WO2021149510A1 - Pyrromethene boron complex, light-emitting element containing same, light-emitting element, display device, and illumination device - Google Patents

Pyrromethene boron complex, light-emitting element containing same, light-emitting element, display device, and illumination device Download PDF

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WO2021149510A1
WO2021149510A1 PCT/JP2021/000458 JP2021000458W WO2021149510A1 WO 2021149510 A1 WO2021149510 A1 WO 2021149510A1 JP 2021000458 W JP2021000458 W JP 2021000458W WO 2021149510 A1 WO2021149510 A1 WO 2021149510A1
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light emitting
groups
aryl
compound
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Japanese (ja)
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星野秀尭
長尾和真
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東レ株式会社
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Priority to CN202180007056.8A priority patent/CN114787170A/en
Priority to KR1020227022664A priority patent/KR102650329B1/en
Publication of WO2021149510A1 publication Critical patent/WO2021149510A1/en

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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/30—Coordination compounds
    • H10K85/321—Metal complexes comprising a group IIIA element, e.g. Tris (8-hydroxyquinoline) gallium [Gaq3]
    • H10K85/322—Metal complexes comprising a group IIIA element, e.g. Tris (8-hydroxyquinoline) gallium [Gaq3] comprising boron
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F5/00—Compounds containing elements of Groups 3 or 13 of the Periodic Table
    • C07F5/02—Boron compounds
    • C07F5/022—Boron compounds without C-boron linkages
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F5/00—Compounds containing elements of Groups 3 or 13 of the Periodic Table
    • C07F5/02—Boron compounds
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/06—Luminescent, e.g. electroluminescent, chemiluminescent materials containing organic luminescent materials
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
    • 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
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2101/00—Properties of the organic materials covered by group H10K85/00
    • H10K2101/20—Delayed fluorescence emission
    • 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
    • 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
    • H10K50/80—Constructional details
    • H10K50/85—Arrangements for extracting light from the devices

Definitions

  • the present invention relates to a pyrromethene boron complex, a light emitting device containing the pyromethene boron complex, a display device, and a lighting device.
  • the organic thin film light emitting element that emits light by recombining the electrons injected from the cathode and the holes injected from the anode in the light emitting layer sandwiched between the two electrodes is thin, has a low drive voltage, and emits high brightness. Furthermore, it has the feature that multicolor light emission is possible by selecting a light emitting material. In particular, by using a host material and a dopant material in combination for the light emitting layer, it is possible to obtain a light emitting element that emits light of the three primary colors of blue, green, and red with high efficiency.
  • a dye having a high fluorescence quantum yield is usually used.
  • a complex having a pyrromethene skeleton is a compound having requirements necessary for obtaining high efficiency as a dopant such as high fluorescence quantum yield, small Stokes shift and small peak half-value width of emission spectrum, and a pyrromethene complex can be used as a dopant.
  • the light emitting element used is known to exhibit good element characteristics (see, for example, Patent Document 1). Further, in recent years, aiming at high luminous efficiency, a light emitting element containing a TADF (Thermally Activated Fluorescence) material and a pyromethene boron complex has been studied (see, for example, Patent Document 2).
  • TADF Thermally Activated Fluorescence
  • the color gamut is represented by a triangle connecting the coordinates of the vertices indicating the emission of red, green, and blue in the xy chromaticity diagram.
  • Chromaticity is determined by the combination of emission peak wavelength and color purity.
  • the color purity is determined by the width of the emission spectrum, and the narrower the width of the emission spectrum and the closer to monochromatic light, the higher the color purity. Increasing the color purity is particularly important for widening the color gamut, and there is a strong demand for a light emitting material having a sharp emission spectrum.
  • an organic thin film light emitting element when used as a display device or a lighting device, it is required to improve the durability of the light emitting element. In order to improve the durability of the light emitting element, it is necessary to improve the stability of the light emitting material.
  • the organic thin film light emitting element is desired to have high luminous efficiency from the viewpoint of improving brightness and power saving. Especially in mobile display devices whose use has been expanding in recent years, power saving has become a particularly important issue.
  • the pyrromethene boron complex is a useful light emitting material that can obtain a sharp emission spectrum when used as a dopant, but is required to have higher luminous efficiency and higher durability in a light emitting device. ..
  • An object of the present invention is to solve the problems of the prior art and to provide a light emitting material having a high fluorescence quantum yield and a sharp emission spectrum, and a light emitting element having high luminous efficiency, color purity and durability. be.
  • the present invention is a pyrromethene boron complex represented by the general formula (1).
  • R 1 to R 6 are independently hydrogen atom, alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, hydroxyl group, thiol group, alkoxy group, alkylthio group, aryl ether group, respectively. It is selected from the group consisting of an arylthioether group, an aryl group, a heteroaryl group, an amino group, a silyl group, a siloxanyl group and a boryl group. These groups may further have substituents. However, at least one of R 1 to R 4 is a hydrogen atom or an alkyl group.
  • X 1 and X 2 are independently alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, hydroxyl group, thiol group, alkoxy group, alkylthio group, arylether group and arylthioether group, respectively. , Heteroaryl group, halogen, and cyano group. These groups may further have substituents.
  • R 7 is represented by the following general formula (2).
  • R 8 to R 10 are independently hydrogen atom, alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, hydroxyl group, thiol group, alkoxy group, alkylthio group, arylether group, respectively.
  • R 11 is an alkyl group, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, a hydroxyl group, a thiol group, an alkoxy group, an alkylthio group, an aryl ether group, an arylthioether group, an aryl group or a heteroaryl group.
  • Ar 1 is a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group.
  • another aspect of the present invention is an element having an anode and a cathode, and a light emitting layer existing between the anode and the cathode, and the light emitting layer emits light by electric energy, and the light emitting layer contains the light emitting layer. It is a light emitting element containing the above-mentioned pyromethene boron complex.
  • the present invention is not limited to the following embodiments, and can be variously modified and implemented according to an object and an application.
  • the pyrromethene boron complex according to the present invention is represented by the general formula (1).
  • R 1 to R 6 are independently hydrogen atom, alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, hydroxyl group, thiol group, alkoxy group, alkylthio group, aryl ether group, respectively. It is selected from the group consisting of an arylthioether group, an aryl group, a heteroaryl group, an amino group, a silyl group, a siloxanyl group and a boryl group. These groups may further have substituents. However, at least one of R 1 to R 4 is a hydrogen atom or an alkyl group.
  • X 1 and X 2 are independently alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, hydroxyl group, thiol group, alkoxy group, alkylthio group, arylether group and arylthioether group, respectively. , Heteroaryl group, halogen, and cyano group. These groups may further have substituents.
  • R 7 is represented by the following general formula (2).
  • R 8 to R 10 are independently hydrogen atom, alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, hydroxyl group, thiol group, alkoxy group, alkylthio group, arylether group, respectively.
  • R 11 is an alkyl group, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, a hydroxyl group, a thiol group, an alkoxy group, an alkylthio group, an aryl ether group, an arylthioether group, an aryl group or a heteroaryl group.
  • Halogen cyano group, aldehyde group, acyl group, carboxyl group, ester group, amide group, sulfonyl group, sulfonic acid ester group, sulfonamide group, amino group, nitro group, silyl group, siroxanyl group, boryl group and phosphine oxide. Selected from the group consisting of groups. These groups may further have substituents.
  • Ar 1 is a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group.
  • bridgehead position In pyrromethene skeleton, there is a case where the site to be substituted by R 7 hereinafter referred to as "bridgehead position".
  • a substance having a pyrromethene skeleton represented by the following formula and a substance having a condensed ring structure in a part of the pyrromethene skeleton and having a wide ring structure are collectively referred to as "pyromethene”.
  • hydrogen may be deuterium.
  • the substituents in the case of substitution include an alkyl group, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an aryl group, a heteroaryl group, a hydroxyl group and a thiol.
  • unsubstituted means that the atom bonded to the target basic skeleton or group is only a hydrogen atom or a deuterium atom.
  • substituted or unsubstituted in the compound described below or its partial structure.
  • the alkyl group refers to a saturated aliphatic hydrocarbon group such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group and a tert-butyl group, which are substituted. It may be non-replaceable.
  • the additional substituent when substituted is not particularly limited, and examples thereof include an alkyl group, a halogen, an aryl group, and a heteroaryl group, and this point is also common to the following description.
  • the number of carbon atoms of the alkyl group is not particularly limited, but is preferably 1 or more and 20 or less, and more preferably 1 or more and 8 or less from the viewpoint of availability and cost.
  • the cycloalkyl group refers to a saturated alicyclic hydrocarbon group such as a cyclopropyl group, a cyclohexyl group, a norbornyl group, or an adamantyl group, which may be substituted or unsubstituted.
  • the number of carbon atoms in the alkyl group moiety is not particularly limited, but is preferably in the range of 3 or more and 20 or less.
  • the heterocyclic group refers to an aliphatic ring having an atom other than carbon such as a pyran ring, a piperidine ring, and a cyclic amide in the ring, which may be substituted or unsubstituted.
  • the number of carbon atoms of the heterocyclic group is not particularly limited, but is preferably in the range of 2 or more and 20 or less.
  • the alkenyl group refers to an unsaturated aliphatic hydrocarbon group containing a double bond such as a vinyl group, an allyl group, or a butadienyl group, which may be substituted or unsubstituted.
  • the carbon number of the alkenyl group is not particularly limited, but is preferably in the range of 2 or more and 20 or less.
  • the cycloalkenyl group refers to an unsaturated alicyclic hydrocarbon group containing a double bond such as a cyclopentenyl group, a cyclopentadienyl group, a cyclohexenyl group, etc., which may be substituted or unsubstituted. ..
  • the number of carbon atoms of the cycloalkenyl group is not particularly limited, but is preferably in the range of 3 or more and 20 or less.
  • the alkynyl group refers to an unsaturated aliphatic hydrocarbon group containing a triple bond such as an ethynyl group, which may be substituted or unsubstituted.
  • the number of carbon atoms of the alkynyl group is not particularly limited, but is preferably in the range of 2 or more and 20 or less.
  • the alkoxy group refers to a functional group in which an aliphatic hydrocarbon group is bonded via an ether bond such as a methoxy group, an ethoxy group, or a propoxy group, and the aliphatic hydrocarbon group may be substituted or unsubstituted. good.
  • the number of carbon atoms of the alkoxy group is not particularly limited, but is preferably in the range of 1 or more and 20 or less.
  • the alkylthio group is one in which the oxygen atom of the ether bond of the alkoxy group is replaced with a sulfur atom.
  • the hydrocarbon group of the alkylthio group may be substituted or unsubstituted.
  • the number of carbon atoms of the alkylthio group is not particularly limited, but is preferably in the range of 1 or more and 20 or less.
  • the aryl ether group refers to a functional group in which an aromatic hydrocarbon group is bonded via an ether bond, such as a phenoxy group, and the aromatic hydrocarbon group may be substituted or unsubstituted.
  • the number of carbon atoms of the aryl ether group is not particularly limited, but is preferably in the range of 6 or more and 40 or less.
  • the arylthio ether group is one in which the oxygen atom of the ether bond of the aryl ether group is replaced with a sulfur atom.
  • the aromatic hydrocarbon group in the arylthioether group may be substituted or unsubstituted.
  • the number of carbon atoms of the arylthioether group is not particularly limited, but is preferably in the range of 6 or more and 40 or less.
  • the aryl group may be either a monocyclic ring or a fused ring, and may be, for example, a phenyl group, a naphthyl group, a fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthryl group, an anthrasenyl group, a benzophenanthryl group or a benzo.
  • aromatic hydrocarbon group such as anthrasenyl group, chrysenyl group, pyrenyl group, fluoranthenyl group, triphenylenyl group, benzofluoranthenyl group, dibenzoanthrasenyl group, perylenel group and helisenyl group.
  • a group selected from the group consisting of a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a phenanthryl group, an anthracenyl group, a pyrenyl group, a fluoranthenyl group and a triphenylenyl group is preferable.
  • the aryl group may be substituted or unsubstituted.
  • a group in which a plurality of phenyl groups such as a biphenyl group and a terphenyl group are bonded via a single bond is treated as a phenyl group having an aryl group as a substituent.
  • the number of carbon atoms of the aryl group is not particularly limited, but is preferably in the range of 6 or more and 40 or less, and more preferably 6 or more and 30 or less. Further, in the case of a phenyl group, when there are substituents on two adjacent carbon atoms in the phenyl group, a ring structure may be formed between these substituents.
  • the heteroaryl group may be either a monocyclic group or a fused ring, and may be, for example, a pyridyl group, a furanyl group, a thiophenyl group, a quinolinyl group, an isoquinolinyl group, a pyrazinyl group, a pyrimidyl group, a pyridadinyl group, a triazinyl group, a naphthyldinyl group, a synnolinyl group, Phtalazinyl group, quinoxalinyl group, quinazolinyl group, benzofuranyl group, benzothiophenyl group, indolyl group, dibenzofuranyl group, dibenzothiophenyl group, carbazolyl group, benzocarbazolyl group, carbolinyl group, indolocarbazolyl group, benzo Flocarbazolyl group, benzothienocarbazolyl group,
  • hetero atom a nitrogen atom, an oxygen atom, or a sulfur atom is preferable.
  • the heteroaryl group may be substituted or unsubstituted.
  • the number of carbon atoms of the heteroaryl group is not particularly limited, but is preferably in the range of 2 or more and 40 or less, and more preferably 2 or more and 30 or less.
  • Halogen refers to an atom selected from fluorine, chlorine, bromine and iodine.
  • the cyano group is a functional group whose structure is represented by -CN. Here, it is the carbon atom that is bonded to the other group.
  • the acyl group refers to a functional group in which an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, etc. are bonded via a carbonyl group, such as an acetyl group, a propionyl group, a benzoyl group, and an acryryl group. .. These substituents may be further substituted.
  • the number of carbon atoms of the acyl group is not particularly limited, but is preferably 2 or more and 40 or less, and more preferably 2 or more and 30 or less.
  • the ester group refers to, for example, a functional group in which an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, or the like is bonded via an ester bond. These substituents may be further substituted.
  • the number of carbon atoms of the ester group is not particularly limited, but is preferably in the range of 1 or more and 20 or less.
  • a methyl ester group such as a methoxycarbonyl group, an ethyl ester group such as an ethoxycarbonyl group, a propyl ester group such as a propoxycarbonyl group, a butyl ester group such as a butoxycarbonyl group, and an isopropyl such as an isopropoxymethoxycarbonyl group.
  • examples thereof include an ester group, a hexyl ester group such as a hexyloxycarbonyl group, and a phenyl ester group such as a phenoxycarbonyl group.
  • the amide group refers to, for example, a functional group in which an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group or the like is bonded via an amide bond. These substituents may be further substituted.
  • the number of carbon atoms of the amide group is not particularly limited, but is preferably in the range of 1 or more and 20 or less. More specifically, a methylamide group, an ethylamide group, a propylamide group, a butylamide group, an isopropylamide group, a hexylamide group, a phenylamide group and the like can be mentioned.
  • the number of carbon atoms of the sulfonyl group is not particularly limited, but is preferably in the range of 1 or more and 20 or less.
  • the sulfonic acid ester group refers to, for example, a functional group in which an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group and the like are bonded via a sulfonic acid ester bond.
  • these substituents may be further substituted.
  • the number of carbon atoms of the sulfonic acid ester group is not particularly limited, but is preferably in the range of 1 or more and 20 or less.
  • the sulfonamide group refers to, for example, a functional group in which an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group and the like are bonded via a sulfonamide bond.
  • these substituents may be further substituted.
  • the number of carbon atoms of the sulfonamide group is not particularly limited, but is preferably in the range of 1 or more and 20 or less.
  • the amino group is a substituted or unsubstituted amino group.
  • substituents in the case of substitution include an aryl group, a heteroaryl group, a linear alkyl group and a branched alkyl group.
  • aryl group and heteroaryl group a phenyl group, a naphthyl group, a pyridyl group and a quinolinyl group are preferable. These substituents may be further substituted.
  • the number of carbon atoms is not particularly limited, but is preferably 2 or more and 50 or less, more preferably 6 or more and 40 or less, and particularly preferably 6 or more and 30 or less.
  • the silyl group refers to a functional group to which a substituted or unsubstituted silicon atom is bonded, and is, for example, an alkylsilyl group such as a trimethylsilyl group, a triethylsilyl group, a tert-butyldimethylsilyl group, a propyldimethylsilyl group, or a vinyldimethylsilyl group.
  • arylsilyl groups such as phenyldimethylsilyl group, tert-butyldiphenylsilyl group, triphenylsilyl group and trinaphthylsilyl group.
  • Substituents on silicon may be further substituted.
  • the number of carbon atoms of the silyl group is not particularly limited, but is preferably in the range of 1 or more and 30 or less.
  • the siloxanyl group refers to a silicon compound group via an ether bond such as a trimethylsiloxanyl group. Substituents on silicon may be further substituted.
  • the boryl group is a substituted or unsubstituted boryl group.
  • substituent in the case of substitution include an aryl group, a heteroaryl group, a linear alkyl group, a branched alkyl group, an aryl ether group, an alkoxy group and a hydroxyl group, and among them, an aryl group and an aryl ether group are preferable.
  • R 50 and R 51 are each independently selected from the same group as R 1 to R 6.
  • the pyromethene boron complex has a strong and highly flat skeleton, and therefore exhibits a high fluorescence quantum yield. Further, since the peak half width of the emission spectrum is small, efficient emission and high color purity can be achieved in the emission element.
  • the substituent R 7 is introduced into the bridgehead position of the pyrromethene skeleton.
  • the introduction of the R 7, it is possible to provide a high fluorescence quantum yield and semi-width small Pirometenhou boron complex.
  • Ar 1 and R 11 in the substituent R 7 are the above groups, respectively, it is possible to suppress the intramolecular rotation of the bridge head position with respect to the pyrromethene skeleton and cause energy deactivation. It is advantageous for improving the luminous efficiency.
  • R 1 to R 4 is a hydrogen atom or an alkyl group, vibrational relaxation in the excited state can be reduced, and the half width of the emission spectrum can be reduced.
  • the stability of the pyromethene boron complex affects the durability of the light emitting device.
  • R 11 is preferably a bulky substituent, preferably a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group.
  • R 1 and R 4 are selected from the above group and affect the emission peak wavelength, crystallinity, sublimation temperature, etc. of the pyrromethene boron complex. From the viewpoint of reducing the half width of the emission spectrum, R 1 and R 4 are preferably hydrogen atoms or alkyl groups. Further, from the viewpoint of further improving the fluorescence quantum yield, it is more preferable that R 1 and R 4 are alkyl groups.
  • R 2 and R 3 are selected from the above group and mainly affect the emission peak wavelength, the half width of the emission spectrum, the stability, or the crystallinity of the pyrromethene boron complex. At least one or preferably both of R 2 and R 3 are hydrogen atoms, from the viewpoint of making the half-value width of the emission spectrum smaller, improving the stability, and easiness of synthesis including recrystallization. It is preferably a group selected from the group consisting of substituted or unsubstituted alkyl groups, substituted or unsubstituted aryl groups and substituted or unsubstituted heteroaryl groups. Further, from the viewpoint of further reducing the half width, it is more preferable that R 2 and R 3 are alkyl groups.
  • R 5 and R 6 are selected from the above group and mainly affect the emission peak wavelength, the half width of the emission spectrum, the stability, or the crystallinity of the pyrromethene boron complex. From the viewpoint of reducing the half width of the emission spectrum, improving the stability, and easiness of synthesis including recrystallization purification, at least one or preferably both of R 5 and R 6 are hydrogen atoms. Alternatively, it is preferably a substituted or unsubstituted alkyl group.
  • X 1 and X 2 are selected from the above. From the viewpoint of luminescence properties and thermal stability, X 1 and X 2 are selected from the group consisting of an alkoxy group, a haloalkyl group, a haloalkoxy group, an aryl ether group, a haloaryl ether group, a haloaryl group, a halogen atom and a cyano group. It is preferably a group.
  • the haloalkyl group is an alkyl group substituted with at least one halogen.
  • a haloaryl group is an aryl group substituted with at least one halogen.
  • X 1 and X 2 are fluorine atoms, fluorine-containing alkyl groups, and fluorine-containing alkoxy groups. It is more preferably a group selected from the group consisting of a fluorine-containing aryl group and a cyano group, further preferably a fluorine atom or a cyano group, and most preferably a fluorine atom.
  • These are electron-attracting groups, which can reduce the electron density of the pyrromethene skeleton and increase the stability of the compound.
  • the pyrromethene boron complex represented by the general formula (1) is J. Org. Chem., Vol.64, No. 21, pp.7813-7819 (1999), Angew. Chem., Int. Ed. Engl., It can be manufactured by referring to the methods described in vol.36, pp.1333-1335 (1997), Org. Lett., Vol.12, pp.296 (2010), etc.
  • a coupling reaction between a halogenated derivative of the pyromethene boron complex and a boronic acid or boronic acid ester derivative is used. Examples include, but are not limited to, methods of forming carbon-carbon bonds.
  • carbon-nitrogen is used by using a coupling reaction between a halogenated derivative of the pyromethene boron complex and an amine or carbazole derivative. Examples include, but are not limited to, methods of generating bonds.
  • the obtained pyromethene boron complex is subjected to organic synthetic purification such as recrystallization and column chromatography, and then the low boiling point component is removed by purification by heating under reduced pressure, which is generally called sublimation purification, to improve the purity. Is preferable.
  • the heating temperature in the sublimation purification is not particularly limited, but is preferably 330 ° C. or lower, more preferably 300 ° C. or lower, from the viewpoint of preventing thermal decomposition of the pyromethene boron complex.
  • the purity of the pyrromethene boron complex produced in this manner is preferably 99% by weight or more from the viewpoint of enabling the light emitting device to exhibit stable characteristics.
  • the optical properties of the pyrromethene boron complex represented by the general formula (1) can be obtained by measuring the absorption spectrum and the emission spectrum of the diluted solution.
  • the solvent is not particularly limited as long as it dissolves the pyrromethene boron complex and the absorption spectrum of the solvent is transparent and does not overlap with the absorption spectrum of the pyromethene boron complex.
  • toluene and the like are exemplified.
  • the concentration of the solution is not particularly limited as long as it has sufficient absorbance and does not cause concentration dimming, but it is preferably in the range of 1 ⁇ 10 -4 mol / L to 1 ⁇ 10 -7 mol / L.
  • the absorption spectrum can be measured by a general ultraviolet-visible spectrophotometer.
  • the emission spectrum can be measured by a general fluorescence spectrophotometer.
  • the emission spectrum of the light emitted by the pyrromethene boron complex represented by the general formula (1) by irradiation with excitation light is sharp.
  • high brightness and high color purity can be achieved by the resonance effect of the microcavity structure in the top emission element, which is the mainstream in display devices and lighting devices, but when the emission spectrum is sharp, this resonance effect appears more strongly and is high. It is advantageous for efficiency.
  • the half width of the emission spectrum is preferably 60 nm or less, more preferably 50 nm or less, further preferably 45 nm or less, and particularly preferably 28 nm or less.
  • the luminous efficiency of the light emitting element depends on the fluorescence quantum yield of the light emitting material itself. Therefore, it is desired that the fluorescence quantum yield of the light emitting material is as close to 100% as possible.
  • the pyromethene boron complex represented by the general formula (1) has a high fluorescence quantum yield by suppressing rotation and vibration at the bridge head position and reducing heat deactivation by having R 11 and Ar 1 as described above. You can get the rate. From the above viewpoint, the fluorescence quantum yield of the pyrromethene boron complex is preferably 90% or more, more preferably 95% or more. However, the fluorescence quantum yield shown here is obtained by measuring a diluted solution using toluene as a solvent with an absolute quantum yield measuring device.
  • the pyrromethene boron complex represented by the general formula (1) can achieve high luminous efficiency, it is used as a light emitting element material in a light emitting element.
  • the light emitting device material in the present invention represents a material used for any layer of the light emitting device, and is selected from a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer, as will be described later.
  • the material used for the protective film (cap layer) of the electrode is also included.
  • the pyrromethene boron complex represented by the general formula (1) has high light emitting performance, and therefore is preferably a material used for the light emitting layer.
  • the light emitting device of the present invention has an anode and a cathode, and an organic layer existing between the anode and the cathode.
  • the organic layer preferably includes at least a light emitting layer, and the light emitting layer is an organic electroluminescent device that emits light by electric energy.
  • the light emitting element of the present invention may be either a bottom emission type or a top emission type.
  • the layer structure of the organic layer between the anode and the cathode includes not only the light emitting layer but also 1) light emitting layer / electron transporting layer, 2) hole transporting layer / light emitting layer, and 3).
  • Hole transport layer / light emitting layer / electron transport layer 4) hole injection layer / hole transport layer / light emitting layer / electron transport layer, 5) hole transport layer / light emitting layer / electron transport layer / electron injection layer, 6 ) Hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer, 7) hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer, 8) Examples thereof include a laminated structure such as a hole injection layer / a hole transport layer / an electron blocking layer / a light emitting layer / a hole blocking layer / an electron transport layer / an electron injection layer.
  • tandem type light emitting element in which a plurality of the above laminated configurations are laminated via an intermediate layer may be used.
  • the intermediate layer generally include an intermediate electrode, an intermediate conductive layer, a charge generation layer, an electron extraction layer, a connection layer, an intermediate insulation layer, and the like, and known material configurations can be used.
  • Preferred specific examples of the tandem type light emitting element are 9) hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / charge generation layer / hole injection layer / hole transport layer / light emitting layer / electron.
  • Laminated configurations such as transport layer / electron injection layer can be mentioned.
  • each of the above layers may be either a single layer or a plurality of layers, and may be doped. Further, there is also an element configuration including a layer using a capping material for improving the luminous efficiency due to the optical interference effect.
  • the pyrromethene boron complex represented by the general formula (1) may be used for any layer in the above device configuration, but since it has a high fluorescence quantum yield and thin film stability, it is a light emitting layer. It is preferable to use it for.
  • the substrate is not particularly limited, and examples thereof include a glass plate, a ceramic plate, a resin film, a resin thin film, and a metal thin plate.
  • a glass substrate is preferably used from the viewpoint of being transparent and easy to process.
  • a glass substrate having high transparency is preferable for a bottom emission element that extracts light through the substrate.
  • flexible displays and foldable displays are increasing in mobile devices such as smartphones, and resin films and resin thin films obtained by curing varnish are preferably used for this purpose.
  • a heat-resistant film is used as the resin film, and specific examples thereof include a polyimide film and a polyethylene naphthalate film.
  • various wirings, circuits, and TFT switching elements for driving the organic EL may be provided on the surface of the substrate.
  • the anode is formed on the substrate.
  • various wirings, circuits, and switching elements may be interposed between the substrate and the anode.
  • the material used for the anode is not particularly limited as long as it can efficiently inject holes into the organic layer, but it is preferably a transparent or translucent electrode for a bottom emission type element, and a reflective electrode for a top emission type element. Is preferable.
  • Materials for the transparent or translucent electrode include conductive metal oxides such as zinc oxide, tin oxide, indium oxide, indium tin oxide (ITO) and indium zinc oxide (IZO); or gold, silver, aluminum, chromium and the like.
  • conductive metal oxides such as zinc oxide, tin oxide, indium oxide, indium tin oxide (ITO) and indium zinc oxide (IZO); or gold, silver, aluminum, chromium and the like.
  • Metals; conductive polymers such as polythiophene, polypyrrole, polyaniline and the like are exemplified. However, when a metal is used, it is preferable to reduce the film thickness so that light can be semi-transmitted.
  • ITO indium tin oxide
  • ITO indium tin oxide
  • the material of the reflective electrode is preferably one that does not absorb all light and has high reflectance. Specifically, metals such as aluminum, silver, and platinum are exemplified.
  • the optimum method can be adopted depending on the forming material, and examples thereof include a sputtering method, a vapor deposition method, and an inkjet method.
  • a sputtering method is used when an anode is formed of a metal oxide
  • a thin-film deposition method is used when an anode is formed of a metal.
  • the film thickness of the anode is not particularly limited, but is preferably several nm to several hundred nm.
  • these electrode materials may be used alone, or a plurality of materials may be laminated or mixed.
  • the cathode is formed on the surface opposite the anode with the organic layer in between, and is particularly preferably formed on the electron transport layer or the electron injection layer.
  • the material used for the cathode is not particularly limited as long as it can efficiently inject electrons into the light emitting layer, but it is preferably a reflective electrode for a bottom emission type element and a translucent electrode for a top emission type element. Is preferable.
  • Metals such as platinum, gold, silver, copper, iron, tin, aluminum and indium are generally used as cathode materials; these metals are combined with low work function metals such as lithium, sodium, potassium, calcium and magnesium. Alloys and multilayer laminated films; or conductive metal oxides such as zinc oxide, indium tin oxide (ITO), and indium zinc oxide (IZO) are preferable. Among them, a metal selected from aluminum, silver and magnesium as a main component is preferable from the viewpoints of electric resistance value, ease of film formation, film stability, luminous efficiency and the like. Further, when the cathode is composed of magnesium and silver, electron injection into the electron transport layer and the electron injection layer in the present invention becomes easy, and low voltage drive becomes possible, which is preferable.
  • a protective layer (Protective layer) To protect the cathode, it is preferable to laminate a protective layer (cap layer) on the cathode.
  • the material constituting the protective layer is not particularly limited, but for example, metals such as platinum, gold, silver, copper, iron, tin, aluminum and indium; alloys using these metals; silica, titania, silicon nitride and the like.
  • Inorganic substances Organic polymer compounds such as polyvinyl alcohol, polyvinyl chloride, and hydrocarbon-based polymer compounds can be mentioned. However, when the light emitting element has an element structure (top emission structure) that extracts light from the cathode side, the material used for the protective layer is selected from materials having light transmission in the visible light region.
  • the hole injection layer is a layer that is inserted between the anode and the hole transport layer to facilitate hole injection.
  • the hole injection layer may be one layer or a plurality of layers may be laminated.
  • the presence of a hole injection layer between the hole transport layer and the anode enables lower voltage drive, which not only improves the durable life of the device, but also improves the carrier balance of the device and improves the luminous efficiency. It is preferable to do so.
  • a preferable example of the hole injection material is an electron donating hole injection material (donor material). These are materials whose HOMO level is shallower than that of the hole transport layer and which is close to the work function of the anode, so that the energy barrier with the anode can be reduced.
