CN113045735A - Nano material and preparation method thereof, quantum dot light-emitting diode and preparation method thereof - Google Patents

Nano material and preparation method thereof, quantum dot light-emitting diode and preparation method thereof Download PDF

Info

Publication number
CN113045735A
CN113045735A CN201911383589.7A CN201911383589A CN113045735A CN 113045735 A CN113045735 A CN 113045735A CN 201911383589 A CN201911383589 A CN 201911383589A CN 113045735 A CN113045735 A CN 113045735A
Authority
CN
China
Prior art keywords
quantum dot
nio
dot light
pedot
mixed solution
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201911383589.7A
Other languages
Chinese (zh)
Inventor
何斯纳
吴龙佳
吴劲衡
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
TCL Corp
TCL Research America Inc
Original Assignee
TCL Research America Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by TCL Research America Inc filed Critical TCL Research America Inc
Priority to CN201911383589.7A priority Critical patent/CN113045735A/en
Publication of CN113045735A publication Critical patent/CN113045735A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G61/00—Macromolecular compounds obtained by reactions forming a carbon-to-carbon link in the main chain of the macromolecule
    • C08G61/12—Macromolecular compounds containing atoms other than carbon in the main chain of the macromolecule
    • C08G61/122—Macromolecular compounds containing atoms other than carbon in the main chain of the macromolecule derived from five- or six-membered heterocyclic compounds, other than imides
    • C08G61/123—Macromolecular compounds containing atoms other than carbon in the main chain of the macromolecule derived from five- or six-membered heterocyclic compounds, other than imides derived from five-membered heterocyclic compounds
    • C08G61/126—Macromolecular compounds containing atoms other than carbon in the main chain of the macromolecule derived from five- or six-membered heterocyclic compounds, other than imides derived from five-membered heterocyclic compounds with a five-membered ring containing one sulfur atom in the ring
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y10/00—Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/20—Oxides; Hydroxides
    • C08K3/22—Oxides; Hydroxides of metals
    • 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]
    • H10K50/14—Carrier transporting layers
    • H10K50/15—Hole transporting layers
    • H10K50/155—Hole transporting layers comprising dopants
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
    • 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
    • H10K85/10—Organic polymers or oligomers
    • H10K85/111—Organic polymers or oligomers comprising aromatic, heteroaromatic, or aryl chains, e.g. polyaniline, polyphenylene or polyphenylene vinylene
    • H10K85/113—Heteroaromatic compounds comprising sulfur or selene, e.g. polythiophene
    • H10K85/1135—Polyethylene dioxythiophene [PEDOT]; Derivatives thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G2261/00—Macromolecular compounds obtained by reactions forming a carbon-to-carbon link in the main chain of the macromolecule
    • C08G2261/10—Definition of the polymer structure
    • C08G2261/11—Homopolymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G2261/00—Macromolecular compounds obtained by reactions forming a carbon-to-carbon link in the main chain of the macromolecule
    • C08G2261/30—Monomer units or repeat units incorporating structural elements in the main chain
    • C08G2261/32—Monomer units or repeat units incorporating structural elements in the main chain incorporating heteroaromatic structural elements in the main chain
    • C08G2261/324—Monomer units or repeat units incorporating structural elements in the main chain incorporating heteroaromatic structural elements in the main chain condensed
    • C08G2261/3243—Monomer units or repeat units incorporating structural elements in the main chain incorporating heteroaromatic structural elements in the main chain condensed containing one or more sulfur atoms as the only heteroatom, e.g. benzothiophene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/20—Oxides; Hydroxides
    • C08K3/22—Oxides; Hydroxides of metals
    • C08K2003/2293—Oxides; Hydroxides of metals of nickel
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K2201/00—Specific properties of additives
    • C08K2201/011—Nanostructured additives
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2102/00—Constructional details relating to the organic devices covered by this subclass

Abstract

The invention provides a nano material which is a core-shell structure nano material and comprises NiO nano particles and PEDOT shell layers coated on the surfaces of the NiO nano particles. According to the nano material with the core-shell structure, the PEDOT shell layer is coated on the surface of the NiO nano particles and plays a role of a carrier, so that agglomeration of the NiO nano particles can be blocked, the nano particles with uniform size distribution can be obtained, and the stability of the NiO/PEDOT core-shell nano material is improved. Meanwhile, because PEDOT has a lower empty orbital energy level relative to NiO, electrons are transferred from the HOMO energy level of NiO to the empty orbital of PEDOT in a relatively large amount after the NiO and the PEDOT are compounded, so that more free holes are formed, and the hole transport performance of the nano material is improved.

