A nanomaterial, a light emitting diode device and a preparation method thereof

Abstract

The application discloses a kind of nanometer materials, light emitting diode device and its preparation method, wherein the nanometer material includes ZnO nanoparticles, and In2O3 shell layer is coated on the surface of the ZnO nanoparticles.The application forms ZnO@In2O3 core-shell structure by coating In2O3 shell layer on the surface of ZnO nanoparticles, that is, nanometer material is prepared.The application uses wide-band gap In2O3 as shell layer to cover relatively narrow-band gap semiconductor ZnO nanoparticles, which can effectively passivate the surface of ZnO nanoparticles, reduce its surface defects, relieve its lattice mismatch, and also effectively block the transmission of holes from the light emitting layer to the cathode, improve the recombination efficiency of electrons and holes in the light emitting layer, and thus improve the light emitting performance of the light emitting device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of quantum dots, in particular to a nanomaterial, a light emitting diode device and a preparation method thereof. BACKGROUND

[0002] ZnO is a direct band gap n-type semiconductor material, with a wide band gap of 3.37eV and a low work function of 3.7eV, and has the advantages of good stability, high transparency, safety and non-toxicity, so that ZnO can become a suitable electron transport layer material. ZnO has many potential advantages: first, its exciton binding energy is as high as 60meV, which is much higher than that of other wide band gap semiconductor materials (GaN is 25meV), which is 2.3 times the room temperature thermal energy (26meV), so the exciton of ZnO can exist stably at room temperature. Secondly, ZnO has a hexagonal wurtzite structure, which shows strong spontaneous polarization; in ZnO-based heterostructures, the strain of the material will cause strong piezoelectric polarization, which in turn causes polarization effect in the ZnO-based heterostructure; the polarization electric field generated by the polarization induces a high concentration of interface polarization charges at the ZnO heterojunction surface, thereby regulating the energy band of the material and affecting the performance of related structures and devices.

[0003] However, when ZnO nanoparticles are used as an electron transport layer, surface defects such as hydroxyl and oxygen vacancies of ZnO inevitably lead to a decrease in device performance.

[0004] Therefore, the prior art still needs to be improved and developed. SUMMARY

[0005] In view of the above shortcomings of the prior art, the purpose of the present application is to provide a nanomaterial, a light emitting diode device and a preparation method thereof, which aims to solve the problem of performance degradation of a light emitting diode device using ZnO nanoparticles as an electron transport layer due to the presence of many defects on the surface of the ZnO nanoparticles.

[0006] The technical scheme of the present application is as follows:

[0007] A nanomaterial, comprising ZnO nanoparticles, and an In2O3 shell layer coated on the surface of the ZnO nanoparticles.

[0008] A preparation method of a nanomaterial, comprising the following steps:

[0009] providing ZnO nanoparticles;

[0010] depositing an In2O3 shell layer on the surface of the ZnO nanoparticles to obtain the nanomaterial.

[0011] A preparation method of a light emitting diode, comprising the following steps:

[0012] An electron transport layer is prepared on the cathode, the electron transport layer material is a nanomaterial, the nanomaterial includes ZnO nanoparticles and an In2O3 shell layer coated on the surface of the ZnO nanoparticles;

[0013] An emitting layer is prepared on the electron transport layer;

[0014] An anode is prepared on the emitting layer, and the light emitting diode is prepared;

[0015] Alternatively, an emitting layer is prepared on the anode;

[0016] An electron transport layer is prepared on the emitting layer, the electron transport layer material is a nanomaterial, the nanomaterial includes ZnO nanoparticles and an In2O3 shell layer coated on the surface of the ZnO nanoparticles;

[0017] A cathode is prepared on the electron transport layer, and the light emitting diode is prepared

[0018] A light emitting diode device, wherein the device includes a cathode, an anode, an emitting layer arranged between the cathode and the anode, and an electron transport layer arranged between the cathode and the emitting layer, the electron transport layer material is the nanomaterial prepared by the preparation method of the application.

[0019] Beneficial effects: The application forms a ZnO@In2O3 core-shell structure by coating an In2O3 shell layer on the surface of ZnO nanoparticles, i.e. a nanomaterial is prepared. The application coats a wide-bandgap In2O3 shell layer on a semiconductor ZnO nanoparticle with a relatively narrow bandgap, which can effectively passivate the surface of the ZnO nanoparticle, reduce the surface defects of the ZnO nanoparticle, relieve the lattice mismatch, effectively block the transmission of holes from the emitting layer to the cathode, improve the recombination efficiency of electrons and holes in the emitting layer, and thus improve the light emitting performance of the light emitting device. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The first flow chart of a preferred embodiment of the preparation method of the nanomaterial of the application.