  • benzidine derivatives 4,4', 4 "-tris (3-methylphenyl (phenyl) amino) triphenylamine (m-MTDATA), 4,4', 4" -tris (1-naphthyl (1-naphthyl)
  • Aromatic amine materials such as starburst arylamines such as phenyl) amino) triphenylamine (1-TNATA); carbazole derivatives, pyrazoline derivatives, stilben compounds, hydrazone compounds, benzofuran derivatives, thiophene derivatives, oxadiasols.
  • Heterocyclic compounds such as derivatives, phthalocyanine derivatives, and porphyrin derivatives
  • examples of polymer systems include polycarbonate and styrene derivatives having the monomer in the side chain, polythiophene such as PEDOT / PSS, polyaniline, polyfluorene, polyvinylcarbazole, and polysilane. Will be done. These materials may be used alone or in combination of two or more kinds of materials. Further, a plurality of materials may be laminated to form a hole injection layer.
  • the hole injection material is an electron acceptor hole injection material (acceptor material).
  • the hole injection layer may be composed of the acceptor material alone, or the donor material may be doped with the acceptor material.
  • the acceptor material is a material that forms a charge transfer complex between the adjacent hole transport layers when used alone and with the donor material when used by doping the donor material. It is more preferable to use such a material because it contributes to the improvement of the conductivity of the hole injection layer and the decrease of the driving voltage of the element, and the effects of improving the luminous efficiency and improving the durable life can be obtained.
  • Acceptor materials include metal oxides such as molybdenum oxide, vanadium oxide, tungsten oxide, ruthenium oxide; charge transfer complexes such as tris (4-bromophenyl) aminium hexachloroantimonate (TBPAH); 1,4,5 , 8,9,11-Hexaazatriphenylene-hexacarbonitrile (HAT-CN6), 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), N-type organic semiconductor compounds such as fluorinated copper phthalocyanine; fullerene and the like are exemplified.
  • the hole injection layer may be one layer or may be composed of a plurality of layers laminated.
  • the hole transport layer is a layer that transports holes injected from the anode to the light emitting layer.
  • the hole transport layer may be a single layer or may be formed by laminating a plurality of layers.
  • the hole transport layer is formed by one type of hole transport material alone, or by laminating or mixing two or more types of hole transport materials. Further, the hole transport material preferably has high hole injection efficiency and efficiently transports the injected holes. For that purpose, it is required to be a substance having an appropriate ionization potential, a high hole mobility, excellent stability, and less likely to generate impurities as traps.
  • the substance satisfying such conditions is not particularly limited, but for example, a benzidine derivative, an aromatic amine-based material group called starburst arylamine; a carbazole derivative, a pyrazoline derivative, a stillben-based compound, a hydrazone-based compound, and the like.
  • Heterocyclic compounds such as benzofuran derivatives, dibenzofuran derivatives, thiophene derivatives, benzothiophene derivatives, dibenzothiophene derivatives, fluorene derivatives, spirofluorene derivatives, oxadiazole derivatives, phthalocyanine derivatives, porphyrin derivatives; Examples thereof include polycarbonate and styrene derivatives, polythiophene, polyaniline, polyfluorene, polyvinylcarbazole and polysilane.
  • the light emitting layer is a layer that emits light by the excitation energy generated by the recombination of holes and electrons.
  • the light emitting layer may be composed of a single material, but from the viewpoint of color purity, it is preferable to have a first compound and a second compound which is a dopant exhibiting strong light emission.
  • Suitable examples of the first compound include a host material responsible for charge transfer and a thermally activated delayed fluorescent compound.
  • the pyrromethene boron complex represented by the general formula (1) is a dopant of the light emitting layer because it has a particularly excellent fluorescence quantum yield and the half width of the emission spectrum is narrow and high color purity can be achieved. It is preferably used as the second compound. If the doping amount of the second compound is too large, a concentration quenching phenomenon occurs. Therefore, it is preferably 20% by weight or less, more preferably 10% by weight or less, and 5% by weight or less, based on the total weight of the light emitting layer. More preferably, 2% by weight or less is most preferable. Further, if the doping concentration is too low, sufficient energy transfer is unlikely to occur. Therefore, the weight is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, based on the weight of the entire light emitting layer.
  • the host material does not have to be limited to only one type of compound, and two or more types may be mixed and used, or may be used in a laminated manner.
  • the host material is not particularly limited, but is a compound having a fused aryl ring such as naphthacene, pyrene, anthracene, and fluoranten and a derivative thereof; N, N'-dinaphthyl-N, N'-diphenyl-4,4'-diphenyl-.
  • Aromatic amine derivatives such as 1,1'-diamine; metal chelated oxynoid compounds such as tris (8-quinolinate) aluminum (III); bisstyryl derivatives such as distyrylbenzene derivatives; tetraphenylbutadiene derivatives, inden derivatives, Cmarin derivative, oxadiazole derivative, pyrolopyridine derivative, perinone derivative, pyrolopyrrole derivative, thiadiazolopyridine derivative, dibenzofuran derivative, carbazole derivative, indolocarbazole derivative, triazine derivative; Derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, polythiophene derivatives and the like can be used. Particularly preferred as the host material are anthracene derivatives or naphthacene derivatives.
  • the dopant material is not particularly limited, but may contain a fluorescent material other than the pyrromethene boron complex represented by the general formula (1).
  • a fluorescent material other than the pyrromethene boron complex represented by the general formula (1).
  • compounds having a condensed aryl ring such as naphthacene, pyrene, anthracene, and fluorantene and derivatives thereof; compounds having a heteroaryl ring and derivatives thereof; dystylylbenzene derivatives, aminostyryl derivatives, tetraphenylbutadiene derivatives, stilben derivatives, Examples thereof include aldazine derivatives, pyromethene derivatives, diketopyrrolo [3,4-c] pyrrole derivatives, coumarin derivatives, azole derivatives and metal complexes thereof, and aromatic amine derivatives.
  • a phosphorescent light emitting material may be contained as a dopant material.
  • the dopant that emits phosphorescent light is at least one metal selected from the group consisting of iridium (Ir), ruthenium (Ru), palladium (Pd), platinum (Pt), osmium (Os), and renium (Re). It is preferably a metal complex compound containing, and an iridium complex or a platinum complex is more preferable from the viewpoint of high-efficiency light emission.
  • the ligand preferably has, but is not limited to, a nitrogen-containing heteroaryl group such as a phenylpyridine skeleton or a phenylquinoline skeleton or a carbene skeleton.
  • the dopant material is preferably a pyrromethene boron complex represented by one kind of general formula (1).
  • the light emitting layer may further contain a third component for adjusting the carrier balance in the light emitting layer and for stabilizing the layer structure of the light emitting layer.
  • a third component a material that does not cause an interaction between the host material and the dopant material is selected.
  • Thermally Activated Delayed Fluorescent Compounds also commonly referred to as TADF materials, reduce the energy gap between the singlet excited state energy level and the triplet excited state energy level to reduce the energy gap from the triplet excited state to singlet. It is a material that promotes inverse intersystem crossing to the term excited state and improves the generation probability of singlet excited states.
  • the difference between the lowest excited singlet energy level and the lowest excited triplet energy level (referred to as ⁇ EST) in the TADF material is preferably 0.3 eV or less.
  • the singlet exciton of the second compound Fluorescent emission is observed.
  • the lowest excited singlet energy level of the first compound is larger than the lowest excited singlet energy level of the second compound.
  • the second compound is a fluorescent light emitting material having a sharp light emitting spectrum, a light emitting element having high efficiency and high color purity can be obtained.
  • the light emitting layer contains a thermally activated delayed fluorescent compound, high-efficiency light emission is possible, which contributes to low power consumption of the display.
  • the Thermally Activated Delayed Fluorescence Compound may be a compound that exhibits Thermally Activated Delayed Fluorescence with a Single Material, or exhibits Thermally Activated Delayed Fluorescence with a plurality of compounds as in the case of forming an exciplex complex. It may be a compound.
  • thermally activated delayed fluorescent compound a single compound or a plurality of compounds may be mixed and used, and known materials can be used. Specific examples thereof include benzonitrile derivatives, triazine derivatives, disulfoxide derivatives, carbazole derivatives, indolocarbazole derivatives, dihydrophenazine derivatives, thiazole derivatives, oxaziazole derivatives and the like.
  • a compound having an electron donating part (donor part) and an electron attracting part (acceptor part) in the same molecule is preferable.
  • the electron donating part (donor part) and the electron attracting part may be directly bonded via a single bond or a spiro bond, or may be bonded via a linking group. Examples of such a compound include a compound containing a structure represented by the following general formula (3).
  • A is an electron attracting part
  • B is an electron donating part
  • L is a linking group.
  • A's are the same or different from each other, and the A's may be bonded to each other to form a ring structure.
  • B's are the same or different from each other, and the B's may be bonded to each other to form a ring structure.
  • L is a directly bonded or substituted or unsubstituted ring-forming aromatic hydrocarbon group having 6 to 30 carbon atoms, a substituted or unsubstituted ring-forming atomic ring-forming heteroaromatic ring group having 5 to 30 atoms, and these groups are mutually exclusive. It is a group selected from the group consisting of 2 to 5 linked groups and a methylene group having an alkyl fluoride group.
  • the direct bond includes a single bond and a spiro bond.
  • the heteroaromatic ring group does not include an aromatic amino group having an electron donating property or a ⁇ -electron excess heterocyclic functional group.
  • a and b are independently integers of 1 to 5.
  • a plurality of L may exist in the same molecule.
  • the plurality of L's are the same or different from each other, and the L's may be bonded to each other to form a saturated or unsaturated ring.
  • a plurality of Ls may be connected via A and / or B.
  • a plurality of A and / or B and L are present, a plurality of A and / or B may be bound to the same L or may be bound to different L.
  • the electron donating part indicates a part that is relatively electron-rich with respect to the adjacent part.
  • an aromatic amino group and a ⁇ -electron excess heterocyclic functional group can be mentioned.
  • Examples include linked groups. These groups may or may not be further substituted. Examples of the substituent in the case of substitution include the above-mentioned preferred substituent.
  • the electron attractor part indicates a part that is relatively electron deficient with respect to the adjacent part.
  • a phenyl group having an electron-attracting group or an electron-attracting group as a substituent and a ⁇ -electron-deficient heterocyclic functional group can be mentioned.
  • Specific examples thereof include an electron-attracting group selected from a carbonyl group, a sulfonyl group, a cyano group and a fluorine atom, a phenyl group having an electron-attracting group as a substituent, a pyrimidinyl group and a triazinyl group. These groups may or may not be further substituted. Examples of the substituent in the case of substitution include the above-mentioned preferred substituent.
  • Examples of the aromatic hydrocarbon group having 6 to 30 ring-forming carbon atoms used as the linking group L include a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a benzofluorenyl group and a dibenzofluorenyl group.
  • heteroaromatic ring group having 5 to 30 ring-forming atoms used as the linking group L examples include a pyridyl group, a furanyl group, a thiophenyl group, a quinolinyl group, an isoquinolinyl group, a pyrazinyl group, a pyrimidyl group, a pyridadinyl group and a triazinyl group.
  • a family group can be mentioned.
  • As the hetero atom a nitrogen atom, an oxygen atom, or a sulfur atom is preferable.
  • the heteroaromatic ring group may be
  • the thermally activated delayed fluorescent compound is not particularly limited, but examples thereof include the following.
  • the first compound is a thermally activated delayed fluorescent compound and the second compound is a pyrometheneboron complex represented by the general formula (1).
  • the light emitting layer further contains a third compound having a singlet energy larger than that of the first compound.
  • the third compound can have a function of confining the energy of the light emitting material in the light emitting layer, and can efficiently emit light. It is also preferable that the lowest excited triplet energy of the third compound is larger than the lowest excited triplet energy of the first compound.
  • a third compound it is preferable that it is an organic compound having a high charge transporting ability and a high glass transition temperature.
  • the third compound is not particularly limited, and examples thereof include the following.
  • the third compound may be a single compound or may be composed of two or more kinds of materials.
  • the third compound has an electron transporting property and the third compound has a hole transporting property.
  • the charge balance in the light emitting layer is adjusted and the bias of the light emitting region is suppressed to suppress the bias of the light emitting device. It can improve reliability and durability.
  • an excited complex may be formed between the electron-transporting third compound and the hole-transporting third compound. From the above viewpoint, it is preferable that the first compound and the third compound satisfy the relational expressions of the following formulas 1 to 4, respectively.
  • S1 represents the energy level of the lowest excited singlet state of each compound
  • T1 represents the energy level of the lowest excited triplet state of each compound.
  • Examples of the third electron-transporting compound include compounds containing a ⁇ -electron-deficient heteroaromatic ring. Specifically, 2- (4-biphenyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (PBD), 3- (4-biphenylyl) -4-phenyl-5- (4-tert-butylphenyl) -1,2,4-triazole (TAZ), 1,3-bis [5- (p-tert-butylphenyl) -1,3,4-oxadiazol-2-yl ] Benzene (OXD-7), 9- [4- (5-phenyl-1,3,4-oxadiazol-2-yl) phenyl] -9H-carbazole (CO11), 2,2', 2'' -(1,3,5-Benzenetriyl) Tris (1-phenyl-1H-benzoimidazole) (TPBI), 2- [3- (dibenzo
  • a compound containing a ⁇ -electron excess type heteroaromatic ring and the like can be mentioned.
  • the electron transport layer is a layer in which electrons are injected from the cathode and further electrons are transported.
  • the electron transport material used for the electron transport layer is required to have a high electron affinity, a high electron mobility, excellent stability, and a substance in which impurities that serve as traps are unlikely to be generated. Further, a compound having a molecular weight of 400 or more is preferable because a compound having a low molecular weight tends to crystallize and deteriorate the film quality.
  • the electron transport layer in the present invention also includes a hole blocking layer capable of efficiently blocking the movement of holes as a synonym.
  • the hole blocking layer and the electron transporting layer may be formed alone or by laminating a plurality of materials.
  • the electron transporting material examples include polycyclic aromatic derivatives, styryl-based aromatic ring derivatives, quinone derivatives, phosphoroxide derivatives, quinolinol complexes such as tris (8-quinolinolate) aluminum (III), benzoquinolinol complexes, hydroxyazole complexes, and azomethine complexes. , Tropolone metal complexes and various metal complexes such as flavonol metal complexes. Since the driving voltage can be reduced and high-efficiency light emission can be obtained, it is preferable to use a compound having a heteroaryl group containing electron-accepting nitrogen.
  • the electron-accepting nitrogen represents a nitrogen atom forming a multiple bond with an adjacent atom.
  • the heteroaryl group containing electron-accepting nitrogen has a large electron affinity, electrons can be easily injected from the cathode, and a lower voltage drive becomes possible. In addition, the supply of electrons to the light emitting layer is increased, and the recombination probability is increased, so that the luminous efficiency is improved.
  • the compound having a heteroaryl group structure containing electron-accepting nitrogen include a pyridine derivative, a triazine derivative, a pyrazine derivative, a pyrimidine derivative, a quinoline derivative, a quinoxaline derivative, a quinazoline derivative, a naphthylidine derivative, a benzoquinoline derivative, a phenanthroline derivative, and an imidazole.
  • Preferred compounds include derivatives, oxazole derivatives, thiazole derivatives, triazole derivatives, oxaziazole derivatives, thiadiazol derivatives, benzimidazole derivatives, benzoxazole derivatives, benzthiazole derivatives, phenanthle midazole derivatives, and oligopyridine derivatives such as bipyridine and tarpyridine.
  • imidazole derivatives such as tris (N-phenylbenzimidazole-2-yl) benzene
  • oxadiazole derivatives such as 1,3-bis [(4-tert-butylphenyl) -1,3,4-oxadiazolyl] phenylene.
  • Triazole derivatives such as N-naphthyl-2,5-diphenyl-1,3,4-triazole; phenanthroline derivatives such as vasocproin and 1,3-bis (1,10-phenanthroline-9-yl) benzene; 2,2 Benzene (benzo [h] quinoline-2-yl) -9,9'-benzoquinoline derivatives such as spirobifluorene; 2,5-bis (6'-(2', 2 "-bipyridyl))-1 , 1-Dimethyl-3,4-diphenylsilol and other bipyridine derivatives; 1,3-bis (4'-(2,2': 6'2 "-terpyridinyl)) benzene and other terpyridine derivatives; bis (1-naphthyl) ) -4- (1,8-naphthylidine-2-yl) naphthylidine derivatives such as phenylphosphine oxide
  • the electron transport material has a condensed polycyclic aromatic skeleton because the glass transition temperature is improved, the electron mobility is large, and the voltage can be lowered.
  • a condensed polycyclic aromatic skeleton a fluoranthene skeleton, an anthracene skeleton, a pyrene skeleton or a phenanthroline skeleton is preferable, and a fluoranthene skeleton or a phenanthroline skeleton is particularly preferable.
  • the electron transport material may be used alone or in combination of two or more. Further, the electron transport layer may contain a donor material.
  • the donor material is a compound that facilitates electron injection from the cathode or the electron injection layer into the electron transport layer by improving the electron injection barrier, and further improves the electrical conductivity of the electron transport layer.
  • the donor material include an alkali metal such as Li, an inorganic salt containing an alkali metal such as LiF, a complex of an alkali metal such as lithium quinolinol and an organic substance, an alkaline earth metal, and an alkaline earth metal.
  • alkali metal such as Li
  • an inorganic salt containing an alkali metal such as LiF
  • a complex of an alkali metal such as lithium quinolinol and an organic substance
  • an alkaline earth metal and an alkaline earth metal.
  • examples thereof include inorganic salts, complexes of alkaline earth metals and organic substances, rare earth metals such as Eu and Yb, inorganic salts containing rare earth metals, and complexes of rare earth metals and organic substances.
  • metallic lithium, rare earth metal, or lithium quinolinol (Liq) is particularly preferable.
  • an electron injection layer may be provided between the cathode and the electron transport layer.
  • the electron injection layer is formed for the purpose of assisting the injection of electrons from the cathode to the electron transport layer, and is composed of a compound having a heteroaryl ring structure containing electron-accepting nitrogen and the above-mentioned donor material.
  • a phenanthroline derivative represented by the general formula (4) described later is preferable.
  • an insulator or a semiconductor inorganic substance for the electron injection layer. It is preferable to use these materials because it is possible to prevent a short circuit of the light emitting element and improve the electron injection property.
  • At least one metal compound selected from the group consisting of alkali metal chalcogenides, alkaline earth metal chalcogenides, alkali metal halides and alkaline earth metal halides.
  • the charge generation layer in the present invention is a layer that generates or separates charges by applying a voltage and injects charges into adjacent layers.
  • the charge generation layer may be formed of one layer, or a plurality of layers may be laminated.
  • a layer that easily generates electrons as an electric charge is called an n-type charge generation layer, and a layer that easily generates holes is called a p-type charge generation layer.
  • the charge generation layer is preferably composed of a bilayer, and more preferably a pn junction type charge generation layer composed of an n-type charge generation layer and a p-type charge generation layer.
  • the pn junction type charge generation layer an electric charge is generated by applying a voltage in a light emitting element, or the charge is separated into holes and electrons, and these holes and electrons are separated into a hole transport layer and an electron transport layer. Is injected into the light emitting layer via.
  • the n-type charge generating layer supplies electrons to the first light emitting layer existing on the anode side to supply p-type charges.
  • the generation layer supplies holes to the second light emitting layer existing on the cathode side. Therefore, in a light emitting device having two or more light emitting layers, by having one or more charge generating layers between the light emitting layers, it is possible to further improve the element efficiency and reduce the driving voltage. The durability of the element can be further improved.
  • the n-type charge generation layer is composed of an n-type dopant and an n-type host, and conventional materials can be used for these.
  • the donor material exemplified as the material of the electron transport layer is preferably used.
  • alkali metals or salts thereof and rare earth metals are preferable, and materials selected from metallic lithium, lithium fluoride (LiF), lithium quinolinol (Liq) and metallic ytterbium are more preferable.
  • the n-type host those exemplified as the electron transport material are preferably used.
  • a material selected from a triazine derivative, a phenanthroline derivative and an oligopyridine derivative is preferable, a phenanthroline derivative or a terpyridine derivative is more preferable, and a phenanthroline derivative represented by the following general formula (4) is further preferable. That is, it is preferable that the charge generation layer contains the phenanthroline derivative represented by the general formula (4).
  • Ar 2 is selected from the group consisting of a p-valent aromatic hydrocarbon group and a p-valent heteroaromatic ring group.
  • p is a natural number from 1 to 3.
  • R 15 to R 22 may be the same or different from each other, and are selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, a heterocyclic group, an aryl group and a heteroaryl group.
  • the substitution position by p phenanthrolyl groups is an arbitrary position.
  • aromatic hydrocarbon group and the heteroaromatic ring group examples include those described in the above-mentioned examples of aryl groups and heteroaryl groups, but are not limited thereto.
  • the aromatic hydrocarbon group or heteroaromatic ring group may further have a substituent in addition to the phenanthryl group.
  • p is preferably 2.
  • the p-type charge generation layer is composed of a p-type dopant and a p-type host, and conventional materials can be used for these.
  • the acceptor material exemplified as the material of the hole injection layer, iodine, FeCl 3 , FeF 3 , SbCl 5, and the like are preferably used. Specific examples thereof include HAT-CN6, F4-TCNQ, tetracyanoquinodimethane derivative, radialene derivative, iodine, FeCl 3 , FeF 3 , SbCl 5 and the like.
  • a thin film of the p-type dopant may be formed, and the film thickness is preferably 10 nm or less. Further, an arylamine derivative is preferable as the p-type host.
  • the method for forming each of the above layers constituting the light emitting element may be either a dry process or a wet process, and is not particularly limited, such as resistance heating vapor deposition, electron beam vapor deposition, sputtering, molecular lamination method, coating method, inkjet method, and printing method. Usually, resistance heating vapor deposition is preferable from the viewpoint of device characteristics.
  • the thickness of the organic layer cannot be limited because it depends on the resistance value of the luminescent substance, but it is preferably 1 to 1000 nm.
  • the film thicknesses of the light emitting layer, the electron transport layer, and the hole transport layer are preferably 1 nm or more and 200 nm or less, and more preferably 5 nm or more and 100 nm or less, respectively.
  • the light emitting device has a function of converting electric energy into light.
  • direct current is mainly used as electrical energy, but pulse current and alternating current can also be used.
  • the current value and the voltage value are not particularly limited, and the characteristic values required differ depending on the purpose of the device, but it is preferable that high brightness can be obtained at a low voltage from the viewpoint of power consumption and life of the device.
  • the half width of the light emission spectrum by energization is preferably 60 nm or less, more preferably 50 nm or less, and more preferably 45 nm or less. It is more preferably 30 nm or less, and particularly preferably 30 nm or less.
  • the light emitting device of the present invention has a narrow half width of the light emitting spectrum, it is more preferable to use it as a top emission type light emitting device. Due to the resonance effect of the microcavity, the top emission type light emitting element has higher luminous efficiency as the half width is narrower. Therefore, it is possible to achieve both high color purity and high luminous efficiency.
  • the light emitting element according to the embodiment of the present invention is suitably used as a display device such as a display that displays in a matrix and / or segment system, for example.
  • the light emitting element according to the embodiment of the present invention is preferably used as a backlight for various devices and the like.
  • the backlight is mainly used for the purpose of improving the visibility of display devices such as displays that do not emit light by itself, and is used for display devices such as liquid crystal displays, clocks, audio devices, automobile panels, display boards and signs.
  • the light emitting element of the present invention is preferably used for a liquid crystal display, particularly a backlight for a personal computer whose thinness is being studied, and can provide a backlight thinner and lighter than the conventional one.
  • the light emitting element according to the embodiment of the present invention is preferably used as various lighting devices.
  • the light emitting element according to the embodiment of the present invention can achieve both high luminous efficiency and high color purity, and can be made thinner and lighter, so that low power consumption and bright emission color can be achieved.
  • a lighting device with high design can be realized.
  • reaction product 360 mL of dichloromethane and 5.90 mL of diisopropylethylamine were added and stirred at room temperature for 30 minutes. Further, 4.10 mL of boron trifluorinated diethyl ether complex was added and stirred at room temperature for 4 hours, and then the solvent was distilled off. The mixture was removed, water was added, and the mixture was stirred. The organic layer was separated and washed with saturated brine. The organic layer was dried over magnesium sulfate, filtered, and the solvent was distilled off. The obtained reaction product was purified by silica gelation chromatography to obtain 580 mg of a red powder.
  • Sublimation purification was performed to further increase the purity.
  • a metal container containing compound D-1 was placed in a glass tube, and this was heated at 190 ° C. under a pressure of 1 ⁇ 10 -3 Pa using an oil diffusion pump to sublimate compound D-1.
  • the solid adhering to the glass tube wall was recovered and confirmed by LC-MS analysis to have a purity of 99%.
  • reaction product 8.81 g of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and 200 mL of toluene were placed in a flask and stirred at 40 ° C. for 30 minutes. Then, 17.2 mL of diisopropylethylamine and 12.2 mL of boron trifluorinated diethyl ether complex were added and stirred at room temperature for 30 minutes, and then water was added and stirred. The organic layer was separated and washed with saturated brine. The organic layer was dried over magnesium sulfate, filtered, and the solvent was distilled off.
  • DDQ 2,3-dichloro-5,6-dicyano-1,4-benzoquinone
  • the obtained reaction product was purified by silica gelation chromatography to obtain 3.63 g of a red powder.
  • the obtained powder was analyzed by 1 H-NMR and LC-MS, and it was confirmed that the red powder was compound D-2 which is a pyrromethene boron complex.
  • 1 1 H-NMR (CDCl 3 (d ppm)): 7.72-7.63 (m, 4H), 7.47 (d, 2H), 7.23-7.12 (m, 8H), 5 .81 (s, 2H), 2.38 (s, 6H), 1.57 (s, 6H), 1.32 (s, 9H), 1.22 (s, 18H) MS (m / z) molecular weight; 721.
  • Sublimation purification was performed to further increase the purity.
  • a metal container containing compound D-2 was placed in a glass tube, and this was heated at 240 ° C. under a pressure of 1 ⁇ 10 -3 Pa using an oil diffusion pump to sublimate compound D-2.
  • the solid adhering to the glass tube wall was recovered and confirmed by LC-MS analysis to have a purity of 99%.
  • the pyrometheneboron complex used in the following examples and comparative examples is the compound shown below.
  • Table 1 shows the molecular weight and luminescence characteristics of these pyrromethene boron complexes measured in a toluene solution.
  • Example 1 Evaluation of fluorescent light emitting element
  • a glass substrate manufactured by Geomatec Co., Ltd., 11 ⁇ / ⁇ , sputtered product having an ITO transparent conductive film deposited at 165 nm as an anode was cut into a size of 38 ⁇ 46 mm and etched.
  • the obtained substrate was ultrasonically cleaned with "Semicoclean 56" (trade name, manufactured by Furuuchi Chemical Co., Ltd.) for 15 minutes, then washed with ultrapure water and dried.
  • This substrate was subjected to UV-ozone treatment for 1 hour immediately before the device was manufactured, placed in a vacuum vapor deposition apparatus, and exhausted until the pressure in the apparatus became 5 ⁇ 10 -4 Pa or less.
  • HAT-CN6 was first deposited at 10 nm as a hole injection layer, and HT-1 was deposited at 50 nm as a hole transport layer.
  • H-1 as a host material and compound D-1 as a dopant material were vapor-deposited to a thickness of 20 nm so that the doping concentration was 1.0% by weight.
  • ET-1 was used as the electron transport layer and 2E-1 was used as the donor material, and the layers were laminated to a thickness of 30 nm so that the vapor deposition rate ratio of ET-1 and 2E-1 was 1: 1.
  • magnesium and silver were co-deposited at 1000 nm to form a cathode, and a 5 ⁇ 5 mm square device was manufactured.
  • the light emitting characteristics were an emission peak wavelength of 529 nm, a half width of 26 nm, and an external quantum efficiency of 4.0%. Further, the durability was evaluated by the time when the initial brightness was continuously energized with a current of 1000 cd / m 2 and the brightness became 90% of the initial brightness (hereinafter referred to as LT90). As a result, the LT90 of this light emitting element was 99 hours.
  • HAT-CN6, HT-1, H-1, ET-1 and 2E-1 are the compounds shown below, respectively.
  • Examples 2 to 15 Comparative Examples 1 to 3 A light emitting device was produced and evaluated in the same manner as in Example 1 except that the compounds shown in Table 2 were used instead of the compound D-1 as the dopant material. The results are shown in Table 2.
  • Example 16 A glass substrate (manufactured by Geomatec Co., Ltd., 11 ⁇ / ⁇ , sputtered product) having an ITO transparent conductive film deposited at 100 nm as an anode was cut into a size of 38 ⁇ 46 mm and etched. The obtained substrate was ultrasonically cleaned with "Semicoclean 56" (trade name, manufactured by Furuuchi Chemical Co., Ltd.) for 15 minutes, and then washed with ultrapure water.
  • “Semicoclean 56" trade name, manufactured by Furuuchi Chemical Co., Ltd.
  • This substrate was subjected to UV-ozone treatment for 1 hour immediately before the device was manufactured, placed in a vacuum vapor deposition apparatus, and evacuated until the degree of vacuum in the apparatus became 5 ⁇ 10 -4 Pa or less.
  • HAT-CN6 was first deposited at 10 nm as a hole injection layer, and HT-1 was deposited at 40 nm as a hole transport layer.
  • the host material H-2, the compound D-1, and the TADF material compound H-3 are adjusted to a weight ratio of 79.5: 0.5: 20 to 30 nm. It was deposited to the thickness of.
  • compound ET-1 is used as the electron transport material and 2E-1 is used as the donor material, and the thickness of the compounds ET-1 and 2E-1 is 50 nm so that the vapor deposition rate ratio is 1: 1. It was laminated on the surface. Next, after depositing 2E-1 at 0.5 nm as an electron injection layer, magnesium and silver were co-deposited at 1000 nm to form a cathode, and a 5 ⁇ 5 mm square device was manufactured.
  • H-2 and H-3 are the compounds shown below.
  • Examples 17 to 20 Comparative Examples 4 to 6 A light emitting device was produced and evaluated in the same manner as in Example 16 except that the compounds shown in Table 3 were used as the dopant material. The results are shown in Table 3.
  • a light emitting device having high color purity, luminous efficiency and device durability can be manufactured.
  • the luminous efficiency can be increased in the manufacture of display devices such as displays and lighting devices.