Description

Nano material and preparation method thereof, quantum dot light-emitting diode and preparation method thereof
Technical Field
The invention belongs to the technical field of display, and particularly relates to a nano material and a preparation method thereof, and a quantum dot light-emitting diode and a preparation method thereof.
Background
The semiconductor quantum dots have quantum size effect, and people can realize the required light emission with specific wavelength by regulating and controlling the size of the quantum dots, for example, the light emission wavelength tuning range of CdSe QDs can be from blue light to red light. In a conventional inorganic electroluminescent device, electrons and holes are injected from a cathode and an anode, respectively, and then recombined in a light emitting layer to form excitons for light emission. Conduction band electrons in wide bandgap semiconductors can be accelerated under high electric fields to obtain high enough energy to strike Quantum Dots (QDs) to cause them to emit light. In recent years, inorganic semiconductors have been studied as an electron transport layer in a relatively hot manner. As the nanometer NiO is used as a p-type semiconductor material, the nanometer NiO has adjustable band gaps (the band gap is 3.6eV-4.0eV, the HOMO energy level is-5.4 eV-5.0 eV, and the LUMO energy level is-1.6 eV), so that the nanometer NiO has higher light transmission performance, excellent chemical stability and unique optical, electrical and magnetic properties in an ultraviolet light region, a visible light region and a near infrared light region, and is widely applied to electrochromic devices, organic light emitting diodes, gas sensors, dye-sensitized solar cells and p-n heterojunctions. However, the hole transport material based on nano NiO is likely to be aggregated when processed into a film by a solution method, and there is room for further improvement in hole transport performance.
Disclosure of Invention
The invention aims to provide a nano material and a preparation method thereof, and aims to solve the problems that a NiO nano material is easy to agglomerate when a film is formed and the hole transport performance is not high.
The invention also aims to provide a quantum dot light-emitting diode using the nano material as a hole transport layer material and a preparation method thereof.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a nano material which is a core-shell structure nano material and comprises NiO nano particles and PEDOT shell layers coated on the surfaces of the NiO nano particles.
The second aspect of the present invention provides a method for preparing a nanomaterial, comprising the steps of:
dissolving nickel oxide and an EDOT monomer in an organic solvent to prepare a mixed solution of the nickel oxide and the EDOT monomer;
and adding an oxidant into the mixed solution, and heating for reaction to prepare the nano material with the NiO nano particles coated with the PEDOT shell layer.
The third aspect of the invention provides a quantum dot light-emitting diode, which comprises a cathode and an anode which are oppositely arranged, a quantum dot light-emitting layer arranged between the cathode and the anode, and a hole transport layer arranged between the anode and the quantum dot light-emitting layer, wherein the hole transport layer is made of a core-shell structure nano material and comprises NiO nano particles and a PEDOT shell layer coated on the surfaces of the NiO nano particles.
The fourth aspect of the present invention provides a method for manufacturing a quantum dot light emitting diode, comprising the steps of:
providing a substrate;
dissolving nickel oxide and an EDOT monomer in an organic solvent to prepare a mixed solution of the nickel oxide and the EDOT monomer; adding an oxidant into the mixed solution, and heating for reaction to prepare a nano material solution with the NiO nano particles coated with PEDOT shell layers;
and after the nano material solution is deposited on the surface of the substrate, annealing treatment is carried out to obtain the hole transport layer.
The nano material with the core-shell structure comprises NiO nano particles and PEDOT shells coated on the surfaces of the NiO nano particles (namely NiO/PEDOT core-shell nano material). PEDOT (polymer of 3, 4-ethylenedioxythiophene) is used as a good electronic conductor, and has high conductivity, environmental stability and good optical transparency. The PEDOT shell layer is coated on the surface of the NiO nano-particles and plays a role of a carrier, so that agglomeration of the NiO nano-particles can be blocked, the nano-particles with uniform size distribution can be obtained, and the stability of the NiO/PEDOT core-shell nano-material can be improved. Meanwhile, because PEDOT has a lower empty orbital energy level relative to NiO, electrons are transferred from the HOMO energy level of NiO to the empty orbital of PEDOT in a relatively large amount after the NiO and the PEDOT are compounded, so that more free holes are formed, and the hole transport performance of the nano material is improved. When the nano material is used as a hole transport layer material of a quantum dot light-emitting diode, the injection balance of electrons and holes can be promoted, the light-emitting efficiency of the quantum dot light-emitting diode is improved, the influence of exciton accumulation on the light-emitting efficiency of the quantum dot light-emitting diode is reduced, and the performance of the quantum dot light-emitting diode is finally improved.
The preparation method of the nano material provided by the invention can be obtained by only dissolving nickel oxide and EDOT monomers in an organic solvent and then adding an oxidant for reaction. The method is simple to operate and easy to realize large-scale preparation. More importantly, the nano material prepared by the method provided by the invention can improve the hole transmission capability, and when the nano material is used as a hole transmission layer material of a quantum dot light-emitting diode, the injection balance of electrons and holes can be promoted, the light-emitting efficiency of the quantum dot light-emitting diode is improved, the influence of exciton accumulation on the light-emitting efficiency of the quantum dot light-emitting diode is reduced, and the performance of the quantum dot light-emitting diode is finally improved.
The quantum dot light-emitting diode provided by the invention takes the NiO/PEDOT core-shell nano material as a hole transport layer material. The NiO/PEDOT core-shell nano material has good particle uniformity, so that the stability of the hole transport layer can be improved; meanwhile, after the surface of NiO is coated with the PEDOT shell layer, the hole transmission capability of the whole nanometer material can be improved, the injection balance of electrons and holes is promoted, the luminous efficiency of the quantum dot light-emitting diode is improved, the influence of exciton accumulation on the luminous efficiency of the quantum dot light-emitting diode is reduced, and finally the performance of the quantum dot light-emitting diode is improved.
The preparation method of the quantum dot light-emitting diode provided by the invention is characterized in that nickel oxide and an EDOT monomer are dissolved in an organic solvent, then an oxidant is added for reaction, and a hole transport layer can be prepared after deposition and film formation. The obtained hole transport layer is made of NiO/PEDOT core-shell nano materials, so that the quantum dot light-emitting diode prepared by the method can improve the hole transport capacity, promote the effective combination of electrons and holes in the quantum dot light-emitting layer, further reduce the influence of exciton accumulation on the performance of the device, promote the injection balance of electrons and holes, improve the light-emitting efficiency of the quantum dot light-emitting diode, reduce the influence of exciton accumulation on the light-emitting efficiency of the quantum dot light-emitting diode device, and finally improve the performance of the quantum dot light-emitting diode device.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
FIG. 1 is a schematic structural diagram of a nanomaterial provided by an embodiment of the present invention;
FIG. 2 is a schematic flow chart of the preparation of the nanomaterial provided by the embodiment of the invention;
fig. 3 is a schematic structural diagram of a quantum dot light-emitting diode provided in an embodiment of the present invention;
fig. 4 is a schematic diagram of a quantum dot light emitting diode according to an embodiment of the present invention.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In the description of the present invention, it is to be understood that the terms "first", "second" and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
The weight of the related components mentioned in the description of the embodiments of the present invention may not only refer to the specific content of each component, but also represent the proportional relationship of the weight among the components, and therefore, the content of the related components is scaled up or down within the scope disclosed in the description of the embodiments of the present invention as long as it is in accordance with the description of the embodiments of the present invention. Specifically, the weight described in the description of the embodiment of the present invention may be a unit of mass known in the chemical industry field, such as μ g, mg, g, and kg.
As shown in fig. 1, in a first aspect, an embodiment of the present invention provides a nanomaterial, where the nanomaterial is a core-shell nanomaterial and includes a NiO nanoparticle and a PEDOT shell layer coated on the surface of the NiO nanoparticle.
The nano material with the core-shell structure provided by the embodiment of the invention comprises NiO nano particles and PEDOT shell layers (namely NiO/PEDOT core-shell nano material) coated on the surfaces of the NiO nano particles. PEDOT (polymer of 3, 4-ethylenedioxythiophene) is used as a good electronic conductor, and has high conductivity, environmental stability and good optical transparency. The PEDOT shell layer is coated on the surface of the NiO nano-particles and plays a role of a carrier, so that agglomeration of the NiO nano-particles can be blocked, the nano-particles with uniform size distribution can be obtained, and the stability of the NiO/PEDOT core-shell nano-material can be improved. Meanwhile, because PEDOT has a lower empty orbital energy level relative to NiO, electrons are transferred from the HOMO energy level of NiO to the empty orbital of PEDOT in a relatively large amount after the NiO and the PEDOT are compounded, so that more free holes are formed, and the hole transport performance of the nano material is improved. When the nano material is used as a hole transport layer material of a quantum dot light-emitting diode, the injection balance of electrons and holes can be promoted, the light-emitting efficiency of the quantum dot light-emitting diode is improved, the influence of exciton accumulation on the light-emitting efficiency of the quantum dot light-emitting diode is reduced, and the performance of the quantum dot light-emitting diode is finally improved.