[0021] Figure 2 The second flow chart of a preferred embodiment of the preparation method of the nanomaterial of the application.

[0022] Figure 3 The structure schematic diagram of a preferred embodiment of the QLED device of the application. DETAILED DESCRIPTION

[0023] The application provides a nanomaterial, a light emitting diode device and a preparation method thereof. In order to make the purpose, technical scheme and effect of the application more clear and explicit, the application is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the application and not to limit the application.

[0024] ZnO is a direct band gap n-type semiconductor material, which has a wide band gap of 3.37 eV and a low work function of 3.7 eV, and has the advantages of good stability, high transparency, safety and non-toxicity, so that ZnO can become a suitable electron transport layer material. However, when ZnO nanoparticles are used as an electron transport layer, surface defects such as hydroxyl and oxygen vacancies of ZnO inevitably lead to a decrease in device performance.

[0025] Based on this, the embodiment of the application provides a nanomaterial, which comprises ZnO nanoparticles and an In2O3 shell layer coated on the surface of the ZnO nanoparticles.

[0026] Similar to ZnO, In2O3 is a semiconductor with a wider band gap than ZnO (3.55-3.75 eV). In this embodiment, ZnO nanoparticles are used as a core, and In2O3 is used as a shell layer coated on the surface of the ZnO nanoparticles. The In2O3 shell layer can effectively passivate the surface of the ZnO nanoparticles, reduce the surface defects, relieve the lattice mismatch, and effectively block the transmission of holes from the light emitting layer to the cathode, thereby improving the recombination efficiency of electrons and holes in the light emitting layer and the light emitting performance of the light emitting device.

[0027] In some embodiments, the nanomaterial further comprises Au atoms or Au microclusters loaded on the In2O3 shell layer. In this embodiment, due to the difference in electronegativity between the In2O3 shell layer and the Au atoms or Au microclusters, the In2O3 shell layer can be adsorbed together with the Au atoms or Au microclusters through electrostatic interaction. In this embodiment, the Au microcluster refers to an aggregate formed by several Au atoms or Au molecules, which has properties close to a single Au atom. The atomic level dispersion greatly improves the utilization rate of Au atoms and reduces the use of noble metals. The Au atoms or Au microclusters form a contact interface on the In2O3 material, and after activation, Au δ+ -In2O 3-x interface, Au δ+ atoms (or partially delocalized Au ions) with positive charges are activated on the interface. The Au atoms have a large specific surface area, which interacts with adjacent coordinated In atoms, causing the charge around the In atoms to redistribute, thereby causing charge redistribution and building a new electron transport path to improve the electron transport performance.

[0028] In some embodiments, a preparation method of the nanomaterial is also provided, for example,Figure 1 as shown, comprising steps of:

[0029] S10, providing ZnO nanoparticles;

[0030] S20, depositing an In2O3 shell layer on the surface of the ZnO nanoparticles to obtain the nanomaterial.

[0031] In the embodiment, the ZnO nanoparticles can be prepared by a solution method, which is relatively simple, has strong versatility and is suitable for large-scale preparation. The In2O3 shell layer on the surface of the ZnO nanoparticles can be prepared by a chemical co-precipitation method, which has simple preparation process, low cost and controllable conditions. In the embodiment, the In2O3 shell layer on the surface of the ZnO nanoparticles can effectively passivate the surface of the ZnO nanoparticles, reduce the surface defects of the ZnO nanoparticles, relieve the lattice mismatch, effectively block the transmission of holes from the light-emitting layer to the cathode, improve the recombination efficiency of electrons and holes in the light-emitting layer, and thus improve the light-emitting performance of the light-emitting device.

[0032] In some specific embodiments, the preparation of the ZnO nanoparticles comprises the steps of: dissolving a zinc salt in an organic solvent to obtain a zinc salt solution; adding a lye to the zinc salt solution and stirring to obtain a ZnO nanoparticle solution; and performing precipitation and drying treatment on the ZnO nanoparticle solution to obtain ZnO nanoparticles.