  • Example 21 A glass substrate (manufactured by Geomatec Co., Ltd., 11 ⁇ / ⁇ , sputtered product) having an ITO transparent conductive film deposited at 165 nm as an anode was cut into 38 mm ⁇ 46 mm and etched. The obtained substrate was ultrasonically cleaned with "Semicoclean" 56 (trade name, manufactured by Furuuchi Chemical Co., Ltd.) for 15 minutes, and then washed with ultrapure water.
  • “Semicoclean” 56 trade name, manufactured by Furuuchi Chemical Co., Ltd.
  • This substrate was subjected to UV-ozone treatment for 1 hour immediately before the device was manufactured, placed in a vacuum vapor deposition apparatus, and evacuated until the degree of vacuum in the apparatus became 5 ⁇ 10 -4 Pa or less.
  • HAT-CN6 was first deposited at 5 nm as a hole injection layer, and then HT-1 was deposited at 50 nm as a hole transport layer.
  • H-1 was used as the hole blocking layer at 10 nm
  • the host material H-1 and the dopant compound D-1 were used as the light emitting layer in a weight ratio of 99.5: 0.5 to 20 nm. It was deposited to a thickness.
  • ET-1 was laminated to a thickness of 10 nm as an electron blocking layer
  • compound ET-3 was laminated to a thickness of 35 nm as an electron transporting layer.
  • the compound ET-3 which is an n-type host
  • metallic lithium which is an n-type dopant
  • HAT-CN6 was laminated at 10 nm as a p-type charge generation layer.
  • a hole transport layer of 50 nm, a hole blocking layer of 10 mn, and a light emitting layer of 20 nm were formed on the hole transport layer in the same manner as described above.
  • ET-2 was deposited at 10 nm as an electron blocking layer
  • ET-3 was deposited at 35 nm as an electron transporting layer.
  • magnesium and silver were co-deposited at 1000 nm to serve as a cathode, and a tandem type light emitting device of 5 mm ⁇ 5 mm square was produced.
  • the light emitting characteristics were an emission peak wavelength of 530 nm, a half width of 25 nm, an external quantum efficiency of 4.3%, and an LT90 of 110 hours. It was confirmed that the durability was improved as compared with Example 1 in which the light emitting layer was only one layer.
  • ET-2 and ET-3 are the compounds shown below.

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Abstract

By means of a pyrromethene boron complex represented by general formula (1), provided are: a light-emitting material having a high fluorescence quantum yield and a sharp light-emitting spectrum; and a light-emitting element having a high light-emitting efficiency, color purity, and a durability. (R1-R6 are each independently selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, a hydroxyl group, a thiol group, an alkoxy group, an alkylthio group, an aryl ether group, an aryl thioether group, an aryl group, a heteroaryl group, an amino group, a silyl group, a siloxanyl group, and a boryl group. Said groups may also be substituents. Here, at least one among R1 to R4 is a hydrogen atom or an alkyl group. X1 and X2 are each independently selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, a hydroxyl group, a thiol group, an alkoxy group, an alkylthio group, an aryl ether group, an aryl thioether group, an aryl group, a heteroaryl group, halogen, a cyano group, an aldehyde group, an acyl group, a carboxyl group, an ester group, an amide group, a sulfonyl group, a sulfonic acid ester group, a sulfonamide group, an amino group, a nitro group, a silyl group, a siloxanyl group, a boryl group, and a phosphine oxide group. Said groups may also be substituents. R7 is represented by general formula (2).) (R8-R10 are each independently selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, a hydroxyl group, a thiol group, an alkoxy group, an alkylthio group, an arylether group, an arylthioether group, an aryl group, a heteroaryl group, halogen, a cyano group, an aldehyde group, an acyl group, a carboxyl group, an ester group, an amide group, a sulfonyl group, a sulfonic acid ester group, a sulfonamide group, an amino group, a nitro group, a silyl group, a siloxanyl group, a boryl group, and a phosphine oxide group. Said groups may also be substituents. R11 is selected from the group consisting of an alkyl group, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, a hydroxyl group, a thiol group, an alkoxy group, an alkylthio group, an arylether group, an arylthioether group, an aryl group, a heteroaryl group, halogen, a cyano group, an aldehyde group, an acyl group, a carboxyl group, an ester group, an amide group, a sulfonyl group, a sulfonic acid ester group, a sulfonamide group, an amino group, a nitro group, a silyl group, a siloxanyl group, a boryl group, and a phosphine oxide group. Said groups may also be substituents. Ar1 is a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group.)

Description

ピロメテンホウ素錯体、それを含有する発光素子、表示装置および照明装置Pyromethene boron complex, light emitting element containing it, display device and lighting device
　本発明は、ピロメテンホウ素錯体、それを含有する発光素子、表示装置および照明装置に関する。 The present invention relates to a pyrromethene boron complex, a light emitting device containing the pyromethene boron complex, a display device, and a lighting device.
　陰極から注入された電子と陽極から注入された正孔が両極に挟まれた発光層内で再結合することにより発光する有機薄膜発光素子は、薄型であり、かつ、低駆動電圧および高輝度発光が可能、さらに発光材料を選ぶことにより多色発光が可能という特徴を有する。特に、発光層にホスト材料とドーパント材料を組み合わせて用いることにより、青、緑および赤の三原色の光を高効率に発光する発光素子を得ることができる。 The organic thin film light emitting element that emits light by recombining the electrons injected from the cathode and the holes injected from the anode in the light emitting layer sandwiched between the two electrodes is thin, has a low drive voltage, and emits high brightness. Furthermore, it has the feature that multicolor light emission is possible by selecting a light emitting material. In particular, by using a host material and a dopant material in combination for the light emitting layer, it is possible to obtain a light emitting element that emits light of the three primary colors of blue, green, and red with high efficiency.
　ドーパントとしては、蛍光量子収率の高い色素が通常用いられる。例えばピロメテン骨格を有する錯体は、蛍光量子収率が高い、ストークスシフトおよび発光スペクトルのピーク半値幅が小さいといったドーパントとして高い効率を得るのに必要な要件を備えた化合物であり、ドーパントとしてピロメテン錯体を用いた発光素子は、良好な素子特性を示すことが知られている（例えば、特許文献１参照）。さらに近年では、高発光効率を目指して、ＴＡＤＦ（Ｔｈｅｒｍａｌｌｙ　Ａｃｔｉｖａｔｅｄ　Ｄｅｌａｙｅｄ　Ｆｌｕｏｒｅｓｃｅｎｃｅ、熱活性化遅延蛍光）材料とピロメテンホウ素錯体を含む発光素子が検討されている（例えば、特許文献２参照）。 As the dopant, a dye having a high fluorescence quantum yield is usually used. For example, a complex having a pyrromethene skeleton is a compound having requirements necessary for obtaining high efficiency as a dopant such as high fluorescence quantum yield, small Stokes shift and small peak half-value width of emission spectrum, and a pyrromethene complex can be used as a dopant. The light emitting element used is known to exhibit good element characteristics (see, for example, Patent Document 1). Further, in recent years, aiming at high luminous efficiency, a light emitting element containing a TADF (Thermally Activated Fluorescence) material and a pyromethene boron complex has been studied (see, for example, Patent Document 2).
特開２００３－１２６７６号公報Japanese Unexamined Patent Publication No. 2003-12676 国際公開第２０１６／０５６５５９号International Publication No. 2016/056559
　有機薄膜発光素子を表示装置や照明装置として利用する場合、色域を広くすることが求められている。色域はｘｙ色度図において赤、緑および青のそれぞれの発光を示す頂点座標を決め、それらを結んだ三角形で表される。色域を広くするためには、該三角形の面積が広くなるように赤、緑および青の各頂点座標を適切な色度にすることが必要であり、そのために様々な色設計が行われている。 When using an organic thin film light emitting element as a display device or a lighting device, it is required to widen the color gamut. The color gamut is represented by a triangle connecting the coordinates of the vertices indicating the emission of red, green, and blue in the xy chromaticity diagram. In order to widen the color gamut, it is necessary to set the coordinates of each vertex of red, green, and blue to an appropriate chromaticity so that the area of the triangle is wide, and various color designs are performed for that purpose. There is.
　色度は発光ピーク波長と色純度の組合せにより決められる。色純度は発光スペクトルの幅により決まり、発光スペクトルの幅が狭くなり単色光に近づくほど色純度が高くなる。広色域化のためには色純度を上げることが特に重要であり、シャープな発光スペクトルを持つ発光材料が強く求められている。 Chromaticity is determined by the combination of emission peak wavelength and color purity. The color purity is determined by the width of the emission spectrum, and the narrower the width of the emission spectrum and the closer to monochromatic light, the higher the color purity. Increasing the color purity is particularly important for widening the color gamut, and there is a strong demand for a light emitting material having a sharp emission spectrum.
　また、有機薄膜発光素子を表示装置や照明装置として利用する場合、発光素子の耐久性を向上することが求められている。発光素子の耐久性を向上させるためには、発光材料の安定性を高める必要がある。 Further, when an organic thin film light emitting element is used as a display device or a lighting device, it is required to improve the durability of the light emitting element. In order to improve the durability of the light emitting element, it is necessary to improve the stability of the light emitting material.
　一方、有機薄膜発光素子は輝度向上と省電力の観点から、高い発光効率が望まれている。特に近年使用が拡大しているモバイル表示装置においては、省電力化が特に重要な課題となっている。 On the other hand, the organic thin film light emitting element is desired to have high luminous efficiency from the viewpoint of improving brightness and power saving. Especially in mobile display devices whose use has been expanding in recent years, power saving has become a particularly important issue.
　このような状況において、ピロメテンホウ素錯体は、ドーパントとして用いた場合、シャープな発光スペクトルを得られる、有用な発光材料ではあるものの、発光素子においてより高い発光効率とより高い耐久性が求められている。しかしシャープな発光スペクトルを保持しつつ、高い発光効率と高い耐久性を有する発光素子を達成することは困難であった。 In such a situation, the pyrromethene boron complex is a useful light emitting material that can obtain a sharp emission spectrum when used as a dopant, but is required to have higher luminous efficiency and higher durability in a light emitting device. .. However, it has been difficult to achieve a light emitting device having high luminous efficiency and high durability while maintaining a sharp emission spectrum.
　本発明は、かかる従来技術の問題を解決し、蛍光量子収率が高く発光スペクトルがシャープな発光材料および、発光効率、色純度および耐久性が高い発光素子を提供することを目的とするものである。 An object of the present invention is to solve the problems of the prior art and to provide a light emitting material having a high fluorescence quantum yield and a sharp emission spectrum, and a light emitting element having high luminous efficiency, color purity and durability. be.
　本発明は、一般式（１）で表されるピロメテンホウ素錯体である。 The present invention is a pyrromethene boron complex represented by the general formula (1).
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000004
Ｒ１～Ｒ６は、それぞれ独立に、水素原子、アルキル基、シクロアルキル基、複素環基、アルケニル基、シクロアルケニル基、アルキニル基、水酸基、チオール基、アルコキシ基、アルキルチオ基、アリールエーテル基、アリールチオエーテル基、アリール基、ヘテロアリール基、アミノ基、シリル基、シロキサニル基およびボリル基からなる群より選ばれる。これらの基はさらに置換基を有していてもよい。ただし、Ｒ１～Ｒ４のうち少なくとも一つは水素原子もしくはアルキル基である。
Ｘ１およびＸ２は、それぞれ独立に、アルキル基、シクロアルキル基、複素環基、アルケニル基、シクロアルケニル基、アルキニル基、水酸基、チオール基、アルコキシ基、アルキルチオ基、アリールエーテル基、アリールチオエーテル基、アリール基、ヘテロアリール基、ハロゲン、およびシアノ基からなる群より選ばれる。これらの基はさらに置換基を有していてもよい。
Ｒ７は下記一般式（２）で表される。 R 1 to R 6 are independently hydrogen atom, alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, hydroxyl group, thiol group, alkoxy group, alkylthio group, aryl ether group, respectively. It is selected from the group consisting of an arylthioether group, an aryl group, a heteroaryl group, an amino group, a silyl group, a siloxanyl group and a boryl group. These groups may further have substituents. However, at least one of R 1 to R 4 is a hydrogen atom or an alkyl group.
X 1 and X 2 are independently alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, hydroxyl group, thiol group, alkoxy group, alkylthio group, arylether group and arylthioether group, respectively. , Heteroaryl group, halogen, and cyano group. These groups may further have substituents.
R 7 is represented by the following general formula (2).
Figure JPOXMLDOC01-appb-C000005
Figure JPOXMLDOC01-appb-C000005
Ｒ８～Ｒ１０は、それぞれ独立に、水素原子、アルキル基、シクロアルキル基、複素環基、アルケニル基、シクロアルケニル基、アルキニル基、水酸基、チオール基、アルコキシ基、アルキルチオ基、アリールエーテル基、アリールチオエーテル基、アリール基、ヘテロアリール基、ハロゲン、シアノ基、アルデヒド基、アシル基、カルボキシル基、エステル基、アミド基、スルホニル基、スルホン酸エステル基、スルホンアミド基、アミノ基、ニトロ基、シリル基、シロキサニル基、ボリル基およびホスフィンオキシド基からなる群より選ばれる。これらの基はさらに置換基を有していてもよい。
Ｒ１１は、アルキル基、シクロアルキル基、複素環基、アルケニル基、シクロアルケニル基、アルキニル基、水酸基、チオール基、アルコキシ基、アルキルチオ基、アリールエーテル基、アリールチオエーテル基、アリール基、ヘテロアリール基、ハロゲン、シアノ基、アルデヒド基、アシル基、カルボキシル基、エステル基、アミド基、スルホニル基、スルホン酸エステル基、スルホンアミド基、アミノ基、ニトロ基、シリル基、シロキサニル基、ボリル基およびホスフィンオキシド基からなる群より選ばれる。これらの基はさらに置換基を有していてもよい。
Ａｒ１は、置換もしくは無置換のアリール基、または置換もしくは無置換のヘテロアリール基である。 R 8 to R 10 are independently hydrogen atom, alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, hydroxyl group, thiol group, alkoxy group, alkylthio group, arylether group, respectively. Arylthioether group, aryl group, heteroaryl group, halogen, cyano group, aldehyde group, acyl group, carboxyl group, ester group, amide group, sulfonyl group, sulfonic acid ester group, sulfonamide group, amino group, nitro group, silyl group. It is selected from the group consisting of a group, a siloxanyl group, a boryl group and a phosphine oxide group. These groups may further have substituents.
R 11 is an alkyl group, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, a hydroxyl group, a thiol group, an alkoxy group, an alkylthio group, an aryl ether group, an arylthioether group, an aryl group or a heteroaryl group. , Halogen, cyano group, aldehyde group, acyl group, carboxyl group, ester group, amide group, sulfonyl group, sulfonic acid ester group, sulfonamide group, amino group, nitro group, silyl group, siroxanyl group, boryl group and phosphine oxide. Selected from the group consisting of groups. These groups may further have substituents.
Ar 1 is a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group.
　また、本発明の別の態様は、陽極と陰極、および該陽極と該陰極との間に存在する発光層を有し、該発光層が電気エネルギーにより発光する素子であって、前記発光層中に上記のピロメテンホウ素錯体を含有する発光素子である。 Further, another aspect of the present invention is an element having an anode and a cathode, and a light emitting layer existing between the anode and the cathode, and the light emitting layer emits light by electric energy, and the light emitting layer contains the light emitting layer. It is a light emitting element containing the above-mentioned pyromethene boron complex.
　本発明により、蛍光量子収率が高く発光スペクトルがシャープな発光材料および、発光効率、色純度および耐久性が高い発光素子を提供することができる。 INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a light emitting material having a high fluorescence quantum yield and a sharp light emitting spectrum, and a light emitting element having high luminous efficiency, color purity and durability.
　以下、本発明に係るピロメテンホウ素錯体、それを含有する発光素子、表示装置および照明装置の好適な実施の形態を詳細に説明する。ただし、本発明は、以下の実施の形態に限定されるものではなく、目的や用途に応じて種々に変更して実施することができる。 Hereinafter, preferred embodiments of the pyrromethene boron complex according to the present invention, a light emitting device containing the same, a display device, and a lighting device will be described in detail. However, the present invention is not limited to the following embodiments, and can be variously modified and implemented according to an object and an application.
　＜ピロメテンホウ素錯体＞
　本発明に係るピロメテンホウ素錯体は一般式（１）で表される。 <Pyromethene boron complex>
The pyrromethene boron complex according to the present invention is represented by the general formula (1).
Figure JPOXMLDOC01-appb-C000006
Figure JPOXMLDOC01-appb-C000006
　Ｒ１～Ｒ６は、それぞれ独立に、水素原子、アルキル基、シクロアルキル基、複素環基、アルケニル基、シクロアルケニル基、アルキニル基、水酸基、チオール基、アルコキシ基、アルキルチオ基、アリールエーテル基、アリールチオエーテル基、アリール基、ヘテロアリール基、アミノ基、シリル基、シロキサニル基およびボリル基からなる群より選ばれる。これらの基はさらに置換基を有していてもよい。ただし、Ｒ１～Ｒ４のうち少なくとも一つは水素原子もしくはアルキル基である。 R 1 to R 6 are independently hydrogen atom, alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, hydroxyl group, thiol group, alkoxy group, alkylthio group, aryl ether group, respectively. It is selected from the group consisting of an arylthioether group, an aryl group, a heteroaryl group, an amino group, a silyl group, a siloxanyl group and a boryl group. These groups may further have substituents. However, at least one of R 1 to R 4 is a hydrogen atom or an alkyl group.
　Ｘ１およびＸ２は、それぞれ独立に、アルキル基、シクロアルキル基、複素環基、アルケニル基、シクロアルケニル基、アルキニル基、水酸基、チオール基、アルコキシ基、アルキルチオ基、アリールエーテル基、アリールチオエーテル基、アリール基、ヘテロアリール基、ハロゲン、およびシアノ基からなる群より選ばれる。これらの基はさらに置換基を有していてもよい。 X 1 and X 2 are independently alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, hydroxyl group, thiol group, alkoxy group, alkylthio group, arylether group and arylthioether group, respectively. , Heteroaryl group, halogen, and cyano group. These groups may further have substituents.
　Ｒ７は下記一般式（２）で表される。 R 7 is represented by the following general formula (2).
Figure JPOXMLDOC01-appb-C000007
Figure JPOXMLDOC01-appb-C000007
　Ｒ８～Ｒ１０は、それぞれ独立に、水素原子、アルキル基、シクロアルキル基、複素環基、アルケニル基、シクロアルケニル基、アルキニル基、水酸基、チオール基、アルコキシ基、アルキルチオ基、アリールエーテル基、アリールチオエーテル基、アリール基、ヘテロアリール基、ハロゲン、シアノ基、アルデヒド基、アシル基、カルボキシル基、エステル基、アミド基、スルホニル基、スルホン酸エステル基、スルホンアミド基、アミノ基、ニトロ基、シリル基、シロキサニル基、ボリル基およびホスフィンオキシド基からなる群より選ばれる。これらの基はさらに置換基を有していてもよい。 R 8 to R 10 are independently hydrogen atom, alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, hydroxyl group, thiol group, alkoxy group, alkylthio group, arylether group, respectively. Arylthioether group, aryl group, heteroaryl group, halogen, cyano group, aldehyde group, acyl group, carboxyl group, ester group, amide group, sulfonyl group, sulfonic acid ester group, sulfonamide group, amino group, nitro group, silyl group. It is selected from the group consisting of a group, a siloxanyl group, a boryl group and a phosphine oxide group. These groups may further have substituents.
　Ｒ１１は、アルキル基、シクロアルキル基、複素環基、アルケニル基、シクロアルケニル基、アルキニル基、水酸基、チオール基、アルコキシ基、アルキルチオ基、アリールエーテル基、アリールチオエーテル基、アリール基、ヘテロアリール基、ハロゲン、シアノ基、アルデヒド基、アシル基、カルボキシル基、エステル基、アミド基、スルホニル基、スルホン酸エステル基、スルホンアミド基、アミノ基、ニトロ基、シリル基、シロキサニル基、ボリル基およびホスフィンオキシド基からなる群より選ばれる。これらの基はさらに置換基を有していてもよい。 R 11 is an alkyl group, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, a hydroxyl group, a thiol group, an alkoxy group, an alkylthio group, an aryl ether group, an arylthioether group, an aryl group or a heteroaryl group. , Halogen, cyano group, aldehyde group, acyl group, carboxyl group, ester group, amide group, sulfonyl group, sulfonic acid ester group, sulfonamide group, amino group, nitro group, silyl group, siroxanyl group, boryl group and phosphine oxide. Selected from the group consisting of groups. These groups may further have substituents.
　Ａｒ１は、置換もしくは無置換のアリール基、または置換もしくは無置換のヘテロアリール基である。 Ar 1 is a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group.
　ピロメテン骨格において、Ｒ７で置換される部位を以下「橋頭位」と称する場合がある。 In pyrromethene skeleton, there is a case where the site to be substituted by R 7 hereinafter referred to as "bridgehead position".
　本発明においては、下式で表されるピロメテン骨格を有するもの、およびピロメテン骨格の一部に縮環構造を有し、環構造が広がっているものを合わせて「ピロメテン」と称する。 In the present invention, a substance having a pyrromethene skeleton represented by the following formula and a substance having a condensed ring structure in a part of the pyrromethene skeleton and having a wide ring structure are collectively referred to as "pyromethene".
Figure JPOXMLDOC01-appb-C000008
Figure JPOXMLDOC01-appb-C000008
　上記の全ての基において、水素は重水素であってもよい。以下に説明する化合物またはその部分構造においても同様である。 In all the above groups, hydrogen may be deuterium. The same applies to the compounds described below or their partial structures.
　また、上記の全ての基において、置換される場合における置換基としては、アルキル基、シクロアルキル基、複素環基、アルケニル基、シクロアルケニル基、アルキニル基、アリール基、ヘテロアリール基、水酸基、チオール基、アルコキシ基、アルキルチオ基、アリールエーテル基、アリールチオエーテル基、ハロゲン、シアノ基、アルデヒド基、アシル基、カルボキシル基、エステル基、アミド基、アシル基、スルホニル基、スルホン酸エステル基、スルホンアミド基、アミノ基、ニトロ基、シリル基、シロキサニル基、ボリル基、ホスフィンオキシド基およびオキソ基からなる群より選ばれる基が好ましい。さらには、後述の各置換基の説明において好ましいとする具体的な置換基がより好ましい。また、これらの置換基は、さらに上述の置換基により置換されていてもよい。 Further, in all the above groups, the substituents in the case of substitution include an alkyl group, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an aryl group, a heteroaryl group, a hydroxyl group and a thiol. Group, alkoxy group, alkylthio group, arylether group, arylthioether group, halogen, cyano group, aldehyde group, acyl group, carboxyl group, ester group, amide group, acyl group, sulfonyl group, sulfonic acid ester group, sulfonamide group , Amino group, nitro group, silyl group, siroxanyl group, boryl group, phosphine oxide group and oxo group are preferably selected from the group. Furthermore, specific substituents that are preferable in the description of each substituent described later are more preferable. Further, these substituents may be further substituted with the above-mentioned substituents.
　本説明の説明において「無置換」とは、対象となる基本骨格または基に結合する原子が水素原子または重水素原子のみであることを意味する。以下に説明する化合物またはその部分構造において、「置換もしくは無置換の」という場合についても、上記と同様である。 In the explanation of this explanation, "unsubstituted" means that the atom bonded to the target basic skeleton or group is only a hydrogen atom or a deuterium atom. The same applies to the case of "substituted or unsubstituted" in the compound described below or its partial structure.
　アルキル基とは、例えば、メチル基、エチル基、ｎ－プロピル基、イソプロピル基、ｎ－ブチル基、ｓｅｃ－ブチル基、ｔｅｒｔ－ブチル基などの飽和脂肪族炭化水素基を示し、これは置換されていても無置換でもよい。置換されている場合の追加の置換基には特に制限は無く、例えば、アルキル基、ハロゲン、アリール基、ヘテロアリール基等を挙げることができ、この点は、以下の記載にも共通する。アルキル基の炭素数は特に限定されないが、入手の容易性やコストの点から、好ましくは１以上２０以下、より好ましくは１以上８以下の範囲である。 The alkyl group refers to a saturated aliphatic hydrocarbon group such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group and a tert-butyl group, which are substituted. It may be non-replaceable. The additional substituent when substituted is not particularly limited, and examples thereof include an alkyl group, a halogen, an aryl group, and a heteroaryl group, and this point is also common to the following description. The number of carbon atoms of the alkyl group is not particularly limited, but is preferably 1 or more and 20 or less, and more preferably 1 or more and 8 or less from the viewpoint of availability and cost.
　シクロアルキル基とは、例えば、シクロプロピル基、シクロヘキシル基、ノルボルニル基、アダマンチル基などの飽和脂環式炭化水素基を示し、これは置換されていても無置換でもよい。アルキル基部分の炭素数は特に限定されないが、好ましくは、３以上２０以下の範囲である。 The cycloalkyl group refers to a saturated alicyclic hydrocarbon group such as a cyclopropyl group, a cyclohexyl group, a norbornyl group, or an adamantyl group, which may be substituted or unsubstituted. The number of carbon atoms in the alkyl group moiety is not particularly limited, but is preferably in the range of 3 or more and 20 or less.
　複素環基とは、例えば、ピラン環、ピペリジン環、環状アミドなどの炭素以外の原子を環内に有する脂肪族環を示し、これは置換されていても無置換でもよい。複素環基の炭素数は特に限定されないが、好ましくは、２以上２０以下の範囲である。 The heterocyclic group refers to an aliphatic ring having an atom other than carbon such as a pyran ring, a piperidine ring, and a cyclic amide in the ring, which may be substituted or unsubstituted. The number of carbon atoms of the heterocyclic group is not particularly limited, but is preferably in the range of 2 or more and 20 or less.
　アルケニル基とは、例えば、ビニル基、アリル基、ブタジエニル基などの二重結合を含む不飽和脂肪族炭化水素基を示し、これは置換されていても無置換でもよい。アルケニル基の炭素数は特に限定されないが、好ましくは、２以上２０以下の範囲である。 The alkenyl group refers to an unsaturated aliphatic hydrocarbon group containing a double bond such as a vinyl group, an allyl group, or a butadienyl group, which may be substituted or unsubstituted. The carbon number of the alkenyl group is not particularly limited, but is preferably in the range of 2 or more and 20 or less.
　シクロアルケニル基とは、例えば、シクロペンテニル基、シクロペンタジエニル基、シクロヘキセニル基などの二重結合を含む不飽和脂環式炭化水素基を示し、これは置換されていても無置換でもよい。シクロアルケニル基の炭素数は特に限定されないが、好ましくは、３以上２０以下の範囲である。 The cycloalkenyl group refers to an unsaturated alicyclic hydrocarbon group containing a double bond such as a cyclopentenyl group, a cyclopentadienyl group, a cyclohexenyl group, etc., which may be substituted or unsubstituted. .. The number of carbon atoms of the cycloalkenyl group is not particularly limited, but is preferably in the range of 3 or more and 20 or less.
　アルキニル基とは、例えば、エチニル基などの三重結合を含む不飽和脂肪族炭化水素基を示し、これは置換されていても無置換でもよい。アルキニル基の炭素数は特に限定されないが、好ましくは、２以上２０以下の範囲である。 The alkynyl group refers to an unsaturated aliphatic hydrocarbon group containing a triple bond such as an ethynyl group, which may be substituted or unsubstituted. The number of carbon atoms of the alkynyl group is not particularly limited, but is preferably in the range of 2 or more and 20 or less.
　アルコキシ基とは、例えば、メトキシ基、エトキシ基、プロポキシ基などのエーテル結合を介して脂肪族炭化水素基が結合した官能基を示し、この脂肪族炭化水素基は置換されていても無置換でもよい。アルコキシ基の炭素数は特に限定されないが、好ましくは、１以上２０以下の範囲である。 The alkoxy group refers to a functional group in which an aliphatic hydrocarbon group is bonded via an ether bond such as a methoxy group, an ethoxy group, or a propoxy group, and the aliphatic hydrocarbon group may be substituted or unsubstituted. good. The number of carbon atoms of the alkoxy group is not particularly limited, but is preferably in the range of 1 or more and 20 or less.
　アルキルチオ基とは、アルコキシ基のエーテル結合の酸素原子が硫黄原子に置換されたものである。アルキルチオ基の炭化水素基は置換されていても無置換でもよい。アルキルチオ基の炭素数は特に限定されないが、好ましくは、１以上２０以下の範囲である。 The alkylthio group is one in which the oxygen atom of the ether bond of the alkoxy group is replaced with a sulfur atom. The hydrocarbon group of the alkylthio group may be substituted or unsubstituted. The number of carbon atoms of the alkylthio group is not particularly limited, but is preferably in the range of 1 or more and 20 or less.
　アリールエーテル基とは、例えば、フェノキシ基など、エーテル結合を介して芳香族炭化水素基が結合した官能基を示し、芳香族炭化水素基は置換されていても無置換でもよい。アリールエーテル基の炭素数は特に限定されないが、好ましくは、６以上４０以下の範囲である。 The aryl ether group refers to a functional group in which an aromatic hydrocarbon group is bonded via an ether bond, such as a phenoxy group, and the aromatic hydrocarbon group may be substituted or unsubstituted. The number of carbon atoms of the aryl ether group is not particularly limited, but is preferably in the range of 6 or more and 40 or less.
　アリールチオエーテル基とは、アリールエーテル基のエーテル結合の酸素原子が硫黄原子に置換されたものである。アリールチオエーテル基における芳香族炭化水素基は置換されていても無置換でもよい。アリールチオエーテル基の炭素数は特に限定されないが、好ましくは、６以上４０以下の範囲である。 The arylthio ether group is one in which the oxygen atom of the ether bond of the aryl ether group is replaced with a sulfur atom. The aromatic hydrocarbon group in the arylthioether group may be substituted or unsubstituted. The number of carbon atoms of the arylthioether group is not particularly limited, but is preferably in the range of 6 or more and 40 or less.
