element having higher brightness or excellent durability.
　低屈折率層としては、例えばエアロゲル、多孔質シリカ、フッ化マグネシウム、フッ素系ポリマーなどが挙げられる。透明基板の屈折率は一般に１．５～１．７程度の範囲内であるので、低屈折率層は、屈折率がおよそ１．５以下であることが好ましい。またさらに１．３５以下であることが好ましい。
　また、低屈折率媒質の厚さは、媒質中の波長の２倍以上となるのが望ましい。これは、低屈折率媒質の厚さが、光の波長程度になってエバネッセントで染み出した電磁波が基板内に入り込む膜厚になると、低屈折率層の効果が薄れるからである。 Examples of the low refractive index layer include airgel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate is generally in the range of about 1.5 to 1.7, it is preferable that the low refractive index layer has a refractive index of about 1.5 or less. Further, it is preferably 1.35 or less.
Further, it is desirable that the thickness of the low refractive index medium is at least twice the wavelength in the medium. This is because the effect of the low refractive index layer diminishes when the thickness of the low refractive index medium becomes about the wavelength of light and the electromagnetic wave exuded by evanescent enters the substrate.
　全反射を起こす界面又は、いずれかの媒質中に回折格子を導入する方法は、光取り出し効率の向上効果が高いという特徴がある。この方法は、回折格子が１次の回折や、２次の回折といった、いわゆるブラッグ回折により、光の向きを屈折とは異なる特定の向きに変えることができる性質を利用して、発光層から発生した光のうち、層間での全反射等により外に出ることができない光を、いずれかの層間又は、媒質中（透明基板内や透明電極内）に回折格子を導入することで光を回折させ、光を外に取り出そうとするものである。 The method of introducing a diffraction grating into an interface that causes total reflection or in any medium is characterized by a high effect of improving light extraction efficiency. This method is generated from the light emitting layer by utilizing the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction such as first-order diffraction or second-order diffraction. Of the generated light, the light that cannot go out due to total reflection between the layers is diffracted by introducing a diffraction grating in one of the layers or in the medium (inside the transparent substrate or in the transparent electrode). , Trying to get the light out.
　導入する回折格子は、二次元的な周期屈折率を持っていることが望ましい。これは、発光層で発光する光はあらゆる方向にランダムに発生するので、ある方向にのみ周期的な屈折率分布を持っている一般的な一次元回折格子では、特定の方向に進む光しか回折されず、光の取り出し効率がさほど上がらない。
　しかしながら、屈折率分布を二次元的な分布にすることにより、あらゆる方向に進む光が回折され、光の取り出し効率が上がる。 It is desirable that the diffraction grating to be introduced has a two-dimensional periodic refractive index. This is because the light emitted by the light emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating that has a periodic refractive index distribution only in a certain direction, only the light traveling in a specific direction is diffracted. The light extraction efficiency does not increase so much.
However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and the light extraction efficiency is improved.
　回折格子を導入する位置としては、いずれかの層間、又は媒質中（透明基板内や透明電極内）でもよいが、光が発生する場所である有機発光層の近傍が好ましい。このとき、回折格子の周期は、媒質中の光の波長の約１／２～３倍程度の範囲内が好ましい。回折格子の配列は、正方形のラチス状、三角形のラチス状、ハニカムラチス状など、二次元的に配列が繰り返されることが好ましい。 The position where the diffraction grating is introduced may be in any of the layers or in the medium (inside the transparent substrate or in the transparent electrode), but it is preferably in the vicinity of the organic light emitting layer where light is generated. At this time, the period of the diffraction grating is preferably in the range of about 1/2 to 3 times the wavelength of the light in the medium. As for the arrangement of the diffraction grating, it is preferable that the arrangement is repeated two-dimensionally, such as a square lattice shape, a triangular lattice shape, and a honeycomb lattice shape.
　《集光シート》
　本発明の有機ＥＬ素子は、支持基板（基板）の光取出し側に、例えばマイクロレンズアレイ上の構造を設けるように加工すること、又は、いわゆる集光シートと組み合わせることにより、特定方向、例えば素子発光面に対し正面方向に集光することにより、特定方向上の輝度を高めることができる。
　マイクロレンズアレイの例としては、基板の光取り出し側に一辺が３０μｍでその頂角が９０度となるような四角錐を二次元に配列する。一辺は１０～１００μｍの範囲内が好ましい。これより小さくなると回折の効果が発生して色付く、大きすぎると厚さが厚くなり好ましくない。 《Condensing sheet》
The organic EL element of the present invention is processed so as to provide a structure on a microlens array, for example, on the light extraction side of a support substrate (substrate), or by combining with a so-called condensing sheet, a specific direction, for example, an element By condensing light in the front direction with respect to the light emitting surface, it is possible to increase the brightness in a specific direction.
As an example of a microlens array, a quadrangular pyramid having a side of 30 μm and an apex angle of 90 degrees is arranged two-dimensionally on the light extraction side of the substrate. One side is preferably in the range of 10 to 100 μm. If it is smaller than this, the effect of diffraction is generated and it is colored, and if it is too large, the thickness becomes thick, which is not preferable.
　集光シートとしては、例えば液晶表示装置のＬＥＤバックライトで実用化されているものを用いることが可能である。このようなシートとして、例えば住友スリーエム社製輝度上昇フィルム（ＢＥＦ）などを用いることができる。プリズムシートの形状としては、例えば基材に頂角９０度、ピッチ５０μｍの△状のストライプが形成されたものであってもよいし、頂角が丸みを帯びた形状、ピッチをランダムに変化させた形状、その他の形状であってもよい。
　また、有機ＥＬ素子からの光放射角を制御するために光拡散板・フィルムを、集光シートと併用してもよい。例えば（株）きもと製拡散フィルム（ライトアップ）などを用いることができる。 As the condensing sheet, for example, a sheet that has been put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness increasing film (BEF) manufactured by Sumitomo 3M Ltd. can be used. The shape of the prism sheet may be, for example, a base material having a Δ-shaped stripe having an apex angle of 90 degrees and a pitch of 50 μm, or a shape having a rounded apex angle and a random pitch change. Shape or other shape may be used.
Further, the light diffusing plate / film may be used in combination with the condensing sheet in order to control the light emission angle from the organic EL element. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.
　（その他：タンデム構造を有する有機ＥＬ素子）
　本発明の有機ＥＬ素子は、少なくとも１層の発光層を含む発光ユニットを複数積層した、いわゆるタンデム構造の素子であってもよい。
　タンデム構造の代表的な素子構成としては、例えば以下の構成を挙げることができる。
　陽極／第１発光ユニット／第２発光ユニット／第３発光ユニット／陰極
　陽極／第１発光ユニット／中間層／第２発光ユニット／中間層／第３発光ユニット／陰極
　ここで、上記第１発光ユニット、第２発光ユニット及び第３発光ユニットは全て同じであっても、異なっていてもよい。また二つの発光ユニットが同じであり、残る一つが異なっていてもよい。
　また、第３発光ユニットはなくてもよく、一方で第３発光ユニットと電極の間にさらに発光ユニットや中間層を設けてもよい。 (Other: Organic EL element with tandem structure)
The organic EL device of the present invention may be a device having a so-called tandem structure in which a plurality of light emitting units including at least one light emitting layer are laminated.
As a typical element configuration of the tandem structure, for example, the following configuration can be mentioned.
Anode / 1st light emitting unit / 2nd light emitting unit / 3rd light emitting unit / cathode Anode / 1st light emitting unit / intermediate layer / 2nd light emitting unit / intermediate layer / 3rd light emitting unit / cathode Here, the first light emitting unit , The second light emitting unit and the third light emitting unit may all be the same or different. Further, the two light emitting units may be the same, and the remaining one may be different.
Further, the third light emitting unit may not be provided, while a light emitting unit or an intermediate layer may be further provided between the third light emitting unit and the electrode.
　複数の発光ユニットは直接積層されていても、中間層を介して積層されていてもよく、中間層は、一般的に中間電極、中間導電層、電荷発生層、電子引抜層、接続層、中間絶縁層とも呼ばれ、陽極側の隣接層に電子を、陰極側の隣接層に正孔を供給する機能を持った層であれば、公知の材料及び構成を用いることができる。 The plurality of light emitting units may be directly laminated or may be laminated via an intermediate layer, and the intermediate layer is generally an intermediate electrode, an intermediate conductive layer, a charge generation layer, an electron extraction layer, a connection layer, or an intermediate layer. A known material and structure can be used as long as it is also called an insulating layer and has a function of supplying electrons to the adjacent layer on the anode side and holes to the adjacent layer on the cathode side.