In the embodiment of the application, the content of PEDOT influences the stability and the hole transport performance of the NiO/PEDOT core-shell nano material, and particularly when the NiO/PEDOT core-shell nano material is used as a hole transport layer material of a quantum dot light-emitting diode, the performance of a hole transport layer of the quantum dot light-emitting diode can be directly influenced. Specifically, the nano material consists of NiO nano particles and PEDOT shells coated on the surfaces of the NiO nano particles, and the molar ratio of Ni elements to S elements in the nano material is 1: 0.2-0.5. When the molar ratio of the Ni element to the S element in the nano material is less than 1:0.2, PEDOT can not be uniformly polymerized on the surface of nickel oxide to form a shell layer or the obtained PEDOT shell layer is not enough in coverage, so that the stability and the hole transport layer of the NiO/PEDOT core-shell nano material can not be effectively improved. When the molar ratio of the Ni element to the S element in the nano material is more than 1: at 0.5, the thickness of a PEDOT shell layer formed by cross-linking polymerization of the EDOT monomer on the surface of the nickel oxide crystal grains is larger and larger, and the component proportion of the nano nickel oxide is reduced, so that the property of the nickel oxide nano material is changed, and the hole transport performance is reduced.
The nano material provided by the embodiment of the invention can be prepared by the following method.
Accordingly, with reference to fig. 2, a second aspect of the embodiments of the present invention provides a method for preparing a nanomaterial, including the following steps:
s01, dissolving nickel oxide and an EDOT monomer in an organic solvent to prepare a mixed solution of the nickel oxide and the EDOT monomer;
and S02, adding an oxidant into the mixed solution, and heating to react to prepare the nano material with the surface of the NiO nano particles coated with the PEDOT shell layer.
The preparation method of the nano material provided by the embodiment of the invention can be obtained by only dissolving nickel oxide and EDOT monomers in an organic solvent and then adding an oxidant for reaction. The method is simple to operate and easy to realize large-scale preparation. More importantly, the nanomaterial prepared by the method provided by the embodiment of the invention can improve the hole transport capability, and when the nanomaterial is used as a hole transport layer material of a quantum dot light-emitting diode, the nanomaterial can promote the injection balance of electrons and holes, improve the light-emitting efficiency of the quantum dot light-emitting diode, reduce the influence of exciton accumulation on the light-emitting efficiency of the quantum dot light-emitting diode, and finally improve the performance of the quantum dot light-emitting diode.
Specifically, in step S01, nickel oxide and an EDOT monomer are provided as raw materials for preparing the nanomaterial, where the nickel oxide is used as an inner core material of the NiO/PEDOT core-shell nanomaterial, and the EDOT monomer is used to provide a monomer raw material for preparing a PEDOT shell layer of the nanomaterial.
In some embodiments, the nickel oxide may be prepared by: and dissolving nickel salt in an organic solvent, adding alkali liquor after dissolution, heating for reaction, cooling, purifying and drying to obtain the NiO nano-particles.
Specifically, the nickel salt is selected from nickel salts capable of being dissolved in an organic solvent, and in the organic solvent environment, nickel ions in the nickel salt can react with hydroxide ions provided by the alkali liquor to grow into nickel oxide nano-grains. In the examples of the present application, the nickel salt is selected from inorganic nickel salts or organic nickel salts, and specifically includes but is not limited to nickel acetate, nickel nitrate, nickel chloride, nickel sulfate, and nickel acetate tetrahydrate.
In the examples of the present application, a nickel salt solution was prepared by dissolving a nickel salt in an organic solvent. The organic solvent is preferably an organic alcohol solvent. The organic alcohol solvent not only has better solubility for the nickel salt listed above, but also is milder as a reaction medium, and provides a good reaction environment for the metal salt ions to react with alkali liquor to grow into nano-crystalline grains. Preferably, the organic solvent is selected from at least one of isopropyl alcohol, ethanol, propanol, butanol, pentanol, hexanol, but is not limited thereto.
In some embodiments, the nickel salt is dissolved in an organic solvent, and the dissolution of the nickel salt may be facilitated by constant temperature stirring to prepare a nickel salt solution. Preferably, the constant-temperature stirring is carried out at a temperature of 60 ℃ to 80 ℃. This temperature generally prevents the volatilization of the organic solvent, such as an organic alcohol, that dissolves the nickel salt, and also promotes the rapid dissolution of the nickel salt.
In some embodiments, the concentration of nickel salt in the nickel salt solution is between 0.2mol/l and 1 mol/l.
Adding alkali liquor into the nickel salt solution, wherein the alkali liquor is selected from organic alkali or inorganic alkali capable of generating hydroxide ions in the reaction system. On one hand, hydroxyl ions provided by the alkali are used as an oxygen source and react with nickel ions in nickel salt under an alkaline condition to prepare the nickel oxide nano material; in another aspect, the base provides suitable alkaline reaction conditions for the reaction of nickel ions with hydroxide ions.
In some embodiments, in the step of adding an alkali solution to the nickel salt solution, the alkali solution is added to the nickel salt solution according to a molar ratio of nickel ions provided by the nickel salt to hydroxyl ions provided by the alkali solution of 1: 1.8-2.5, which is beneficial to obtain nickel oxide nanoparticles with uniformly distributed particles. When the molar ratio of the nickel ions provided by the nickel salt to the hydroxyl ions provided by the alkali liquor is 1: 1.8-2.5, the nickel ions and the alkali liquor can be controlled to react to generate nickel oxide crystal nuclei. When the content of the alkali is too high and the molar ratio of the nickel ions provided by the nickel salt to the hydroxide ions provided by the alkali liquor is not in the range of 1: 1.8-2.5, the reaction speed of the nickel ions and the hydroxide ions provided by the alkali in the reaction system can be reduced due to too high pH of the liquid. If the content of the alkali liquor is too low, and the molar ratio of nickel ions provided by the nickel salt to hydroxyl ions provided by the alkali liquor is not in the range of 1: 1.8-2.5, the excessive nickel ions cannot fully react due to the limitation of the hydroxyl ions provided by the alkali liquor, so that the obtained nano material is easily doped with a nickel salt material, and the performance of the nickel oxide nano material is finally influenced.
In the examples of the present application, the alkali solution is selected from organic bases or inorganic bases capable of providing hydroxide ions and adjusting the pH of the reaction system to 12-13. Specifically, the alkali solution is at least one selected from ammonia, potassium hydroxide, sodium hydroxide, lithium hydroxide, ethanolamine, ethylene glycol, diethanolamine, triethanolamine, and ethylenediamine, but is not limited thereto. In some embodiments, the alkali solution is selected from one of ammonia, potassium hydroxide, sodium hydroxide, lithium hydroxide, ethanolamine, ethylene glycol, diethanolamine, triethanolamine, and ethylenediamine. In some embodiments, the alkali solution is selected from the group consisting of ammonia and ethylene diamine, diethanolamine and triethanolamine, potassium hydroxide and sodium hydroxide, ethylene diamine and ethanolamine, ethylene diamine and ethylene glycol. In some embodiments, the alkali solution is selected from the group consisting of ammonia and ethylene diamine and ethylene glycol, diethanolamine and triethanolamine and ethanolamine, potassium hydroxide and sodium hydroxide and lithium hydroxide.
In the embodiment of the present application, in the step of adding an alkali to the mixed solution and heating for reaction, the temperature of the heating treatment is not higher than the boiling point temperature of the organic solvent, and the heating for reaction is preferably achieved by stirring at a constant temperature. In some embodiments, the step of adding alkali liquor to the nickel salt solution and heating for reaction is performed at a temperature of 60 ℃ to 90 ℃ for 2h to 4 h. Under the temperature condition, the nickel salt and the alkali liquor are favorably reacted, and the nickel oxide nano-crystal is prepared.
After the reaction is finished, cooling the liquid phase system to room temperature. The room temperature in the embodiment of the invention refers to the room temperature of 10-35 ℃. Then settling to separate out nickel oxide nano crystals, collecting the sediment, cleaning and drying to obtain the nano material. The sedimentation treatment may be achieved by adding a precipitant. The precipitant is a weakly polar and non-polar solvent such as ethyl acetate, heptane, octane, etc., but is not limited thereto.
After providing the nickel oxide and EDOT monomers, the nickel oxide and EDOT monomers. In this step, nickel oxide and EDOT monomer are dissolved in an organic solvent to prepare a mixed solution of nickel oxide and EDOT monomer. In some embodiments, nickel oxide and EDOT monomer are simultaneously dissolved in an organic solvent to form a mixed solution of the two; in some embodiments, after the nickel oxide and the EDOT monomer are respectively dissolved in the organic solvent, the two solutions are mixed to form a mixed solution of the two; in some embodiments, after the nickel salt is dissolved, the EDOT monomer is added to prepare a mixed solution of the two; in some examples, a mixed solution of the two is prepared by dissolving EDOT monomer and adding nickel salt.
In the present embodiment, the organic solvent is preferably an organic alcohol solvent. The organic alcohol solvent not only has better solubility for the nickel salt and the EDOT monomer listed above, but also is milder as a reaction medium, and provides a good reaction environment for the polymerization reaction of the EDOT monomer. Preferably, the organic solvent is selected from at least one of isopropyl alcohol, ethanol, propanol, butanol, pentanol, hexanol, but is not limited thereto.
In some embodiments, in the step of preparing the mixed solution of nickel oxide and EDOT monomers, the nickel oxide and EDOT monomers are dissolved in an organic solvent at a molar ratio of 1: 0.5-0.8 to prepare the mixed solution of nickel oxide and EDOT monomers. When the molar ratio of nickel oxide to EDOT monomers constituting the PEDOT shell layer is less than 1:0.5, the EDOT monomer can not be uniformly polymerized on the surface of the nickel oxide to form a PEDOT shell layer or the obtained PEDOT shell layer is not enough in coverage, so that the stability and the hole transport layer of the NiO/PEDOT core-shell nano material can not be effectively improved. When the molar ratio of nickel oxide to EDOT monomers constituting the PEDOT shell layer is more than 1: at 0.8, the thickness of a PEDOT shell layer formed by cross-linking polymerization of the EDOT monomer on the surface of the nickel oxide crystal grains is larger and larger, and the component proportion of the nano nickel oxide is reduced, so that the property of the nickel oxide nano material is changed, and the hole transport performance is reduced.