　アリール基は、単環もしくは縮合環のいずれでもよく、例えば、フェニル基、ナフチル基、フルオレニル基、ベンゾフルオレニル基、ジベンゾフルオレニル基、フェナントリル基、アントラセニル基、ベンゾフェナントリル基、ベンゾアントラセニル基、クリセニル基、ピレニル基、フルオランテニル基、トリフェニレニル基、ベンゾフルオランテニル基、ジベンゾアントラセニル基、ペリレニル基、ヘリセニル基などの芳香族炭化水素基を示す。中でも、フェニル基、ビフェニル基、ターフェニル基、ナフチル基、フルオレニル基、フェナントリル基、アントラセニル基、ピレニル基、フルオランテニル基およびトリフェニレニル基からなる群より選ばれる基が好ましい。アリール基は、置換されていても無置換でもよい。本発明では、ビフェニル基、ターフェニル基など複数のフェニル基が単結合を介して結合している基は、アリール基を置換基として有するフェニル基として扱うものとする。アリール基の炭素数は特に限定されないが、好ましくは６以上４０以下、より好ましくは６以上３０以下の範囲である。また、フェニル基においては、そのフェニル基中の隣接する２つの炭素原子上に各々置換基がある場合、それらの置換基同士で環構造を形成していてもよい。 The aryl group may be either a monocyclic ring or a fused ring, and may be, for example, a phenyl group, a naphthyl group, a fluorenyl group, a benzofluorenyl group, a dibenzofluorenyl group, a phenanthryl group, an anthrasenyl group, a benzophenanthryl group or a benzo. It shows an aromatic hydrocarbon group such as anthrasenyl group, chrysenyl group, pyrenyl group, fluoranthenyl group, triphenylenyl group, benzofluoranthenyl group, dibenzoanthrasenyl group, perylenel group and helisenyl group. Of these, a group selected from the group consisting of a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a phenanthryl group, an anthracenyl group, a pyrenyl group, a fluoranthenyl group and a triphenylenyl group is preferable. The aryl group may be substituted or unsubstituted. In the present invention, a group in which a plurality of phenyl groups such as a biphenyl group and a terphenyl group are bonded via a single bond is treated as a phenyl group having an aryl group as a substituent. The number of carbon atoms of the aryl group is not particularly limited, but is preferably in the range of 6 or more and 40 or less, and more preferably 6 or more and 30 or less. Further, in the case of a phenyl group, when there are substituents on two adjacent carbon atoms in the phenyl group, a ring structure may be formed between these substituents.
　ヘテロアリール基は、単環もしくは縮合環のいずれでもよく、例えば、ピリジル基、フラニル基、チオフェニル基、キノリニル基、イソキノリニル基、ピラジニル基、ピリミジル基、ピリダジニル基、トリアジニル基、ナフチリジニル基、シンノリニル基、フタラジニル基、キノキサリニル基、キナゾリニル基、ベンゾフラニル基、ベンゾチオフェニル基、インドリル基、ジベンゾフラニル基、ジベンゾチオフェニル基、カルバゾリル基、ベンゾカルバゾリル基、カルボリニル基、インドロカルバゾリル基、ベンゾフロカルバゾリル基、ベンゾチエノカルバゾリル基、ジヒドロインデノカルバゾリル基、ベンゾキノリニル基、アクリジニル基、ジベンゾアクリジニル基、ベンゾイミダゾリル基、イミダゾピリジル基、ベンゾオキサゾリル基、ベンゾチアゾリル基、フェナントロリニル基などの、炭素および水素以外の原子、すなわちヘテロ原子を一個または複数個環内に有する環状芳香族基を示す。ヘテロ原子としては窒素原子、酸素原子、または硫黄原子が好ましい。ヘテロアリール基は置換されていても無置換でもよい。ヘテロアリール基の炭素数は特に限定されないが、好ましくは、２以上４０以下、より好ましくは２以上３０以下の範囲である。 The heteroaryl group may be either a monocyclic group or a fused ring, and may be, for example, a pyridyl group, a furanyl group, a thiophenyl group, a quinolinyl group, an isoquinolinyl group, a pyrazinyl group, a pyrimidyl group, a pyridadinyl group, a triazinyl group, a naphthyldinyl group, a synnolinyl group, Phtalazinyl group, quinoxalinyl group, quinazolinyl group, benzofuranyl group, benzothiophenyl group, indolyl group, dibenzofuranyl group, dibenzothiophenyl group, carbazolyl group, benzocarbazolyl group, carbolinyl group, indolocarbazolyl group, benzo Flocarbazolyl group, benzothienocarbazolyl group, dihydroindenocarbazolyl group, benzoquinolinyl group, acridinyl group, dibenzoacrydinyl group, benzoimidazolyl group, imidazole pyridyl group, benzoxazolyl group, benzothiazolyl group, fe Indicates a cyclic aromatic group having an atom other than carbon and hydrogen, that is, a hetero atom in one or more rings, such as a nantrolinyl group. As the hetero atom, a nitrogen atom, an oxygen atom, or a sulfur atom is preferable. The heteroaryl group may be substituted or unsubstituted. The number of carbon atoms of the heteroaryl group is not particularly limited, but is preferably in the range of 2 or more and 40 or less, and more preferably 2 or more and 30 or less.
　ハロゲンとは、フッ素、塩素、臭素およびヨウ素から選ばれる原子を示す。 Halogen refers to an atom selected from fluorine, chlorine, bromine and iodine.
　シアノ基とは、構造が－ＣＮで表される官能基である。ここで他の基と結合するのは炭素原子である。 The cyano group is a functional group whose structure is represented by -CN. Here, it is the carbon atom that is bonded to the other group.
　アルデヒド基とは、構造が－Ｃ（＝Ｏ）Ｈで表される官能基である。ここで他の基と結合するのは炭素原子である。 The aldehyde group is a functional group whose structure is represented by -C (= O) H. Here, it is the carbon atom that is bonded to the other group.
　アシル基とは、例えばアセチル基、プロピオニル基、ベンゾイル基、アクリリル基など、カルボニル基を介してアルキル基、シクロアルキル基、アルケニル基、アルキニル基、アリール基、ヘテロアリール基が結合した官能基を示す。これらの置換基はさらに置換されていてもよい。アシル基の炭素数は特に限定されないが、好ましくは、２以上４０以下、より好ましくは２以上３０以下である。 The acyl group refers to a functional group in which an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, etc. are bonded via a carbonyl group, such as an acetyl group, a propionyl group, a benzoyl group, and an acryryl group. .. These substituents may be further substituted. The number of carbon atoms of the acyl group is not particularly limited, but is preferably 2 or more and 40 or less, and more preferably 2 or more and 30 or less.
　エステル基とは、例えば、アルキル基、シクロアルキル基、アリール基、ヘテロアリール基などがエステル結合を介して結合した官能基を示す。これらの置換基はさらに置換されていてもよい。エステル基の炭素数は特に限定されないが、好ましくは、１以上２０以下の範囲である。より具体的には、メトキシカルボニル基などのメチルエステル基、エトキシカルボニル基などのエチルエステル基、プロポキシカルボニル基などのプロピルエステル基、ブトキシカルボニル基などのブチルエステル基、イソプロポキシメトキシカルボニル基などのイソプロピルエステル基、ヘキシロキシカルボニル基などのヘキシルエステル基、フェノキシカルボニル基などのフェニルエステル基などが挙げられる。 The ester group refers to, for example, a functional group in which an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group, or the like is bonded via an ester bond. These substituents may be further substituted. The number of carbon atoms of the ester group is not particularly limited, but is preferably in the range of 1 or more and 20 or less. More specifically, a methyl ester group such as a methoxycarbonyl group, an ethyl ester group such as an ethoxycarbonyl group, a propyl ester group such as a propoxycarbonyl group, a butyl ester group such as a butoxycarbonyl group, and an isopropyl such as an isopropoxymethoxycarbonyl group. Examples thereof include an ester group, a hexyl ester group such as a hexyloxycarbonyl group, and a phenyl ester group such as a phenoxycarbonyl group.
　アミド基とは、例えば、アルキル基、シクロアルキル基、アリール基、ヘテロアリール基などがアミド結合を介して結合した官能基を示す。これらの置換基はさらに置換されていてもよい。アミド基の炭素数は特に限定されないが、好ましくは、１以上２０以下の範囲である。より具体的には、メチルアミド基、エチルアミド基、プロピルアミド基、ブチルアミド基、イソプロピルアミド基、ヘキシルアミド基、フェニルアミド基などが挙げられる。 The amide group refers to, for example, a functional group in which an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group or the like is bonded via an amide bond. These substituents may be further substituted. The number of carbon atoms of the amide group is not particularly limited, but is preferably in the range of 1 or more and 20 or less. More specifically, a methylamide group, an ethylamide group, a propylamide group, a butylamide group, an isopropylamide group, a hexylamide group, a phenylamide group and the like can be mentioned.
　スルホニル基とは、例えば、アルキル基、シクロアルキル基、アリール基、ヘテロアリール基などが－Ｓ（＝Ｏ）２－結合を介して結合した官能基を示す。これらの置換基はさらに置換されていてもよい。スルホニル基の炭素数は特に限定されないが、好ましくは、１以上２０以下の範囲である。 The sulfonyl group refers to, for example, a functional group in which an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group and the like are bonded via an —S (= O) 2-bond. These substituents may be further substituted. The number of carbon atoms of the sulfonyl group is not particularly limited, but is preferably in the range of 1 or more and 20 or less.
　スルホン酸エステル基とは、例えば、アルキル基、シクロアルキル基、アリール基、ヘテロアリール基などがスルホン酸エステル結合を介して結合した官能基を示す。ここでスルホン酸エステル結合とは、エステル結合のカルボニル部、すなわち－Ｃ（＝Ｏ）－がスルホニル部、すなわち－Ｓ（＝Ｏ）２－に置換されたものを指す。また、これらの置換基はさらに置換されていてもよい。スルホン酸エステル基の炭素数は特に限定されないが、好ましくは、１以上２０以下の範囲である。 The sulfonic acid ester group refers to, for example, a functional group in which an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group and the like are bonded via a sulfonic acid ester bond. Here, the sulfonic acid ester bond refers to a carbonyl portion of the ester bond, that is, -C (= O)-replaced with a sulfonyl moiety, that is, -S (= O) 2- . Moreover, these substituents may be further substituted. The number of carbon atoms of the sulfonic acid ester group is not particularly limited, but is preferably in the range of 1 or more and 20 or less.
　スルホンアミド基とは、例えば、アルキル基、シクロアルキル基、アリール基、ヘテロアリール基などがスルホンアミド結合を介して結合した官能基を示す。ここでスルホンアミド結合とは、エステル結合のカルボニル部、すなわち－Ｃ（＝Ｏ）－がスルホニル部、すなわち－Ｓ（＝Ｏ）２－に置換されたものを指す。また、これらの置換基はさらに置換されていてもよい。スルホンアミド基の炭素数は特に限定されないが、好ましくは、１以上２０以下の範囲である。 The sulfonamide group refers to, for example, a functional group in which an alkyl group, a cycloalkyl group, an aryl group, a heteroaryl group and the like are bonded via a sulfonamide bond. Here, the sulfone amide bond refers to a carbonyl portion of the ester bond, that is, -C (= O)-replaced with a sulfonyl moiety, that is, -S (= O) 2- . Moreover, these substituents may be further substituted. The number of carbon atoms of the sulfonamide group is not particularly limited, but is preferably in the range of 1 or more and 20 or less.
　アミノ基とは、置換もしくは無置換のアミノ基である。置換する場合の置換基としては、例えば、アリール基、ヘテロアリール基、直鎖アルキル基、分岐アルキル基が挙げられる。アリール基、ヘテロアリール基としては、フェニル基、ナフチル基、ピリジル基、キノリニル基が好ましい。これら置換基はさらに置換されてもよい。炭素数は特に限定されないが、好ましくは、２以上５０以下、より好ましくは６以上４０以下、特に好ましくは６以上３０以下の範囲である。 The amino group is a substituted or unsubstituted amino group. Examples of the substituent in the case of substitution include an aryl group, a heteroaryl group, a linear alkyl group and a branched alkyl group. As the aryl group and heteroaryl group, a phenyl group, a naphthyl group, a pyridyl group and a quinolinyl group are preferable. These substituents may be further substituted. The number of carbon atoms is not particularly limited, but is preferably 2 or more and 50 or less, more preferably 6 or more and 40 or less, and particularly preferably 6 or more and 30 or less.
　シリル基とは、置換もしくは無置換のケイ素原子が結合した官能基を示し、例えば、トリメチルシリル基、トリエチルシリル基、ｔｅｒｔ－ブチルジメチルシリル基、プロピルジメチルシリル基、ビニルジメチルシリル基などのアルキルシリル基や、フェニルジメチルシリル基、ｔｅｒｔ－ブチルジフェニルシリル基、トリフェニルシリル基、トリナフチルシリル基などのアリールシリル基を示す。ケイ素上の置換基はさらに置換されてもよい。シリル基の炭素数は特に限定されないが、好ましくは、１以上３０以下の範囲である。 The silyl group refers to a functional group to which a substituted or unsubstituted silicon atom is bonded, and is, for example, an alkylsilyl group such as a trimethylsilyl group, a triethylsilyl group, a tert-butyldimethylsilyl group, a propyldimethylsilyl group, or a vinyldimethylsilyl group. , And arylsilyl groups such as phenyldimethylsilyl group, tert-butyldiphenylsilyl group, triphenylsilyl group and trinaphthylsilyl group. Substituents on silicon may be further substituted. The number of carbon atoms of the silyl group is not particularly limited, but is preferably in the range of 1 or more and 30 or less.
　シロキサニル基とは、例えばトリメチルシロキサニル基などのエーテル結合を介したケイ素化合物基を示す。ケイ素上の置換基はさらに置換されてもよい。 The siloxanyl group refers to a silicon compound group via an ether bond such as a trimethylsiloxanyl group. Substituents on silicon may be further substituted.
　ボリル基とは、置換もしくは無置換のボリル基である。置換する場合の置換基としては、例えば、アリール基、ヘテロアリール基、直鎖アルキル基、分岐アルキル基、アリールエーテル基、アルコキシ基、ヒドロキシル基が挙げられ、中でもアリール基、アリールエーテル基が好ましい。 The boryl group is a substituted or unsubstituted boryl group. Examples of the substituent in the case of substitution include an aryl group, a heteroaryl group, a linear alkyl group, a branched alkyl group, an aryl ether group, an alkoxy group and a hydroxyl group, and among them, an aryl group and an aryl ether group are preferable.
　ホスフィンオキシド基とは、－Ｐ（＝Ｏ）Ｒ５０Ｒ５１で表される基である。Ｒ５０およびＲ５１はそれぞれ独立にＲ１～Ｒ６と同様の群から選ばれる。 The phosphine oxide group is a group represented by −P (= O) R 50 R 51. R 50 and R 51 are each independently selected from the same group as R 1 to R 6.
　ピロメテンホウ素錯体は、強固で平面性の高い骨格を有するため、高い蛍光量子収率を示す。また、発光スペクトルのピーク半値幅が小さいため、発光素子において効率的な発光と高い色純度を達成することができる。 The pyromethene boron complex has a strong and highly flat skeleton, and therefore exhibits a high fluorescence quantum yield. Further, since the peak half width of the emission spectrum is small, efficient emission and high color purity can be achieved in the emission element.
　発光効率のさらなる向上のためには、ピロメテンホウ素錯体の置換基の回転・振動を抑制し、エネルギー損失を減少させて蛍光量子収率を向上させることが有効である。また、色純度向上のためにはピロメテンホウ素錯体の励起状態における振動緩和を減少させ、発光スペクトルの半値幅を減少させることが有効である。 In order to further improve the luminous efficiency, it is effective to suppress the rotation and vibration of the substituent of the pyromethene boron complex, reduce the energy loss, and improve the fluorescence quantum yield. Further, in order to improve the color purity, it is effective to reduce the vibrational relaxation in the excited state of the pyrromethene boron complex and reduce the half width of the emission spectrum.
　この観点から、ピロメテン骨格の橋頭位に置換基Ｒ７が導入されている。Ｒ７の導入によって、高い蛍光量子収率かつ半値幅の小さいピロメテンホウ素錯体を提供することができる。中でも、置換基Ｒ７中、Ａｒ１およびＲ１１がそれぞれ上記の基であることによって、橋頭位がピロメテン骨格に対して分子内回転し、エネルギー失活を起こすことを抑制することができるため、発光効率向上に有利である。 In this respect, the substituent R 7 is introduced into the bridgehead position of the pyrromethene skeleton. The introduction of the R 7, it is possible to provide a high fluorescence quantum yield and semi-width small Pirometenhou boron complex. Above all, since Ar 1 and R 11 in the substituent R 7 are the above groups, respectively, it is possible to suppress the intramolecular rotation of the bridge head position with respect to the pyrromethene skeleton and cause energy deactivation. It is advantageous for improving the luminous efficiency.
　また、Ｒ１～Ｒ４のうち少なくとも一つが水素原子もしくはアルキル基であることにより、励起状態における振動緩和が減少し、発光スペクトルの半値幅を減少させることができる。 Further, since at least one of R 1 to R 4 is a hydrogen atom or an alkyl group, vibrational relaxation in the excited state can be reduced, and the half width of the emission spectrum can be reduced.
　また、ピロメテンホウ素錯体の安定性は発光素子の耐久性に影響する。その安定性をより向上させるため、橋頭位に嵩高い置換基を導入することが好ましい。嵩高い置換基を導入することにより、ピロメテン骨格を周囲の他分子との相互作用から保護することができる。置換基Ｒ７中、Ａｒ１およびＲ１１がそれぞれ上記の基であることによって、ピロメテンホウ素錯体の安定性を向上させ、発光素子の耐久性を向上させることができる。この観点から、Ｒ１１は、より嵩高い置換基であることが好ましく、置換もしくは無置換のアリール基、または置換もしくは無置換のヘテロアリール基であることが好ましい。 In addition, the stability of the pyromethene boron complex affects the durability of the light emitting device. In order to further improve the stability, it is preferable to introduce a bulky substituent at the bridge head position. By introducing a bulky substituent, the pyrromethene skeleton can be protected from interaction with other surrounding molecules. When Ar 1 and R 11 are the above-mentioned groups in the substituent R 7 , the stability of the pyromethene boron complex can be improved and the durability of the light emitting device can be improved. From this point of view, R 11 is preferably a bulky substituent, preferably a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group.
　Ｒ１およびＲ４は、上記した群から選ばれ、ピロメテンホウ素錯体の発光ピーク波長、結晶性、昇華温度などに影響する。発光スペクトルの半値幅をより小さくする観点から、Ｒ１およびＲ４は、水素原子またはアルキル基であることが好ましい。さらに、蛍光量子収率がより向上する観点から、Ｒ１およびＲ４はアルキル基であることがより好ましい。 R 1 and R 4 are selected from the above group and affect the emission peak wavelength, crystallinity, sublimation temperature, etc. of the pyrromethene boron complex. From the viewpoint of reducing the half width of the emission spectrum, R 1 and R 4 are preferably hydrogen atoms or alkyl groups. Further, from the viewpoint of further improving the fluorescence quantum yield, it is more preferable that R 1 and R 4 are alkyl groups.
　Ｒ２およびＲ３は上記した群から選ばれ、主にピロメテンホウ素錯体の発光ピーク波長、発光スペクトルの半値幅、安定性、または結晶性に影響する。発光スペクトルの半値幅をより小さくする観点、安定性をより向上させる観点、および再結晶生成を含む合成の容易性の観点から、Ｒ２およびＲ３の少なくとも一方、好ましくは両方が、水素原子、置換もしくは無置換のアルキル基、置換もしくは無置換のアリール基および置換もしくは無置換のヘテロアリール基からなる群から選ばれた基であることが好ましい。さらに、半値幅をより減少する観点から、Ｒ２およびＲ３はアルキル基であることがより好ましい。 R 2 and R 3 are selected from the above group and mainly affect the emission peak wavelength, the half width of the emission spectrum, the stability, or the crystallinity of the pyrromethene boron complex. At least one or preferably both of R 2 and R 3 are hydrogen atoms, from the viewpoint of making the half-value width of the emission spectrum smaller, improving the stability, and easiness of synthesis including recrystallization. It is preferably a group selected from the group consisting of substituted or unsubstituted alkyl groups, substituted or unsubstituted aryl groups and substituted or unsubstituted heteroaryl groups. Further, from the viewpoint of further reducing the half width, it is more preferable that R 2 and R 3 are alkyl groups.
　Ｒ５およびＲ６は上記した群から選ばれ、主にピロメテンホウ素錯体の発光ピーク波長、発光スペクトルの半値幅、安定性、または結晶性に影響する。発光スペクトルの半値幅をより小さくする観点、安定性をより向上させる観点、および再結晶精製を含む合成の容易性の観点から、Ｒ５およびＲ６の少なくとも一方、好ましくは両方が、水素原子、または置換もしくは無置換のアルキル基であることが好ましい。 R 5 and R 6 are selected from the above group and mainly affect the emission peak wavelength, the half width of the emission spectrum, the stability, or the crystallinity of the pyrromethene boron complex. From the viewpoint of reducing the half width of the emission spectrum, improving the stability, and easiness of synthesis including recrystallization purification, at least one or preferably both of R 5 and R 6 are hydrogen atoms. Alternatively, it is preferably a substituted or unsubstituted alkyl group.
　Ｘ１およびＸ２は上記の中から選ばれる。発光特性と熱的安定性の観点から、Ｘ１およびＸ２はアルコキシ基、ハロアルキル基、ハロアルコキシ基、アリールエーテル基、ハロアリールエーテル基、ハロアリール基、ハロゲン原子およびシアノ基からなる群から選ばれた基であることが好ましい。ここで、ハロアルキル基とは、少なくとも１つのハロゲンで置換されたアルキル基である。ハロアリール基とは、少なくとも１つのハロゲンで置換されたアリール基である。 X 1 and X 2 are selected from the above. From the viewpoint of luminescence properties and thermal stability, X 1 and X 2 are selected from the group consisting of an alkoxy group, a haloalkyl group, a haloalkoxy group, an aryl ether group, a haloaryl ether group, a haloaryl group, a halogen atom and a cyano group. It is preferably a group. Here, the haloalkyl group is an alkyl group substituted with at least one halogen. A haloaryl group is an aryl group substituted with at least one halogen.
　また、励起状態が安定でより高い蛍光量子収率が得られる観点、および耐久性を向上させることができる観点から、Ｘ１およびＸ２は、フッ素原子、含フッ素アルキル基、含フッ素アルコキシ基、含フッ素アリール基およびシアノ基からなる群から選ばれた基であることがより好ましく、フッ素原子またはシアノ基であることがさらに好ましく、フッ素原子であることが最も好ましい。これらは電子求引性基であり、ピロメテン骨格の電子密度を下げ化合物の安定性を増すことができる。 Further, from the viewpoint that the excited state is stable and a higher fluorescence quantum yield can be obtained, and the durability can be improved, X 1 and X 2 are fluorine atoms, fluorine-containing alkyl groups, and fluorine-containing alkoxy groups. It is more preferably a group selected from the group consisting of a fluorine-containing aryl group and a cyano group, further preferably a fluorine atom or a cyano group, and most preferably a fluorine atom. These are electron-attracting groups, which can reduce the electron density of the pyrromethene skeleton and increase the stability of the compound.
　一般式（１）で表されるピロメテンホウ素錯体の一例を以下に示すが、これらに限定されるものではない。 An example of the pyrromethene boron complex represented by the general formula (1) is shown below, but the present invention is not limited thereto.
Figure JPOXMLDOC01-appb-C000009
Figure JPOXMLDOC01-appb-C000009
Figure JPOXMLDOC01-appb-C000010
Figure JPOXMLDOC01-appb-C000010
Figure JPOXMLDOC01-appb-C000011
Figure JPOXMLDOC01-appb-C000011
Figure JPOXMLDOC01-appb-C000012
Figure JPOXMLDOC01-appb-C000012
Figure JPOXMLDOC01-appb-C000013
Figure JPOXMLDOC01-appb-C000013
Figure JPOXMLDOC01-appb-C000014
Figure JPOXMLDOC01-appb-C000014
Figure JPOXMLDOC01-appb-C000015
Figure JPOXMLDOC01-appb-C000015
Figure JPOXMLDOC01-appb-C000016
Figure JPOXMLDOC01-appb-C000016
Figure JPOXMLDOC01-appb-C000017
Figure JPOXMLDOC01-appb-C000017
Figure JPOXMLDOC01-appb-C000018
Figure JPOXMLDOC01-appb-C000018
Figure JPOXMLDOC01-appb-C000019
Figure JPOXMLDOC01-appb-C000019
Figure JPOXMLDOC01-appb-C000020
Figure JPOXMLDOC01-appb-C000020
Figure JPOXMLDOC01-appb-C000021
Figure JPOXMLDOC01-appb-C000021
Figure JPOXMLDOC01-appb-C000022
Figure JPOXMLDOC01-appb-C000022
Figure JPOXMLDOC01-appb-C000023
Figure JPOXMLDOC01-appb-C000023
Figure JPOXMLDOC01-appb-C000024
Figure JPOXMLDOC01-appb-C000024
　一般式（１）で表されるピロメテンホウ素錯体は、J. Org. Chem., vol.64, No.21, pp.7813-7819 (1999)、Angew. Chem., Int. Ed. Engl., vol.36, pp.1333-1335 (1997)、Org. Lett., vol.12, pp.296  (2010)などに記載されている方法を参考に製造することができる。 The pyrromethene boron complex represented by the general formula (1) is J. Org. Chem., Vol.64, No. 21, pp.7813-7819 (1999), Angew. Chem., Int. Ed. Engl., It can be manufactured by referring to the methods described in vol.36, pp.1333-1335 (1997), Org. Lett., Vol.12, pp.296 (2010), etc.
　さらに、ピロメテン骨格にアリール基やヘテロアリール基を導入するには、例えば、パラジウムなどの金属触媒下で、ピロメテンホウ素錯体のハロゲン化誘導体とボロン酸あるいはボロン酸エステル誘導体とのカップリング反応を用いて炭素－炭素結合を生成する方法が挙げられるが、これに限定されるものではない。同様に、ピロメテン骨格にアミノ基やカルバゾリル基を導入するには、例えば、パラジウムなどの金属触媒下で、ピロメテンホウ素錯体のハロゲン化誘導体とアミンあるいはカルバゾール誘導体とのカップリング反応を用いて炭素－窒素結合を生成する方法が挙げられるが、これに限定されるものではない。 Furthermore, in order to introduce an aryl group or a heteroaryl group into the pyromethene skeleton, for example, under a metal catalyst such as palladium, a coupling reaction between a halogenated derivative of the pyromethene boron complex and a boronic acid or boronic acid ester derivative is used. Examples include, but are not limited to, methods of forming carbon-carbon bonds. Similarly, to introduce an amino group or carbazolyl group into the pyromethene skeleton, for example, under a metal catalyst such as palladium, carbon-nitrogen is used by using a coupling reaction between a halogenated derivative of the pyromethene boron complex and an amine or carbazole derivative. Examples include, but are not limited to, methods of generating bonds.
　得られたピロメテンホウ素錯体は、再結晶やカラムクロマトグラフィーなどの有機合成的な精製を行った後、さらに一般的に昇華精製と呼ばれる減圧加熱による精製により低沸点成分を除去し、純度を向上させることが好ましい。昇華精製における加熱温度は特に限定されないが、ピロメテンホウ素錯体の熱分解を防ぐ観点から３３０℃以下が好ましく、３００℃以下がより好ましい。 The obtained pyromethene boron complex is subjected to organic synthetic purification such as recrystallization and column chromatography, and then the low boiling point component is removed by purification by heating under reduced pressure, which is generally called sublimation purification, to improve the purity. Is preferable. The heating temperature in the sublimation purification is not particularly limited, but is preferably 330 ° C. or lower, more preferably 300 ° C. or lower, from the viewpoint of preventing thermal decomposition of the pyromethene boron complex.
　このようにして製造されたピロメテンホウ素錯体の純度は、発光素子が安定した特性を示すことが可能となる観点から９９重量％以上であることが好ましい。 The purity of the pyrromethene boron complex produced in this manner is preferably 99% by weight or more from the viewpoint of enabling the light emitting device to exhibit stable characteristics.
　一般式（１）で表されるピロメテンホウ素錯体の光学特性は、希釈溶液の吸収スペクトルおよび発光スペクトルを測定することで得られる。溶媒としては、ピロメテンホウ素錯体を溶解し、かつ溶媒の吸収スペクトルがピロメテンホウ素錯体の吸収スペクトルと重ならない透明なものであれば特に限定されない。具体的にはトルエンなどが例示される。溶液の濃度は十分な吸光度があり、かつ濃度消光が起きない濃度範囲であれば特に限定されないが、１×１０－４ｍｏｌ／Ｌ～１×１０－７ｍｏｌ／Ｌの範囲であることが好ましく、１×１０－５ｍｏｌ／Ｌ～１×１０－６ｍｏｌ／Ｌの範囲であることがより好ましい。吸収スペクトルは一般的な紫外可視分光光度計により測定できる。また発光スペクトルは一般的な蛍光分光光度計により測定できる。さらに蛍光量子収率の測定には積分球を用いた絶対量子収率測定装置を利用することが好ましい。 The optical properties of the pyrromethene boron complex represented by the general formula (1) can be obtained by measuring the absorption spectrum and the emission spectrum of the diluted solution. The solvent is not particularly limited as long as it dissolves the pyrromethene boron complex and the absorption spectrum of the solvent is transparent and does not overlap with the absorption spectrum of the pyromethene boron complex. Specifically, toluene and the like are exemplified. The concentration of the solution is not particularly limited as long as it has sufficient absorbance and does not cause concentration dimming, but it is preferably in the range of 1 × 10 -4 mol / L to 1 × 10 -7 mol / L. More preferably, it is in the range of 1 × 10 -5 mol / L to 1 × 10 -6 mol / L. The absorption spectrum can be measured by a general ultraviolet-visible spectrophotometer. The emission spectrum can be measured by a general fluorescence spectrophotometer. Further, it is preferable to use an absolute quantum yield measuring device using an integrating sphere for measuring the fluorescence quantum yield.
　高色純度を実現するために、一般式（１）で表されるピロメテンホウ素錯体が励起光の照射により発する光の発光スペクトルがシャープであることが好ましい。また表示装置や照明装置で主流となっているトップエミッション素子ではマイクロキャビティ構造による共振効果により高輝度および高色純度を達成できるが、発光スペクトルがシャープであるとこの共振効果がより強く表れ、高効率化に有利である。この観点から、発光スペクトルの半値幅は６０ｎｍ以下であることが好ましく、５０ｎｍ以下であることがより好ましく、４５ｎｍ以下であることがさらに好ましく、２８ｎｍ以下であることが特に好ましい。 In order to achieve high color purity, it is preferable that the emission spectrum of the light emitted by the pyrromethene boron complex represented by the general formula (1) by irradiation with excitation light is sharp. In addition, high brightness and high color purity can be achieved by the resonance effect of the microcavity structure in the top emission element, which is the mainstream in display devices and lighting devices, but when the emission spectrum is sharp, this resonance effect appears more strongly and is high. It is advantageous for efficiency. From this viewpoint, the half width of the emission spectrum is preferably 60 nm or less, more preferably 50 nm or less, further preferably 45 nm or less, and particularly preferably 28 nm or less.