　中間層に用いられる材料としては、例えばＩＴＯ（インジウム・スズ酸化物）、ＩＺＯ（インジウム・亜鉛酸化物）、ＺｎＯ２、ＴｉＮ、ＺｒＮ、ＨｆＮ、ＴｉＯｘ、ＶＯｘ、ＣｕＩ、ＩｎＮ、ＧａＮ、ＣｕＡｌＯ２、ＣｕＧａＯ２、ＳｒＣｕ２Ｏ２、ＬａＢ６、ＲｕＯ２、Ａｌ等の導電性無機化合物層や、Ａｕ／Ｂｉ２Ｏ３等の２層膜や、ＳｎＯ２／Ａｇ／ＳｎＯ２、ＺｎＯ／Ａｇ／ＺｎＯ、Ｂｉ２Ｏ３／Ａｕ／Ｂｉ２Ｏ３、ＴｉＯ２／ＴｉＮ／ＴｉＯ２、ＴｉＯ２／ＺｒＮ／ＴｉＯ２等の多層膜、またＣ６０等のフラーレン類、オリゴチオフェン等の導電性有機物層、金属フタロシアニン類、無金属フタロシアニン類、金属ポルフィリン類、無金属ポルフィリン類等の導電性有機化合物層等が挙げられるが、本発明はこれらに限定されない。 Examples of the material used for the intermediate layer include ITO (inorganic tin oxide), IZO ( inorganic zinc oxide), ZnO 2 , TiN, ZrN, HfN, TiOx, VOx, CuI, InN, GaN, and CuAlO 2 . Conductive inorganic compound layers such as CuGaO 2 , SrCu 2 O 2 , LaB 6 , RuO 2 , Al, bilayer films such as Au / Bi 2 O 3 , SnO 2 / Ag / SnO 2 , ZnO / Ag / ZnO , Bi 2 O 3 / Au / Bi 2 O 3, TiO 2 / TiN / TiO 2, TiO 2 / ZrN / TiO 2 or the like multilayer film, also fullerenes such as C 60, conductive organic material layer such as oligothiophene, Examples thereof include conductive organic compound layers such as metallic phthalocyanines, metal-free phthalocyanines, metal porphyrins, and metal-free porphyrins, but the present invention is not limited thereto.
　発光ユニット内の好ましい構成としては、例えば上記の代表的な素子構成で挙げた（ｉ）～（ｖｉｉ）の構成から、陽極と陰極を除いたもの等が挙げられるが、本発明はこれらに限定されない。 Preferred configurations in the light emitting unit include, for example, configurations in which the anode and the cathode are removed from the configurations (i) to (vii) mentioned in the above typical element configurations, but the present invention is limited thereto. Not done.
　タンデム型有機ＥＬ素子の具体例としては、例えば米国特許第６３３７４９２号、米国特許第７４２０２０３号、米国特許第７４７３９２３号、米国特許第６８７２４７２号、米国特許第６１０７７３４号、米国特許第６３３７４９２号、国際公開第２００５／００９０８７号、特開２００６－２２８７１２号公報、特開２００６－２４７９１号公報、特開２００６－４９３９３号公報、特開２００６－４９３９４号公報、特開２００６－４９３９６号公報、特開２０１１－９６６７９号公報、特開２００５－３４０１８７号公報、特許第４７１１４２４号、特許第３４９６６８１号、特許第３８８４５６４号、特許第４２１３１６９号、特開２０１０－１９２７１９号公報、特開２００９－０７６９２９号公報、特開２００８－０７８４１４号公報、特開２００７－０５９８４８号公報、特開２００３－２７２８６０号公報、特開２００３－０４５６７６号公報、国際公開第２００５／０９４１３０号等に記載の素子構成や構成材料等が挙げられるが、本発明はこれらに限定されない。 Specific examples of the tandem organic EL element include, for example, US Pat. No. 6,337,492, US Pat. No. 7,420,203, US Pat. No. 7,473,923, US Pat. No. 6,872,472, US Patent No. 6107734, US Pat. No. 6,337,492, International Publication. 2005/09087, Japanese Patent Application Laid-Open No. 2006-228712, Japanese Patent Application Laid-Open No. 2006-24791, Japanese Patent Application Laid-Open No. 2006-49393, Japanese Patent Application Laid-Open No. 2006-49394, Japanese Patent Application Laid-Open No. 2006-49396, Japanese Patent Application Laid-Open No. 2011- 96679, 2005-340187, 4711424, 3496681, Patent 38845664, 421369, 2010-192719, 2009-076929, Japanese Patent Application Laid-Open No. 96679, JP-A-2005-340187 Examples thereof include element configurations and constituent materials described in Japanese Patent Application Laid-Open No. 2008-078441, Japanese Patent Application Laid-Open No. 2007-059848, Japanese Patent Application Laid-Open No. 2003-272860, Japanese Patent Application Laid-Open No. 2003-045676, International Publication No. 2005/094130, and the like. However, the present invention is not limited to these.
　（用途）
　本発明の有機ＥＬ素子は、表示デバイス、ディスプレイ、各種発光光源として用いることができる。
　発光光源として、例えば照明装置（家庭用照明、車内照明）、時計や液晶用バックライト、看板広告、信号機、光記憶媒体の光源、電子写真複写機の光源、光通信処理機の光源、光センサーの光源等が挙げられるがこれに限定するものではないが、特に液晶表示装置のバックライト、照明用光源としての用途に有効に用いることができる。
　本発明における有機ＥＬ素子においては、必要に応じ成膜時にメタルマスクやインクジェット印刷法等でパターニングを施してもよい。パターニングする場合は、電極のみをパターニングしてもよいし、電極と発光層をパターニングしてもよいし、素子全層をパターニングしてもよく、素子の作製においては、従来公知の方法を用いることができる。 (Use)
The organic EL element of the present invention can be used as a display device, a display, and various light emitting light sources.
As a light source, for example, a lighting device (household lighting, in-car lighting), a backlight for a clock or a liquid crystal, a signboard advertisement, a traffic light, a light source of an optical storage medium, a light source of an electrophotographic copying machine, a light source of an optical communication processor, an optical sensor. The light source is not limited to this, but can be effectively used as a backlight of a liquid crystal display device or a light source for lighting.
If necessary, the organic EL device of the present invention may be patterned by a metal mask, an inkjet printing method, or the like at the time of film formation. In the case of patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or all the layers of the device may be patterned. In the fabrication of the device, a conventionally known method is used. Can be done.
　《照明装置の一態様》
　本発明の有機ＥＬ素子を具備した、照明装置の一態様について説明する。
　前記有機ＥＬ素子の非発光面をガラスケースで覆い、厚さ３００μｍのガラス基板を封止用基板として用いて、周囲にシール材として、エポキシ系光硬化型接着剤（東亞合成社製ラックストラックＬＣ０６２９Ｂ）を適用し、これを陰極上に重ねて透明支持基板と密着させ、ガラス基板側からＵＶ光を照射して、硬化させて、封止し、図３、図４に示すような照明装置を形成することができる。 << One aspect of lighting equipment >>
An aspect of a lighting device including the organic EL element of the present invention will be described.
The non-light emitting surface of the organic EL element is covered with a glass case, a glass substrate having a thickness of 300 μm is used as a sealing substrate, and an epoxy-based photocurable adhesive (Luxtrac LC0629B manufactured by Toa Synthetic Co., Ltd.) is used as a sealing material around the glass substrate. ) Is applied, this is placed on the cathode and brought into close contact with the transparent support substrate, UV light is irradiated from the glass substrate side, the curing is performed, and the sealing is performed. Can be formed.
　図３は、照明装置の概略図を示し、本発明に係る有機ＥＬ素子（１０１）はガラスカバー（１０２）で覆われている（なお、ガラスカバーでの封止作業は、有機ＥＬ素子（１０１）を大気に接触させることなく窒素雰囲気下のグローブボックス（純度９９．９９９％以上の高純度窒素ガスの雰囲気下）で行った。）。
　図４は、照明装置の断面図を示し、図４において、（１０５）は陰極、（１０６）は有機ＥＬ層、（１０７）は透明電極付きガラス基板を示す。なお、ガラスカバー（１０２）内には窒素ガス（１０８）が充填され、捕水剤（１０９）が設けられている。 FIG. 3 shows a schematic view of the lighting device, and the organic EL element (101) according to the present invention is covered with a glass cover (102) (note that the sealing work with the glass cover is performed by the organic EL element (101). ) Was carried out in a glove box under a nitrogen atmosphere (under an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more) without contacting the air.
FIG. 4 shows a cross-sectional view of the lighting device, in which (105) shows a cathode, (106) shows an organic EL layer, and (107) shows a glass substrate with a transparent electrode. The glass cover (102) is filled with nitrogen gas (108), and a water catching agent (109) is provided.
　以下、実施例を挙げて本発明を具体的に説明するが、本発明はこれらに限定されるものではない。なお、実施例において「部」あるいは「％」の表示を用いるが、特に断りがない限り「質量部」あるいは「質量％」を表す。
　実施例及び比較例で用いた化合物を以下に示す。 Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the examples, the indication of "parts" or "%" is used, but unless otherwise specified, it indicates "parts by mass" or "% by mass".
The compounds used in Examples and Comparative Examples are shown below.
Figure JPOXMLDOC01-appb-C000010
Figure JPOXMLDOC01-appb-C000010
（実施例１）
　《有機ＥＬ素子の作製》
　〔有機ＥＬ素子（１－１）の作製〕
　陽極として、１００ｍｍ×１００ｍｍ×１．１ｍｍのガラス基板上に、ＩＴＯ（インジウム・スズ酸化物）を厚さ１００ｎｍの成膜を施した基板（ＮＨテクノグラス製ＮＡ４５）を用意し、その基板上にパターニングを行った。その後、このＩＴＯ透明電極を設けた基板をイソプロピルアルコールで超音波洗浄し、乾燥窒素ガスで乾燥し、さらにＵＶオゾン洗浄を５分間行った。 (Example 1)
<< Fabrication of organic EL elements >>
[Manufacturing of organic EL element (1-1)]
As an anode, a substrate (NA45 manufactured by NH Technoglass) having a film formation of ITO (indium tin oxide) having a thickness of 100 nm was prepared on a glass substrate of 100 mm × 100 mm × 1.1 mm, and the substrate was placed on the substrate. Patterning was performed. Then, the substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and further subjected to UV ozone cleaning for 5 minutes.
　この基板上に、ポリ（３，４－エチレンジオキシチオフェン）－ポリスチレンスルホネート（ＰＥＤＯＴ／ＰＳＳ、Ｂａｙｅｒ製、Ｂａｙｔｒｏｎ　Ｐ　Ａｌ　４０８３）を純水で７０％に希釈した溶液を３０００ｒｐｍ、３０秒でスピンコート法により成膜した後、２００℃にて１時間乾燥し、厚さ３０ｎｍの正孔輸送層を設けた。 A solution of poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, manufactured by Bayer, Baytron P Al 4083) diluted to 70% with pure water was spin-coated on this substrate at 3000 rpm for 30 seconds. After forming a film by the method, it was dried at 200 ° C. for 1 hour to provide a hole transport layer having a thickness of 30 nm.