Specifically, the nickel oxide and the EDOT monomer are dissolved in an organic solvent, and the dissolution of the nickel oxide and the EDOT monomer can be promoted by stirring at a constant temperature, so that a mixed solution of the nickel oxide and the EDOT monomer is prepared. Preferably, the constant-temperature stirring is carried out at a temperature of 60 ℃ to 80 ℃. This temperature generally prevents volatilization of the organic solvent that dissolves the nickel oxide and EDOT monomers, and also promotes rapid dissolution of the nickel oxide and EDOT monomers.
In the step S02, an oxidizing agent is added to the mixed solution, and the oxidizing agent is used to promote the EDOT monomer to polymerize on the surface of the nickel oxide nanoparticles to form a PEDOT shell, and the stability and the hole transport property of the nickel oxide nanoparticles are adjusted by coating the PEDOT shell.
In some embodiments, the oxidizing agent is selected from at least one of ferric chloride, ammonium persulfate, and hydrogen peroxide. The oxidant is a medium strength oxidant. Specifically, the reaction for producing PEDOT by polymerization of EDOT monomer is as follows
Figure BDA0002342905570000091
In some embodiments, in the step of adding the oxidant into the mixed solution, the oxidant is added into the mixed solution according to a molar ratio of the EDOT monomer in the mixed solution to the oxidant of 1: 1-1.5, which is beneficial to preparing the NiO/PEDOT core-shell nano material with uniformly distributed particles. When the molar ratio of the EDOT monomer to the oxidant is greater than 1:1, the EDOT monomer is excessive, redundant EDOT monomer cannot be well polymerized into PEDOT, and the oxidative polymerization reaction efficiency is low; when the molar weight ratio of the EDOT monomer to the oxidant is less than 1:1.5, the oxidant is excessive, the redundant oxidant is not easy to remove in the subsequent steps, and the excess oxidant is doped in the NiO/PEDOT core-shell nano material, so that the stability and the hole transmission performance of the NiO/PEDOT core-shell nano material are reduced, and meanwhile, the photoelectric performance of the NiO/PEDOT core-shell nano material serving as a hole transmission layer of a quantum dot light-emitting diode is influenced.
In some embodiments, in the step of adding an oxidizing agent to the mixed solution and heating for reaction, the heating is performed at a temperature of 60 ℃ to 80 ℃ for 2 hours to 4 hours. Under the temperature condition, the EDOT monomer is uniformly polymerized on the surface of the nickel oxide nano-particles under the action of an oxidant to form a PEDOT shell layer to coat the nickel oxide nano-particles, and the PEDOT shell layer with a proper film thickness is finally obtained after 2-4 hours of reaction.
As shown in fig. 3, a quantum dot light emitting diode according to a third aspect of the embodiments of the present invention includes a cathode and an anode that are disposed opposite to each other, a quantum dot light emitting layer disposed between the cathode and the anode, and a hole transport layer disposed between the anode and the quantum dot light emitting layer, where the hole transport layer is made of a core-shell structured nano material, and includes NiO nanoparticles and a PEDOT shell layer coated on the surfaces of the NiO nanoparticles.
The quantum dot light-emitting diode provided by the embodiment of the invention takes the NiO/PEDOT core-shell nano material as a hole transport layer material. The NiO/PEDOT core-shell nano material has good particle uniformity, so that the stability of the hole transport layer can be improved; meanwhile, after the surface of NiO is coated with the PEDOT shell layer, the hole transmission capability of the whole nanometer material can be improved, the injection balance of electrons and holes is promoted, the luminous efficiency of the quantum dot light-emitting diode is improved, the influence of exciton accumulation on the luminous efficiency of the quantum dot light-emitting diode is reduced, and finally the performance of the quantum dot light-emitting diode is improved.
The material of the hole transport layer in the embodiment of the present invention is the above-mentioned nanomaterial, and the specific principle of using the material of the hole transport layer to improve the hole transport performance of the device is as described above, and for saving space, it is not described here again.
In some embodiments, the hole transport layer is made of a core-shell structure nano material composed of NiO nanoparticles and PEDOT shell layers coated on the surfaces of the NiO nanoparticles, and the molar ratio of Ni elements to S elements in the core-shell structure nano material is 1: 0.2-0.5. When the molar ratio of the Ni element to the S element in the core-shell structure nano material is less than 1:0.2, PEDOT can not be uniformly polymerized on the surface of nickel oxide to form a shell layer or the obtained PEDOT shell layer is not enough in coverage, so that the stability and the hole transport layer of the NiO/PEDOT core-shell nano material can not be effectively improved. When the molar ratio of the Ni element to the S element in the core-shell structure nano material is more than 1: at 0.5, the thickness of a PEDOT shell layer formed by cross-linking polymerization of the EDOT monomer on the surface of the nickel oxide crystal grains is larger and larger, and the component proportion of the nano nickel oxide is reduced, so that the property of the nickel oxide nano material is changed, and the hole transport performance is reduced.
In some embodiments, the hole transport layer has a thickness of 20 to 60 nm. If the thickness of the hole transport layer is too thin, the effect of the hole transport layer on promoting the transport of the holes in the quantum dot light-emitting diode is not obvious.
Specifically, the quantum dot light emitting diode according to the embodiment of the present invention has a positive structure and an inversion structure.
In one embodiment, a positive structure quantum dot light emitting diode includes an anode and a cathode disposed opposite each other, a quantum dot light emitting layer disposed between the anode and the cathode, a hole transport layer disposed between the anode and the quantum dot light emitting layer, and the anode is disposed on a substrate. Further, a hole injection layer can be arranged between the anode and the hole transport layer, and an electronic function layer such as a hole blocking layer can be arranged between the anode and the quantum dot light emitting layer; an electron-transport layer, an electron-injection layer, a hole-blocking layer and other electron-functional layers can be arranged between the cathode and the quantum dot light-emitting layer. In some embodiments of the positive-type structure device, the quantum dot light emitting diode includes a substrate, an anode disposed on a surface of the substrate, the hole injection layer disposed on a surface of the anode, a hole transport layer disposed on a surface of the hole injection layer, a quantum dot light emitting layer disposed on a surface of the hole transport layer, an electron transport layer disposed on a surface of the quantum dot light emitting layer, and a cathode disposed on a surface of the electron transport layer.
In one embodiment, an inverted structure quantum dot light emitting diode includes a stacked structure including an anode and a cathode disposed opposite each other, a quantum dot light emitting layer disposed between the anode and the cathode, a hole transport layer disposed between the anode and the quantum dot light emitting layer, and the cathode disposed on a substrate. Further, a hole injection layer can be arranged between the anode and the hole transport layer, and a hole functional layer such as an electron blocking layer can be arranged between the anode and the quantum dot light emitting layer; and a hole function layer such as an electron transport layer, an electron injection layer and a hole barrier layer can be arranged between the cathode and the quantum dot light-emitting layer. In some embodiments of the device with the inverted structure, the quantum dot light emitting diode includes a substrate, a cathode disposed on a surface of the substrate, an electron transport layer disposed on a surface of the cathode, a quantum dot light emitting layer disposed on a surface of the electron transport layer, a hole transport layer disposed on a surface of the quantum dot light emitting layer, a hole injection layer disposed on a surface of the hole transport layer, and an anode disposed on a surface of the hole injection layer.
Specifically, the selection of the anode is not limited strictly, and ITO may be selected, but is not limited thereto. The thickness of the anode is 15-30 nm.
The material of the quantum dot light-emitting layer can be conventional quantum dot material according to conventional quantum dot type. For example, the quantum dot of the quantum dot light-emitting layer can be one of red quantum dot, green quantum dot, blue quantum dot and yellow quantum dot; the quantum dot material may or may not contain cadmium; the quantum dots can be oil-soluble quantum dots comprising binary phase, ternary phase and quaternary phase quantum dots. In some embodiments, the quantum dot material may be selected from at least one of semiconductor nanocrystals of CdS, CdSe, CdTe, ZnSe, ZnTe, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InSb, AlAs, AlP, CuInS, CuInSe, AgS, PbS, PbSe, and core-shell structured quantum dots or alloy structured quantum dots formed of the above materials; in some embodiments, the quantum dot material may be selected from ZnXCd1-XS、CuXIn1-XS、ZnXCd1-XSe、ZnXSe1-XS、ZnXCd1-XTe、PbSeXS1-XAnd at least one of a core-shell structure quantum dot or an alloy structure quantum dot formed by the material. In some embodiments, the quantum dot material may be selected from ZnXCd1-XS/ZnSe、CuXIn1-XS/ZnS、ZnXCd1-XSe/ZnS、CuInSeS、ZnXCd1-XTe/ZnS、PbSeXS1-XThe nano-crystalline material comprises/ZnS semiconductor nano-crystalline and at least one of core-shell structure quantum dots or alloy structure quantum dots formed by the material. The quantum dot light-emitting layer formed by the quantum dot material has the characteristics of wide excitation spectrum, continuous distribution, high emission spectrum stability and the like. The thickness of the quantum dot light-emitting layer is 20-60 nm.
The cathode can be made of conventional cathode materials, such as metal silver or metal aluminum, or a nano Ag wire or a nano Cu wire, and the materials have low resistance so that carriers can be injected smoothly. The thickness of the cathode is 15-30 nm.
The electron transport layer can be made of electron transport materials conventional in the field, and can be ZnO or TiO2、CsF、LiF、CsCO3And Alq3But is not limited thereto.