　発光素子の発光効率は、発光材料自身の蛍光量子収率に依存する。そのため発光材料の蛍光量子収率は、可能な限り１００％に近いことが望まれる。一般式（１）で表されるピロメテンホウ素錯体は、Ｒ１１およびＡｒ１が上記の通りであることで、橋頭位の回転・振動を抑制し、熱失活を減少させることで高い蛍光量子収率を得ることができる。以上の観点から、ピロメテンホウ素錯体の蛍光量子収率は９０％以上であることが好ましく、９５％以上であることがより好ましい。ただし、ここで示す蛍光量子収率はトルエンを溶媒とした希釈溶液を絶対量子収率測定装置で測定したものである。 The luminous efficiency of the light emitting element depends on the fluorescence quantum yield of the light emitting material itself. Therefore, it is desired that the fluorescence quantum yield of the light emitting material is as close to 100% as possible. The pyromethene boron complex represented by the general formula (1) has a high fluorescence quantum yield by suppressing rotation and vibration at the bridge head position and reducing heat deactivation by having R 11 and Ar 1 as described above. You can get the rate. From the above viewpoint, the fluorescence quantum yield of the pyrromethene boron complex is preferably 90% or more, more preferably 95% or more. However, the fluorescence quantum yield shown here is obtained by measuring a diluted solution using toluene as a solvent with an absolute quantum yield measuring device.
　＜発光素子材料＞
　一般式（１）で表されるピロメテンホウ素錯体は、高発光効率を達成できることから、発光素子において、発光素子材料として用いられる。ここで本発明における発光素子材料とは、発光素子のいずれかの層に使用される材料を表し、後述するように、正孔注入層、正孔輸送層、発光層および電子輸送層から選ばれる層に使用される材料であるほか、電極の保護膜（キャップ層）に使用される材料も含む。 <Light emitting element material>
Since the pyrromethene boron complex represented by the general formula (1) can achieve high luminous efficiency, it is used as a light emitting element material in a light emitting element. Here, the light emitting device material in the present invention represents a material used for any layer of the light emitting device, and is selected from a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer, as will be described later. In addition to the material used for the layer, the material used for the protective film (cap layer) of the electrode is also included.
　一般式（１）で表されるピロメテンホウ素錯体は、高い発光性能を有することから、発光層に使用される材料であることが好ましい。 The pyrromethene boron complex represented by the general formula (1) has high light emitting performance, and therefore is preferably a material used for the light emitting layer.
　＜発光素子＞
　次に、本発明の発光素子の実施の形態について説明する。本発明の発光素子は、陽極と陰極、および該陽極と該陰極との間に存在する有機層を有する。該有機層は少なくとも発光層を含み、該発光層が電気エネルギーにより発光する有機電界発光素子であることが好ましい。 <Light emitting element>
Next, an embodiment of the light emitting device of the present invention will be described. The light emitting device of the present invention has an anode and a cathode, and an organic layer existing between the anode and the cathode. The organic layer preferably includes at least a light emitting layer, and the light emitting layer is an organic electroluminescent device that emits light by electric energy.
　本発明の発光素子は、ボトムエミッション型、またはトップエミッション型のいずれであってもよい。 The light emitting element of the present invention may be either a bottom emission type or a top emission type.
　このような発光素子における陽極と陰極の間の有機層の層構成は、発光層のみからなる構成の他に、１）発光層／電子輸送層、２）正孔輸送層／発光層、３）正孔輸送層／発光層／電子輸送層、４）正孔注入層／正孔輸送層／発光層／電子輸送層、５）正孔輸送層／発光層／電子輸送層／電子注入層、６）正孔注入層／正孔輸送層／発光層／電子輸送層／電子注入層、７）正孔注入層／正孔輸送層／発光層／正孔阻止層／電子輸送層／電子注入層、８）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／電子注入層のような積層構成が挙げられる。 In such a light emitting element, the layer structure of the organic layer between the anode and the cathode includes not only the light emitting layer but also 1) light emitting layer / electron transporting layer, 2) hole transporting layer / light emitting layer, and 3). Hole transport layer / light emitting layer / electron transport layer, 4) hole injection layer / hole transport layer / light emitting layer / electron transport layer, 5) hole transport layer / light emitting layer / electron transport layer / electron injection layer, 6 ) Hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer, 7) hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer, 8) Examples thereof include a laminated structure such as a hole injection layer / a hole transport layer / an electron blocking layer / a light emitting layer / a hole blocking layer / an electron transport layer / an electron injection layer.
　さらに、上記の積層構成を、中間層を介して複数積層したタンデム型の発光素子であってもよい。中間層としては、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、中間絶縁層などが挙げられ、公知の材料構成を用いることができる。タンデム型発光素子の好ましい具体例として９）正孔注入層／正孔輸送層／発光層／電子輸送層／電子注入層／電荷発生層／正孔注入層／正孔輸送層／発光層／電子輸送層／電子注入層のような積層構成が挙げられる。 Further, a tandem type light emitting element in which a plurality of the above laminated configurations are laminated via an intermediate layer may be used. Examples of the intermediate layer generally include an intermediate electrode, an intermediate conductive layer, a charge generation layer, an electron extraction layer, a connection layer, an intermediate insulation layer, and the like, and known material configurations can be used. Preferred specific examples of the tandem type light emitting element are 9) hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / charge generation layer / hole injection layer / hole transport layer / light emitting layer / electron. Laminated configurations such as transport layer / electron injection layer can be mentioned.
　また、上記各層は、それぞれ単一層、複数層のいずれでもよく、ドーピングされていてもよい。さらに光学干渉効果に起因して発光効率を向上させるためのキャッピング材料を用いた層を含む素子構成も挙げられる。 Further, each of the above layers may be either a single layer or a plurality of layers, and may be doped. Further, there is also an element configuration including a layer using a capping material for improving the luminous efficiency due to the optical interference effect.
　一般式（１）で表されるピロメテンホウ素錯体は、上記の素子構成において、いずれの層に用いられてもよいが、蛍光量子収率が高く、薄膜安定性を有しているため、発光層に用いることが好ましい。 The pyrromethene boron complex represented by the general formula (1) may be used for any layer in the above device configuration, but since it has a high fluorescence quantum yield and thin film stability, it is a light emitting layer. It is preferable to use it for.
　以下に発光素子の構成の具体例を挙げるが、本発明の構成はこれらに限定されるものではない。 Specific examples of the configuration of the light emitting element are given below, but the configuration of the present invention is not limited to these.
　（基板）
　発光素子の機械的強度を保ち、熱変形が少なく、発光層に水蒸気や酸素が侵入することを防ぐバリア性を有するために、発光素子を基板上に形成することが好ましい。基板としては特に限定されないが、例えばガラス板、セラミック板、樹脂製フィルム、樹脂薄膜、金属製薄板などが挙げられる。この中で透明であり、かつ、加工が容易である観点から、ガラス基板が好適に用いられる。特に基板を通して光を取り出すボトムエミッション素子では高い透明性を有するガラス基板が好ましい。また、スマートフォンなどのモバイル機器においてフレキシブルディスプレイやフォルダブルディスプレイが増加しており、この用途には樹脂製フィルムやワニスを硬化した樹脂薄膜が好適に用いられる。樹脂製フィルムとしては耐熱フィルムが使用されており、具体的にはポリイミドフィルム、ポリエチレンナフタレートフィルムなどが例示される。 (substrate)
It is preferable to form the light emitting element on the substrate in order to maintain the mechanical strength of the light emitting element, reduce thermal deformation, and have a barrier property to prevent water vapor and oxygen from entering the light emitting layer. The substrate is not particularly limited, and examples thereof include a glass plate, a ceramic plate, a resin film, a resin thin film, and a metal thin plate. Among these, a glass substrate is preferably used from the viewpoint of being transparent and easy to process. In particular, a glass substrate having high transparency is preferable for a bottom emission element that extracts light through the substrate. In addition, flexible displays and foldable displays are increasing in mobile devices such as smartphones, and resin films and resin thin films obtained by curing varnish are preferably used for this purpose. A heat-resistant film is used as the resin film, and specific examples thereof include a polyimide film and a polyethylene naphthalate film.
　また基板の表面には有機ＥＬを駆動させるための各種配線、回路、およびＴＦＴによるスイッチング素子が設けられていてもよい。 Further, various wirings, circuits, and TFT switching elements for driving the organic EL may be provided on the surface of the substrate.
　（陽極）
　陽極は前記基板上に形成される。ここで基板と陽極の間に各種配線、回路、およびスイッチング素子が介在してもよい。陽極に用いる材料は、正孔を有機層に効率よく注入できる材料であれば特に限定されないが、ボトムエミッション型の素子では透明または半透明電極であることが好ましく、トップエミッション型の素子では反射電極であることが好ましい。 (anode)
The anode is formed on the substrate. Here, various wirings, circuits, and switching elements may be interposed between the substrate and the anode. The material used for the anode is not particularly limited as long as it can efficiently inject holes into the organic layer, but it is preferably a transparent or translucent electrode for a bottom emission type element, and a reflective electrode for a top emission type element. Is preferable.
　透明または半透明電極の材料としては、酸化亜鉛、酸化錫、酸化インジウム、酸化錫インジウム（ＩＴＯ）、酸化亜鉛インジウム（ＩＺＯ）などの導電性金属酸化物；あるいは、金、銀、アルミニウム、クロムなどの金属；ポリチオフェン、ポリピロール、ポリアニリンなどの導電性ポリマーが例示される。ただし金属を用いるときは光を半透過できるように膜厚を薄くすることが好ましい。以上のうち、透明性と安定性の観点から酸化錫インジウム（ＩＴＯ）がより好ましい。 Materials for the transparent or translucent electrode include conductive metal oxides such as zinc oxide, tin oxide, indium oxide, indium tin oxide (ITO) and indium zinc oxide (IZO); or gold, silver, aluminum, chromium and the like. Metals; conductive polymers such as polythiophene, polypyrrole, polyaniline and the like are exemplified. However, when a metal is used, it is preferable to reduce the film thickness so that light can be semi-transmitted. Of the above, indium tin oxide (ITO) is more preferable from the viewpoint of transparency and stability.
　反射電極の材料としては、全ての光に対し吸収がなく高い反射率を有するものが好ましい。具体的には、アルミニウム、銀、白金などの金属が例示される。 The material of the reflective electrode is preferably one that does not absorb all light and has high reflectance. Specifically, metals such as aluminum, silver, and platinum are exemplified.
　陽極の形成方法は、その形成材料に応じて最適な方法を採用できるが、スパッタ法、蒸着法、インクジェット法などが挙げられる。例えば、金属酸化物によって陽極を形成する場合にはスパッタ法、金属によって陽極を形成する場合には蒸着法が用いられる。陽極の膜厚は特に限定されないが、数ｎｍ～数百ｎｍであることが好ましい。 As the method for forming the anode, the optimum method can be adopted depending on the forming material, and examples thereof include a sputtering method, a vapor deposition method, and an inkjet method. For example, a sputtering method is used when an anode is formed of a metal oxide, and a thin-film deposition method is used when an anode is formed of a metal. The film thickness of the anode is not particularly limited, but is preferably several nm to several hundred nm.
　また、これらの電極材料は、単独で用いてもよいが、複数の材料を積層または混合して用いてもよい。 Further, these electrode materials may be used alone, or a plurality of materials may be laminated or mixed.
　（陰極）
　陰極は有機層を挟んで陽極の反対側の表面に形成され、特に電子輸送層または電子注入層の上に形成されることが好ましい。陰極に用いる材料は、電子を効率よく発光層に注入できる材料であれば特に限定されないが、ボトムエミッション型の素子では反射電極であることが好ましく、トップエミッション型の素子では半透明電極であることが好ましい。 (cathode)
The cathode is formed on the surface opposite the anode with the organic layer in between, and is particularly preferably formed on the electron transport layer or the electron injection layer. The material used for the cathode is not particularly limited as long as it can efficiently inject electrons into the light emitting layer, but it is preferably a reflective electrode for a bottom emission type element and a translucent electrode for a top emission type element. Is preferable.
　陰極の材料としては、一般的には白金、金、銀、銅、鉄、錫、アルミニウム、インジウムなどの金属；これらの金属とリチウム、ナトリウム、カリウム、カルシウム、マグネシウムなどの低仕事関数金属との合金や多層積層膜；または酸化亜鉛、酸化錫インジウム（ＩＴＯ）、酸化亜鉛インジウム（ＩＺＯ）などの導電性金属酸化物などが好ましい。中でも、主成分としてはアルミニウム、銀およびマグネシウムから選ばれた金属が、電気抵抗値、製膜しやすさ、膜の安定性、発光効率などの面から好ましい。また、陰極がマグネシウムと銀で構成されると、本発明における電子輸送層および電子注入層への電子注入が容易になり、低電圧駆動が可能になるため好ましい。 Metals such as platinum, gold, silver, copper, iron, tin, aluminum and indium are generally used as cathode materials; these metals are combined with low work function metals such as lithium, sodium, potassium, calcium and magnesium. Alloys and multilayer laminated films; or conductive metal oxides such as zinc oxide, indium tin oxide (ITO), and indium zinc oxide (IZO) are preferable. Among them, a metal selected from aluminum, silver and magnesium as a main component is preferable from the viewpoints of electric resistance value, ease of film formation, film stability, luminous efficiency and the like. Further, when the cathode is composed of magnesium and silver, electron injection into the electron transport layer and the electron injection layer in the present invention becomes easy, and low voltage drive becomes possible, which is preferable.
　（保護層）
　陰極保護のために、陰極上に保護層（キャップ層）を積層することが好ましい。保護層を構成する材料としては、特に限定されないが、例えば、白金、金、銀、銅、鉄、錫、アルミニウムおよびインジウムなどの金属；これら金属を用いた合金；シリカ、チタニアおよび窒化ケイ素などの無機物；ポリビニルアルコール、ポリ塩化ビニル、炭化水素系高分子化合物などの有機高分子化合物などが挙げられる。ただし、発光素子が、陰極側から光を取り出す素子構造（トップエミッション構造）である場合は、保護層に用いられる材料は、可視光領域で光透過性のある材料から選択される。 (Protective layer)
To protect the cathode, it is preferable to laminate a protective layer (cap layer) on the cathode. The material constituting the protective layer is not particularly limited, but for example, metals such as platinum, gold, silver, copper, iron, tin, aluminum and indium; alloys using these metals; silica, titania, silicon nitride and the like. Inorganic substances: Organic polymer compounds such as polyvinyl alcohol, polyvinyl chloride, and hydrocarbon-based polymer compounds can be mentioned. However, when the light emitting element has an element structure (top emission structure) that extracts light from the cathode side, the material used for the protective layer is selected from materials having light transmission in the visible light region.
　（正孔注入層）
　正孔注入層は、陽極と正孔輸送層の間に挿入され、正孔注入を容易にする層である。正孔注入層は１層であっても複数の層が積層されていてもよい。正孔輸送層と陽極の間に正孔注入層が存在すると、より低電圧駆動が可能であり、素子の耐久寿命も向上するだけでなく、さらに素子のキャリアバランスが向上して発光効率も向上するため好ましい。 (Hole injection layer)
The hole injection layer is a layer that is inserted between the anode and the hole transport layer to facilitate hole injection. The hole injection layer may be one layer or a plurality of layers may be laminated. The presence of a hole injection layer between the hole transport layer and the anode enables lower voltage drive, which not only improves the durable life of the device, but also improves the carrier balance of the device and improves the luminous efficiency. It is preferable to do so.
　正孔注入材料の好ましい一例として、電子供与性正孔注入材料（ドナー材料）が挙げられる。これらはＨＯＭＯ準位が正孔輸送層より浅く、かつ陽極の仕事関数に近いため陽極とのエネルギー障壁を小さくできる材料である。具体的には、ベンジジン誘導体、４，４’，４”－トリス（３－メチルフェニル（フェニル）アミノ）トリフェニルアミン（ｍ－ＭＴＤＡＴＡ）、４，４’，４”－トリス（１－ナフチル（フェニル）アミノ）トリフェニルアミン（１－ＴＮＡＴＡ）などのスターバーストアリールアミンなどの芳香族アミン系材料群；カルバゾール誘導体、ピラゾリン誘導体、スチルベン系化合物、ヒドラゾン系化合物、ベンゾフラン誘導体、チオフェン誘導体、オキサジアゾール誘導体、フタロシアニン誘導体、ポルフィリン誘導体などの複素環化合物；ポリマー系では前記単量体を側鎖に有するポリカーボネートやスチレン誘導体、ＰＥＤＯＴ／ＰＳＳのようなポリチオフェン、ポリアニリン、ポリフルオレン、ポリビニルカルバゾールおよびポリシランなどが例示される。これらの材料は単独で用いてもよいし、２種以上の材料を混合して用いてもよい。また、複数の材料を積層して正孔注入層としてもよい。 A preferable example of the hole injection material is an electron donating hole injection material (donor material). These are materials whose HOMO level is shallower than that of the hole transport layer and which is close to the work function of the anode, so that the energy barrier with the anode can be reduced. Specifically, benzidine derivatives, 4,4', 4 "-tris (3-methylphenyl (phenyl) amino) triphenylamine (m-MTDATA), 4,4', 4" -tris (1-naphthyl (1-naphthyl) Aromatic amine materials such as starburst arylamines such as phenyl) amino) triphenylamine (1-TNATA); carbazole derivatives, pyrazoline derivatives, stilben compounds, hydrazone compounds, benzofuran derivatives, thiophene derivatives, oxadiasols. Heterocyclic compounds such as derivatives, phthalocyanine derivatives, and porphyrin derivatives; examples of polymer systems include polycarbonate and styrene derivatives having the monomer in the side chain, polythiophene such as PEDOT / PSS, polyaniline, polyfluorene, polyvinylcarbazole, and polysilane. Will be done. These materials may be used alone or in combination of two or more kinds of materials. Further, a plurality of materials may be laminated to form a hole injection layer.
　また正孔注入材料の別の好ましい一例として、電子受容性正孔注入材料（アクセプター材料）が挙げられる。ここで正孔注入層はアクセプター材料単独で構成されていても、前記のドナー材料にアクセプター材料をドープして用いてもよい。アクセプター材料は、単独で用いる場合は隣接している正孔輸送層との間で、またドナー材料にドープして用いる場合はドナー材料との間で電荷移動錯体を形成する材料である。このような材料を用いると正孔注入層の導電性向上と、素子の駆動電圧低下に寄与し、発光効率の向上、耐久寿命向上といった効果が得られるため、より好ましい。アクセプター材料としては、酸化モリブデン、酸化バナジウム、酸化タングステン、酸化ルテニウムのような金属酸化物；トリス（４－ブロモフェニル）アミニウムヘキサクロロアンチモネート（ＴＢＰＡＨ）のような電荷移動錯体；１，４，５，８，９，１１－ヘキサアザトリフェニレン－ヘキサカルボニトリル（ＨＡＴ－ＣＮ６）、２，３，５，６－テトラフルオロ－７，７，８，８－テトラシアノキノジメタン（Ｆ４－ＴＣＮＱ）、フッ素化銅フタロシアニンのようなｎ型有機半導体化合物；フラーレンなどが例示される。正孔注入層にアクセプター材料を含む場合、正孔注入層は１層であってもよいし、複数の層が積層されて構成されていてもよい。 Another preferable example of the hole injection material is an electron acceptor hole injection material (acceptor material). Here, the hole injection layer may be composed of the acceptor material alone, or the donor material may be doped with the acceptor material. The acceptor material is a material that forms a charge transfer complex between the adjacent hole transport layers when used alone and with the donor material when used by doping the donor material. It is more preferable to use such a material because it contributes to the improvement of the conductivity of the hole injection layer and the decrease of the driving voltage of the element, and the effects of improving the luminous efficiency and improving the durable life can be obtained. Acceptor materials include metal oxides such as molybdenum oxide, vanadium oxide, tungsten oxide, ruthenium oxide; charge transfer complexes such as tris (4-bromophenyl) aminium hexachloroantimonate (TBPAH); 1,4,5 , 8,9,11-Hexaazatriphenylene-hexacarbonitrile (HAT-CN6), 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), N-type organic semiconductor compounds such as fluorinated copper phthalocyanine; fullerene and the like are exemplified. When the hole injection layer contains an acceptor material, the hole injection layer may be one layer or may be composed of a plurality of layers laminated.
　（正孔輸送層）
　正孔輸送層は、陽極から注入された正孔を発光層まで輸送する層である。正孔輸送層は単層であっても複数の層が積層されて構成されていてもよい。 (Hole transport layer)
The hole transport layer is a layer that transports holes injected from the anode to the light emitting layer. The hole transport layer may be a single layer or may be formed by laminating a plurality of layers.
　正孔輸送層は、一種の正孔輸送材料単独で、または二種以上の正孔輸送材料を積層または混合することによって形成される。また正孔輸送材料は、正孔注入効率が高くかつ注入された正孔を効率良く輸送することが好ましい。そのためには適切なイオン化ポテンシャルを持ち、しかも正孔移動度が大きく、さらに安定性に優れ、トラップとなる不純物が発生しにくい物質であることが要求される。 The hole transport layer is formed by one type of hole transport material alone, or by laminating or mixing two or more types of hole transport materials. Further, the hole transport material preferably has high hole injection efficiency and efficiently transports the injected holes. For that purpose, it is required to be a substance having an appropriate ionization potential, a high hole mobility, excellent stability, and less likely to generate impurities as traps.
　このような条件を満たす物質として、特に限定されるものではないが、例えば、ベンジジン誘導体、スターバーストアリールアミンと呼ばれる芳香族アミン系材料群；カルバゾール誘導体、ピラゾリン誘導体、スチルベン系化合物、ヒドラゾン系化合物、ベンゾフラン誘導体、ジベンゾフラン誘導体、チオフェン誘導体、ベンゾチオフェン誘導体、ジベンゾチオフェン誘導体、フルオレン誘導体、スピロフルオレン誘導体、オキサジアゾール誘導体、フタロシアニン誘導体、ポルフィリン誘導体などの複素環化合物；ポリマー系では前記単量体を側鎖に有するポリカーボネートやスチレン誘導体、ポリチオフェン、ポリアニリン、ポリフルオレン、ポリビニルカルバゾールおよびポリシランなどが挙げられる。 The substance satisfying such conditions is not particularly limited, but for example, a benzidine derivative, an aromatic amine-based material group called starburst arylamine; a carbazole derivative, a pyrazoline derivative, a stillben-based compound, a hydrazone-based compound, and the like. Heterocyclic compounds such as benzofuran derivatives, dibenzofuran derivatives, thiophene derivatives, benzothiophene derivatives, dibenzothiophene derivatives, fluorene derivatives, spirofluorene derivatives, oxadiazole derivatives, phthalocyanine derivatives, porphyrin derivatives; Examples thereof include polycarbonate and styrene derivatives, polythiophene, polyaniline, polyfluorene, polyvinylcarbazole and polysilane.
　（発光層）
　発光層は、正孔と電子の再結合によって発生した励起エネルギーにより発光する層である。発光層は単一の材料で構成されていてもよいが、色純度の観点から第一の化合物と、強い発光を示すドーパントである第二の化合物とを有することが好ましい。第一の化合物としては、例えば電荷移動を担うホスト材料や、熱活性化遅延蛍光性の化合物が好適な例として挙げられる。 (Light emitting layer)
The light emitting layer is a layer that emits light by the excitation energy generated by the recombination of holes and electrons. The light emitting layer may be composed of a single material, but from the viewpoint of color purity, it is preferable to have a first compound and a second compound which is a dopant exhibiting strong light emission. Suitable examples of the first compound include a host material responsible for charge transfer and a thermally activated delayed fluorescent compound.
　一般式（１）で表されるピロメテンホウ素錯体は、特に優れた蛍光量子収率を有していること、および発光スペクトルの半値幅が狭く高色純度を達成できることから、発光層のドーパントである第二の化合物として用いることが好ましい。第二の化合物のドープ量は、多すぎると濃度消光現象が起きるため、発光層全体の重量に対して２０重量％以下であることが好ましく、１０重量％以下がより好ましく、５重量％以下がさらに好ましく、２重量％以下が最も好ましい。またドープ濃度が低すぎると十分なエネルギー移動が起きにくいことから、発光層全体の重量に対して０．１重量％以上であることが好ましく、０．５％重量以上がより好ましい。 The pyrromethene boron complex represented by the general formula (1) is a dopant of the light emitting layer because it has a particularly excellent fluorescence quantum yield and the half width of the emission spectrum is narrow and high color purity can be achieved. It is preferably used as the second compound. If the doping amount of the second compound is too large, a concentration quenching phenomenon occurs. Therefore, it is preferably 20% by weight or less, more preferably 10% by weight or less, and 5% by weight or less, based on the total weight of the light emitting layer. More preferably, 2% by weight or less is most preferable. Further, if the doping concentration is too low, sufficient energy transfer is unlikely to occur. Therefore, the weight is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, based on the weight of the entire light emitting layer.
　ホスト材料は、化合物一種のみに限る必要はなく、二種類以上を混合して用いてもよく、また、積層して用いてもよい。ホスト材料としては、特に限定されないが、ナフタセン、ピレン、アントラセン、フルオランテンなどの縮合アリール環を有する化合物やその誘導体；Ｎ，Ｎ’－ジナフチル－Ｎ，Ｎ’－ジフェニル－４，４’－ジフェニル－１，１’－ジアミンなどの芳香族アミン誘導体；トリス（８－キノリナート）アルミニウム（III）をはじめとする金属キレート化オキシノイド化合物；ジスチリルベンゼン誘導体などのビススチリル誘導体；テトラフェニルブタジエン誘導体、インデン誘導体、クマリン誘導体、オキサジアゾール誘導体、ピロロピリジン誘導体、ペリノン誘導体、ピロロピロール誘導体、チアジアゾロピリジン誘導体、ジベンゾフラン誘導体、カルバゾール誘導体、インドロカルバゾール誘導体、トリアジン誘導体；ポリマー系では、ポリフェニレンビニレン誘導体、ポリパラフェニレン誘導体、ポリフルオレン誘導体、ポリビニルカルバゾール誘導体、ポリチオフェン誘導体などが使用できる。ホスト材料として特に好ましいものは、アントラセン誘導体またはナフタセン誘導体である。 The host material does not have to be limited to only one type of compound, and two or more types may be mixed and used, or may be used in a laminated manner. The host material is not particularly limited, but is a compound having a fused aryl ring such as naphthacene, pyrene, anthracene, and fluoranten and a derivative thereof; N, N'-dinaphthyl-N, N'-diphenyl-4,4'-diphenyl-. Aromatic amine derivatives such as 1,1'-diamine; metal chelated oxynoid compounds such as tris (8-quinolinate) aluminum (III); bisstyryl derivatives such as distyrylbenzene derivatives; tetraphenylbutadiene derivatives, inden derivatives, Cmarin derivative, oxadiazole derivative, pyrolopyridine derivative, perinone derivative, pyrolopyrrole derivative, thiadiazolopyridine derivative, dibenzofuran derivative, carbazole derivative, indolocarbazole derivative, triazine derivative; Derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, polythiophene derivatives and the like can be used. Particularly preferred as the host material are anthracene derivatives or naphthacene derivatives.
　ドーパント材料は、特に限定されないが、一般式（１）で表されるピロメテンホウ素錯体以外の蛍光発光材料を含んでいてもよい。具体的にはナフタセン、ピレン、アントラセン、フルオランテンなどの縮合アリール環を有する化合物やその誘導体；ヘテロアリール環を有する化合物やその誘導体；ジスチリルベンゼン誘導体、アミノスチリル誘導体、テトラフェニルブタジエン誘導体、スチルベン誘導体、アルダジン誘導体、ピロメテン誘導体、ジケトピロロ［３，４－ｃ］ピロール誘導体、クマリン誘導体、アゾール誘導体およびその金属錯体、ならびに芳香族アミン誘導体などが挙げられる。 The dopant material is not particularly limited, but may contain a fluorescent material other than the pyrromethene boron complex represented by the general formula (1). Specifically, compounds having a condensed aryl ring such as naphthacene, pyrene, anthracene, and fluorantene and derivatives thereof; compounds having a heteroaryl ring and derivatives thereof; dystylylbenzene derivatives, aminostyryl derivatives, tetraphenylbutadiene derivatives, stilben derivatives, Examples thereof include aldazine derivatives, pyromethene derivatives, diketopyrrolo [3,4-c] pyrrole derivatives, coumarin derivatives, azole derivatives and metal complexes thereof, and aromatic amine derivatives.
　またドーパント材料としてリン光発光材料が含まれていてもよい。リン光発光を行うドーパントとしては、イリジウム（Ir）、ルテニウム（Ru）、パラジウム（Pd）、白金（Pt）、オスミウム（Os）、およびレニウム（Re）からなる群から選択される少なくとも一つの金属を含む金属錯体化合物であることが好ましく、高効率発光の観点からイリジウム錯体または白金錯体がより好ましい。配位子は、フェニルピリジン骨格またはフェニルキノリン骨格またはカルベン骨格などの含窒素ヘテロアリール基を有することが好ましいが、これらに限定されるものではない。 Further, a phosphorescent light emitting material may be contained as a dopant material. The dopant that emits phosphorescent light is at least one metal selected from the group consisting of iridium (Ir), ruthenium (Ru), palladium (Pd), platinum (Pt), osmium (Os), and renium (Re). It is preferably a metal complex compound containing, and an iridium complex or a platinum complex is more preferable from the viewpoint of high-efficiency light emission. The ligand preferably has, but is not limited to, a nitrogen-containing heteroaryl group such as a phenylpyridine skeleton or a phenylquinoline skeleton or a carbene skeleton.
　ただし色純度を高くする観点から、ドーパント材料は１種類の一般式（１）で表されるピロメテンホウ素錯体であることが好ましい。 However, from the viewpoint of increasing the color purity, the dopant material is preferably a pyrromethene boron complex represented by one kind of general formula (1).