　この基板を窒素雰囲気下に移し、下記の発光性ドーパント層組成物１を正孔輸送層上に５００ｒｐｍ、１２０秒の条件下、スピンコート法により成膜（厚さ約１００ｎｍ）し、１２０℃で９０分間加熱乾燥し、発光層を形成した。 This substrate was transferred to a nitrogen atmosphere, and the following luminescent dopant layer composition 1 was formed on the hole transport layer at 500 rpm for 120 seconds by a spin coating method (thickness: about 100 nm) at 120 ° C. It was heated and dried for 90 minutes to form a light emitting layer.
（発光性ドーパント層組成物１）
　４ＣｚＩＰＮ　　　　　　　　　　　　　　　　　　　　　　　　５．０質量部
　ポリスチレン　　　　　　　　　　　　　　　　　　　　　　　　７．５質量部
　ジエチレングリコール　　　　　　　　　　　　　　　　　　　　１００質量部 (Luminescent Dopant Layer Composition 1)
4CzIPN 5.0 parts by mass Polystyrene 7.5 parts by mass Diethylene glycol 100 parts by mass
　この基板を真空蒸着装置の基板ホルダーに固定し、真空槽を４×１０－４Ｐａまで減圧した後、Ａｇを蒸着して厚さ１００ｎｍの陰極を形成し、有機ＥＬ素子（１－１）を作製した。 This substrate is fixed to the substrate holder of the vacuum vapor deposition apparatus, the vacuum chamber is depressurized to 4 × 10 -4 Pa, and then Ag is vapor-deposited to form a cathode having a thickness of 100 nm, and the organic EL element (1-1) is formed. Made.
　〔有機ＥＬ素子（１－２）～（１－５）の作製〕
　有機ＥＬ素子１の作製において、発光性ドーパント層組成物１の発光性ドーパントとホスト化合物を表Iのように変化させた以外は同様にして、有機ＥＬ素子（１－２）～（１－５）を作製した。 [Manufacturing of organic EL elements (1-2) to (1-5)]
In the production of the organic EL element 1, the organic EL elements (1-2) to (1-5) are similarly changed except that the luminescent dopant and the host compound of the luminescent dopant layer composition 1 are changed as shown in Table I. ) Was prepared.
　〔有機ＥＬ素子（１－６）の作製〕
　陽極として、１００ｍｍ×１００ｍｍ×１．１ｍｍのガラス基板上に、ＩＴＯ（酸化インジウム・スズ）を厚さ１００ｎｍの成膜を施した基板（ＮＨテクノグラス製ＮＡ４５）を用意し、その基板上にパターニングを行った。その後、このＩＴＯ透明電極を設けた基板をイソプロピルアルコールで超音波洗浄し、乾燥窒素ガスで乾燥し、さらにＵＶオゾン洗浄を５分間行った。
　この基板上に、ポリ（３，４－エチレンジオキシチオフェン）－ポリスチレンスルホネート（ＰＥＤＯＴ／ＰＳＳ、Ｂａｙｅｒ製、Ｂａｙｔｒｏｎ　Ｐ　Ａｌ　４０８３）を純水で７０％に希釈した溶液を３０００ｒｐｍ、３０秒でスピンコート法により成膜した後、２００℃にて１時間乾燥し、厚さ３０ｎｍの正孔輸送層を設けた。 [Manufacturing of organic EL element (1-6)]
As an anode, a substrate (NA45 manufactured by NH Technoglass) in which ITO (indium tin oxide) is formed into a film having a thickness of 100 nm is prepared on a glass substrate of 100 mm × 100 mm × 1.1 mm, and patterning is performed on the substrate. Was done. Then, the substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and further subjected to UV ozone cleaning for 5 minutes.
A solution of poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, manufactured by Bayer, Baytron P Al 4083) diluted to 70% with pure water was spin-coated on this substrate at 3000 rpm for 30 seconds. After forming a film by the method, it was dried at 200 ° C. for 1 hour to provide a hole transport layer having a thickness of 30 nm.
　この基板を窒素雰囲気下に移し、正孔輸送層上に８０ｍｇのポリスチレンを１０ｍｌのジエチレングリコールジメチルエーテルに溶解した溶液を５００ｒｐｍ、１２０秒の条件下、スピンコート法により成膜（厚さ約６０ｎｍ）し、１２０℃で９０分間加熱乾燥し、ホスト層とした。 This substrate was transferred to a nitrogen atmosphere, and a solution of 80 mg of polystyrene dissolved in 10 ml of diethylene glycol dimethyl ether was formed on a hole transport layer by a spin coating method at 500 rpm for 120 seconds (thickness: about 60 nm). It was heated and dried at 120 ° C. for 90 minutes to prepare a host layer.
　さらに、下記の発光性ドーパント層組成物２をインクジェットヘッド（エプソン製；ＭＪ８００Ｃ）を用いてウェット膜厚が４μｍになるように吐出注入した。この基板を、上下隔壁を設け、隔壁上部と下部とにそれぞれ独立の乾燥風温度調整機を備えた乾燥箱の基板ホルダーに固定し、基板上面（発光層塗布面）に１２０℃に制御した加熱乾燥窒素を循環させ、基板裏面側は８０℃に制御した加熱乾燥窒素を循環させた。この状態で、１０分間の乾燥処理を施した。なお、基板両面にそれぞれ循環させた乾燥窒素の温度は乾燥開始から終了まで±１℃以内に制御されていることを確認した。別途作製した基板をＴＯＦ－ＳＩＭＳにより分析することで、下記ドーパント層組成物を吐出注入時、ホスト層がドーパント層組成物中のクロロホルムに一部溶解し、ホスト層とドーパント層の界面がなくなっていることが分かった。 Further, the following luminescent dopant layer composition 2 was ejected and injected using an inkjet head (manufactured by Epson; MJ800C) so that the wet film thickness was 4 μm. This substrate is fixed to a substrate holder of a drying box provided with upper and lower partition walls and independent drying air temperature regulators at the upper and lower portions of the partition wall, and heating is controlled to 120 ° C. on the upper surface of the substrate (light emitting layer coating surface). Dry nitrogen was circulated, and heat-dried nitrogen controlled at 80 ° C. was circulated on the back surface side of the substrate. In this state, a drying treatment was performed for 10 minutes. It was confirmed that the temperature of the dry nitrogen circulated on both sides of the substrate was controlled within ± 1 ° C. from the start to the end of drying. By analyzing the separately prepared substrate by TOF-SIMS, when the following dopant layer composition is discharged and injected, the host layer is partially dissolved in chloroform in the dopant layer composition, and the interface between the host layer and the dopant layer disappears. It turned out that there was.
（発光性ドーパント層組成物２）
　４ＣｚＩＰＮ　　　　　　　　　　　　　　　　　　　　　　　　５．０質量部
　クロロホルム　　　　　　　　　　　　　　　　　　　　　　　　１００質量部 (Luminescent Dopant Layer Composition 2)
4CzIPN 5.0 parts by mass Chloroform 100 parts by mass
　この基板を真空蒸着装置の基板ホルダーに固定し、真空槽を４×１０－４Ｐａまで減圧した後、Ａｇを蒸着して厚さ１００ｎｍの陰極を形成し、有機ＥＬ素子（１－６）を作製した。 This substrate is fixed to the substrate holder of the vacuum vapor deposition apparatus, the vacuum chamber is depressurized to 4 × 10 -4 Pa, and then Ag is vapor-deposited to form a cathode having a thickness of 100 nm, and the organic EL element (1-6) is formed. Made.
　〔有機ＥＬ素子（１－７）の作製〕
　陽極として、１００ｍｍ×１００ｍｍ×１．１ｍｍのガラス基板上に、ＩＴＯ（酸化インジウム・スズ）を厚さ１００ｎｍの成膜を施した基板（ＮＨテクノグラス製ＮＡ４５）を用意し、その基板上にパターニングを行った。その後、このＩＴＯ透明電極を設けた基板をイソプロピルアルコールで超音波洗浄し、乾燥窒素ガスで乾燥し、さらにＵＶオゾン洗浄を５分間行った。
　この基板上に、ポリ（３，４－エチレンジオキシチオフェン）－ポリスチレンスルホネート（ＰＥＤＯＴ／ＰＳＳ、Ｂａｙｅｒ製、Ｂａｙｔｒｏｎ　Ｐ　Ａｌ　４０８３）を純水で７０％に希釈した溶液を３０００ｒｐｍ、３０秒でスピンコート法により成膜した後、２００℃にて１時間乾燥し、厚さ３０ｎｍの正孔輸送層を設けた。 [Manufacturing of organic EL element (1-7)]
As an anode, a substrate (NA45 manufactured by NH Technoglass) in which ITO (indium tin oxide) is formed into a film having a thickness of 100 nm is prepared on a glass substrate of 100 mm × 100 mm × 1.1 mm, and patterning is performed on the substrate. Was done. Then, the substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and further subjected to UV ozone cleaning for 5 minutes.
A solution of poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, manufactured by Bayer, Baytron P Al 4083) diluted to 70% with pure water was spin-coated on this substrate at 3000 rpm for 30 seconds. After forming a film by the method, it was dried at 200 ° C. for 1 hour to provide a hole transport layer having a thickness of 30 nm.
　この基板を窒素雰囲気下に移し、正孔輸送層上に８０ｍｇのポリスチレンを１０ｍｌのジエチレングリコールジメチルエーテルに溶解した溶液を５００ｒｐｍ、１２０秒の条件下、スピンコート法により成膜（厚さ約６０ｎｍ）し、１２０℃で９０分間加熱乾燥し、ホスト層とした。 This substrate was transferred to a nitrogen atmosphere, and a solution of 80 mg of polystyrene dissolved in 10 ml of diethylene glycol dimethyl ether was formed on a hole transport layer by a spin coating method at 500 rpm for 120 seconds (thickness: about 60 nm). It was heated and dried at 120 ° C. for 90 minutes to prepare a host layer.
　さらに、下記の発光性ドーパント層組成物３をインクジェットヘッド（エプソン製；ＭＪ８００Ｃ）を用いてウェット膜厚が４μｍになるように吐出注入した。この基板を、上下隔壁を設け、隔壁上部と下部とにそれぞれ独立の乾燥風温度調整機を備えた乾燥箱の基板ホルダーに固定し、基板上面（発光層塗布面）に１２０℃に制御した加熱乾燥窒素を循環させ、基板裏面側は８０℃に制御した加熱乾燥窒素を循環させた。この状態で、１０分間の乾燥処理を施すことにより発光性ドーパント層を乾燥させた。なお、基板両面にそれぞれ循環させた乾燥窒素の温度は乾燥開始から終了まで±１℃以内に制御されていることを確認した。この際、別途作製した基板をＴＯＦ－ＳＩＭＳにより分析することで、ホスト層の上に発光層が積層していることが分かった。 Further, the following luminescent dopant layer composition 3 was ejected and injected using an inkjet head (manufactured by Epson; MJ800C) so that the wet film thickness was 4 μm. This substrate is fixed to a substrate holder of a drying box provided with upper and lower partition walls and independent drying air temperature regulators at the upper and lower portions of the partition wall, and heating is controlled to 120 ° C. on the upper surface of the substrate (light emitting layer coating surface). Dry nitrogen was circulated, and heat-dried nitrogen controlled at 80 ° C. was circulated on the back surface side of the substrate. In this state, the luminescent dopant layer was dried by performing a drying treatment for 10 minutes. It was confirmed that the temperature of the dry nitrogen circulated on both sides of the substrate was controlled within ± 1 ° C. from the start to the end of drying. At this time, by analyzing the separately prepared substrate by TOF-SIMS, it was found that the light emitting layer was laminated on the host layer.