In some embodiments, the qd-led may further comprise an encapsulation layer. The packaging layer can be arranged on the surface of a top electrode (an electrode far away from the substrate) and can also be arranged on the surface of the whole quantum dot light-emitting diode.
The quantum dot light-emitting diode provided by the embodiment of the invention can be prepared by the following method.
With reference to fig. 4, a fourth aspect of the embodiments of the present invention provides a method for manufacturing a quantum dot light emitting diode, including the following steps:
E01. providing a substrate;
E02. dissolving nickel oxide and an EDOT monomer in an organic solvent to prepare a mixed solution of the nickel oxide and the EDOT monomer; adding an oxidant into the mixed solution, and heating for reaction to prepare a nano material solution with the NiO nano particles coated with PEDOT shell layers;
E03. and after the nano material solution is deposited on the surface of the substrate, annealing treatment is carried out to obtain the hole transport layer.
According to the preparation method of the quantum dot light-emitting diode provided by the embodiment of the invention, nickel oxide and an EDOT monomer are dissolved in an organic solvent, then an oxidant is added for reaction, and an electron transport layer can be prepared after deposition and film formation. The obtained hole transport layer is made of NiO/PEDOT core-shell nanometer materials, so that the quantum dot light-emitting diode prepared by the embodiment of the invention can improve the hole transport capacity, promote the effective combination of electrons and holes in the quantum dot light-emitting layer, further reduce the influence of exciton accumulation on the performance of the device, promote the injection balance of the electrons and the holes, improve the light-emitting efficiency of the quantum dot light-emitting diode, reduce the influence of the exciton accumulation on the light-emitting efficiency of the quantum dot light-emitting diode device, and finally improve the performance of the quantum dot light-emitting diode device.
Specifically, in step E01, in the positive type structure quantum dot light emitting diode, the bottom electrode provided on the substrate is an anode, that is, the substrate at least includes an anode substrate. In some embodiments of the invention, the substrate is an anode substrate with an anode disposed on a substrate. In some embodiments of the present invention, the substrate may be a laminated substrate in which an anode is disposed on a substrate and a hole injection layer is disposed on a surface of the anode. It should be understood that the present invention is not limited to the structures of the above-described embodiments.
In step E01, in the case of the inverse quantum dot light emitting diode, the bottom electrode provided on the substrate is a cathode, that is, the substrate at least includes a cathode substrate. In some embodiments of the invention, the substrate is a laminated substrate with a quantum dot light emitting layer disposed on a substrate. In still other embodiments of the present invention, the substrate is a laminated substrate in which a cathode is provided on a substrate, an electron transport layer is provided on a surface of the cathode, and a quantum dot light emitting layer is provided on a surface of the electron transport layer. Of course, other electron functional layers, such as an electron injection layer, may also be provided between the cathode and the electron transport layer.
In the preparation method of the quantum dot light-emitting diode provided by the embodiment of the invention, before the functional layer is prepared on the surface of the anode substrate or the cathode substrate, the anode substrate or the cathode substrate is preferably subjected to pretreatment. In a preferred embodiment, the step of pre-treating comprises: cleaning the anode substrate or the cathode substrate with a cleaning agent to primarily remove stains on the surface, and then sequentially performing ultrasonic cleaning in deionized water, acetone, absolute ethyl alcohol and deionized water for 10-30 min, preferably 20min, to remove impurities on the surface; and finally, drying the anode substrate or the cathode substrate by using high-purity nitrogen to obtain the surface of the anode substrate or the cathode substrate.
In the step E02, dissolving nickel oxide and EDOT monomer in an organic solvent to prepare a mixed solution of nickel oxide and EDOT monomer; the steps of adding an oxidant into the mixed solution, and heating for reaction to prepare the nano material solution in which the surface of the NiO nano particles is coated with the PEDOT shell layer are the same as those described above, specifically as described above. In some embodiments, in the step of preparing the mixed solution of nickel oxide and EDOT monomers, the nickel oxide and EDOT monomers are dissolved in an organic solvent at a molar ratio of 1: 0.5-0.8 to prepare the mixed solution of nickel oxide and EDOT monomers. In some embodiments, the oxidizing agent is selected from at least one of ferric chloride, ammonium persulfate, and hydrogen peroxide. In some embodiments, in the step of adding an oxidizing agent to the mixed solution, the oxidizing agent is added to the mixed solution in a ratio of a molar ratio of the EDOT monomer to the oxidizing agent in the mixed solution of 1:1 to 1.5. In some embodiments, in the step of adding an oxidizing agent to the mixed solution and heating for reaction, the heating is performed at a temperature of 60 ℃ to 80 ℃ for 2 hours to 4 hours.
In step E03, depositing the nanomaterial solution on the substrate surface can be achieved by using a conventional solution processing method, including but not limited to, dropping coating, spin coating, dipping, coating, printing, evaporation, and the like. The embodiment of the invention can control the film thickness by adjusting the concentration of the solution, the printing or spin coating speed and the deposition time. After the nano material solution is deposited, thermal annealing treatment is carried out at 300-350 ℃, the solvent in the nano material solution is volatilized, the nano materials with the core-shell structure are promoted to be uniformly and compactly arranged, and the compact film layer is prepared.
The functional layers (including but not limited to hole injection layer, electron transport layer, hole blocking layer, electron blocking layer) except the anode and cathode of the embodiments of the present application can be prepared by conventional solution processing methods including but not limited to inkjet printing, spin coating, drop coating, dipping, coating, and evaporation. Similarly, the film thickness of each layer can be controlled by adjusting the concentration of the solution, the printing or spin coating speed and the deposition time; and thermal annealing treatment is carried out after the solution is deposited. In some embodiments, the electron transport layer can be prepared by placing the substrate in a vacuum evaporation chamber, and controlling the evaporation speed to be 0.01-0.5 nm/s, so as to prepare the electron transport layer with a proper thickness.
In some embodiments, the method further comprises performing packaging treatment on the obtained quantum dot light emitting diode. The packaging process can adopt common machine packaging or manual packaging. Preferably, the oxygen content and the water content in the packaging treatment environment are both lower than 0.1ppm so as to ensure the stability of the device.
The following description will be given with reference to specific examples and comparative examples.
Example 1
A preparation method of a NiO/PEDOT core-shell nano material comprises the following steps:
adding appropriate amount of nickel chloride into 50ml ethanol to form nickel salt solution with nickel ion concentration of 0.5mol/L, stirring and dissolving at 70 deg.C according to OH-：Ni2+In a molar ratio of 2: an ethanol solution of sodium hydroxide (10ml of ethanol) was added at a ratio of 1(pH 12). Stirring at 70 deg.C for 4h to obtain uniform transparent solution. And after the solution is cooled, separating out the solution by using ethyl acetate, centrifuging, dissolving by using a small amount of ethanol (repeating the operation, washing for 3 times), and drying to obtain the NiO nano-particles.
NiO nanoparticles and EDOT monomers were added to 30ml ethanol to form a solution with a total concentration of 0.5mol/L, where nickel: the molar ratio of EDOT is 1: 0.5. then dissolved with stirring at a temperature of 70 ℃ according to the molar ratio of EDOT monomers: fe3+In a molar ratio of 1:1, adding FeCl3Ethanol solution (5ml ethanol). And continuously stirring for 4 hours at the temperature of 70 ℃, then, after the solution is cooled, precipitating by using ethyl acetate, dissolving by using a small amount of ethanol after centrifugation, repeating the precipitation and dissolution steps for 3 times, and drying to obtain the NiO/PEDOT core-shell nano material.
Example 2
A preparation method of a NiO/PEDOT core-shell nano material comprises the following steps:
adding appropriate amount of nickel chloride into 50ml methanol to form nickel salt solution with nickel ion concentration of 0.5mol/L, stirring and dissolving at 60 deg.C according to OH-：Ni2+Mole ofThe ratio is 2: a solution of sodium hydroxide in methanol (10ml of methanol) was added at a ratio of 1(pH 12). Stirring at 60 deg.C for 4h to obtain uniform transparent solution. And after the solution is cooled, separating out the solution by using ethyl acetate, centrifuging, dissolving by using a small amount of ethanol (repeating the operation, washing for 3 times), and drying to obtain the NiO nano-particles.
NiO nanoparticles and EDOT monomer were added to 30ml of methanol to form a solution with a total concentration of 0.8mol/L, where nickel: the molar ratio of EDOT is 1: 0.6. then dissolved with stirring at a temperature of 60 ℃ according to the molar ratio of EDOT monomers: the molar ratio of ammonium persulfate is 1: 1.2, a methanol solution of ammonium persulfate (5ml of methanol) was added. And continuously stirring for 3 hours at the temperature of 60 ℃, then, after the solution is cooled, precipitating by using ethyl acetate, dissolving by using a small amount of ethanol after centrifugation, repeating the precipitation and dissolution steps for 3 times, and drying to obtain the NiO/PEDOT core-shell nano material.
Example 2
A preparation method of a NiO/PEDOT core-shell nano material comprises the following steps:
adding appropriate amount of nickel chloride into 50ml propanol to form nickel salt solution with nickel ion concentration of 0.5mol/L, stirring and dissolving at 80 deg.C according to OH-：Ni2+In a molar ratio of 2: a solution of potassium hydroxide in propanol (10ml of propanol) was added at a ratio of 1(pH 12). Stirring at 80 deg.C for 4h to obtain uniform transparent solution. And after the solution is cooled, separating out the solution by using ethyl acetate, centrifuging, dissolving by using a small amount of ethanol (repeating the operation, washing for 3 times), and drying to obtain the NiO nano-particles.