　発光層には上記ホスト材料またはドーパント材料の他に、発光層内のキャリアバランスを調整するためや発光層の層構造を安定化させるための第３成分をさらに含んでいてもよい。ただし、第３成分としては、ホスト材料およびドーパント材料との間で相互作用を起こさないような材料を選択する。 In addition to the above host material or dopant material, the light emitting layer may further contain a third component for adjusting the carrier balance in the light emitting layer and for stabilizing the layer structure of the light emitting layer. However, as the third component, a material that does not cause an interaction between the host material and the dopant material is selected.
　熱活性化遅延蛍光性化合物は、一般的に、ＴＡＤＦ材料とも呼ばれ、一重項励起状態のエネルギー準位と三重項励起状態エネルギー準位のエネルギーギャップを小さくすることで、三重項励起状態から一重項励起状態への逆項間交差を促進し、一重項励起子の生成確率を向上させた材料である。ＴＡＤＦ材料における最低励起一重項エネルギー準位と最低励起三重項エネルギー準位の差（ΔＥＳＴとする）は０．３ｅＶ以下であることが好ましい。このＴＡＤＦ機構による遅延蛍光を利用することにより、理論的内部効率を１００％まで高めることができる。さらに熱活性化遅延蛍光性を有する第一の化合物の一重項励起子から第二の化合物の一重項励起子へフェルスター型のエネルギー移動が起こる場合、第二の化合物の一重項励起子からの蛍光発光が観測される。このようなエネルギー移動が起きるためには第一の化合物の最低励起一重項エネルギー準位が、第二の化合物の最低励起一重項エネルギー準位より大きいことが好ましい。ここで第二の化合物がシャープな発光スペクトルを有する蛍光発光材である場合、高効率かつ高色純度の発光素子を得ることができる。このように、発光層が熱活性化遅延蛍光性化合物を含有すると、高効率発光が可能となり、ディスプレイの低消費電力化に寄与する。熱活性化遅延蛍光性化合物は、単一の材料で熱活性化遅延蛍光を示す化合物であってもいいし、エキサイプレックス錯体を形成する場合のように複数の化合物で熱活性化遅延蛍光を示す化合物であってもよい。 Thermally Activated Delayed Fluorescent Compounds, also commonly referred to as TADF materials, reduce the energy gap between the singlet excited state energy level and the triplet excited state energy level to reduce the energy gap from the triplet excited state to singlet. It is a material that promotes inverse intersystem crossing to the term excited state and improves the generation probability of singlet excited states. The difference between the lowest excited singlet energy level and the lowest excited triplet energy level (referred to as ΔEST) in the TADF material is preferably 0.3 eV or less. By utilizing delayed fluorescence by this TADF mechanism, the theoretical internal efficiency can be increased up to 100%. Furthermore, when Felster-type energy transfer occurs from the singlet exciton of the first compound having thermal activated delayed fluorescence to the singlet exciton of the second compound, the singlet exciton of the second compound Fluorescent emission is observed. In order for such energy transfer to occur, it is preferable that the lowest excited singlet energy level of the first compound is larger than the lowest excited singlet energy level of the second compound. Here, when the second compound is a fluorescent light emitting material having a sharp light emitting spectrum, a light emitting element having high efficiency and high color purity can be obtained. As described above, when the light emitting layer contains a thermally activated delayed fluorescent compound, high-efficiency light emission is possible, which contributes to low power consumption of the display. The Thermally Activated Delayed Fluorescence Compound may be a compound that exhibits Thermally Activated Delayed Fluorescence with a Single Material, or exhibits Thermally Activated Delayed Fluorescence with a plurality of compounds as in the case of forming an exciplex complex. It may be a compound.
　熱活性化遅延蛍光性化合物としては、単一の化合物でも複数の化合物を混合して用いてもよく、公知の材料を用いることができる。具体的には、例えば、ベンゾニトリル誘導体、トリアジン誘導体、ジスルホキシド誘導体、カルバゾール誘導体、インドロカルバゾール誘導体、ジヒドロフェナジン誘導体、チアゾール誘導体、オキサジアゾール誘導体などが挙げられる。特に同一分子内に電子供与性部（ドナー部）と電子求引性部（アクセプター部）を有する化合物であることが好ましい。電子供与性部（ドナー部）と電子求引性部は単結合またはスピロ結合を介して直接結合していてもよいし、連結基を介して結合していてもよい。このような化合物の例としては、下記一般式（３）で表される構造を含む化合物が挙げられる。 As the thermally activated delayed fluorescent compound, a single compound or a plurality of compounds may be mixed and used, and known materials can be used. Specific examples thereof include benzonitrile derivatives, triazine derivatives, disulfoxide derivatives, carbazole derivatives, indolocarbazole derivatives, dihydrophenazine derivatives, thiazole derivatives, oxaziazole derivatives and the like. In particular, a compound having an electron donating part (donor part) and an electron attracting part (acceptor part) in the same molecule is preferable. The electron donating part (donor part) and the electron attracting part may be directly bonded via a single bond or a spiro bond, or may be bonded via a linking group. Examples of such a compound include a compound containing a structure represented by the following general formula (3).
Figure JPOXMLDOC01-appb-C000025
Figure JPOXMLDOC01-appb-C000025
　前記一般式（３）において、Ａは電子求引性部、Ｂは電子供与性部、Ｌは連結基である。Ａが複数存在する場合、複数のＡは互いに同一または異なり、Ａ同士が結合して環構造を形成してもよい。Ｂが複数存在する場合、複数のＢは互いに同一または異なり、Ｂ同士が結合して環構造を形成してもよい。 In the general formula (3), A is an electron attracting part, B is an electron donating part, and L is a linking group. When a plurality of A's are present, the plurality of A's are the same or different from each other, and the A's may be bonded to each other to form a ring structure. When a plurality of B's are present, the plurality of B's are the same or different from each other, and the B's may be bonded to each other to form a ring structure.
　Ｌは、直接結合、または、置換もしくは無置換の環形成炭素数６～３０の芳香族炭化水素基、置換もしくは無置換の環形成原子数５～３０の複素芳香環基、これらの基が互いに２～５個連結した基、およびフッ化アルキル基を有するメチレン基からなる群から選ばれる基である。ここで、直接結合とは、単結合およびスピロ結合を含む。ただし、複素芳香環基において、電子供与性を有する芳香族アミノ基やπ電子過剰型複素環官能基は含まない。 L is a directly bonded or substituted or unsubstituted ring-forming aromatic hydrocarbon group having 6 to 30 carbon atoms, a substituted or unsubstituted ring-forming atomic ring-forming heteroaromatic ring group having 5 to 30 atoms, and these groups are mutually exclusive. It is a group selected from the group consisting of 2 to 5 linked groups and a methylene group having an alkyl fluoride group. Here, the direct bond includes a single bond and a spiro bond. However, the heteroaromatic ring group does not include an aromatic amino group having an electron donating property or a π-electron excess heterocyclic functional group.
　ａおよびｂは、それぞれ独立に、１～５の整数である。 A and b are independently integers of 1 to 5.
　Ｌは、同一分子内に複数存在していても良い。Ｌが複数存在する場合、複数のＬは互いに同一または異なり、Ｌ同士が結合して飽和または不飽和の環を形成してもよい。また、複数のＬがＡおよび／またはＢを介して結合していてもよい。Ａおよび／またはＢならびにＬが、それぞれ複数存在する場合、複数のＡおよび／またはＢが同一のＬに結合してもよく、異なるＬに結合してもよい。 A plurality of L may exist in the same molecule. When a plurality of L's are present, the plurality of L's are the same or different from each other, and the L's may be bonded to each other to form a saturated or unsaturated ring. Further, a plurality of Ls may be connected via A and / or B. When a plurality of A and / or B and L are present, a plurality of A and / or B may be bound to the same L or may be bound to different L.
　ここで電子供与性部（ドナー部）とは隣接部位に対して相対的に電子豊富な部位を示す。例えば、芳香族アミノ基やπ電子過剰型複素環官能基が挙げられる。具体的にはジアリールアミノ基、カルバゾリル基、ベンゾカルバゾリル基、ジベンゾカルバゾリル基、インドロカルバゾリル基、ジヒドロアクリジニル基、フェノキサジニル基およびジヒドロフェナジニル基およびこれらの基が複数連結した基などが例示される。これらの基はさらに置換されていても置換されていなくてもよい。置換される場合における置換基としては、前述の好ましい置換基の例が挙げられる。 Here, the electron donating part (donor part) indicates a part that is relatively electron-rich with respect to the adjacent part. For example, an aromatic amino group and a π-electron excess heterocyclic functional group can be mentioned. Specifically, there are a plurality of diarylamino groups, carbazolyl groups, benzocarbazolyl groups, dibenzocarbazolyl groups, indolocarbazolyl groups, dihydroacridinyl groups, phenoxadinyl groups and dihydrophenazinyl groups, and a plurality of these groups. Examples include linked groups. These groups may or may not be further substituted. Examples of the substituent in the case of substitution include the above-mentioned preferred substituent.
　また電子求引性部（アクセプター部）とは隣接部位に対して相対的に電子欠乏性の部位を示す。例えば、電子求引性基や電子求引性基を置換基として有するフェニル基やπ電子不足型複素環官能基が挙げられる。具体的には、カルボニル基、スルホニル基、シアノ基およびフッ素原子から選択される電子求引性基や、電子求引性基を置換基として有するフェニル基、ピリミジニル基やトリアジニル基が例示される。これらの基はさらに置換されていても置換されていなくてもよい。置換される場合における置換基としては、前述の好ましい置換基の例が挙げられる。 Also, the electron attractor part (acceptor part) indicates a part that is relatively electron deficient with respect to the adjacent part. For example, a phenyl group having an electron-attracting group or an electron-attracting group as a substituent and a π-electron-deficient heterocyclic functional group can be mentioned. Specific examples thereof include an electron-attracting group selected from a carbonyl group, a sulfonyl group, a cyano group and a fluorine atom, a phenyl group having an electron-attracting group as a substituent, a pyrimidinyl group and a triazinyl group. These groups may or may not be further substituted. Examples of the substituent in the case of substitution include the above-mentioned preferred substituent.
　連結基Ｌとして用いられる環形成炭素数６～３０の芳香族炭化水素基としては、例えば、フェニル基、ビフェニル基、ターフェニル基、ナフチル基、フルオレニル基、ベンゾフルオレニル基、ジベンゾフルオレニル基、フェナントリル基、アントラセニル基、ベンゾフェナントリル基、ベンゾアントラセニル基、クリセニル基、ピレニル基、フルオランテニル基、トリフェニレニル基、ベンゾフルオランテニル基、ジベンゾアントラセニル基、ペリレニル基、ヘリセニル基などのアリール基から水素原子を一部除いた、（ａ＋ｂ）価の基が挙げられる。 Examples of the aromatic hydrocarbon group having 6 to 30 ring-forming carbon atoms used as the linking group L include a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorenyl group, a benzofluorenyl group and a dibenzofluorenyl group. Group, phenanthryl group, anthracenyl group, benzophenanthryl group, benzoanthrasenyl group, chrysenyl group, pyrenyl group, fluoranthenyl group, triphenylenyl group, benzofluoranthenyl group, dibenzoanthrasenyl group, peryleneyl group, helisenyl group Examples thereof include a (a + b) valent group obtained by removing a part of a hydrogen atom from an aryl group such as a group.
　連結基Ｌとして用いられる環形成原子数５～３０の複素芳香環基としては、例えば、ピリジル基、フラニル基、チオフェニル基、キノリニル基、イソキノリニル基、ピラジニル基、ピリミジル基、ピリダジニル基、トリアジニル基、ナフチリジニル基、シンノリニル基、フタラジニル基、キノキサリニル基、キナゾリニル基、ベンゾフラニル基、ベンゾチオフェニル基、インドリル基、ジベンゾフラニル基、ジベンゾチオフェニル基、ベンゾキノリニル基、ベンゾイミダゾリル基、イミダゾピリジル基、ベンゾオキサゾリル基、ベンゾチアゾリル基、フェナントロリニル基などの、炭素および水素以外の原子、すなわちヘテロ原子を一個または複数個環内に有するヘテロアリール基から水素を一部除いた、（ａ＋ｂ）価の環状芳香族基が挙げられる。ヘテロ原子としては窒素原子、酸素原子、または硫黄原子が好ましい。複素芳香環基は置換されていても無置換でもよい。 Examples of the heteroaromatic ring group having 5 to 30 ring-forming atoms used as the linking group L include a pyridyl group, a furanyl group, a thiophenyl group, a quinolinyl group, an isoquinolinyl group, a pyrazinyl group, a pyrimidyl group, a pyridadinyl group and a triazinyl group. Naftyridinyl group, cinnolinyl group, phthalazinyl group, quinoxalinyl group, quinazolinyl group, benzofuranyl group, benzothiophenyl group, indolyl group, dibenzofuranyl group, dibenzothiophenyl group, benzoquinolinyl group, benzoimidazolyl group, imidazoly pyridyl group, benzoxazolyl A (a + b) -valent cyclic aromatic group obtained by removing a part of hydrogen from an atom other than carbon and hydrogen, that is, a heteroaryl group having one or more heteroatoms in a ring, such as a group, a benzothiazolyl group, and a phenanthrolinyl group. A family group can be mentioned. As the hetero atom, a nitrogen atom, an oxygen atom, or a sulfur atom is preferable. The heteroaromatic ring group may be substituted or unsubstituted.
　このような熱活性化遅延蛍光性化合物として、特に限定されるものではないが、以下のような例が挙げられる。 The thermally activated delayed fluorescent compound is not particularly limited, but examples thereof include the following.
Figure JPOXMLDOC01-appb-C000026
Figure JPOXMLDOC01-appb-C000026
Figure JPOXMLDOC01-appb-C000027
Figure JPOXMLDOC01-appb-C000027
Figure JPOXMLDOC01-appb-C000028
Figure JPOXMLDOC01-appb-C000028
Figure JPOXMLDOC01-appb-C000029
Figure JPOXMLDOC01-appb-C000029
Figure JPOXMLDOC01-appb-C000030
Figure JPOXMLDOC01-appb-C000030
Figure JPOXMLDOC01-appb-C000031
Figure JPOXMLDOC01-appb-C000031
Figure JPOXMLDOC01-appb-C000032
Figure JPOXMLDOC01-appb-C000032
Figure JPOXMLDOC01-appb-C000033
Figure JPOXMLDOC01-appb-C000033
Figure JPOXMLDOC01-appb-C000034
Figure JPOXMLDOC01-appb-C000034
Figure JPOXMLDOC01-appb-C000035
Figure JPOXMLDOC01-appb-C000035
Figure JPOXMLDOC01-appb-C000036
Figure JPOXMLDOC01-appb-C000036
Figure JPOXMLDOC01-appb-C000037
Figure JPOXMLDOC01-appb-C000037
Figure JPOXMLDOC01-appb-C000038
Figure JPOXMLDOC01-appb-C000038
Figure JPOXMLDOC01-appb-C000039
Figure JPOXMLDOC01-appb-C000039
　上記第一の化合物が、熱活性化遅延蛍光性化合物であり、上記第二の化合物が、上記一般式（１）で表されるピロメテンホウ素錯体であることが好ましい。また、第一の化合物が熱活性化遅延蛍光性化合物である場合、発光層がさらに一重項エネルギーが第一の化合物の一重項エネルギーよりも大きい第三の化合物を含むことが好ましい。これにより、第三の化合物は発光材料のエネルギーを発光層内に閉じ込める機能を有することができ、効率よく発光させることが可能となる。また、第三の化合物の最低励起三重項エネルギーが第一の化合物の最低励起三重項エネルギーよりも大きいことも好ましい。 It is preferable that the first compound is a thermally activated delayed fluorescent compound and the second compound is a pyrometheneboron complex represented by the general formula (1). When the first compound is a thermally activated delayed fluorescent compound, it is preferable that the light emitting layer further contains a third compound having a singlet energy larger than that of the first compound. As a result, the third compound can have a function of confining the energy of the light emitting material in the light emitting layer, and can efficiently emit light. It is also preferable that the lowest excited triplet energy of the third compound is larger than the lowest excited triplet energy of the first compound.
　このような第三の化合物としては、電荷輸送能が高く、かつガラス転移温度が高い有機化合物であることが好ましい。第三の化合物として、特に限定されるものではないが、以下のような例が挙げられる。 As such a third compound, it is preferable that it is an organic compound having a high charge transporting ability and a high glass transition temperature. The third compound is not particularly limited, and examples thereof include the following.
Figure JPOXMLDOC01-appb-C000040
Figure JPOXMLDOC01-appb-C000040
Figure JPOXMLDOC01-appb-C000041
Figure JPOXMLDOC01-appb-C000041
Figure JPOXMLDOC01-appb-C000042
Figure JPOXMLDOC01-appb-C000042
Figure JPOXMLDOC01-appb-C000043
Figure JPOXMLDOC01-appb-C000043
Figure JPOXMLDOC01-appb-C000044
Figure JPOXMLDOC01-appb-C000044
Figure JPOXMLDOC01-appb-C000045
Figure JPOXMLDOC01-appb-C000045
Figure JPOXMLDOC01-appb-C000046
Figure JPOXMLDOC01-appb-C000046
Figure JPOXMLDOC01-appb-C000047
Figure JPOXMLDOC01-appb-C000047
Figure JPOXMLDOC01-appb-C000048
Figure JPOXMLDOC01-appb-C000048
Figure JPOXMLDOC01-appb-C000049
Figure JPOXMLDOC01-appb-C000049
Figure JPOXMLDOC01-appb-C000050
Figure JPOXMLDOC01-appb-C000050
　また第三の化合物は単一でも２種類以上の材料により構成されていてもよい。第三の化合物として２種類以上の材料を用いる場合には、電子輸送性の第三の化合物と正孔輸送性の第三の化合物の組み合わせであることが好ましい。電子輸送性の第三の化合物と正孔輸送性の第三の化合物を適切な混合比で組み合わせることにより、発光層内の電荷バランスを調整し、発光領域の偏りを抑制することで発光素子の信頼性を向上させ、耐久性を上げることができる。また電子輸送性の第三の化合物と正孔輸送性の第三の化合物との間で励起錯体を形成してもよい。以上の観点から、第一の化合物と第三の化合物が下記の式１～式４の関係式をそれぞれ満たすことが好ましい。また、式１および式２を満たすことがより好ましく、式３および式４を満たすことがさらに好ましい。また、式１～式４を全て満たすことがよりさらに好ましい。
Ｓ１（電子輸送性の第三の化合物）＞Ｓ１（第一の化合物）（式１）
Ｓ１（正孔輸送性の第三の化合物）＞Ｓ１（第一の化合物）（式２）
Ｔ１（電子輸送性の第三の化合物）＞Ｔ１（第一の化合物）（式３）
Ｔ１（正孔輸送性の第三の化合物）＞Ｔ１（第一の化合物）（式４）
ここで、Ｓ１はそれぞれの化合物の最低励起一重項状態のエネルギー準位、Ｔ１はそれぞれの化合物の最低励起三重項状態のエネルギー準位を表している。 Further, the third compound may be a single compound or may be composed of two or more kinds of materials. When two or more kinds of materials are used as the third compound, it is preferable that the third compound has an electron transporting property and the third compound has a hole transporting property. By combining the third compound with electron transporting property and the third compound with hole transporting property at an appropriate mixing ratio, the charge balance in the light emitting layer is adjusted and the bias of the light emitting region is suppressed to suppress the bias of the light emitting device. It can improve reliability and durability. Further, an excited complex may be formed between the electron-transporting third compound and the hole-transporting third compound. From the above viewpoint, it is preferable that the first compound and the third compound satisfy the relational expressions of the following formulas 1 to 4, respectively. Further, it is more preferable to satisfy the formulas 1 and 2, and it is further preferable to satisfy the formulas 3 and 4. Further, it is more preferable to satisfy all of the formulas 1 to 4.
S1 (electron-transporting third compound)> S1 (first compound) (formula 1)
S1 (hole transporting third compound)> S1 (first compound) (formula 2)
T1 (electron-transporting third compound)> T1 (first compound) (formula 3)
T1 (hole-transporting third compound)> T1 (first compound) (formula 4)
Here, S1 represents the energy level of the lowest excited singlet state of each compound, and T1 represents the energy level of the lowest excited triplet state of each compound.
　電子輸送性の第三の化合物としては、π電子不足型複素芳香環を含む化合物などが挙げられる。具体的には２－（４－ビフェニル）－５－（４－ｔｅｒｔ－ブチルフェニル）－１，３，４－オキサジアゾール（ＰＢＤ）、３－（４－ビフェニリル）－４－フェニル－５－（４－ｔｅｒｔ－ブチルフェニル）－１，２，４－トリアゾール（ＴＡＺ）、１，３－ビス［５－（ｐ－ｔｅｒｔ－ブチルフェニル）－１，３，４－オキサジアゾール－２－イル］ベンゼン（ＯＸＤ－７）、９－［４－（５－フェニル－１，３，４－オキサジアゾール－２－イル）フェニル］－９Ｈ－カルバゾール（ＣＯ１１）、２，２’，２’’－（１，３，５－ベンゼントリイル）トリス（１－フェニル－１Ｈ－ベンゾイミダゾール）（ＴＰＢＩ）、２－［３－（ジベンゾチオフェン－４－イル）フェニル］－１－フェニル－１Ｈ－ベンゾイミダゾール（ｍＤＢＴＢＩｍ－ＩＩ）などのポリアゾール骨格を有する複素環化合物；２－［３－（ジベンゾチオフェン－４－イル）フェニル］ジベンゾ［ｆ，ｈ］キノキサリン（２ｍＤＢＴＰＤＢｑ－ＩＩ）、２－［３’－（ジベンゾチオフェン－４－イル）ビフェニル－３－イル］ジベンゾ［ｆ，ｈ］キノキサリン（２ｍＤＢＴＢＰＤＢｑ－ＩＩ）、２－［４－（３，６－ジフェニル－９Ｈ－カルバゾール－９－イル）フェニル］ジベンゾ［ｆ，ｈ］キノキサリン（２ＣｚＰＤＢｑ－ＩＩＩ）、７－［３－（ジベンゾチオフェン－４－イル）フェニル］ジベンゾ［ｆ，ｈ］キノキサリン（７ｍＤＢＴＰＤＢｑ－ＩＩ）、および６－［３－（ジベンゾチオフェン－４－イル）フェニル］ジベンゾ［ｆ，ｈ］キノキサリン（６ｍＤＢＴＰＤＢｑ－ＩＩ）、２－［３’－（９Ｈ－カルバゾール－９－イル）ビフェニル－３－イル］ジベンゾ［ｆ，ｈ］キノキサリン（２ｍＣｚＢＰＤＢｑ）などのキノキサリン骨格またはジベンゾキノキサリン骨格を有する複素環化合物；４，６－ビス［３－（フェナントレン－９－イル）フェニル］ピリミジン（４，６ｍＰｎＰ２Ｐｍ）、４，６－ビス［３－（９Ｈ－カルバゾール－９－イル）フェニル］ピリミジン（４，６ｍＣｚＰ２Ｐｍ）、４，６－ビス［３－（４－ジベンゾチエニル）フェニル］ピリミジン（４，６ｍＤＢＴＰ２Ｐｍ－ＩＩ）などのジアジン骨格（ピリミジン骨格やピラジン骨格）を有する複素環化合物；３，５－ビス［３－（９Ｈ－カルバゾール－９－イル）フェニル］ピリジン（３，５ＤＣｚＰＰｙ）、１，３，５－トリ［３－（３－ピリジル）フェニル］ベンゼン（ＴｍＰｙＰＢ）、３，３’，５，５’－テトラ［（ｍ－ピリジル）－フェン－３－イル］ビフェニル（ＢＰ４ｍＰｙ）などのピリジン骨格を有する複素環化合物が例示される。 Examples of the third electron-transporting compound include compounds containing a π-electron-deficient heteroaromatic ring. Specifically, 2- (4-biphenyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (PBD), 3- (4-biphenylyl) -4-phenyl-5- (4-tert-butylphenyl) -1,2,4-triazole (TAZ), 1,3-bis [5- (p-tert-butylphenyl) -1,3,4-oxadiazol-2-yl ] Benzene (OXD-7), 9- [4- (5-phenyl-1,3,4-oxadiazol-2-yl) phenyl] -9H-carbazole (CO11), 2,2', 2'' -(1,3,5-Benzenetriyl) Tris (1-phenyl-1H-benzoimidazole) (TPBI), 2- [3- (dibenzothiophen-4-yl) phenyl] -1-phenyl-1H-benzo Heterocyclic compounds with a polyazole skeleton such as imidazole (mDBTBIm-II); 2- [3- (dibenzothiophen-4-yl) phenyl] dibenzo [f, h] quinoxalin (2mDBTPDBq-II), 2- [3'- (Dibenzothiophen-4-yl) biphenyl-3-yl] dibenzo [f, h] quinoxalin (2mDBTBPDBq-II), 2- [4- (3,6-diphenyl-9H-carbazole-9-yl) phenyl] dibenzo [F, h] quinoxalin (2CzPDBq-III), 7- [3- (dibenzothiophen-4-yl) phenyl] dibenzo [f, h] quinoxalin (7mDBTPDBq-II), and 6- [3- (dibenzothiophene-). 4-Il) Phenyl] dibenzo [f, h] quinoxalin (6mDBTPDBq-II), 2- [3'-(9H-carbazole-9-yl) biphenyl-3-yl] dibenzo [f, h] quinoxalin (2mCzBPDBq) Heterocyclic compounds having a quinoxalin skeleton or dibenzoquinoxalin skeleton such as; 4,6-bis [3- (phenanthren-9-yl) phenyl] pyrimidin (4,6 mPnP2Pm), 4,6-bis [3- (9H-carbazole) -9-Il) Phenyl] pyrimidine (4.6mCzP2Pm), 4,6-bis [3- (4-dibenzothienyl) phenyl] pyrimidin (4.6mDBTP2Pm-II) and other diazine skeletons (pyrimidine skeleton and pyrazine skeleton) Heterocyclic compound; 3,5-bis [3- (9H-carbazole-9-yl) phenyl] pyridine (3,5DCzPPy), 1,3,5-tri [3- (3-pyridyl) Heterocyclic compounds having a pyridine skeleton such as phenyl] benzene (TmPyPB), 3,3', 5,5'-tetra [(m-pyridyl) -phen-3-yl] biphenyl (BP4mPy) are exemplified.
　また上記の正孔輸送性の第三の化合物としてはπ電子過剰型複素芳香環を含む化合物などが挙げられる。具体的には１，３－ビス（Ｎ－カルバゾリル）ベンゼン、４，４’－ジ（Ｎ－カルバゾリル）ビフェニル（ＣＢＰ）、３，３’－ジ（Ｎ－カルバゾリル）ビフェニル（ｍＣＢＰ）、１，３，５－トリス［４－（Ｎ－カルバゾリル）フェニル］ベンゼン（ＴＣＰＢ）、９－［４－（１０－フェニル－９－アントラセニル）フェニル］－９Ｈ－カルバゾール（ＣｚＰＡ）、１，４－ビス［４－（Ｎ－カルバゾリル）フェニル］－２，３，５，６－テトラフェニルベンゼン、９－フェニル－９Ｈ－３－（９－フェニル－９Ｈ－カルバゾール－３－イル）カルバゾール、３，６－ビス［Ｎ－（９－フェニルカルバゾール－３－イル）－Ｎ－フェニルアミノ］－９－フェニルカルバゾール（ＰＣｚＰＣＡ２）、３－［Ｎ－（１－ナフチル）－Ｎ－（９－フェニルカルバゾール－３－イル）アミノ］－９－フェニルカルバゾール（ＰＣｚＰＣＮ１）、９－（［１，１-ビフェニル］－４－イル）－９’－（［１，１’：４’、１”-ターフェニル］-４-イル）－９Ｈ，９’Ｈ-３，３’-ビカルバゾール、９-（［１，１’：４’、１”－ターフェニル］－４－イル）－９’－（ナフタレンー２－イル）－９Ｈ，９’Ｈ-３，３’－ビカルバゾール、９，９’、９”－トリフェニル－９Ｈ，９’Ｈ，９”Ｈ－３，３’：６’、３”－トリカルバゾールなどのカルバゾール骨格を有する化合物が例示される。 Further, as the above-mentioned third hole-transporting compound, a compound containing a π-electron excess type heteroaromatic ring and the like can be mentioned. Specifically, 1,3-bis (N-carbazolyl) benzene, 4,4'-di (N-carbazolyl) biphenyl (CBP), 3,3'-di (N-carbazolyl) biphenyl (mCBP), 1, 3,5-Tris [4- (N-carbazolyl) phenyl] benzene (TCPB), 9- [4- (10-phenyl-9-anthracenyl) phenyl] -9H-carbazole (CzPA), 1,4-bis [ 4- (N-carbazolyl) phenyl] -2,3,5,6-tetraphenylbenzene, 9-phenyl-9H-3- (9-phenyl-9H-carbazole-3-yl) carbazole, 3,6-bis [N- (9-phenylcarbazole-3-yl) -N-phenylamino] -9-phenylcarbazole (PCzPCA2), 3- [N- (1-naphthyl) -N- (9-phenylcarbazole-3-yl) ) Amino] -9-phenylcarbazole (PCzPCN1), 9-([1,1-biphenyl] -4-yl) -9'-([1,1': 4', 1 "-terphenyl] -4- Il) -9H, 9'H-3,3'-bicarbazole, 9-([1,1': 4', 1 "-terphenyl] -4-yl) -9'-(naphthalen-2-yl) -9H, 9'H-3,3'-bicarbazole, 9,9', 9 "-triphenyl-9H, 9'H, 9" H-3,3': 6', 3 "-tricarbazole, etc. Examples of compounds having the carbazole skeleton of.
　（電子輸送層）
　電子輸送層は、陰極から電子が注入され、さらに電子を輸送する層である。電子輸送層に用いられる電子輸送材料としては、電子親和力が大きいこと、電子移動度が大きいこと、安定性に優れること、およびトラップとなる不純物が発生しにくい物質であることが要求される。また低分子量の化合物は結晶化して膜質が劣化しやすいため分子量４００以上の化合物が好ましい。 (Electronic transport layer)
The electron transport layer is a layer in which electrons are injected from the cathode and further electrons are transported. The electron transport material used for the electron transport layer is required to have a high electron affinity, a high electron mobility, excellent stability, and a substance in which impurities that serve as traps are unlikely to be generated. Further, a compound having a molecular weight of 400 or more is preferable because a compound having a low molecular weight tends to crystallize and deteriorate the film quality.