（発光性ドーパント層組成物３）
　４ＣｚＩＰＮ　　　　　　　　　　　　　　　　　　　　　　　　５．０質量部
　トルエン　　　　　　　　　　　　　　　　　　　　　　　　　　１００質量部 (Luminescent Dopant Layer Composition 3)
4CzIPN 5.0 parts by mass Toluene 100 parts by mass
　次に、この基板をホットプレート上に載せて、１７０℃で１時間加熱してホスト層を融解させ、ホスト化合物及び発光性ドーパントの組成が厚さ方向で連続的に変化しており、陰極側から陽極側に向かって、発光性ドーパントの濃度が連続的に減少している発光層を形成した。 Next, this substrate is placed on a hot plate and heated at 170 ° C. for 1 hour to melt the host layer, and the compositions of the host compound and the luminescent dopant are continuously changed in the thickness direction on the cathode side. A light emitting layer was formed in which the concentration of the light emitting dopant was continuously decreased from the to the anode side.
　この基板を真空蒸着装置の基板ホルダーに固定し、真空槽を４×１０－４Ｐａまで減圧した後、Ａｇを蒸着して厚さ１００ｎｍの陰極を形成し、有機ＥＬ素子（１－７）を作製した。 This substrate is fixed to the substrate holder of the vacuum vapor deposition apparatus, the vacuum chamber is depressurized to 4 × 10 -4 Pa, and then Ag is vapor-deposited to form a cathode having a thickness of 100 nm, and the organic EL element (1-7) is formed. Made.
　〔有機ＥＬ素子（１－８）～（１－１１）の作製〕
　有機ＥＬ素子（１－７）の作製において、発光性ドーパント層組成物２の発光性ドーパントとホスト化合物を表Iのように変化させた以外は同様にして、有機ＥＬ素子（１－８）～（１－１１）を作製した。 [Manufacturing of organic EL elements (1-8) to (1-11)]
In the production of the organic EL element (1-7), the organic EL element (1-8) to the organic EL element (1-8) to the same except that the luminescent dopant and the host compound of the luminescent dopant layer composition 2 were changed as shown in Table I. (1-11) was prepared.
　《有機ＥＬ素子の評価》
　作製した有機ＥＬ素子について、下記のようにして発光輝度及び輝度ムラを評価した。 << Evaluation of organic EL elements >>
With respect to the produced organic EL element, the emission brightness and the brightness unevenness were evaluated as follows.
　〔発光性ドーパントの濃度分布〕
　得られた有機ＥＬ素子の発光層中に含まれる発光性ドーパントの濃度分布は、ＴＯＦ－ＳＩＭＳ（飛行時間型二次イオン質量分析）（測定装置：Ｐｈｙｓｉｃａｌ　Ｅｌｅｃｔｒｏｎｉｃｓ社製　２１００ＴＲＩＦＴ２　一次イオン：Ｇａ　一次イオン加速電圧：２５ｋＶ　一次イオン電流：２ｐＡ　ラスター範囲：２０μｍ　測定質量数：０．５－１０００Ｄａ　測定温度：－１００℃）により、層厚方向での発光性ドーパントの分析することで検出した。 [Concentration distribution of luminescent dopant]
The concentration distribution of the luminescent dopant contained in the light emitting layer of the obtained organic EL element is TOF-SIMS (time-of-flight secondary ion mass spectrometry) (measuring device: Physical Electricals 2100TRIFT2 primary ion: Ga primary ion acceleration. voltage: 25 kV primary ion current: 2 pA raster range: 20 [mu] m measured mass number: 0.5 - 1000 Da measurement temperature: - by 100 ° C.), was detected by analyzing the luminescent dopant in the layer thickness direction.
　〔発光輝度〕
　上記作製した各有機ＥＬ素子を、室温（約２５℃）で、０．５ｍＡ／ｃｍ２の定電流条件下で発光させ、発光輝度を分光放射輝度計ＣＳ－２０００（コニカミノルタ社製）を用い、０．０１ｍ間隔で位置を変えて１００点測定した。１００点の測定値の平均を各素子の発光輝度とした。表Iに、得られた発光輝度の相対値（有機ＥＬ素子（１－１）の発光輝度に対する相対値）を示した。 [Emission brightness]
Each of the above-produced organic EL elements is made to emit light at room temperature (about 25 ° C.) under a constant current condition of 0.5 mA / cm 2 , and the emission brightness is measured using a spectral radiance meter CS-2000 (manufactured by Konica Minolta). , 100 points were measured by changing the position at intervals of 0.01 m. The average of the measured values at 100 points was taken as the emission brightness of each element. Table I shows the relative values of the obtained emission luminance (relative values to the emission luminance of the organic EL element (1-1)).
　〔輝度の均一性〕
　上記作製した各有機ＥＬ素子を、室温（約２５℃）で、０．５ｍＡ／ｃｍ２の定電流条件下で発光させ、発光輝度を分光放射輝度計ＣＳ－２０００（コニカミノルタ社製）を用い、０．０１ｍ間隔で位置を変えて１００点測定した。１００点の測定値のうち、最大輝度値、最小輝度値、平均輝度値を求めて、下記式により輝度のばらつきを求め、輝度の均一性を評価した。
　輝度のばらつき＝｛（最大輝度値－最小輝度値）／平均輝度｝×１００ [Brightness uniformity]
Each of the above-produced organic EL elements is made to emit light at room temperature (about 25 ° C.) under a constant current condition of 0.5 mA / cm 2 , and the emission brightness is measured using a spectral radiance meter CS-2000 (manufactured by Konica Minolta). , 100 points were measured by changing the position at intervals of 0.01 m. Of the 100 measured values, the maximum brightness value, the minimum brightness value, and the average brightness value were obtained, the variation in brightness was obtained by the following formula, and the uniformity of brightness was evaluated.
Luminance variation = {(maximum brightness value-minimum brightness value) / average brightness} x 100
　求めた輝度のばらつきから、乾燥の均一性を下記のように評価した。
　○：輝度のばらつきが１．０未満であり、均一に成膜ができている。
　×：輝度のばらつきが１．０以上であり、均一に成膜ができていない。 From the obtained variation in brightness, the uniformity of drying was evaluated as follows.
◯: The variation in brightness is less than 1.0, and the film is uniformly formed.
X: The variation in brightness is 1.0 or more, and the film is not uniformly formed.
　下記表Iは、評価結果を示している。
Figure JPOXMLDOC01-appb-T000011
 Table I below shows the evaluation results.
Figure JPOXMLDOC01-appb-T000011
　表Iに示すように、比較例の素子（１－１）及び（１－６）と本発明の（１－７）との対比、同様に、素子（１－２）と（１－９）との対比、素子（１－３）と（１－１０）との対比、素子（１－４）と（１－１１）との対比、及び素子（１－５）と（１－８）との対比から、本発明の有機ＥＬ素子（１－７）～（１－１１）によれば、輝度のばらつきを抑えることができ、発光輝度が優れていることが分かる。
　なお、比較例の有機ＥＬ素子（１－６）は、発光性ドーパント液にホスト層が残存溶媒に溶解したことにより膜厚ムラが生じ、そのため輝度のばらつきが大きくなったと推測される。 As shown in Table I, the comparison between the elements (1-1) and (1-6) of the comparative example and (1-7) of the present invention, as well as the elements (1-2) and (1-9). Contrast with, element (1-3) and (1-10), element (1-4) and (1-11), and element (1-5) and (1-8) From the comparison of the above, it can be seen that according to the organic EL elements (1-7) to (1-11) of the present invention, the variation in brightness can be suppressed and the emission brightness is excellent.
In the organic EL element (1-6) of the comparative example, it is presumed that the film thickness unevenness occurred due to the host layer being dissolved in the residual solvent in the luminescent dopant solution, and as a result, the brightness variation became large.
（実施例２）
　《有機ＥＬ素子の作製》
　〔有機ＥＬ素子（２－１）の作製〕
　陽極として、１００ｍｍ×１００ｍｍ×１．１ｍｍのガラス基板上に、ＩＴＯ（インジウム・スズ酸化物）を厚さ１００ｎｍの成膜を施した基板（ＮＨテクノグラス製ＮＡ４５）を用意し、その基板上にパターニングを行った。その後、このＩＴＯ透明電極を設けた基板をイソプロピルアルコールで超音波洗浄し、乾燥窒素ガスで乾燥し、さらにＵＶオゾン洗浄を５分間行った。 (Example 2)
<< Fabrication of organic EL elements >>
[Manufacturing of organic EL element (2-1)]
As an anode, a substrate (NA45 manufactured by NH Technoglass) having a film formation of ITO (indium tin oxide) having a thickness of 100 nm was prepared on a glass substrate of 100 mm × 100 mm × 1.1 mm, and the substrate was placed on the substrate. Patterning was performed. Then, the substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and further subjected to UV ozone cleaning for 5 minutes.
　この基板上に、ポリ（３，４－エチレンジオキシチオフェン）－ポリスチレンスルホネート（ＰＥＤＯＴ／ＰＳＳ、Ｂａｙｅｒ製、Ｂａｙｔｒｏｎ　Ｐ　Ａｌ　４０８３）を純水で７０％に希釈した溶液を３０００ｒｐｍ、３０秒でスピンコート法により成膜した後、２００℃にて１時間乾燥し、厚さ３０ｎｍの正孔輸送層を設けた。 A solution of poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, manufactured by Bayer, Baytron P Al 4083) diluted to 70% with pure water was spin-coated on this substrate at 3000 rpm for 30 seconds. After forming a film by the method, it was dried at 200 ° C. for 1 hour to provide a hole transport layer having a thickness of 30 nm.