[0033] In the embodiment, the preparation method of the ZnO nanoparticles is a solution method, which is relatively simple, has strong versatility and is suitable for large-scale preparation. The zinc salt can be one or more of zinc chloride, zinc nitrate and zinc acetate, but is not limited thereto. The organic solvent can be one or both of DMSO and DMF, but is not limited thereto. The lye can be one or more of sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide and ammonia water, but is not limited thereto.

[0034] In the embodiment, the concentration of the zinc salt solution is 0.1-1M, the concentration of the lye is 0.1-1M, and the molar ratio of hydroxide ions to zinc ions in the lye is (1.5-3.0):1. When the molar ratio of hydroxide ions to zinc ions is less than 1.5:1, the metal salt is excessive; when the molar ratio of hydroxide ions to zinc ions is greater than 3:1, the high pH value will slow down the reaction speed of the system. Optimally, when the molar ratio of hydroxide ions to zinc ions is (1.5-3.0):1, the pH value can be 12-14, which can ultimately make the surface of the film obtained subsequently have uniform particle distribution.

[0035] In some embodiments, the step of depositing an In2O3 shell on the surface of the ZnO nanoparticles comprises: dissolving an indium salt in an organic solvent to obtain an indium salt solution; dissolving the ZnO nanoparticles in an organic alcohol to obtain a ZnO nanoparticle alcohol solution; adding the ZnO nanoparticle alcohol solution to the indium salt solution, then adding a lye and stirring to obtain an In2O3 shell coated ZnO nanoparticle solution; and performing precipitation and drying treatment on the In2O3 shell coated ZnO nanoparticle solution to obtain the In2O3 shell coated ZnO nanoparticles.

[0036] In this embodiment, the chemical co-precipitation method is used to deposit the In2O3 shell on the surface of the ZnO nanoparticles, and the preparation process is simple, the cost is low, and the conditions are controllable. Specifically, the indium salt is one or more of indium nitrate, indium chloride and indium acetate, but is not limited thereto; the organic solvent is one or more of methanol, ethanol and isopropyl alcohol, but is not limited thereto; the organic alcohol includes but is not limited to at least one of methanol, ethanol and ethylene glycol; and the lye is one or more of sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide and ammonia water, but is not limited thereto. In this embodiment, the concentration of the indium salt solution is 0.1-0.3M.

[0037] During the reaction, the pH value of the solution greatly affects the purity and yield of the product. For example, the pH value of the reaction condition is maintained at 8-10.

[0038] In some embodiments, a method for preparing a nanomaterial is also provided, as shown in Figure 2 The method comprises the steps of:

[0039] S10, providing ZnO nanoparticles;

[0040] S20, depositing an In2O3 shell on the surface of the ZnO nanoparticles;

[0041] S30, loading Au atoms and / or Au microclusters on the In2O3 shell to obtain the nanomaterial.

[0042] Specifically, the In2O3 shell coated ZnO nanoparticles are dissolved in an organic alcohol to obtain an In2O3 coated ZnO nanoparticle alcohol solution; gold salt and the In2O3 shell coated ZnO nanoparticle alcohol solution are added to a mixed solution composed of oleylamine and octadecene, and stirring is performed at 80-150°C to load Au atoms and / or Au microclusters on the In2O3 shell to obtain the nanomaterial.

[0043] In this embodiment, the octadecene as a reducing agent can reduce the gold salt into Au atoms and load on the In2O3 shell, and the oleylamine as a dispersing agent can inhibit the excessive agglomeration of the Au atoms. By introducing the Au atoms and / or Au microclusters on the In2O3 shell, the Au microclusters refer to aggregates formed by several Au atoms or Au molecules, the property of which is close to a single Au atom, the atomic level dispersion greatly improves the utilization rate of the Au atoms, and the use of the noble metal is reduced; the Au atoms or Au microclusters form a contact interface on the In2O3 material, and the activated Au atoms (or partially delocalized Au ions) with positive charges on the interface have a large specific surface area, interact with adjacent coordinated In atoms, cause the charge redistribution around the In atoms, cause the charge redistribution, build a new electron transport path, and improve the electron transport performance. δ+ -In2O 3-x interface, the Au δ+ atoms with positive charges on the interface have a large specific surface area, interact with adjacent coordinated In atoms, cause the charge redistribution around the In atoms, cause the charge redistribution, build a new electron transport path, and improve the electron transport performance.