　本発明における電子輸送層には、正孔の移動を効率よく阻止できる正孔阻止層も同義のものとして含まれる。正孔阻止層および電子輸送層は単独でも複数の材料が積層されて構成されていてもよい。 The electron transport layer in the present invention also includes a hole blocking layer capable of efficiently blocking the movement of holes as a synonym. The hole blocking layer and the electron transporting layer may be formed alone or by laminating a plurality of materials.
　電子輸送材料としては、多環芳香族誘導体、スチリル系芳香環誘導体、キノン誘導体、リンオキサイド誘導体、トリス（８－キノリノラート）アルミニウム（III）などのキノリノール錯体、ベンゾキノリノール錯体、ヒドロキシアゾール錯体、アゾメチン錯体、トロポロン金属錯体およびフラボノール金属錯体などの各種金属錯体が挙げられる。駆動電圧を低減し高効率発光が得られることから、電子受容性窒素を含むヘテロアリール基を有する化合物を用いることが好ましい。ここで電子受容性窒素とは、隣接原子との間に多重結合を形成している窒素原子を表す。電子受容性窒素を含むヘテロアリール基は、電子親和力が大きいため、陰極から電子が注入しやすくなり、より低電圧駆動が可能となる。また発光層への電子の供給が多くなり、再結合確率が高くなるので発光効率が向上する。電子受容性窒素を含むヘテロアリール基構造を有する化合物としては、例えば、ピリジン誘導体、トリアジン誘導体、ピラジン誘導体、ピリミジン誘導体、キノリン誘導体、キノキサリン誘導体、キナゾリン誘導体、ナフチリジン誘導体、ベンゾキノリン誘導体、フェナントロリン誘導体、イミダゾール誘導体、オキサゾール誘導体、チアゾール誘導体、トリアゾール誘導体、オキサジアゾール誘導体、チアジアゾール誘導体、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、フェナンスロイミダゾール誘導体、およびビピリジンやターピリジンなどのオリゴピリジン誘導体などが好ましい化合物として挙げられる。中でも、トリス（Ｎ－フェニルベンズイミダゾール－２－イル）ベンゼンなどのイミダゾール誘導体、１，３－ビス［（４－ｔｅｒｔ－ブチルフェニル）－１，３，４－オキサジアゾリル］フェニレンなどのオキサジアゾール誘導体；Ｎ－ナフチル－２，５－ジフェニル－１，３，４－トリアゾールなどのトリアゾール誘導体；バソクプロインや１，３－ビス（１，１０－フェナントロリン－９－イル）ベンゼンなどのフェナントロリン誘導体；２，２’－ビス（ベンゾ［ｈ］キノリン－２－イル）－９，９’－スピロビフルオレンなどのベンゾキノリン誘導体；２，５－ビス（６’－（２’，２”－ビピリジル））－１，１－ジメチル－３，４－ジフェニルシロールなどのビピリジン誘導体；１，３－ビス（４’－（２，２’：６’２”－ターピリジニル））ベンゼンなどのターピリジン誘導体；ビス（１－ナフチル）－４－（１，８－ナフチリジン－２－イル）フェニルホスフィンオキサイドなどのナフチリジン誘導体およびトリアジン誘導体が、電子輸送能の観点から好ましく用いられる。 Examples of the electron transporting material include polycyclic aromatic derivatives, styryl-based aromatic ring derivatives, quinone derivatives, phosphoroxide derivatives, quinolinol complexes such as tris (8-quinolinolate) aluminum (III), benzoquinolinol complexes, hydroxyazole complexes, and azomethine complexes. , Tropolone metal complexes and various metal complexes such as flavonol metal complexes. Since the driving voltage can be reduced and high-efficiency light emission can be obtained, it is preferable to use a compound having a heteroaryl group containing electron-accepting nitrogen. Here, the electron-accepting nitrogen represents a nitrogen atom forming a multiple bond with an adjacent atom. Since the heteroaryl group containing electron-accepting nitrogen has a large electron affinity, electrons can be easily injected from the cathode, and a lower voltage drive becomes possible. In addition, the supply of electrons to the light emitting layer is increased, and the recombination probability is increased, so that the luminous efficiency is improved. Examples of the compound having a heteroaryl group structure containing electron-accepting nitrogen include a pyridine derivative, a triazine derivative, a pyrazine derivative, a pyrimidine derivative, a quinoline derivative, a quinoxaline derivative, a quinazoline derivative, a naphthylidine derivative, a benzoquinoline derivative, a phenanthroline derivative, and an imidazole. Preferred compounds include derivatives, oxazole derivatives, thiazole derivatives, triazole derivatives, oxaziazole derivatives, thiadiazol derivatives, benzimidazole derivatives, benzoxazole derivatives, benzthiazole derivatives, phenanthle midazole derivatives, and oligopyridine derivatives such as bipyridine and tarpyridine. Is listed as. Among them, imidazole derivatives such as tris (N-phenylbenzimidazole-2-yl) benzene, and oxadiazole derivatives such as 1,3-bis [(4-tert-butylphenyl) -1,3,4-oxadiazolyl] phenylene. Triazole derivatives such as N-naphthyl-2,5-diphenyl-1,3,4-triazole; phenanthroline derivatives such as vasocproin and 1,3-bis (1,10-phenanthroline-9-yl) benzene; 2,2 Benzene (benzo [h] quinoline-2-yl) -9,9'-benzoquinoline derivatives such as spirobifluorene; 2,5-bis (6'-(2', 2 "-bipyridyl))-1 , 1-Dimethyl-3,4-diphenylsilol and other bipyridine derivatives; 1,3-bis (4'-(2,2': 6'2 "-terpyridinyl)) benzene and other terpyridine derivatives; bis (1-naphthyl) ) -4- (1,8-naphthylidine-2-yl) naphthylidine derivatives such as phenylphosphine oxide and triazine derivatives are preferably used from the viewpoint of electron transport ability.
　また、電子輸送材料が縮合多環芳香族骨格を有していると、ガラス転移温度が向上し、かつ電子移動度が大きく低電圧化が可能なためより好ましい。このような縮合多環芳香族骨格としては、フルオランテン骨格、アントラセン骨格、ピレン骨格またはフェナントロリン骨格が好ましく、フルオランテン骨格またはフェナントロリン骨格が特に好ましい。 Further, it is more preferable that the electron transport material has a condensed polycyclic aromatic skeleton because the glass transition temperature is improved, the electron mobility is large, and the voltage can be lowered. As such a condensed polycyclic aromatic skeleton, a fluoranthene skeleton, an anthracene skeleton, a pyrene skeleton or a phenanthroline skeleton is preferable, and a fluoranthene skeleton or a phenanthroline skeleton is particularly preferable.
　電子輸送材料は単独でも２種以上を混合して用いても構わない。また、電子輸送層はドナー性材料を含有してもよい。ここで、ドナー性材料とは電子注入障壁の改善により、陰極または電子注入層からの電子輸送層への電子注入を容易にし、さらに電子輸送層の電気伝導性を向上させる化合物である。 The electron transport material may be used alone or in combination of two or more. Further, the electron transport layer may contain a donor material. Here, the donor material is a compound that facilitates electron injection from the cathode or the electron injection layer into the electron transport layer by improving the electron injection barrier, and further improves the electrical conductivity of the electron transport layer.
　ドナー性材料の好ましい例としては、Ｌｉなどのアルカリ金属、ＬｉＦなどのアルカリ金属を含有する無機塩、リチウムキノリノールなどのアルカリ金属と有機物との錯体、アルカリ土類金属、アルカリ土類金属を含有する無機塩、アルカリ土類金属と有機物との錯体、ＥｕやＹｂなどの希土類金属、希土類金属を含有する無機塩、希土類金属と有機物との錯体などが挙げられる。ドナー性材料としては、金属リチウム、希土類金属、またはリチウムキノリノール（Ｌｉｑ）が特に好ましい。 Preferred examples of the donor material include an alkali metal such as Li, an inorganic salt containing an alkali metal such as LiF, a complex of an alkali metal such as lithium quinolinol and an organic substance, an alkaline earth metal, and an alkaline earth metal. Examples thereof include inorganic salts, complexes of alkaline earth metals and organic substances, rare earth metals such as Eu and Yb, inorganic salts containing rare earth metals, and complexes of rare earth metals and organic substances. As the donor material, metallic lithium, rare earth metal, or lithium quinolinol (Liq) is particularly preferable.
　（電子注入層）
　本発明において、陰極と電子輸送層の間に電子注入層を設けてもよい。一般的に電子注入層は陰極から電子輸送層への電子の注入を助ける目的で形成され、電子受容性窒素を含むヘテロアリール環構造を有する化合物や、上記のドナー性材料により構成される。例えば、後述の一般式（４）で表されるフェナントロリン誘導体が好ましい。 (Electron injection layer)
In the present invention, an electron injection layer may be provided between the cathode and the electron transport layer. Generally, the electron injection layer is formed for the purpose of assisting the injection of electrons from the cathode to the electron transport layer, and is composed of a compound having a heteroaryl ring structure containing electron-accepting nitrogen and the above-mentioned donor material. For example, a phenanthroline derivative represented by the general formula (4) described later is preferable.
　また電子注入層に絶縁体や半導体の無機物を用いることもできる。これらの材料を用いることで発光素子の短絡を防止して、かつ電子注入性を向上させることができるので好ましい。 It is also possible to use an insulator or a semiconductor inorganic substance for the electron injection layer. It is preferable to use these materials because it is possible to prevent a short circuit of the light emitting element and improve the electron injection property.
　このような絶縁体としては、アルカリ金属カルコゲナイド、アルカリ土類金属カルコゲナイド、アルカリ金属のハロゲン化物およびアルカリ土類金属のハロゲン化物からなる群から選択される少なくとも一つの金属化合物を使用するのが好ましい。 As such an insulator, it is preferable to use at least one metal compound selected from the group consisting of alkali metal chalcogenides, alkaline earth metal chalcogenides, alkali metal halides and alkaline earth metal halides.
　（電荷発生層）
　本発明における電荷発生層は、電圧の印加により電荷を発生または分離し、隣接する層へ電荷を注入する層である。電荷発生層は、一つの層で形成されていてもよく、複数の層が積層されていてもよい。一般的に、電荷として電子を発生しやすいものはｎ型電荷発生層と呼ばれ、正孔を発生しやすいものはｐ型電荷発生層と呼ばれる。電荷発生層は二重層からなることが好ましく、ｎ型電荷発生層およびｐ型電荷発生層からなるｐｎ接合型電荷発生層がより好ましい。ｐｎ接合型電荷発生層は、発光素子中において、電圧が印加されることにより電荷を発生、または電荷を正孔および電子に分離し、これらの正孔および電子を正孔輸送層および電子輸送層を経由して発光層に注入する。具体的には、複数の発光層を含む発光素子において、中間層として電荷発生層を用いた場合、ｎ型電荷発生層は陽極側に存在する第一発光層に電子を供給し、ｐ型電荷発生層は陰極側に存在する第二発光層に正孔を供給する。そのため、２層以上の発光層を有する発光素子において、発光層と発光層の間に１層以上の電荷発生層を有することにより、素子効率をより向上させ、駆動電圧を低減することができ、素子の耐久性をより向上させることができる。 (Charge generation layer)
The charge generation layer in the present invention is a layer that generates or separates charges by applying a voltage and injects charges into adjacent layers. The charge generation layer may be formed of one layer, or a plurality of layers may be laminated. Generally, a layer that easily generates electrons as an electric charge is called an n-type charge generation layer, and a layer that easily generates holes is called a p-type charge generation layer. The charge generation layer is preferably composed of a bilayer, and more preferably a pn junction type charge generation layer composed of an n-type charge generation layer and a p-type charge generation layer. In the pn junction type charge generation layer, an electric charge is generated by applying a voltage in a light emitting element, or the charge is separated into holes and electrons, and these holes and electrons are separated into a hole transport layer and an electron transport layer. Is injected into the light emitting layer via. Specifically, in a light emitting device including a plurality of light emitting layers, when a charge generating layer is used as an intermediate layer, the n-type charge generating layer supplies electrons to the first light emitting layer existing on the anode side to supply p-type charges. The generation layer supplies holes to the second light emitting layer existing on the cathode side. Therefore, in a light emitting device having two or more light emitting layers, by having one or more charge generating layers between the light emitting layers, it is possible to further improve the element efficiency and reduce the driving voltage. The durability of the element can be further improved.
　ｎ型電荷発生層は、ｎ型ドーパントおよびｎ型ホストからなり、これらは従来の材料を用いることができる。例えば、ｎ型ドーパントとして、電子輸送層の材料として例示したドナー性材料が好適に用いられる。これらの中でも、アルカリ金属もしくはその塩、希土類金属が好ましく、金属リチウム、フッ化リチウム（ＬｉＦ）、リチウムキノリノール（Ｌｉｑ）および金属イッテルビウムから選ばれた材料がさらに好ましい。また、ｎ型ホストとしては、電子輸送材料として例示したものが好適に用いられる。これらの中でも、トリアジン誘導体、フェナントロリン誘導体およびオリゴピリジン誘導体から選ばれた材料が好ましく、フェナントロリン誘導体またはターピリジン誘導体がより好ましく、下記一般式（４）で表されるフェナントロリン誘導体がさらに好ましい。すなわち、電荷発生層に一般式（４）で表されるフェナントロリン誘導体を含有することが好ましい。 The n-type charge generation layer is composed of an n-type dopant and an n-type host, and conventional materials can be used for these. For example, as the n-type dopant, the donor material exemplified as the material of the electron transport layer is preferably used. Among these, alkali metals or salts thereof and rare earth metals are preferable, and materials selected from metallic lithium, lithium fluoride (LiF), lithium quinolinol (Liq) and metallic ytterbium are more preferable. Further, as the n-type host, those exemplified as the electron transport material are preferably used. Among these, a material selected from a triazine derivative, a phenanthroline derivative and an oligopyridine derivative is preferable, a phenanthroline derivative or a terpyridine derivative is more preferable, and a phenanthroline derivative represented by the following general formula (4) is further preferable. That is, it is preferable that the charge generation layer contains the phenanthroline derivative represented by the general formula (4).
Figure JPOXMLDOC01-appb-C000051
Figure JPOXMLDOC01-appb-C000051
　上記一般式（４）中、Ａｒ２は、ｐ価の芳香族炭化水素基、およびｐ価の複素芳香環基からなる群より選ばれる。ｐは１～３の自然数である。Ｒ１５～Ｒ２２は、それぞれ同じでも異なっていてもよく、水素原子、アルキル基、シクロアルキル基、複素環基、アリール基およびヘテロアリール基からなる群より選ばれる。Ａｒ２のうち、ｐ個のフェナントロリル基による置換位置は任意の位置である。 In the above general formula (4), Ar 2 is selected from the group consisting of a p-valent aromatic hydrocarbon group and a p-valent heteroaromatic ring group. p is a natural number from 1 to 3. R 15 to R 22 may be the same or different from each other, and are selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, a heterocyclic group, an aryl group and a heteroaryl group. Of Ar 2, the substitution position by p phenanthrolyl groups is an arbitrary position.
　芳香族炭化水素基および複素芳香環基としては、例えば前述のアリール基およびヘテロアリール基の例に記載のものが挙げられるが、それらに限定されるものではない。芳香族炭化水素基または複素芳香環基は、フェナントリル基以外にさらに置換基を有していてもよい。 Examples of the aromatic hydrocarbon group and the heteroaromatic ring group include those described in the above-mentioned examples of aryl groups and heteroaryl groups, but are not limited thereto. The aromatic hydrocarbon group or heteroaromatic ring group may further have a substituent in addition to the phenanthryl group.
　昇華性および薄膜形成性の観点から、ｐは２が好ましい。 From the viewpoint of sublimation and thin film formation, p is preferably 2.
　一般式（４）で表されるフェナントロリン誘導体の一例を以下に示す。 An example of the phenanthroline derivative represented by the general formula (4) is shown below.
Figure JPOXMLDOC01-appb-C000052
Figure JPOXMLDOC01-appb-C000052
　上記ｐ型電荷発生層は、ｐ型ドーパントおよびｐ型ホストからなり、これらは従来の材料を用いることができる。例えば、ｐ型ドーパントとして、正孔注入層の材料として例示したアクセプター材料や、ヨウ素、ＦｅＣｌ３、ＦｅＦ３、ＳｂＣｌ５などが好適に用いられる。具体的には、ＨＡＴ－ＣＮ６、Ｆ４－ＴＣＮＱ、テトラシアノキノジメタン誘導体、ラジアレン誘導体、ヨウ素、ＦｅＣｌ３、ＦｅＦ３、ＳｂＣｌ５などが挙げられる。これらの中でも、ＨＡＴ－ＣＮ６や、（２Ｅ，２’Ｅ，２’’Ｅ）－２，２’，２’’－（シクロプロパン－１，２，３－トリイリデン）トリス（２－（ペルフルオロフェニル）－アセトニトリル）、（２Ｅ，２’Ｅ，２’’Ｅ）－２，２’，２’’－（シクロプロパン－１，２，３－トリイリデン）トリス（２－（４－シアノペルフルオロフェニル）－アセトニトリル）などのラジアレン誘導体がより好ましい。ｐ型ドーパントの薄膜を形成してもよく、その膜厚は１０ｎｍ以下が好ましい。また、ｐ型ホストとして、アリールアミン誘導体が好ましい。 The p-type charge generation layer is composed of a p-type dopant and a p-type host, and conventional materials can be used for these. For example, as the p-type dopant, the acceptor material exemplified as the material of the hole injection layer, iodine, FeCl 3 , FeF 3 , SbCl 5, and the like are preferably used. Specific examples thereof include HAT-CN6, F4-TCNQ, tetracyanoquinodimethane derivative, radialene derivative, iodine, FeCl 3 , FeF 3 , SbCl 5 and the like. Among these, HAT-CN6 and (2E, 2'E, 2''E) -2,2', 2''- (cyclopropane-1,2,3-triylidene) tris (2- (perfluorophenyl) )-Utrigate), (2E, 2'E, 2''E) -2,2', 2''- (cyclopropane-1,2,3-triylidene) Tris (2- (4-cyanoperfluorophenyl)) -Radialene derivatives such as acetonitrile) are more preferred. A thin film of the p-type dopant may be formed, and the film thickness is preferably 10 nm or less. Further, an arylamine derivative is preferable as the p-type host.
　（発光素子の形成方法）
　発光素子を構成する上記各層の形成方法は、ドライプロセスまたはウェットプロセスのいずれでもよく、抵抗加熱蒸着、電子ビーム蒸着、スパッタリング、分子積層法、コーティング法、インクジェット法、印刷法など特に限定されないが、通常は、素子特性の点から抵抗加熱蒸着が好ましい。 (Method of forming light emitting element)
The method for forming each of the above layers constituting the light emitting element may be either a dry process or a wet process, and is not particularly limited, such as resistance heating vapor deposition, electron beam vapor deposition, sputtering, molecular lamination method, coating method, inkjet method, and printing method. Usually, resistance heating vapor deposition is preferable from the viewpoint of device characteristics.
　有機層の厚みは、発光物質の抵抗値によるため限定することはできないが、１～１０００ｎｍであることが好ましい。発光層、電子輸送層および正孔輸送層の膜厚は、それぞれ、好ましくは１ｎｍ以上２００ｎｍ以下であり、さらに好ましくは５ｎｍ以上１００ｎｍ以下である。 The thickness of the organic layer cannot be limited because it depends on the resistance value of the luminescent substance, but it is preferably 1 to 1000 nm. The film thicknesses of the light emitting layer, the electron transport layer, and the hole transport layer are preferably 1 nm or more and 200 nm or less, and more preferably 5 nm or more and 100 nm or less, respectively.
　（発光素子の特性）
　本発明の実施の形態に係る発光素子は、電気エネルギーを光に変換できる機能を有する。ここで電気エネルギーとしては主に直流電流が使用されるが、パルス電流や交流電流を用いることも可能である。電流値および電圧値は特に制限はなく、素子の目的によって要求される特性値が異なるが、素子の消費電力や寿命の観点から低電圧で高い輝度が得られることが好ましい。 (Characteristics of light emitting element)
The light emitting device according to the embodiment of the present invention has a function of converting electric energy into light. Here, direct current is mainly used as electrical energy, but pulse current and alternating current can also be used. The current value and the voltage value are not particularly limited, and the characteristic values required differ depending on the purpose of the device, but it is preferable that high brightness can be obtained at a low voltage from the viewpoint of power consumption and life of the device.
　本発明の実施の形態に係る発光素子は、色純度を高める観点から、通電による発光スペクトルの半値幅が６０ｎｍ以下であることが好ましく、５０ｎｍ以下であることがより好ましく、４５ｎｍ以下であることがさらに好ましく、３０ｎｍ以下であることが特に好ましい。 From the viewpoint of increasing the color purity of the light emitting device according to the embodiment of the present invention, the half width of the light emission spectrum by energization is preferably 60 nm or less, more preferably 50 nm or less, and more preferably 45 nm or less. It is more preferably 30 nm or less, and particularly preferably 30 nm or less.
　本発明の発光素子は発光スペクトルの半値幅が狭いため、トップエミッション型の発光素子に用いることがより好ましい。トップエミッション型発光素子はマイクロキャビティによる共振効果により、半値幅が狭いほど発光効率が高くなる。そのため、高色純度と高発光効率を両立することが可能となる。 Since the light emitting device of the present invention has a narrow half width of the light emitting spectrum, it is more preferable to use it as a top emission type light emitting device. Due to the resonance effect of the microcavity, the top emission type light emitting element has higher luminous efficiency as the half width is narrower. Therefore, it is possible to achieve both high color purity and high luminous efficiency.
　（発光素子の用途）
　本発明の実施の形態に係る発光素子は、例えば、マトリクスおよび／またはセグメント方式で表示するディスプレイ等の表示装置として好適に用いられる。 (Application of light emitting element)
The light emitting element according to the embodiment of the present invention is suitably used as a display device such as a display that displays in a matrix and / or segment system, for example.
　また、本発明の実施の形態に係る発光素子は、各種機器等のバックライトとしても好ましく用いられる。バックライトは、主に自発光しないディスプレイ等の表示装置の視認性を向上させる目的に使用され、液晶ディスプレイ、時計、オーディオ装置、自動車パネル、表示板および標識などの表示装置に使用される。特に、液晶ディスプレイ、中でも薄型化が検討されているパソコン用途のバックライトに本発明の発光素子は好ましく用いられ、従来のものより薄型で軽量なバックライトを提供できる。 Further, the light emitting element according to the embodiment of the present invention is preferably used as a backlight for various devices and the like. The backlight is mainly used for the purpose of improving the visibility of display devices such as displays that do not emit light by itself, and is used for display devices such as liquid crystal displays, clocks, audio devices, automobile panels, display boards and signs. In particular, the light emitting element of the present invention is preferably used for a liquid crystal display, particularly a backlight for a personal computer whose thinness is being studied, and can provide a backlight thinner and lighter than the conventional one.
　また、本発明の実施の形態に係る発光素子は、各種照明装置としても好ましく用いられる。本発明の実施の形態に係る発光素子は、高い発光効率と高色純度との両立が可能であり、さらに、薄型化や軽量化が可能であることから、低消費電力と鮮やかな発光色、高いデザイン性を合わせ持った照明装置が実現できる。 Further, the light emitting element according to the embodiment of the present invention is preferably used as various lighting devices. The light emitting element according to the embodiment of the present invention can achieve both high luminous efficiency and high color purity, and can be made thinner and lighter, so that low power consumption and bright emission color can be achieved. A lighting device with high design can be realized.
　以下、実施例をあげて本発明を説明するが、本発明はこれらの例によって限定されるものではない。 Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.
　合成例１
　化合物Ｄ－１の合成方法
　下記の反応スキームに従って、化合物Ｄ－１を合成した。 Synthesis example 1
Method for synthesizing compound D-1 Compound D-1 was synthesized according to the following reaction scheme.
Figure JPOXMLDOC01-appb-C000053
Figure JPOXMLDOC01-appb-C000053
　２，６－ジブロモベンズアルデヒド５．３５ｇ、４－ｔ－ブチルフェニルボロン酸７．４０ｇ、炭酸ナトリウム５．３８ｇ、ジメトキシエタン１００ｍＬ、水２０ｍＬをフラスコに入れ、窒素置換した。ここにビス（トリフェニルホスフィン）パラジウム（II）ジクロリド１４２ｍｇを加え、４時間還流した。反応溶液を室温まで冷却し、有機層を分液した後に硫酸マグネシウムで乾燥し、ろ過後、溶媒を留去した。得られた反応生成物にメタノールを加え、ろ過することで２，６－ビス（p－t－ブチルフェニル）ベンズアルデヒド４．０３ｇを白色固体として得た。 5.35 g of 2,6-dibromobenzaldehyde, 7.40 g of 4-t-butylphenylboronic acid, 5.38 g of sodium carbonate, 100 mL of dimethoxyethane and 20 mL of water were placed in a flask and replaced with nitrogen. To this, 142 mg of bis (triphenylphosphine) palladium (II) dichloride was added, and the mixture was refluxed for 4 hours. The reaction solution was cooled to room temperature, the organic layer was separated, dried over magnesium sulfate, filtered, and the solvent was distilled off. Methanol was added to the obtained reaction product and filtered to obtain 4.03 g of 2,6-bis (pt-butylphenyl) benzaldehyde as a white solid.
　このようにして得られた２，６－ビス（p－t－ブチルフェニル）ベンズアルデヒド４．０３ｇと２，４－ジメチルピロール２．１７ｇを反応容器に入れ、ジクロロメタン３６０ｍＬおよびトリフルオロ酢酸５滴を加えて室温で１週間撹拌した。さらに２，３－ジクロロ－５，６－ジシアノ－１，４－ベンゾキノン（ＤＤＱ）２．７０ｇを加え、室温で４日間撹拌した。その後、ろ過し、溶媒を留去した。得られた反応生成物にジクロロメタン３６０ｍＬとジイソプロピルエチルアミン５．９０ｍＬを加えて室温で３０分間撹拌し、さらに三弗化ホウ素ジエチルエーテル錯体４．１０ｍＬを加えて室温で４時間撹拌した後、溶媒を留去し、水を加えて撹拌した。有機層を分液し、飽和食塩水で洗浄した。この有機層を硫酸マグネシウムで乾燥し、ろ過後溶媒を留去した。得られた反応生成物をシリカゲル化クロマトグラフィーにより精製し、赤色粉末を５８０ｍｇ得た。得られた粉末を１Ｈ－ＮＭＲおよびＬＣ－ＭＳにより分析し、赤色粉末がピロメテンホウ素錯体である化合物Ｄ－１であることを確認した。
１Ｈ－ＮＭＲ（ＣＤＣｌ３　（ｄ＝ｐｐｍ））：７．５２（ｄ、１Ｈ），７．４３（ｄ，２Ｈ），７．２３－７．１７（ｍ，４Ｈ），７．１０（ｄ，４Ｈ），５．７９（ｓ，２Ｈ），２．３８（ｓ，６Ｈ），１．５２（ｓ，６Ｈ），１．２２（ｓ，１８Ｈ）
ＭＳ（ｍ／ｚ）　分子量；５８９。 4.03 g of 2,6-bis (pt-butylphenyl) benzaldehyde thus obtained and 2.17 g of 2,4-dimethylpyrrole are placed in a reaction vessel, and 360 mL of dichloromethane and 5 drops of trifluoroacetic acid are added. Was stirred at room temperature for 1 week. Further, 2.70 g of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) was added, and the mixture was stirred at room temperature for 4 days. Then, it was filtered and the solvent was distilled off. To the obtained reaction product, 360 mL of dichloromethane and 5.90 mL of diisopropylethylamine were added and stirred at room temperature for 30 minutes. Further, 4.10 mL of boron trifluorinated diethyl ether complex was added and stirred at room temperature for 4 hours, and then the solvent was distilled off. The mixture was removed, water was added, and the mixture was stirred. The organic layer was separated and washed with saturated brine. The organic layer was dried over magnesium sulfate, filtered, and the solvent was distilled off. The obtained reaction product was purified by silica gelation chromatography to obtain 580 mg of a red powder. The obtained powder was analyzed by 1 H-NMR and LC-MS, and it was confirmed that the red powder was compound D-1, which is a pyrromethene boron complex.
1 1 H-NMR (CDCl 3 (d = ppm)): 7.52 (d, 1H), 7.43 (d, 2H), 7.23-7.17 (m, 4H), 7.10 (d) , 4H), 5.79 (s, 2H), 2.38 (s, 6H), 1.52 (s, 6H), 1.22 (s, 18H)
MS (m / z) molecular weight; 589.
　化合物Ｄ－１の溶液中の発光特性を以下に示す。
吸収スペクトル（溶媒：トルエン）：λｍａｘ　５１３ｎｍ
蛍光スペクトル（溶媒：トルエン）：λｍａｘ　５２６ｎｍ、半値幅　２３ｎｍ
蛍光量子収率（溶媒：トルエン、励起光：４６０ｎｍ）：１００％。 The emission characteristics of compound D-1 in solution are shown below.
Absorption spectrum (solvent: toluene): λmax 513 nm
Fluorescence spectrum (solvent: toluene): λmax 526 nm, half width 23 nm
Fluorescence quantum yield (solvent: toluene, excitation light: 460 nm): 100%.
　さらに純度を上げるために昇華精製を行った。化合物Ｄ－１の入った金属容器をガラス管中に設置し、これを油拡散ポンプを用いて１×１０－３Ｐａの圧力下、１９０℃で加熱して化合物Ｄ－１を昇華させた。ガラス管壁に付着した固体を回収しＬＣ－ＭＳ分析による純度が９９％であることを確認した。 Sublimation purification was performed to further increase the purity. A metal container containing compound D-1 was placed in a glass tube, and this was heated at 190 ° C. under a pressure of 1 × 10 -3 Pa using an oil diffusion pump to sublimate compound D-1. The solid adhering to the glass tube wall was recovered and confirmed by LC-MS analysis to have a purity of 99%.
　合成例２
　化合物Ｄ－２の合成方法
　下記の反応スキームに従って、化合物Ｄ－２を合成した。 Synthesis example 2
Method for synthesizing compound D-2 Compound D-2 was synthesized according to the following reaction scheme.