　この基板を窒素雰囲気下に移し、下記の発光性ドーパント層組成物１を正孔輸送層上に５００ｒｐｍ、１２０秒の条件下、スピンコート法により成膜（厚さ約１００ｎｍ）し、１２０℃で９０分間加熱乾燥し、発光層を形成した。 This substrate was transferred to a nitrogen atmosphere, and the following luminescent dopant layer composition 1 was formed on the hole transport layer at 500 rpm for 120 seconds by a spin coating method (thickness: about 100 nm) at 120 ° C. It was heated and dried for 90 minutes to form a light emitting layer.
（発光性ドーパント層組成物１）
　４ＣｚＩＰＮ　　　　　　　　　　　　　　　　　　　　　　　　５．０質量部
　ポリスチレン　　　　　　　　　　　　　　　　　　　　　　　　７．５質量部
　ジエチレングリコール　　　　　　　　　　　　　　　　　　　　１００質量部 (Luminescent Dopant Layer Composition 1)
4CzIPN 5.0 parts by mass Polystyrene 7.5 parts by mass Diethylene glycol 100 parts by mass
　次に、この基板を市販の真空蒸着装置の基板ホルダーに固定した。
　真空蒸着装置内の蒸着用るつぼの各々に、各層の構成材料を、各々素子作製に最適の量を充填した。蒸着用るつぼはモリブデン製又はタングステン製の抵抗加熱用材料で作製されたものを用いた。
　真空度１×１０－４Ｐａまで減圧した後、ＳＦ３－ＴＲＺを蒸着速度１．０ｎｍ／秒で蒸着し、層厚５ｎｍの正孔阻止層を形成した。 Next, this substrate was fixed to a substrate holder of a commercially available vacuum vapor deposition apparatus.
Each of the crucibles for vapor deposition in the vacuum vapor deposition apparatus was filled with the constituent materials of each layer in the optimum amount for manufacturing the device. As the crucible for vapor deposition, a crucible made of molybdenum or tungsten made of a resistance heating material was used.
After depressurizing to a vacuum degree of 1 × 10 -4 Pa, SF3-TRZ was vapor-deposited at a vapor deposition rate of 1.0 nm / sec to form a hole blocking layer having a layer thickness of 5 nm.
　その後、ＳＦ３－ＴＲＺとＬｉＱ（８－ヒドロキシキノリノラト－リチウム）が、それぞれ５０％、５０％のモル％になるように蒸着速度１．０ｎｍ／秒で共蒸着し、層厚３０ｎｍの電子輸送層を形成した。 Then, SF3-TRZ and LiQ (8-hydroxyquinolinolato-lithium) are co-deposited at a vapor deposition rate of 1.0 nm / sec so as to be 50% and 50% mol%, respectively, and electron transport with a layer thickness of 30 nm. A layer was formed.
　さらに、フッ化リチウムを膜厚０．５ｎｍで形成した後に、アルミニウム１００ｎｍを蒸着して陰極を形成した。
　上記素子の非発光面側を、純度９９．９９９％以上の高純度窒素ガスの雰囲気下で、缶状ガラスケースで覆い、電極取り出し配線を設置して、有機ＥＬ素子（２－１）を作製した。 Further, after forming lithium fluoride with a film thickness of 0.5 nm, aluminum 100 nm was vapor-deposited to form a cathode.
The non-light emitting surface side of the element is covered with a can-shaped glass case in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more, and an electrode take-out wiring is installed to manufacture an organic EL element (2-1). did.
　〔有機ＥＬ素子（２－２）～（２－５）の作製〕
　有機ＥＬ素子（２－１）の作製において、発光性ドーパント層組成物１の発光性ドーパントとホスト化合物を表Iのように変化させた以外は同様にして、有機ＥＬ素子（２－２）～（２－５）を作製した。 [Manufacturing of organic EL elements (2-2) to (2-5)]
In the production of the organic EL device (2-1), the organic EL device (2-2) to the same except that the luminescent dopant and the host compound of the luminescent dopant layer composition 1 were changed as shown in Table I. (2-5) was prepared.
　〔有機ＥＬ素子（２－６）の作製〕
　陽極として、１００ｍｍ×１００ｍｍ×１．１ｍｍのガラス基板上に、ＩＴＯ（酸化インジウム・スズ）を厚さ１００ｎｍの成膜を施した基板（ＮＨテクノグラス製ＮＡ４５）を用意し、その基板上にパターニングを行った。その後、このＩＴＯ透明電極を設けた基板をイソプロピルアルコールで超音波洗浄し、乾燥窒素ガスで乾燥し、さらにＵＶオゾン洗浄を５分間行った。
　この基板上に、ポリ（３，４－エチレンジオキシチオフェン）－ポリスチレンスルホネート（ＰＥＤＯＴ／ＰＳＳ、Ｂａｙｅｒ製、Ｂａｙｔｒｏｎ　Ｐ　Ａｌ　４０８３）を純水で７０％に希釈した溶液を３０００ｒｐｍ、３０秒でスピンコート法により成膜した後、２００℃にて１時間乾燥し、厚さ３０ｎｍの正孔輸送層を設けた。 [Manufacturing of organic EL element (2-6)]
As an anode, a substrate (NA45 manufactured by NH Technoglass) in which ITO (indium tin oxide) is formed into a film having a thickness of 100 nm is prepared on a glass substrate of 100 mm × 100 mm × 1.1 mm, and patterning is performed on the substrate. Was done. Then, the substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and further subjected to UV ozone cleaning for 5 minutes.
A solution of poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, manufactured by Bayer, Baytron P Al 4083) diluted to 70% with pure water was spin-coated on this substrate at 3000 rpm for 30 seconds. After forming a film by the method, it was dried at 200 ° C. for 1 hour to provide a hole transport layer having a thickness of 30 nm.
　この基板を窒素雰囲気下に移し、正孔輸送層上に８０ｍｇのポリスチレンを１０ｍｌのジエチレングリコールジメチルエーテルに溶解した溶液を５００ｒｐｍ、１２０秒の条件下、スピンコート法により成膜（厚さ約６０ｎｍ）し、１２０℃で９０分間加熱乾燥し、ホスト層とした。 This substrate was transferred to a nitrogen atmosphere, and a solution of 80 mg of polystyrene dissolved in 10 ml of diethylene glycol dimethyl ether was formed on a hole transport layer by a spin coating method at 500 rpm for 120 seconds (thickness: about 60 nm). It was heated and dried at 120 ° C. for 90 minutes to prepare a host layer.
　さらに、下記の発光性ドーパント層組成物２をインクジェットヘッド（エプソン製；ＭＪ８００Ｃ）を用いてウェット膜厚が４μｍになるように吐出注入した。この基板を、上下隔壁を設け、隔壁上部と下部とにそれぞれ独立の乾燥風温度調整機を備えた乾燥箱の基板ホルダーに固定し、基板上面（発光層塗布面）に１２０℃に制御した加熱乾燥窒素を循環させ、基板裏面側は８０℃に制御した加熱乾燥窒素を循環させた。この状態で、１０分間の乾燥処理を施した。なお、基板両面にそれぞれ循環させた乾燥窒素の温度は乾燥開始から終了まで±１℃以内に制御されていることを確認した。別途作製した基板をＴＯＦ－ＳＩＭＳにより分析することで、ドーパント層を吐出注入時、ホスト層がドーパント層組成物中のクロロホルムに一部溶解し、ホスト層とドーパント層の界面がなくなっていることが分かった。 Further, the following luminescent dopant layer composition 2 was ejected and injected using an inkjet head (manufactured by Epson; MJ800C) so that the wet film thickness was 4 μm. This substrate is fixed to a substrate holder of a drying box provided with upper and lower partition walls and independent drying air temperature regulators at the upper and lower portions of the partition wall, and heating is controlled to 120 ° C. on the upper surface of the substrate (light emitting layer coating surface). Dry nitrogen was circulated, and heat-dried nitrogen controlled at 80 ° C. was circulated on the back surface side of the substrate. In this state, a drying treatment was performed for 10 minutes. It was confirmed that the temperature of the dry nitrogen circulated on both sides of the substrate was controlled within ± 1 ° C. from the start to the end of drying. By analyzing the separately prepared substrate by TOF-SIMS, when the dopant layer is ejected and injected, the host layer is partially dissolved in chloroform in the dopant layer composition, and the interface between the host layer and the dopant layer disappears. Do you get it.
（発光性ドーパント層組成物２）
　４ＣｚＩＰＮ　　　　　　　　　　　　　　　　　　　　　　　　５．０質量部
　クロロホルム　　　　　　　　　　　　　　　　　　　　　　　　１００質量部 (Luminescent Dopant Layer Composition 2)
4CzIPN 5.0 parts by mass Chloroform 100 parts by mass
　次に、この基板を市販の真空蒸着装置の基板ホルダーに固定した。
　真空蒸着装置内の蒸着用るつぼの各々に、各層の構成材料を、各々素子作製に最適の量を充填した。蒸着用るつぼはモリブデン製又はタングステン製の抵抗加熱用材料で作製されたものを用いた。
　真空度１×１０－４Ｐａまで減圧した後、ＳＦ３－ＴＲＺを蒸着速度１．０ｎｍ／秒で蒸着し、層厚５ｎｍの正孔阻止層を形成した。 Next, this substrate was fixed to a substrate holder of a commercially available vacuum vapor deposition apparatus.
Each of the crucibles for vapor deposition in the vacuum vapor deposition apparatus was filled with the constituent materials of each layer in the optimum amount for manufacturing the device. As the crucible for vapor deposition, a crucible made of molybdenum or tungsten made of a resistance heating material was used.
After depressurizing to a vacuum degree of 1 × 10 -4 Pa, SF3-TRZ was vapor-deposited at a vapor deposition rate of 1.0 nm / sec to form a hole blocking layer having a layer thickness of 5 nm.
　その後、ＳＦ３－ＴＲＺとＬｉＱ（８－ヒドロキシキノリノラト－リチウム）が、それぞれ５０％、５０％のモル％になるように蒸着速度１．０ｎｍ／秒で共蒸着し、層厚３０ｎｍの電子輸送層を形成した。 Then, SF3-TRZ and LiQ (8-hydroxyquinolinolato-lithium) are co-deposited at a vapor deposition rate of 1.0 nm / sec so as to be 50% and 50% mol%, respectively, and electron transport with a layer thickness of 30 nm. A layer was formed.
　さらに、フッ化リチウムを膜厚０．５ｎｍで形成した後に、アルミニウム１００ｎｍを蒸着して陰極を形成した。
　上記素子の非発光面側を、純度９９．９９９％以上の高純度窒素ガスの雰囲気下で、缶状ガラスケースで覆い、電極取り出し配線を設置して、有機ＥＬ素子（２－６）を作製した。 Further, after forming lithium fluoride with a film thickness of 0.5 nm, aluminum 100 nm was vapor-deposited to form a cathode.
The non-light emitting surface side of the element is covered with a can-shaped glass case in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more, and an electrode take-out wiring is installed to manufacture an organic EL element (2-6). did.
　〔有機ＥＬ素子（２－７）の作製〕
　陽極として、１００ｍｍ×１００ｍｍ×１．１ｍｍのガラス基板上に、ＩＴＯ（酸化インジウム・スズ）を厚さ１００ｎｍの成膜を施した基板（ＮＨテクノグラス製ＮＡ４５）を用意し、その基板上にパターニングを行った。その後、このＩＴＯ透明電極を設けた基板をイソプロピルアルコールで超音波洗浄し、乾燥窒素ガスで乾燥し、さらにＵＶオゾン洗浄を５分間行った。