NiO nanoparticles and EDOT monomers were added to 30ml of methanol to form a solution with a total concentration of 1mol/L, where nickel: the molar ratio of EDOT is 1: 0.8. then dissolved with stirring at a temperature of 80 ℃ according to the molar ratio of EDOT monomers: the molar ratio of hydrogen peroxide is 1:1.5 ratio, hydrogen peroxide in propanol (5ml of propanol) was added. And continuously stirring for 4 hours at the temperature of 80 ℃, then, after the solution is cooled, precipitating by using ethyl acetate, dissolving by using a small amount of ethanol after centrifugation, repeating the precipitation and dissolution steps for 3 times, and drying to obtain the NiO/PEDOT core-shell nano material.
Example 4
A quantum dot light-emitting diode comprises a laminated structure of an anode and a cathode which are oppositely arranged, a quantum dot light-emitting layer arranged between the anode and the cathode, an electron transport layer arranged between the cathode and the quantum dot light-emitting layer, and a hole transport layer arranged between the anode and the quantum dot light-emitting layer, wherein the anode is arranged on a substrate. The substrate is made of a glass sheet, the anode is made of an ITO substrate, the hole transport layer is made of a NiO/PEDOT core-shell nano material, the electron transport layer is made of ZnO, and the cathode is made of Al.
The preparation method of the quantum dot light-emitting diode comprises the following steps:
providing an ITO substrate, and preparing a hole transport layer on the ITO substrate, wherein the hole transport layer is made of the NiO/PEDOT core-shell nano material prepared by the method in the embodiment 1;
depositing a quantum dot light emitting layer on the hole transport layer;
depositing an electron transport layer over the quantum dot light emitting layer;
preparing a cathode on the electron transport layer.
Example 5
A quantum dot light-emitting diode comprises a laminated structure of an anode and a cathode which are oppositely arranged, a quantum dot light-emitting layer arranged between the anode and the cathode, an electron transport layer arranged between the cathode and the quantum dot light-emitting layer, and a hole transport layer arranged between the anode and the quantum dot light-emitting layer, wherein the anode is arranged on a substrate. The substrate is made of a glass sheet, the anode is made of an ITO substrate, the hole transport layer is made of a NiO/PEDOT core-shell nano material, the electron transport layer is made of ZnO, and the cathode is made of Al.
The preparation method of the quantum dot light-emitting diode comprises the following steps:
providing an ITO substrate, and preparing a hole transport layer on the ITO substrate, wherein the hole transport layer is made of the NiO/PEDOT core-shell nano material prepared by the method in the embodiment 2;
depositing a quantum dot light emitting layer on the hole transport layer;
depositing an electron transport layer over the quantum dot light emitting layer;
preparing a cathode on the electron transport layer.
Example 6
A quantum dot light-emitting diode comprises a laminated structure of an anode and a cathode which are oppositely arranged, a quantum dot light-emitting layer arranged between the anode and the cathode, an electron transport layer arranged between the cathode and the quantum dot light-emitting layer, and a hole transport layer arranged between the anode and the quantum dot light-emitting layer, wherein the anode is arranged on a substrate. The substrate is made of a glass sheet, the anode is made of an ITO substrate, the hole transport layer is made of a NiO/PEDOT core-shell nano material, the electron transport layer is made of ZnO, and the cathode is made of Al.
The preparation method of the quantum dot light-emitting diode comprises the following steps:
providing an ITO substrate, and preparing a hole transport layer on the ITO substrate, wherein the hole transport layer is made of the NiO/PEDOT core-shell nano material prepared by the method in the embodiment 3;
depositing a quantum dot light emitting layer on the hole transport layer;
depositing an electron transport layer over the quantum dot light emitting layer;
preparing a cathode on the electron transport layer.
Example 7
A quantum dot light-emitting diode comprises a laminated structure of an anode and a cathode which are oppositely arranged, a quantum dot light-emitting layer arranged between the anode and the cathode, an electron transport layer arranged between the cathode and the quantum dot light-emitting layer, and a hole transport layer arranged between the anode and the quantum dot light-emitting layer, wherein the cathode is arranged on a substrate. The substrate is made of a glass sheet, the cathode is made of an ITO (indium tin oxide) substrate, the hole transport layer is made of a NiO/PEDOT core-shell nano material, the electron transport layer is made of ZnO, and the anode is made of Al.
The preparation method of the quantum dot light-emitting diode comprises the following steps:
providing a cathode substrate, and depositing and preparing an electron transport layer on the cathode substrate;
preparing a quantum dot light-emitting layer on the electron transport layer;
preparing a hole transport layer on the quantum dot light-emitting layer, wherein the hole transport layer is made of the NiO/PPEDOT core-shell nano material prepared by the method in the embodiment 1;
an anode is prepared on the hole transport layer.
Example 8
A quantum dot light-emitting diode comprises a laminated structure of an anode and a cathode which are oppositely arranged, a quantum dot light-emitting layer arranged between the anode and the cathode, an electron transport layer arranged between the cathode and the quantum dot light-emitting layer, and a hole transport layer arranged between the anode and the quantum dot light-emitting layer, wherein the cathode is arranged on a substrate. The substrate is made of a glass sheet, the cathode is made of an ITO (indium tin oxide) substrate, the hole transport layer is made of a NiO/PEDOT core-shell nano material, the electron transport layer is made of ZnO, and the anode is made of Al.
The preparation method of the quantum dot light-emitting diode comprises the following steps:
providing a cathode substrate, and depositing and preparing an electron transport layer on the cathode substrate;
preparing a quantum dot light-emitting layer on the electron transport layer;
preparing a hole transport layer on the quantum dot light-emitting layer, wherein the hole transport layer is made of the NiO/PPEDOT core-shell nano material prepared by the method in the embodiment 2;
an anode is prepared on the hole transport layer.
Example 9
A quantum dot light-emitting diode comprises a laminated structure of an anode and a cathode which are oppositely arranged, a quantum dot light-emitting layer arranged between the anode and the cathode, an electron transport layer arranged between the cathode and the quantum dot light-emitting layer, and a hole transport layer arranged between the anode and the quantum dot light-emitting layer, wherein the cathode is arranged on a substrate. The substrate is made of a glass sheet, the cathode is made of an ITO (indium tin oxide) substrate, the hole transport layer is made of a NiO/PEDOT core-shell nano material, the electron transport layer is made of ZnO, and the anode is made of Al.
The preparation method of the quantum dot light-emitting diode comprises the following steps:
providing a cathode substrate, and depositing and preparing an electron transport layer on the cathode substrate;
preparing a quantum dot light-emitting layer on the electron transport layer;
preparing a hole transport layer on the quantum dot light-emitting layer, wherein the hole transport layer is made of the NiO/PPEDOT core-shell nano material prepared by the method in the embodiment 3;
an anode is prepared on the hole transport layer.
Comparative example 1
A quantum dot light-emitting diode comprises a laminated structure of an anode and a cathode which are oppositely arranged, a quantum dot light-emitting layer arranged between the anode and the cathode, an electron transport layer arranged between the cathode and the quantum dot light-emitting layer, and a hole transport layer arranged between the anode and the quantum dot light-emitting layer, wherein the cathode is arranged on a substrate. The substrate is made of a glass sheet, the anode is made of an ITO (indium tin oxide) substrate, the hole transport layer is made of a commercial NiO material (purchased from sigma company), the electron transport layer is made of ZnO, and the cathode is made of Al.
The performance of the hole transport film prepared in example 1, the hole transport films prepared in comparative examples 1 to 3, the quantum dot light emitting diodes prepared in examples 4 to 9 and comparative example 1 was tested, and the test indexes and the test method were as follows:
(1) hole mobility: testing the current density (J) -voltage (V) of the hole transport film, drawing a curve relation graph, fitting a Space Charge Limited Current (SCLC) region in the relation graph, and then calculating the hole mobility according to a well-known Child's law formula:
J＝(9/8)εrε0μeV2/d3
wherein J represents current density in mAcm-2；εrDenotes the relative dielectric constant,. epsilon0Represents the vacuum dielectric constant; mu.seDenotes hole mobility in cm2V-1s-1(ii) a V represents the drive voltage, in units of V; d represents the film thickness in m.
(2) Resistivity: and measuring the resistivity of the hole transport film by using the same resistivity measuring instrument.
(3) External Quantum Efficiency (EQE): measured using an EQE optical test instrument.
Note: the hole mobility and resistivity were tested as single layer thin film structure devices, i.e.: cathode/hole transport film/anode. The external quantum efficiency test is the QLED device, namely: anode/hole transport film/quantum dot/electron transport film/cathode, or cathode/electron transport film/quantum dot/hole transport film/anode.
The test results are shown in table 1 below:
TABLE 1
Figure BDA0002342905570000211
As can be seen from table 1 above, the materials provided in examples 1 to 3 of the present invention are hole transport films made of NiO/PEDOT core-shell nano materials, the resistivity of the hole transport films is significantly lower than that of the hole transport films made of NiO material in comparative example 1, and the hole mobility of the hole transport films is significantly higher than that of the hole transport films made of metal compound nano materials in comparative example 1.
The external quantum efficiency of the quantum dot light-emitting diode (the hole transport layer is made of NiO/PEDOT core-shell nano material) provided by the embodiments 4-9 of the invention is obviously higher than that of the quantum dot light-emitting diode made of NiO material in the comparative example 1, which shows that the quantum dot light-emitting diode obtained by the embodiments has better luminous efficiency.
It is noted that the embodiments provided by the present invention all use blue light quantum dots CdXZn1-XS/ZnS is used as a luminescent layer material based on a blue light luminescent systemThe system (the blue light quantum dot light-emitting diode is more valuable because the high efficiency is difficult to achieve) does not represent that the invention is only used for the blue light-emitting system.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims (14)