Figure JPOXMLDOC01-appb-C000054
Figure JPOXMLDOC01-appb-C000054
　２，４，６－トリクロロベンズアルデヒド４．１６ｇ、４－ｔ－ブチルフェニルボロン酸１１．０ｇ、リン酸カリウム２１．１２ｇ、ジオキサン１００ｍＬ、水２０ｍＬをフラスコに入れ、窒素置換した。ここにビス(ジベンジリデンアセトン)パラジウム(０)２２９ｍｇとＸＰｈｏｓ３７９ｍｇを加え、２時間還流した。反応溶液を室温まで冷却し、有機層を分液した後に硫酸マグネシウムで乾燥し、ろ過後、溶媒を留去した。得られた反応生成物をシリカゲル化クロマトグラフィーにより精製することで、２，４，６－トリ（p－t－ブチルフェニル）ベンズアルデヒド９．７６ｇを白色固体として得た。 4.16 g of 2,4,6-trichlorobenzaldehyde, 11.0 g of 4-t-butylphenylboronic acid, 21.12 g of potassium phosphate, 100 mL of dioxane, and 20 mL of water were placed in a flask and replaced with nitrogen. To this, 229 mg of bis (dibenzylideneacetone) palladium (0) and 379 mg of XPhos were added, and the mixture was refluxed for 2 hours. The reaction solution was cooled to room temperature, the organic layer was separated, dried over magnesium sulfate, filtered, and the solvent was distilled off. The obtained reaction product was purified by silica gel chromatography to obtain 9.76 g of 2,4,6-tri (pt-butylphenyl) benzaldehyde as a white solid.
　このようにして得られた２，４，６－トリ（p－t－ブチルフェニル）ベンズアルデヒド９．７６ｇと２，４－ジメチルピロール５．５４ｇを反応容器に入れ、トルエン２００ｍＬおよびトリフルオロ酢酸５滴を加えて４０℃で３０分間撹拌した後、水を加えて撹拌し、有機層を分液し、飽和食塩水で洗浄した。この有機層を硫酸マグネシウムで乾燥し、ろ過後、溶媒を留去した。得られた反応生成物と２，３－ジクロロ－５，６－ジシアノ－１，４－ベンゾキノン（ＤＤＱ）８．８１ｇおよびトルエン２００ｍＬをフラスコに入れ、４０℃で３０分間撹拌した。その後、ジイソプロピルエチルアミン１７．２ｍＬと三弗化ホウ素ジエチルエーテル錯体１２．２ｍＬを加えて室温で３０分間撹拌した後、水を加えて撹拌した。有機層を分液し、飽和食塩水で洗浄した。この有機層を硫酸マグネシウムで乾燥し、ろ過後溶媒を留去した。得られた反応生成物をシリカゲル化クロマトグラフィーにより精製し、赤色粉末を３．６３ｇ得た。得られた粉末を１Ｈ－ＮＭＲおよびＬＣ－ＭＳにより分析し、赤色粉末がピロメテンホウ素錯体である化合物Ｄ－２であることを確認した。
１Ｈ－ＮＭＲ（ＣＤＣｌ３　（ｄ＝ｐｐｍ））：７．７２－７．６３（ｍ、４Ｈ），７．４７（ｄ，２Ｈ），７．２３－７．１２（ｍ，８Ｈ），５．８１（ｓ，２Ｈ），２．３８（ｓ，６Ｈ），１．５７（ｓ，６Ｈ），１．３２（ｓ，９Ｈ），１．２２（ｓ，１８Ｈ）
ＭＳ（ｍ／ｚ）　分子量；７２１。 9.76 g of 2,4,6-tri (pt-butylphenyl) benzaldehyde and 5.54 g of 2,4-dimethylpyrol obtained in this manner were placed in a reaction vessel, and 200 mL of toluene and 5 drops of trifluoroacetic acid were added. Was added and the mixture was stirred at 40 ° C. for 30 minutes, water was added and the mixture was stirred, the organic layer was separated, and the mixture was washed with saturated brine. The organic layer was dried over magnesium sulfate, filtered, and then the solvent was distilled off. The obtained reaction product, 8.81 g of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and 200 mL of toluene were placed in a flask and stirred at 40 ° C. for 30 minutes. Then, 17.2 mL of diisopropylethylamine and 12.2 mL of boron trifluorinated diethyl ether complex were added and stirred at room temperature for 30 minutes, and then water was added and stirred. The organic layer was separated and washed with saturated brine. The organic layer was dried over magnesium sulfate, filtered, and the solvent was distilled off. The obtained reaction product was purified by silica gelation chromatography to obtain 3.63 g of a red powder. The obtained powder was analyzed by 1 H-NMR and LC-MS, and it was confirmed that the red powder was compound D-2 which is a pyrromethene boron complex.
1 1 H-NMR (CDCl 3 (d = ppm)): 7.72-7.63 (m, 4H), 7.47 (d, 2H), 7.23-7.12 (m, 8H), 5 .81 (s, 2H), 2.38 (s, 6H), 1.57 (s, 6H), 1.32 (s, 9H), 1.22 (s, 18H)
MS (m / z) molecular weight; 721.
　化合物Ｄ－２の溶液中の発光特性を以下に示す。
吸収スペクトル（溶媒：トルエン）：λｍａｘ　５１３ｎｍ
蛍光スペクトル（溶媒：トルエン）：λｍａｘ　５２７ｎｍ、半値幅　２２ｎｍ
蛍光量子収率（溶媒：トルエン、励起光：４６０ｎｍ）：１００％。 The emission characteristics of compound D-2 in solution are shown below.
Absorption spectrum (solvent: toluene): λmax 513 nm
Fluorescence spectrum (solvent: toluene): λmax 527 nm, half width 22 nm
Fluorescence quantum yield (solvent: toluene, excitation light: 460 nm): 100%.
　さらに純度を上げるために昇華精製を行った。化合物Ｄ－２の入った金属容器をガラス管中に設置し、これを油拡散ポンプを用いて１×１０－３Ｐａの圧力下、２４０℃で加熱して化合物Ｄ－２を昇華させた。ガラス管壁に付着した固体を回収しＬＣ－ＭＳ分析による純度が９９％であることを確認した。 Sublimation purification was performed to further increase the purity. A metal container containing compound D-2 was placed in a glass tube, and this was heated at 240 ° C. under a pressure of 1 × 10 -3 Pa using an oil diffusion pump to sublimate compound D-2. The solid adhering to the glass tube wall was recovered and confirmed by LC-MS analysis to have a purity of 99%.
　下記の実施例および比較例において使用されるピロメテンホウ素錯体は以下に示す化合物である。また、これらピロメテンホウ素錯体のトルエン溶液において測定した分子量および発光特性を表１に示す。 The pyrometheneboron complex used in the following examples and comparative examples is the compound shown below. Table 1 shows the molecular weight and luminescence characteristics of these pyrromethene boron complexes measured in a toluene solution.
Figure JPOXMLDOC01-appb-C000055
Figure JPOXMLDOC01-appb-C000055
Figure JPOXMLDOC01-appb-C000056
Figure JPOXMLDOC01-appb-C000056
Figure JPOXMLDOC01-appb-T000057
Figure JPOXMLDOC01-appb-T000057
　実施例１
　（蛍光発光素子評価）
　陽極としてＩＴＯ透明導電膜を１６５ｎｍ堆積させたガラス基板（ジオマテック（株）製、１１Ω／□、スパッタ品）を３８×４６ｍｍに切断し、エッチングを行った。得られた基板を“セミコクリーン５６”（商品名、フルウチ化学（株）製）で１５分間超音波洗浄してから、超純水で洗浄し、乾燥した。 Example 1
(Evaluation of fluorescent light emitting element)
A glass substrate (manufactured by Geomatec Co., Ltd., 11Ω / □, sputtered product) having an ITO transparent conductive film deposited at 165 nm as an anode was cut into a size of 38 × 46 mm and etched. The obtained substrate was ultrasonically cleaned with "Semicoclean 56" (trade name, manufactured by Furuuchi Chemical Co., Ltd.) for 15 minutes, then washed with ultrapure water and dried.
　この基板を素子作製の直前に１時間ＵＶ－オゾン処理し、真空蒸着装置内に設置して、装置内の圧力が５×１０－４Ｐａ以下になるまで排気した。抵抗加熱法によって、まず正孔注入層として、ＨＡＴ－ＣＮ６を１０ｎｍ、正孔輸送層として、ＨＴ－１を５０ｎｍ蒸着した。次に、発光層として、ホスト材料としてＨ－１を、またドーパント材料として化合物Ｄ－１をドープ濃度が１．０重量％になるようにして２０ｎｍの厚さに蒸着した。さらに電子輸送層としてＥＴ－１を、ドナー性材料として２Ｅ－１を用い、ＥＴ－１と２Ｅ－１の蒸着速度比が１：１になるようにして３０ｎｍの厚さに積層した。次に、電子注入層として２Ｅ－１を０．５ｎｍ蒸着した後、マグネシウムと銀を１０００ｎｍ共蒸着して陰極とし、５×５ｍｍ角の素子を作製した。 This substrate was subjected to UV-ozone treatment for 1 hour immediately before the device was manufactured, placed in a vacuum vapor deposition apparatus, and exhausted until the pressure in the apparatus became 5 × 10 -4 Pa or less. By the resistance heating method, HAT-CN6 was first deposited at 10 nm as a hole injection layer, and HT-1 was deposited at 50 nm as a hole transport layer. Next, as a light emitting layer, H-1 as a host material and compound D-1 as a dopant material were vapor-deposited to a thickness of 20 nm so that the doping concentration was 1.0% by weight. Further, ET-1 was used as the electron transport layer and 2E-1 was used as the donor material, and the layers were laminated to a thickness of 30 nm so that the vapor deposition rate ratio of ET-1 and 2E-1 was 1: 1. Next, after depositing 2E-1 at 0.5 nm as an electron injection layer, magnesium and silver were co-deposited at 1000 nm to form a cathode, and a 5 × 5 mm square device was manufactured.
　この発光素子を１０００ｃｄ／ｍ２で発光させた時の発光特性は、発光ピーク波長５２９ｎｍ、半値幅２６ｎｍ、外部量子効率４．０％であった。また耐久性は、初期輝度を１０００ｃｄ／ｍ２となる電流で連続通電し、初期輝度の９０％の輝度となる時間（以下、ＬＴ９０とする）で評価を行った。その結果、この発光素子のＬＴ９０は９９時間であった。なお、上記において、ＨＡＴ－ＣＮ６、ＨＴ－１、Ｈ－１、ＥＴ－１および２Ｅ－１は、それぞれ下記に示す化合物である。 When this light emitting element was made to emit light at 1000 cd / m 2 , the light emitting characteristics were an emission peak wavelength of 529 nm, a half width of 26 nm, and an external quantum efficiency of 4.0%. Further, the durability was evaluated by the time when the initial brightness was continuously energized with a current of 1000 cd / m 2 and the brightness became 90% of the initial brightness (hereinafter referred to as LT90). As a result, the LT90 of this light emitting element was 99 hours. In the above, HAT-CN6, HT-1, H-1, ET-1 and 2E-1 are the compounds shown below, respectively.
Figure JPOXMLDOC01-appb-C000058
Figure JPOXMLDOC01-appb-C000058
　実施例２～１５、比較例１～３
　ドーパント材料として、化合物Ｄ－１に代えて表２に記載した化合物を用いた以外は実施例１と同様にして発光素子を作製し、評価した。結果を表２に示す。 Examples 2 to 15, Comparative Examples 1 to 3
A light emitting device was produced and evaluated in the same manner as in Example 1 except that the compounds shown in Table 2 were used instead of the compound D-1 as the dopant material. The results are shown in Table 2.
Figure JPOXMLDOC01-appb-T000059
Figure JPOXMLDOC01-appb-T000059
　表２を参照して分かるように、実施例１～１５では比較例１～３に比べて、半値幅を小さく保ちつつ、外部量子効率と素子耐久性（ＬＴ９０）が大幅に向上した。このことから、本発明によれば高い色純度、高い発光効率および高い素子耐久性を備えた発光素子を得られることが分かる。 As can be seen with reference to Table 2, in Examples 1 to 15, the external quantum efficiency and device durability (LT90) were significantly improved while keeping the half width smaller than that in Comparative Examples 1 to 3. From this, it can be seen that according to the present invention, a light emitting device having high color purity, high luminous efficiency and high element durability can be obtained.
　（熱活性化遅延蛍光素子評価）
　実施例１６
　陽極としてＩＴＯ透明導電膜を１００ｎｍ堆積させたガラス基板（ジオマテック（株）製、１１Ω／□、スパッタ品）を３８×４６ｍｍに切断し、エッチングを行った。得られた基板を“セミコクリーン５６”（商品名、フルウチ化学（株）製）で１５分間超音波洗浄してから、超純水で洗浄した。 (Evaluation of Thermally Activated Delayed Fluorescent Element)
Example 16
A glass substrate (manufactured by Geomatec Co., Ltd., 11Ω / □, sputtered product) having an ITO transparent conductive film deposited at 100 nm as an anode was cut into a size of 38 × 46 mm and etched. The obtained substrate was ultrasonically cleaned with "Semicoclean 56" (trade name, manufactured by Furuuchi Chemical Co., Ltd.) for 15 minutes, and then washed with ultrapure water.
　この基板を、素子を作製する直前に１時間ＵＶ－オゾン処理し、真空蒸着装置内に設置して、装置内の真空度が５×１０－４Ｐａ以下になるまで排気した。抵抗加熱法によって、まず正孔注入層として、ＨＡＴ－ＣＮ６を１０ｎｍ、正孔輸送層として、ＨＴ－１を４０ｎｍ蒸着した。次に、発光層として、ホスト材料Ｈ－２と、化合物Ｄ－１と、ＴＡＤＦ材料である化合物Ｈ－３とを、重量比で７９．５：０．５：２０になるようにして、３０ｎｍの厚さに蒸着した。さらに電子輸送層として、電子輸送材料に化合物ＥＴ－１を、ドナー性材料として２Ｅ－１を用い、化合物ＥＴ－１と２Ｅ－１の蒸着速度比が１：１になるようにして５０ｎｍの厚さに積層した。次に、電子注入層として２Ｅ－１を０．５ｎｍ蒸着した後、マグネシウムと銀を１０００ｎｍ共蒸着して陰極とし、５×５ｍｍ角の素子を作製した。 This substrate was subjected to UV-ozone treatment for 1 hour immediately before the device was manufactured, placed in a vacuum vapor deposition apparatus, and evacuated until the degree of vacuum in the apparatus became 5 × 10 -4 Pa or less. By the resistance heating method, HAT-CN6 was first deposited at 10 nm as a hole injection layer, and HT-1 was deposited at 40 nm as a hole transport layer. Next, as the light emitting layer, the host material H-2, the compound D-1, and the TADF material compound H-3 are adjusted to a weight ratio of 79.5: 0.5: 20 to 30 nm. It was deposited to the thickness of. Further, as the electron transport layer, compound ET-1 is used as the electron transport material and 2E-1 is used as the donor material, and the thickness of the compounds ET-1 and 2E-1 is 50 nm so that the vapor deposition rate ratio is 1: 1. It was laminated on the surface. Next, after depositing 2E-1 at 0.5 nm as an electron injection layer, magnesium and silver were co-deposited at 1000 nm to form a cathode, and a 5 × 5 mm square device was manufactured.
　この発光素子を１０００ｃｄ／ｍ２で発光させた時の発光特性は、発光ピーク波長５２９ｎｍ、半値幅２８ｎｍ、外部量子効率１４．２％、ＬＴ９０は８０時間であった。なお、上記において、Ｈ－２およびＨ－３は下記に示す化合物である。 When this light emitting element was made to emit light at 1000 cd / m 2 , the light emitting characteristics were an emission peak wavelength of 529 nm, a half width of 28 nm, an external quantum efficiency of 14.2%, and an LT90 of 80 hours. In the above, H-2 and H-3 are the compounds shown below.
Figure JPOXMLDOC01-appb-C000060
Figure JPOXMLDOC01-appb-C000060
　実施例１７～２０、比較例４～６
　ドーパント材料として表３に記載した化合物を用いた以外は実施例１６と同様にして発光素子を作製し、評価した。結果を表３に示す。 Examples 17 to 20, Comparative Examples 4 to 6
A light emitting device was produced and evaluated in the same manner as in Example 16 except that the compounds shown in Table 3 were used as the dopant material. The results are shown in Table 3.
Figure JPOXMLDOC01-appb-T000061
Figure JPOXMLDOC01-appb-T000061
　表３を参照して分かるように、実施例１６～２０では比較例４～６と比べて、半値幅を小さく保ちつつ、外部量子効率と素子耐久性（ＬＴ９０）が大幅に向上した。このことから、本発明によれば高い色純度、高い発光効率および高い素子耐久性を備えた発光素子を得られることが分かる。 As can be seen with reference to Table 3, in Examples 16 to 20, the external quantum efficiency and device durability (LT90) were significantly improved while keeping the half width smaller than that in Comparative Examples 4 to 6. From this, it can be seen that according to the present invention, a light emitting device having high color purity, high luminous efficiency and high element durability can be obtained.
　以上のように、本発明により、色純度、発光効率および素子耐久性が高い発光素子の作製ができることが示された。これにより、ディスプレイなどの表示装置や照明装置の製造において、発光効率を高くできることが示された。 As described above, it has been shown that according to the present invention, a light emitting device having high color purity, luminous efficiency and device durability can be manufactured. As a result, it was shown that the luminous efficiency can be increased in the manufacture of display devices such as displays and lighting devices.
　（タンデム型蛍光発光素子評価）
　実施例２１
　陽極としてＩＴＯ透明導電膜を１６５ｎｍ堆積させたガラス基板（ジオマテック（株）製、１１Ω／□、スパッタ品）を３８ｍｍ×４６ｍｍに切断し、エッチングを行った。得られた基板を“セミコクリーン”５６（商品名、フルウチ化学（株）製）を用いて１５分間超音波洗浄してから、超純水で洗浄した。 (Evaluation of tandem fluorescent light emitting device)
Example 21
A glass substrate (manufactured by Geomatec Co., Ltd., 11Ω / □, sputtered product) having an ITO transparent conductive film deposited at 165 nm as an anode was cut into 38 mm × 46 mm and etched. The obtained substrate was ultrasonically cleaned with "Semicoclean" 56 (trade name, manufactured by Furuuchi Chemical Co., Ltd.) for 15 minutes, and then washed with ultrapure water.
　この基板を、素子を作製する直前に１時間ＵＶ－オゾン処理し、真空蒸着装置内に設置して、装置内の真空度が５×１０－４Ｐａ以下になるまで排気した。抵抗加熱法によって、まず正孔注入層として、ＨＡＴ－ＣＮ６を５ｎｍ、続いて正孔輸送層として、ＨＴ－１を５０ｎｍ蒸着した。次に、正孔阻止層としてＨ－１を１０ｎｍ、発光層として、ホスト材料Ｈ－１と、ドーパント化合物Ｄ－１を、重量比で９９．５：０．５になるようにして、２０ｎｍの厚さに蒸着した。さらに電子阻止層としてＥＴ－１を１０ｎｍ、電子輸送層として化合物ＥＴ－３を３５ｎｍの厚さに積層した。続いてｎ型電荷発生層として、ｎ型ホストである化合物ＥＴ－３と、ｎ型ドーパントである金属リチウムを、蒸着速度比が９９：１になるようにして１０ｎｍ積層した。さらにｐ型電荷発生層としてＨＡＴ－ＣＮ６を１０ｎｍ積層した。その上に上記と同様に正孔輸送層５０ｎｍ、正孔阻止層１０ｍｎ、発光層２０ｎｍを形成した。さらに電子阻止層としてＥＴ－２を１０ｎｍ、電子輸送層としてＥＴ－３を３５ｎｍ順に蒸着した。次に、電子注入層として２Ｅ－１を０．５ｎｍ蒸着した後、マグネシウムと銀を１０００ｎｍ共蒸着して陰極とし、５ｍｍ×５ｍｍ角のタンデム型発光素子を作製した。 This substrate was subjected to UV-ozone treatment for 1 hour immediately before the device was manufactured, placed in a vacuum vapor deposition apparatus, and evacuated until the degree of vacuum in the apparatus became 5 × 10 -4 Pa or less. By the resistance heating method, HAT-CN6 was first deposited at 5 nm as a hole injection layer, and then HT-1 was deposited at 50 nm as a hole transport layer. Next, H-1 was used as the hole blocking layer at 10 nm, and the host material H-1 and the dopant compound D-1 were used as the light emitting layer in a weight ratio of 99.5: 0.5 to 20 nm. It was deposited to a thickness. Further, ET-1 was laminated to a thickness of 10 nm as an electron blocking layer, and compound ET-3 was laminated to a thickness of 35 nm as an electron transporting layer. Subsequently, as the n-type charge generation layer, the compound ET-3, which is an n-type host, and metallic lithium, which is an n-type dopant, were laminated at 10 nm so that the vapor deposition rate ratio was 99: 1. Further, HAT-CN6 was laminated at 10 nm as a p-type charge generation layer. A hole transport layer of 50 nm, a hole blocking layer of 10 mn, and a light emitting layer of 20 nm were formed on the hole transport layer in the same manner as described above. Further, ET-2 was deposited at 10 nm as an electron blocking layer, and ET-3 was deposited at 35 nm as an electron transporting layer. Next, after depositing 2E-1 at 0.5 nm as an electron injection layer, magnesium and silver were co-deposited at 1000 nm to serve as a cathode, and a tandem type light emitting device of 5 mm × 5 mm square was produced.
　この発光素子を１０００ｃｄ／ｍ２で発光させた時の発光特性は、発光ピーク波長５３０ｎｍ、半値幅２５ｎｍ、外部量子効率４．３％、ＬＴ９０は１１０時間であった。発光層が１層のみの実施例１と比べ、耐久性が向上していることが確認された。なお、上記において、ＥＴ－２およびＥＴ－３は下記に示す化合物である。 When this light emitting element was made to emit light at 1000 cd / m 2 , the light emitting characteristics were an emission peak wavelength of 530 nm, a half width of 25 nm, an external quantum efficiency of 4.3%, and an LT90 of 110 hours. It was confirmed that the durability was improved as compared with Example 1 in which the light emitting layer was only one layer. In the above, ET-2 and ET-3 are the compounds shown below.
Figure JPOXMLDOC01-appb-C000062
Figure JPOXMLDOC01-appb-C000062

Claims (11)

  1. 一般式（１）で表されるピロメテンホウ素錯体：
    Figure JPOXMLDOC01-appb-C000001
     Ｒ１～Ｒ６は、それぞれ独立に、水素原子、アルキル基、シクロアルキル基、複素環基、アルケニル基、シクロアルケニル基、アルキニル基、水酸基、チオール基、アルコキシ基、アルキルチオ基、アリールエーテル基、アリールチオエーテル基、アリール基、ヘテロアリール基、アミノ基、シリル基、シロキサニル基およびボリル基からなる群より選ばれる；これらの基はさらに置換基を有していてもよい；ただし、Ｒ１～Ｒ４のうち少なくとも一つは水素原子もしくはアルキル基である；
    Ｘ１およびＸ２は、それぞれ独立に、アルキル基、シクロアルキル基、複素環基、アルケニル基、シクロアルケニル基、アルキニル基、水酸基、チオール基、アルコキシ基、アルキルチオ基、アリールエーテル基、アリールチオエーテル基、アリール基、ヘテロアリール基、ハロゲン、およびシアノ基からなる群より選ばれる；これらの基はさらに置換基を有していてもよい；
    Ｒ７は下記一般式（２）で表される；
    Figure JPOXMLDOC01-appb-C000002
     Ｒ８～Ｒ１０は、それぞれ独立に、水素原子、アルキル基、シクロアルキル基、複素環基、アルケニル基、シクロアルケニル基、アルキニル基、水酸基、チオール基、アルコキシ基、アルキルチオ基、アリールエーテル基、アリールチオエーテル基、アリール基、ヘテロアリール基、ハロゲン、シアノ基、アルデヒド基、アシル基、カルボキシル基、エステル基、アミド基、スルホニル基、スルホン酸エステル基、スルホンアミド基、アミノ基、ニトロ基、シリル基、シロキサニル基、ボリル基およびホスフィンオキシド基からなる群より選ばれる；これらの基はさらに置換基を有していてもよい；
    Ｒ１１は、アルキル基、シクロアルキル基、複素環基、アルケニル基、シクロアルケニル基、アルキニル基、水酸基、チオール基、アルコキシ基、アルキルチオ基、アリールエーテル基、アリールチオエーテル基、アリール基、ヘテロアリール基、ハロゲン、シアノ基、アルデヒド基、アシル基、カルボキシル基、エステル基、アミド基、スルホニル基、スルホン酸エステル基、スルホンアミド基、アミノ基、ニトロ基、シリル基、シロキサニル基、ボリル基およびホスフィンオキシド基からなる群より選ばれる；これらの基はさらに置換基を有していてもよい；
    Ａｒ１は、置換もしくは無置換のアリール基、または置換もしくは無置換のヘテロアリール基である。     Pyromethene boron complex represented by the general formula (1):
    Figure JPOXMLDOC01-appb-C000001
     R 1 to R 6 are independently hydrogen atom, alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, hydroxyl group, thiol group, alkoxy group, alkylthio group, arylether group, respectively. arylthio ether group, an aryl group, a heteroaryl group, an amino group, a silyl group, selected from the group consisting of siloxanyl group and a boryl group; may have these groups further substituents; provided, R 1 ~ R At least one of the four is a hydrogen atom or an alkyl group;
    X 1 and X 2 are independently alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, hydroxyl group, thiol group, alkoxy group, alkylthio group, arylether group and arylthioether group, respectively. , Heteroaryl group, halogen, and cyano group; these groups may further have substituents;
    R 7 is represented by the following general formula (2);
    Figure JPOXMLDOC01-appb-C000002
     R 8 to R 10 are independently hydrogen atom, alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, hydroxyl group, thiol group, alkoxy group, alkylthio group, arylether group, respectively. Arylthioether group, aryl group, heteroaryl group, halogen, cyano group, aldehyde group, acyl group, carboxyl group, ester group, amide group, sulfonyl group, sulfonic acid ester group, sulfonamide group, amino group, nitro group, silyl group. It is selected from the group consisting of groups, siloxanyl groups, boryl groups and phosphinoxide groups; these groups may further have substituents;
    R 11 is an alkyl group, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, a hydroxyl group, a thiol group, an alkoxy group, an alkylthio group, an aryl ether group, an arylthioether group, an aryl group or a heteroaryl group. , Halogen, cyano group, aldehyde group, acyl group, carboxyl group, ester group, amide group, sulfonyl group, sulfonic acid ester group, sulfonamide group, amino group, nitro group, silyl group, siroxanyl group, boryl group and phosphine oxide. Selected from the group consisting of groups; these groups may further have substituents;
    Ar 1 is a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group.
  2. Ｒ１１が、置換もしくは無置換のアリール基、または置換もしくは無置換のヘテロアリール基である請求項１に記載のピロメテンホウ素錯体。 The pyrromethene boron complex according to claim 1, wherein R 11 is a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group.
  3. Ｒ１およびＲ４が、それぞれ独立に、水素原子またはアルキル基である請求項１または２に記載のピロメテンホウ素錯体。 The pyrromethene boron complex according to claim 1 or 2, wherein R 1 and R 4 are independently hydrogen atoms or alkyl groups, respectively.
  4. Ｒ２およびＲ３が、アルキル基である請求項１～３のいずれかに記載のピロメテンホウ素錯体。 The pyrromethene boron complex according to any one of claims 1 to 3, wherein R 2 and R 3 are alkyl groups.
  5. 陽極と陰極、および該陽極と該陰極との間に存在する発光層を有し、該発光層が電気エネルギーにより発光する素子であって、前記発光層中に請求項１～４のいずれかに記載のピロメテンホウ素錯体を含有する発光素子。 An element having an anode and a cathode, and a light emitting layer existing between the anode and the cathode, and the light emitting layer emits light by electric energy, according to any one of claims 1 to 4 in the light emitting layer. A light emitting element containing the pyromethene boron complex described above.
  6. 前記発光層が第一の化合物および第二の化合物を含み、前記第一の化合物が、熱活性化遅延蛍光性化合物であり、前記第二の化合物が、前記一般式（１）で表されるピロメテンホウ素錯体である、請求項５に記載の発光素子。 The light emitting layer contains a first compound and a second compound, the first compound is a thermally activated delayed fluorescent compound, and the second compound is represented by the general formula (1). The light emitting device according to claim 5, which is a pyromethene boron complex.
  7. 請求項６に記載の熱活性化遅延蛍光性化合物が同一分子内に電子供与性部と電子求引性部を有する化合物である請求項５または６に記載の発光素子。 The light emitting device according to claim 5, wherein the thermally activated delayed fluorescent compound according to claim 6 is a compound having an electron donating part and an electron attracting part in the same molecule.
  8. 陽極と陰極の間に２層以上の発光層を有し、それぞれの発光層と発光層の間に１層以上の電荷発生層を有する請求項５～７のいずれかに記載の発光素子。 The light emitting device according to any one of claims 5 to 7, which has two or more light emitting layers between the anode and the cathode, and has one or more charge generating layers between the respective light emitting layers and the light emitting layers.
  9. 前記電荷発生層に一般式（４）で表されるフェナントロリン誘導体を含有する請求項８に記載の発光素子：
    Figure JPOXMLDOC01-appb-C000003
     上記一般式（４）中、Ａｒ２は、ｐ価の芳香族炭化水素基、およびｐ価の複素芳香環基からなる群より選ばれる；ｐは１～３の自然数である；Ｒ１５～Ｒ２２は、それぞれ同じでも異なっていてもよく、水素原子、アルキル基、シクロアルキル基、複素環基、アリール基、ヘテロアリール基からなる群より選ばれる；Ａｒ２のうち、ｐ個のフェナントロリル基による置換位置は任意の位置である。     The light emitting device according to claim 8, wherein the charge generation layer contains a phenanthroline derivative represented by the general formula (4).
    Figure JPOXMLDOC01-appb-C000003
     In the above general formula (4), Ar 2 is selected from the group consisting of a p-valent aromatic hydrocarbon group and a p-valent heteroaromatic ring group; p is a natural number of 1 to 3; R 15 to R. 22 may be the same or different, respectively, and is selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, a heterocyclic group, an aryl group, and a heteroaryl group; with p phenanthrolyl groups of Ar 2. The replacement position is any position.
  10. 請求項５～９のいずれかに記載の発光素子を含む表示装置。 A display device including the light emitting element according to any one of claims 5 to 9.
  11. 請求項５～９のいずれかに記載の発光素子を含む照明装置。 A lighting device including the light emitting element according to any one of claims 5 to 9.
PCT/JP2021/000458 2020-01-24 2021-01-08 Pyrromethene boron complex, light-emitting element containing same, light-emitting element, display device, and illumination device WO2021149510A1 (en)

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