　この基板上に、ポリ（３，４－エチレンジオキシチオフェン）－ポリスチレンスルホネート（ＰＥＤＯＴ／ＰＳＳ、Ｂａｙｅｒ製、Ｂａｙｔｒｏｎ　Ｐ　Ａｌ　４０８３）を純水で７０％に希釈した溶液を３０００ｒｐｍ、３０秒でスピンコート法により成膜した後、２００℃にて１時間乾燥し、厚さ３０ｎｍの正孔輸送層を設けた。 [Manufacturing of organic EL element (2-7)]
As an anode, a substrate (NA45 manufactured by NH Technoglass) in which ITO (indium tin oxide) is formed into a film having a thickness of 100 nm is prepared on a glass substrate of 100 mm × 100 mm × 1.1 mm, and patterning is performed on the substrate. Was done. Then, the substrate provided with the ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and further subjected to UV ozone cleaning for 5 minutes.
A solution of poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, manufactured by Bayer, Baytron P Al 4083) diluted to 70% with pure water was spin-coated on this substrate at 3000 rpm for 30 seconds. After forming a film by the method, it was dried at 200 ° C. for 1 hour to provide a hole transport layer having a thickness of 30 nm.
　この基板を窒素雰囲気下に移し、正孔輸送層上に８０ｍｇのポリスチレンを１０ｍｌのジエチレングリコールジメチルエーテルに溶解した溶液を５００ｒｐｍ、１２０秒の条件下、スピンコート法により成膜（厚さ約６０ｎｍ）し、１２０℃で９０分間加熱乾燥し、ホスト層とした。 This substrate was transferred to a nitrogen atmosphere, and a solution of 80 mg of polystyrene dissolved in 10 ml of diethylene glycol dimethyl ether was formed on a hole transport layer by a spin coating method at 500 rpm for 120 seconds (thickness: about 60 nm). It was heated and dried at 120 ° C. for 90 minutes to prepare a host layer.
　さらに、下記の発光性ドーパント層組成物３をインクジェットヘッド（エプソン製；ＭＪ８００Ｃ）を用いてウェット膜厚が４μｍになるように吐出注入した。この基板を、上下隔壁を設け、隔壁上部と下部とにそれぞれ独立の乾燥風温度調整機を備えた乾燥箱の基板ホルダーに固定し、基板上面（発光層塗布面）に１２０℃に制御した加熱乾燥窒素を循環させ、基板裏面側は８０℃に制御した加熱乾燥窒素を循環させた。この状態で、１０分間の乾燥処理を施すことにより発光性ドーパント層を乾燥させた。なお、基板両面にそれぞれ循環させた乾燥窒素の温度は乾燥開始から終了まで±１℃以内に制御されていることを確認した。この際、別途作製した基板をＴＯＦ－ＳＩＭＳにより分析することで、ホスト層の上に発光層が積層していることが分かった。 Further, the following luminescent dopant layer composition 3 was ejected and injected using an inkjet head (manufactured by Epson; MJ800C) so that the wet film thickness was 4 μm. This substrate is fixed to a substrate holder of a drying box provided with upper and lower partition walls and independent drying air temperature regulators at the upper and lower portions of the partition wall, and heating is controlled to 120 ° C. on the upper surface of the substrate (light emitting layer coating surface). Dry nitrogen was circulated, and heat-dried nitrogen controlled at 80 ° C. was circulated on the back surface side of the substrate. In this state, the luminescent dopant layer was dried by performing a drying treatment for 10 minutes. It was confirmed that the temperature of the dry nitrogen circulated on both sides of the substrate was controlled within ± 1 ° C. from the start to the end of drying. At this time, by analyzing the separately prepared substrate by TOF-SIMS, it was found that the light emitting layer was laminated on the host layer.
（発光性ドーパント層組成物３）
　４ＣｚＩＰＮ　　　　　　　　　　　　　　　　　　　　　　　　５．０質量部
　トルエン　　　　　　　　　　　　　　　　　　　　　　　　　　１００質量部 (Luminescent Dopant Layer Composition 3)
4CzIPN 5.0 parts by mass Toluene 100 parts by mass
　次に、この基板をホットプレート上に載せ、１７０℃で１時間加熱してホスト層を融解させ、ホスト化合物及び発光性ドーパントの組成が厚さ方向で連続的に変化しており、陰極側から陽極側に向かって、発光性ドーパントの濃度が減少している発光層を形成した。 Next, this substrate is placed on a hot plate and heated at 170 ° C. for 1 hour to melt the host layer, and the compositions of the host compound and the luminescent dopant are continuously changed in the thickness direction from the cathode side. A light emitting layer in which the concentration of the light emitting dopant was reduced was formed toward the anode side.
　次に、この基板を市販の真空蒸着装置の基板ホルダーに固定した。
　真空蒸着装置内の蒸着用るつぼの各々に、各層の構成材料を、各々素子作製に最適の量を充填した。蒸着用るつぼはモリブデン製又はタングステン製の抵抗加熱用材料で作製されたものを用いた。
　真空度１×１０－４Ｐａまで減圧した後、ＳＦ３－ＴＲＺを蒸着速度１．０ｎｍ／秒で蒸着し、層厚５ｎｍの正孔阻止層を形成した。 Next, this substrate was fixed to a substrate holder of a commercially available vacuum vapor deposition apparatus.
Each of the crucibles for vapor deposition in the vacuum vapor deposition apparatus was filled with the constituent materials of each layer in the optimum amount for manufacturing the device. As the crucible for vapor deposition, a crucible made of molybdenum or tungsten made of a resistance heating material was used.
After depressurizing to a vacuum degree of 1 × 10 -4 Pa, SF3-TRZ was vapor-deposited at a vapor deposition rate of 1.0 nm / sec to form a hole blocking layer having a layer thickness of 5 nm.
　その後、ＳＦ３－ＴＲＺとＬｉＱ（８－ヒドロキシキノリノラト－リチウム）が、それぞれ５０％、５０％のモル％になるように蒸着速度１．０ｎｍ／秒で共蒸着し、層厚３０ｎｍの電子輸送層を形成した。 Then, SF3-TRZ and LiQ (8-hydroxyquinolinolato-lithium) are co-deposited at a vapor deposition rate of 1.0 nm / sec so as to be 50% and 50% mol%, respectively, and electron transport with a layer thickness of 30 nm. A layer was formed.
　さらに、フッ化リチウムを膜厚０．５ｎｍで形成した後に、アルミニウム１００ｎｍを蒸着して陰極を形成した。
　上記素子の非発光面側を、純度９９．９９９％以上の高純度窒素ガスの雰囲気下で、缶状ガラスケースで覆い、電極取り出し配線を設置して、有機ＥＬ素子（２－７）を作製した。 Further, after forming lithium fluoride with a film thickness of 0.5 nm, aluminum 100 nm was vapor-deposited to form a cathode.
The non-light emitting surface side of the element is covered with a can-shaped glass case in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more, and an electrode take-out wiring is installed to manufacture an organic EL element (2-7). did.
　〔有機ＥＬ素子（２－８）～（２－１１）の作製〕
　有機ＥＬ素子２－７の作製において、発光性ドーパント層組成物２の発光性ドーパントとホスト化合物を表IIのように変化させた以外は同様にして、有機ＥＬ素子（２－８）～（２－１１）を作製した。 [Manufacturing of organic EL elements (2-8) to (2-11)]
In the production of the organic EL element 2-7, the organic EL elements (2-8) to (2) were similarly changed except that the luminescent dopant and the host compound of the luminescent dopant layer composition 2 were changed as shown in Table II. -11) was prepared.
　《有機ＥＬ素子の評価》
　作製した有機ＥＬ素子（２－１）～（２－１１）について、実施例１と同様に発光輝度を評価した。評価結果を表IIに示す。 << Evaluation of organic EL elements >>
The emission brightness of the produced organic EL devices (2-1) to (2-11) was evaluated in the same manner as in Example 1. The evaluation results are shown in Table II.
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000012
　表IIに示すように、比較例素子（２－１）及び素子（２－６）と本発明の有機ＥＬ素子（２－７）との対比、同様に、素子（２－２）と（２－９）との対比、素子（２－３）と（２－１０）との対比、素子（２－４）と（２－１１）との対比、及び素子（２－５）と（２－８）との対比から、本発明の有機ＥＬ素子（２－７）～（２－１１）は、発光輝度が優れていることが分かる。 As shown in Table II, the comparison between the comparative example element (2-1) and the element (2-6) and the organic EL element (2-7) of the present invention, as well as the elements (2-2) and (2). Contrast with -9), Contrast with elements (2-3) and (2-10), Contrast with elements (2-4) and (2-11), and elements (2-5) and (2-5) From the comparison with 8), it can be seen that the organic EL devices (2-7) to (2-11) of the present invention have excellent emission brightness.
　簡便なプロセスで輝度ムラが改善される有機エレクトロルミネッセンス素子の製造方法及び当該製造方法により製造された有機エレクトロルミネッセンス素子を提供することができる。 It is possible to provide a method for manufacturing an organic electroluminescence device in which brightness unevenness is improved by a simple process, and an organic electroluminescence device manufactured by the manufacturing method.
１、１０１　有機ＥＬ素子
２　基材
３０、１００　インクジェットヘッド
３１、３９　ポンプ
３２　フィルター
３３　配管分岐
３４　廃液タンク
３５　制御部
３６、３７、３８Ａ、３８Ｂ　タンク
５６　筐体
５７　キャップ受板
５９　カバー部材
６１　ノズルプレート
６２　キャップ受板取り付け部
６８　取り付け用孔
７１　ノズル用開口部
８１ａ　第１ジョイト
８１ｂ　第２ジョイント
８２　第３ジョイント
１０１　有機ＥＬ素子
１０２　ガラスカバー
１０５　陰極
１０６　有機ＥＬ層
１０７　透明電極付きガラス基板
１０８　窒素ガス
１０９　捕水剤 1, 101 Organic EL element 2 Base material 30, 100 Inkjet head 31, 39 Pump 32 Filter 33 Piping branch 34 Waste liquid tank 35 Control unit 36, 37, 38A, 38B Tank 56 Housing 57 Cap receiving plate 59 Cover member 61 Nozzle plate 62 Cap receiving plate mounting part 68 Mounting hole 71 Nozzle opening 81a 1st join 81b 2nd joint 82 3rd joint 101 Organic EL element 102 Glass cover 105 Cathode 106 Organic EL layer 107 Glass substrate with transparent electrode 108 Nitrogen gas 109 Water catcher