[0044] In some embodiments, the gold salt is one or more of chloroauric acid, ammonium tetrachloroaurate hydrate, and (triphenylphosphine) gold chloride, but is not limited thereto; and the organic alcohol includes but is not limited to at least one of methanol, ethanol, and ethylene glycol.

[0045] The preparation method of the nanomaterial provided in the embodiment of the application is relatively simple, has strong universality, reduces the use of noble metals, and is suitable for large-scale preparation.

[0046] In some embodiments, a light-emitting diode device is also provided, which comprises an electron transport layer, and the material of the electron transport layer is the nanomaterial provided in the application or the nanomaterial prepared by the preparation method provided in the application. As an example, the light-emitting diode device is a QLED device or an OLED device.

[0047] The nanomaterial, the preparation method thereof, and the light-emitting diode are further explained and described below through specific embodiments:

[0048] Embodiment 1

[0049] The following is a detailed introduction taking zinc chloride, sodium hydroxide, indium nitrate, and chloroauric acid as examples.

[0050] (1) Zinc chloride was added to DMF to form a solution with a total concentration of 0.5 M, and 0.6 M NaOH ethanol solution was added dropwise at room temperature, and stirring was continued for 1.5 h to obtain a clear transparent solution. ZnO nanoparticles were prepared by acetone precipitation and centrifugation.

[0051] (2) The above ZnO nanoparticles were dissolved and dispersed in an appropriate amount of ethanol to obtain a ZnO nanoparticle ethanol solution.

[0052] (3) Indium nitrate was added to ethanol to form a solution with a concentration of 0.2 M, 30 mL of the above ZnO nanoparticle ethanol solution was added, and an appropriate amount of NaOH was added to adjust the pH to 10. The solution was stirred at room temperature for 2 h to obtain an In2O3 shell-coated ZnO nanoparticle solution. After precipitation, In2O3 shell-coated ZnO nanoparticles were obtained.

[0053] (4) The In2O3 shell-coated ZnO nanoparticles were dispersed in an appropriate amount of ethanol to obtain an In2O3 shell-coated ZnO nanoparticle ethanol solution.

[0054] (5) 20 mg of chloroauric acid and 30 mL of the above In2O3 shell-coated ZnO nanoparticle ethanol solution were added to a 20 mL mixture of oleylamine and octadecene, and ultrasonic dispersion was performed. The mixture was stirred at 120°C for 1 h to obtain a mixed solution, which was then cooled to room temperature. The solid was collected by centrifugation to obtain a nanomaterial, which was washed with hexane and dispersed in an appropriate amount of ethanol for device preparation.

[0055] Example 2

[0056] The following examples are described in detail using zinc nitrate hexahydrate, potassium hydroxide, indium nitrate, and chloroauric acid as examples.

[0057] (1) Zinc nitrate was added to DMF to form a solution with a total concentration of 0.5 M, and 0.6 M KOH ethanol solution was added dropwise at room temperature, and stirring was continued for 1.5 h to obtain a clear transparent solution. ZnO nanoparticles were prepared by acetone precipitation and centrifugation.

[0058] (2) The above ZnO nanoparticles were dissolved and dispersed in an appropriate amount of ethanol to obtain a ZnO nanoparticle ethanol solution.

[0059] (3) Indium nitrate was added to ethanol to form a solution with a concentration of 0.2 M, 30 mL of the above ZnO nanoparticle ethanol solution was added, and an appropriate amount of NaOH was added to adjust the pH to 10. The solution was stirred at room temperature for 2 h to obtain an In2O3 shell-coated ZnO nanoparticle solution. After precipitation, In2O3 shell-coated ZnO nanoparticles were obtained.

[0060] (4) Disperse the In2O3 shell coated ZnO nanoparticles in proper amount of ethanol to obtain In2O3 shell coated ZnO nanoparticles ethanol solution.

[0061] (5) Add 20 mg of chloroauric acid and 30 mL of the above In2O3 shell coated ZnO nanoparticles ethanol solution into 20 mL of mixed solution of oleylamine and octadecene, ultrasonic dispersion, stirring at 120℃ for 1 h to obtain a mixed solution, and then cooling to room temperature. Centrifugal collection of the solid to obtain the nanomaterial, and then washing with hexane and dispersing in proper amount of ethanol for device preparation.

[0062] Example 3

[0063] The following is a detailed description of zinc acetate dihydrate, tetramethylammonium hydroxide, indium nitrate, and chloroauric acid as examples.