1. The nanometer material is characterized by being a core-shell structure nanometer material and comprising NiO nanometer particles and PEDOT shell layers coated on the surfaces of the NiO nanometer particles.
2. The nanomaterial of claim 1, wherein the nanomaterial consists of NiO nanoparticles and PEDOT shells coated on the surfaces of the NiO nanoparticles, and the molar ratio of Ni element to S element in the nanomaterial is 1: 0.2-0.5.
3. The preparation method of the nano material is characterized by comprising the following steps of:
dissolving nickel oxide and an EDOT monomer in an organic solvent to prepare a mixed solution of the nickel oxide and the EDOT monomer;
and adding an oxidant into the mixed solution, and heating for reaction to prepare the nano material with the NiO nano particles coated with the PEDOT shell layer.
4. The method for preparing nano-materials according to claim 3, wherein in the step of preparing the mixed solution of nickel oxide and EDOT monomers, the nickel oxide and EDOT monomers are dissolved in an organic solvent at a molar ratio of 1: 0.5-0.8 to prepare the mixed solution of nickel oxide and EDOT monomers.
5. The method according to claim 3, wherein the oxidizing agent is at least one selected from the group consisting of ferric chloride, ammonium persulfate, and hydrogen peroxide.
6. The method of preparing nanomaterial according to claim 4, wherein in the step of adding an oxidizing agent to the mixed solution, the oxidizing agent is added to the mixed solution in a ratio of a molar ratio of EDOT monomer to the oxidizing agent in the mixed solution of 1:1 to 1.5.
7. The method for preparing nanomaterial according to any of claims 3 to 6, wherein in the step of adding an oxidizing agent to the mixed solution and heating to react, the heating reaction is performed at a temperature of 60 ℃ to 80 ℃ for 2 hours to 4 hours.
8. The quantum dot light-emitting diode is characterized by comprising a cathode and an anode which are oppositely arranged, a quantum dot light-emitting layer arranged between the cathode and the anode, and a hole transport layer arranged between the anode and the quantum dot light-emitting layer, wherein the hole transport layer is made of a core-shell structure nano material and comprises NiO nano particles and a PEDOT shell layer coated on the surfaces of the NiO nano particles.
9. The quantum dot light-emitting diode of claim 8, wherein the hole transport layer is made of a core-shell structure nanomaterial comprising NiO nanoparticles and a PEDOT shell layer coated on the surfaces of the NiO nanoparticles, and the molar ratio of Ni elements to S elements in the core-shell structure nanomaterial is 1: 0.2-0.5.
10. A preparation method of a quantum dot light-emitting diode is characterized by comprising the following steps:
providing a substrate;
dissolving nickel oxide and an EDOT monomer in an organic solvent to prepare a mixed solution of the nickel oxide and the EDOT monomer; adding an oxidant into the mixed solution, and heating for reaction to prepare a nano material solution with the NiO nano particles coated with PEDOT shell layers;
and after the nano material solution is deposited on the surface of the substrate, annealing treatment is carried out to obtain the hole transport layer.
11. The method of claim 10, wherein in the step of preparing the mixed solution of nickel oxide and EDOT monomers, the nickel oxide and EDOT monomers are dissolved in an organic solvent at a molar ratio of nickel oxide to EDOT monomers of 1: 0.5-0.8 to prepare the mixed solution of nickel oxide and EDOT monomers.
12. The method of claim 10, wherein the oxidant is at least one selected from the group consisting of ferric chloride, ammonium persulfate, and hydrogen peroxide.
13. The method according to claim 10, wherein in the step of adding an oxidizing agent to the mixed solution, the oxidizing agent is added to the mixed solution in a molar ratio of EDOT monomer to the oxidizing agent in the mixed solution of 1:1 to 1.5.
14. The method for preparing a quantum dot light-emitting diode according to any one of claims 10 to 13, wherein in the step of adding an oxidant to the mixed solution and heating to react, the heating reaction is performed at a temperature of 60 ℃ to 80 ℃ for 2 hours to 4 hours.
CN201911383589.7A 2019-12-28 2019-12-28 Nano material and preparation method thereof, quantum dot light-emitting diode and preparation method thereof Pending CN113045735A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201911383589.7A CN113045735A (en) 2019-12-28 2019-12-28 Nano material and preparation method thereof, quantum dot light-emitting diode and preparation method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201911383589.7A CN113045735A (en) 2019-12-28 2019-12-28 Nano material and preparation method thereof, quantum dot light-emitting diode and preparation method thereof