Claims (9)

  1. 　基板上に、陽極と、少なくとも一層の発光層を含む有機機能層と、陰極とを有する有機エレクトロルミネッセンス素子の製造方法であって、
    　前記発光層をウェット・プロセスで形成する工程を有し、かつ、
    　当該発光層に含有させるホスト化合物と発光性ドーパントの組成を、当該発光層の厚さ方向において、連続的又は断続的に変化させる加熱・融解工程を有する、
    　ことを特徴とする有機エレクトロルミネッセンス素子の製造方法。     A method for manufacturing an organic electroluminescence device having an anode, an organic functional layer including at least one light emitting layer, and a cathode on a substrate.
    It has a step of forming the light emitting layer by a wet process, and
    It has a heating / melting step of continuously or intermittently changing the composition of the host compound and the luminescent dopant contained in the light emitting layer in the thickness direction of the light emitting layer.
    A method for manufacturing an organic electroluminescent device.
  2. 　前記発光層の形成において、前記基板側から、前記ホスト化合物を含有するホスト層と前記発光性ドーパントを含有するドーパント層をこの順に形成し、その後、
    　前記加熱・融解工程において、少なくとも前記ホスト層を融解させることで、当該ホスト層と前記ドーパント層のそれぞれの構成成分を混合させ、かつ、
    　前記発光層の厚さ方向において、前記ホスト化合物と前記発光性ドーパントの組成を連続的又は断続的に変化させる、
    　ことを特徴とする請求項１に記載の有機エレクトロルミネッセンス素子の製造方法。     In the formation of the light emitting layer, the host layer containing the host compound and the dopant layer containing the light emitting dopant are formed in this order from the substrate side, and then the light emitting layer is formed.
    In the heating / melting step, at least the host layer is melted to mix the respective constituent components of the host layer and the dopant layer, and
    The composition of the host compound and the luminescent dopant is continuously or intermittently changed in the thickness direction of the light emitting layer.
    The method for manufacturing an organic electroluminescent device according to claim 1.
  3. 　前記加熱・融解工程において、前記発光層の前記陰極側から前記陽極側に向かう厚さ方向において、前記発光性ドーパントの濃度が連続的又は断続的に減少する領域を形成する、
    　ことを特徴とする請求項１又は請求項２に記載の有機エレクトロルミネッセンス素子の製造方法。     In the heating / melting step, a region is formed in which the concentration of the luminescent dopant is continuously or intermittently decreased in the thickness direction of the light emitting layer from the cathode side to the anode side.
    The method for manufacturing an organic electroluminescent device according to claim 1 or 2, wherein the organic electroluminescence device is characterized.
  4. 　前記発光性ドーパントが、熱活性型遅延蛍光性化合物である、
    　ことを特徴とする請求項１から請求項３までのいずれか一項に記載の有機エレクトロルミネッセンス素子の製造方法。     The luminescent dopant is a thermally activated delayed fluorescent compound.
    The method for manufacturing an organic electroluminescence device according to any one of claims 1 to 3, wherein the organic electroluminescence device is characterized.
  5. 　前記ホスト化合物が、絶縁性の高分子化合物である、
    　ことを特徴とする請求項１から請求項４までのいずれか一項に記載の有機エレクトロルミネッセンス素子の製造方法。     The host compound is an insulating polymer compound.
    The method for manufacturing an organic electroluminescence device according to any one of claims 1 to 4, wherein the organic electroluminescence device is characterized.
  6. 　前記ホスト化合物が、ポリスチレンである、
    　ことを特徴とする請求項１から請求項５までのいずれか一項に記載の有機エレクトロルミネッセンス素子の製造方法     The host compound is polystyrene.
    The method for manufacturing an organic electroluminescent device according to any one of claims 1 to 5, wherein the method is characterized by the above.
  7. 　基板上に、陽極と、少なくとも一層の発光層を含む有機機能層と、陰極とを有する有機エレクトロルミネッセンス素子であって、
    　前記発光層が、前記基板側から前記ホスト化合物を含有するホスト層と前記発光性ドーパントを含有するドーパント層の塗布膜からなり、
    　当該ホスト層と当該ドーパント層とが融解接合されており、かつ、
    　前記発光層の厚さ方向において、前記ホスト化合物と前記発光性ドーパントの組成が連続的又は断続的に変化している、
    　ことを特徴とする有機エレクトロルミネッセンス素子。     An organic electroluminescence device having an anode, an organic functional layer including at least one light emitting layer, and a cathode on a substrate.
    The light emitting layer is composed of a coating film of a host layer containing the host compound and a dopant layer containing the light emitting dopant from the substrate side.
    The host layer and the dopant layer are melt-bonded and
    The composition of the host compound and the luminescent dopant changes continuously or intermittently in the thickness direction of the light emitting layer.
    An organic electroluminescence device characterized by this.
  8. 　前記発光性ドーパントが、熱活性型遅延蛍光性化合物である、
    　ことを特徴とする請求項７に記載の有機エレクトロルミネッセンス素子。     The luminescent dopant is a thermally activated delayed fluorescent compound.
    The organic electroluminescence device according to claim 7.
  9. 　前記ホスト化合物が、絶縁性の高分子化合物である、
    　ことを特徴とする請求項７又は請求項８に記載の有機エレクトロルミネッセンス素子。     The host compound is an insulating polymer compound.
    The organic electroluminescence device according to claim 7 or 8.
PCT/JP2020/034478 2019-09-26 2020-09-11 Organic electroluminescent element manufacturing method and organic electroluminescent element WO2021060024A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2021548803A JP7416079B2 (en) 2019-09-26 2020-09-11 Method for manufacturing organic electroluminescent device and organic electroluminescent device