[0064] (1) Add zinc acetate into DMF to form a solution with a total concentration of 0.5 M, drop 0.6 M tetramethylammonium hydroxide ethanol solution at room temperature, continue stirring for 1.5 h to obtain a clear transparent solution. Precipitate ZnO nanoparticles with acetone, and collect after centrifugation to obtain ZnO nanoparticles.

[0065] (2) Dissolve and disperse the above ZnO nanoparticles in proper amount of ethanol to obtain ZnO nanoparticles ethanol solution.

[0066] (3) Add indium nitrate into ethanol to form a solution with a concentration of 0.2 M, add 30 mL of the above ZnO nanoparticles ethanol solution, and then add proper amount of NaOH to adjust the pH to 10. Stir at room temperature for 2 h to obtain In2O3 shell coated ZnO nanoparticles solution. Precipitate to obtain In2O3 shell coated ZnO nanoparticles.

[0067] (4) Disperse the In2O3 shell coated ZnO nanoparticles in proper amount of ethanol to obtain In2O3 shell coated ZnO nanoparticles ethanol solution.

[0068] (5) Add 20 mg of chloroauric acid and 30 mL of the above In2O3 shell coated ZnO nanoparticles ethanol solution into 20 mL of mixed solution of oleylamine and octadecene, ultrasonic dispersion, stirring at 120℃ for 1 h to obtain a mixed solution, and then cooling to room temperature. Centrifugal collection of the solid to obtain the nanomaterial, and then washing with hexane and dispersing in proper amount of ethanol for device preparation.

[0069] The embodiment of the present application also provides a light emitting diode device, which comprises an electron transport layer, and the electron transport layer material is the nanomaterial or the nanomaterial prepared by the above preparation method. The light emitting diode device is a QLED device or an OLED device.

[0070] In some embodiments, the light emitting diode device is a QLED device, such as Figure 3 As shown, the QLED device comprises, in sequence, a substrate 10, an anode 20, a hole transport layer 30, a quantum dot light emitting layer 40, an electron transport layer 50, and a cathode 60, wherein the material of the electron transport layer 50 is the nanomaterial provided by the present application.

[0071] In some specific embodiments, the method for preparing a QLED device comprises the following steps:

[0072] A. providing a substrate, wherein the substrate is provided with an anode;

[0073] B. growing a hole transport layer on the substrate;

[0074] C. depositing a light emitting functional layer on the hole transport layer;

[0075] D. depositing an electron transport layer on the light emitting functional layer, wherein the material of the electron transport layer is the nanomaterial;

[0076] E. evaporating a cathode on the electron transport layer.

[0077] In some specific embodiments, in order to obtain a high quality nanomaterial layer, the ITO substrate needs to be pretreated. The specific treatment steps include: cleaning the ITO conductive glass with a cleaning agent to preliminarily remove the stains present on the surface, and then sequentially ultrasonic cleaning in deionized water, isopropanol, acetone, and deionized water for 20 min respectively to remove the impurities present on the surface, and finally blowing dry with high-purity nitrogen, thereby obtaining an ITO anode.

[0078] In some specific embodiments, the preparation step of the hole transport layer comprises: placing the ITO substrate on a spin coater, and spin coating a film with a prepared hole transport material solution; controlling the thickness of the film by adjusting the concentration of the solution, the spin coating speed, and the spin coating time, and then performing thermal annealing treatment at an appropriate temperature.

[0079] Specifically, the hole transport layer of the present application can be made of conventional hole transport materials in the art, including but not limited to TFB, PVK, Poly-TPD, TCTA, PEDOT:PSS, CBP, or any combination thereof, or other high-performance hole transport materials.

[0080] Preferably, the concentration of the hole transport material solution is 10 mg / mL, the spin coating speed is 4.5 k rpm / min, and the spin coating time is 30 s.

[0081] In some specific embodiments, the preparation of the quantum dot light-emitting layer comprises: placing the substrate on which the hole transport layer has been spin-coated on a spin coater, spin-coating a prepared solution of the light-emitting substance to form a film, controlling the thickness of the light-emitting layer by adjusting the concentration of the solution, the spin-coating speed and the spin-coating time, and drying at a proper temperature.

[0082] Specifically, the quantum dots of the quantum dot light-emitting layer are any of red, green and blue quantum dots, and the quantum dots include, but are not limited to, at least one of CdS, CdSe, CdTe, ZnO, ZnS, ZnSe, ZnTe, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InSb, AlAs, AlP, CuInS, CuInSe and various core-shell structure quantum dots.