Publications (1)

Publication Number Publication Date
CN113045735A true CN113045735A (en) 2021-06-29

Family

ID=76507219

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201911383589.7A Pending CN113045735A (en) 2019-12-28 2019-12-28 Nano material and preparation method thereof, quantum dot light-emitting diode and preparation method thereof

Country Status (1)

Country Link
CN (1) CN113045735A (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105609651A (en) * 2016-01-07 2016-05-25 东南大学 High-efficiency quantum dot light emitting diode with self-assembly polymer hole transmission layer structure
WO2016209808A1 (en) * 2015-06-22 2016-12-29 University Of Florida Research Foundation, Inc. Dye-doped hole transport layer for organic light emitting diodes
CN106784348A (en) * 2016-12-15 2017-05-31 Tcl集团股份有限公司 QLED containing noble metal nanometer material and preparation method thereof
CN108281553A (en) * 2018-01-10 2018-07-13 苏州大学 A kind of poly- 3,4- ethene dioxythiophenes cladding tungsten oxide nanometer stick, preparation method and applications

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016209808A1 (en) * 2015-06-22 2016-12-29 University Of Florida Research Foundation, Inc. Dye-doped hole transport layer for organic light emitting diodes
CN105609651A (en) * 2016-01-07 2016-05-25 东南大学 High-efficiency quantum dot light emitting diode with self-assembly polymer hole transmission layer structure
CN106784348A (en) * 2016-12-15 2017-05-31 Tcl集团股份有限公司 QLED containing noble metal nanometer material and preparation method thereof
CN108281553A (en) * 2018-01-10 2018-07-13 苏州大学 A kind of poly- 3,4- ethene dioxythiophenes cladding tungsten oxide nanometer stick, preparation method and applications

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
黄大庆等: "聚3,4-乙二氧噻吩包覆碳纳米管的原位化学氧化合成", 《材料工程》 *

Similar Documents

Publication Publication Date Title
CN109980097B (en) Preparation method of thin film and QLED device
CN112538163B (en) Composite material, preparation method thereof and quantum dot light emitting diode
CN109935662B (en) Electron transport material, preparation method thereof and light emitting diode
CN112349850A (en) Inorganic semiconductor material and preparation method thereof
CN113120947A (en) Composite material, preparation method thereof and quantum dot light-emitting diode
CN113121382B (en) Metal compound material and preparation method thereof, quantum dot light emitting diode and light emitting device
CN113045735A (en) Nano material and preparation method thereof, quantum dot light-emitting diode and preparation method thereof
CN112397625B (en) Composite material, preparation method thereof and quantum dot light-emitting diode
CN112625674B (en) Composite material, quantum dot light-emitting diode and preparation method thereof
CN113054062B (en) Nano material and preparation method thereof, quantum dot light-emitting diode and light-emitting device
CN112542554B (en) Composite material, preparation method thereof and quantum dot light-emitting diode
CN112397670B (en) Composite material and preparation method thereof and quantum dot light-emitting diode
CN112397655B (en) Composite material and preparation method thereof and quantum dot light-emitting diode
CN113045211B (en) Composite material, preparation method and application thereof, light-emitting diode and preparation method thereof
CN112397620B (en) Nano composite particle and preparation method and application thereof
CN113707777A (en) Composite material, preparation method thereof and light-emitting device
CN113054145B (en) Composite material, preparation method and application thereof, light-emitting diode and preparation method thereof
CN110963535A (en) Composite material, preparation method thereof and quantum dot light-emitting diode
CN113054118B (en) Composite material, preparation method and application thereof, light-emitting diode and preparation method thereof
CN112397656B (en) Composite material, preparation method thereof and quantum dot light-emitting diode
CN113044882B (en) Nano material and preparation method thereof, and quantum dot light-emitting diode
CN112397661B (en) Nano material, preparation method thereof and quantum dot light-emitting diode
CN111725433B (en) Quantum dot light-emitting diode and preparation method thereof
CN112397617B (en) Doped tungsten oxide nano material, preparation method thereof and inorganic hole transport material
CN112349870B (en) Quantum dot light-emitting diode and preparation method thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
RJ01 Rejection of invention patent application after publication

Application publication date: 20210629

RJ01 Rejection of invention patent application after publication