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2019-174898 2019-09-26
JP2019174898 2019-09-26

Publications (1)

Publication Number Publication Date
WO2021060024A1 true WO2021060024A1 (en) 2021-04-01

Family

ID=75166680

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2020/034478 WO2021060024A1 (en) 2019-09-26 2020-09-11 Organic electroluminescent element manufacturing method and organic electroluminescent element

Country Status (2)

Country Link
JP (1) JP7416079B2 (en)
WO (1) WO2021060024A1 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61501177A (en) * 1984-02-06 1986-06-12 ロジャ−ズ・コ−ポレ−ション Electric circuits and parts
JP2012084415A (en) * 2010-10-13 2012-04-26 Konica Minolta Holdings Inc Method for manufacturing organic electroluminescent element and organic electroluminescent element
JP2014529179A (en) * 2011-07-12 2014-10-30 ウェイク フォレスト ユニバーシティ Photoelectric device and its application
WO2019059056A1 (en) * 2017-09-20 2019-03-28 コニカミノルタ株式会社 Method for producing multilayer film and method for producing electronic device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61501177A (en) * 1984-02-06 1986-06-12 ロジャ−ズ・コ−ポレ−ション Electric circuits and parts
JP2012084415A (en) * 2010-10-13 2012-04-26 Konica Minolta Holdings Inc Method for manufacturing organic electroluminescent element and organic electroluminescent element
JP2014529179A (en) * 2011-07-12 2014-10-30 ウェイク フォレスト ユニバーシティ Photoelectric device and its application
WO2019059056A1 (en) * 2017-09-20 2019-03-28 コニカミノルタ株式会社 Method for producing multilayer film and method for producing electronic device

Also Published As

Publication number Publication date
JP7416079B2 (en) 2024-01-17
JPWO2021060024A1 (en) 2021-04-01

Similar Documents

Publication Publication Date Title
JP6756614B2 (en) Organic electroluminescence device, display device, lighting device, π-conjugated compound, luminescent thin film
US11910628B2 (en) Luminescent film, organic electroluminescent element, organic material composition and method for producing organic electroluminescent element
WO2017018326A1 (en) Organic electroluminescent element, display device, and illumination device
WO2016017684A1 (en) Organic electroluminescent element material, organic electroluminescent element, light-emitting thin film, display device and illumination device
JP6781534B2 (en) Organic electroluminescence elements, display devices and lighting devices
JP7083247B2 (en) Luminescent material, luminescent thin film, organic electroluminescence element, display device and lighting device
WO2016181844A1 (en) Π-conjugated compound, delayed fluorescent body, light-emitting thin film, organic electroluminescence element, display device, and illumination device
JP7081924B2 (en) Luminescent material, luminescent thin film, organic electroluminescence element, display device and lighting device
JP2016225498A (en) Organic electroluminescent element
JP2016210728A (en) π-CONJUGATED TYPE COMPOUND, ORGANIC ELECTROLUMINESCENCE ELEMENT MATERIAL, LUMINESCENT THIN FILM, ORGANIC ELECTROLUMINESCENCE ELEMENT, DISPLAY DEVICE, AND ILLUMINATION DEVICE
JPWO2020059326A1 (en) Benzonitrile derivatives and methods for producing them, ink compositions, organic electroluminescence element materials, light emitting materials, charge transport materials, light emitting thin films and organic electroluminescence elements.
WO2020189283A1 (en) Charge-transporting compound and manufacturing method thereof, ink composition, organic electroluminescence element material, etc.
JP6838268B2 (en) Light conversion material, light conversion film, and light emitting element
WO2021060024A1 (en) Organic electroluminescent element manufacturing method and organic electroluminescent element
JP6941160B2 (en) Manufacturing method of organic electroluminescence device and organic electroluminescence device
JPWO2020059520A1 (en) Benzonitrile derivatives and methods for producing them, ink compositions, organic electroluminescence element materials, light emitting materials, charge transport materials, light emitting thin films and organic electroluminescence elements.
JP7334577B2 (en) Method for producing organic electroluminescence element
JPWO2019146396A1 (en) Luminescent thin film, luminescent laminated film, organic electroluminescence device, and its manufacturing method
JP7476786B2 (en) Organic electroluminescence element, its manufacturing method, display device and lighting device
WO2021059813A1 (en) Organic electroluminescent element
JP7351310B2 (en) Mixed composition for organic electroluminescent devices
JP7196926B2 (en) Mixed composition for organic electroluminescence device
JP7060490B2 (en) Solutions for making nonionic organic electronics materials, electronic devices, organic electroluminescent devices and organic electroluminescent devices
JP7404878B2 (en) Organic electroluminescent device and its manufacturing method
WO2021106366A1 (en) Organic electroluminescence element and light-emitting film

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20869544

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2021548803

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 20869544

Country of ref document: EP

Kind code of ref document: A1