[0083] Preferably, the thickness of the quantum dot light-emitting layer is 20-60 nm.

[0084] Preferably, the concentration of the solution of the light-emitting substance is 20 mg / mL, the spin-coating speed is 4 k rpm / min, and the spin-coating time is 30 s.

[0085] In some specific embodiments, the preparation of the electron transport layer comprises: placing the substrate on which the quantum dot light-emitting layer has been spin-coated on a spin coater, spin-coating a prepared solution of the nanomaterial to form a film, controlling the thickness of the electron transport layer by adjusting the concentration of the solution, the spin-coating speed and the spin-coating time, and annealing to form a film.

[0086] Preferably, the thickness of the electron transport layer is 20-60 nm.

[0087] Preferably, the concentration of the solution of the electron transport layer material is 30 mg / mL, the spin-coating speed is 4 k rpm / min, and the spin-coating time is 30 s.

[0088] In some specific embodiments, the preparation of the cathode comprises: placing the substrate on which the functional layers have been deposited in an evaporation chamber, and evaporating a layer of 30-80 nm of silver or aluminum as the cathode through a mask.

[0089] In some specific embodiments, the obtained QLED device is subjected to packaging treatment, which can be machine packaging or manual packaging.

[0090] Preferably, the oxygen content and the water content in the environment of the packaging treatment are both lower than 0.1 ppm, so as to ensure the stability of the device.

[0091] The QLED device of the present application is further explained and described below through specific examples:

[0092] Example 4

[0093] The material of the substrate 10 is a glass sheet, the material of the anode 20 is an ITO substrate, the material of the hole transport layer 30 is TFB, the material of the electron transport layer 50 is the nanomaterial prepared in Example 1, and the material of the cathode 60 is Al.

[0094] Example 5

[0095] The material of the substrate 10 is a glass sheet, the material of the anode 20 is an ITO substrate, the material of the hole transport layer 30 is TFB, the material of the electron transport layer 50 is the nanomaterial prepared in Example 2, and the material of the cathode 60 is Al.

[0096] Example 6

[0097] The material of the substrate 10 is a glass sheet, the material of the anode 20 is an ITO substrate, the material of the hole transport layer 30 is TFB, the material of the electron transport layer 50 is the nanomaterial prepared in Example 3, and the material of the cathode 60 is Al.

[0098] Comparative Example

[0099] The material of the substrate 10 is a glass sheet, the material of the anode 20 is an ITO substrate, the material of the hole transport layer 30 is TFB, the material of the electron transport layer 50 is ZnO nanoparticles, and the material of the cathode 60 is Al.

[0100] The QLEDs prepared in Example 4, Example 5, Example 6 and the Comparative Example are tested for performance, and the luminous efficiency and stability of both are measured as follows:

[0101] Turn-on voltage (V) Emission efficiency (EQE) (%) Comparative Example 5.33 2.49 Example 4 2.54 6.33 Example 5 3.07 5.60 Example 6 3.24 5.31

[0102] Compared with the Comparative Example, the luminous efficiency of Example 4, 5 and 6 is obviously improved, and the stability of the diode is also improved to some extent.

[0103] In summary, the nanomaterial provided in the application covers the surface of ZnO with an In2O3 layer, uses In2O3 as a shell layer to coat the semiconductor ZnO nanoparticles with a relatively narrow band gap, effectively blocks the transmission of holes from the light-emitting layer to the electron transport layer, passivates the surface defects of ZnO, reduces the capture of defects on electrons, and improves the electron-hole recombination efficiency; at the same time, the conductive component Au atoms or Au microclusters are introduced and loaded onto the surface of the In2O3 shell layer to form isolated Au atoms and Au microclusters, the atomically dispersed Au atoms have a large specific surface area, interact with the adjacent In atoms, cause the charge around the In atoms to redistribute, and can build a new electron transport channel to accelerate electron transmission and improve the electron transport performance of the device, thereby synergistically improving the electron transport performance and stability of the device.

[0104] It is to be understood that the application is not limited to the examples described above, which can be modified or adapted in several ways by those skilled in the art without departing from the scope of the present application, as defined by the appended claims.

Claims

1. A method for preparing nanomaterials, characterized in that, Including the following steps: Provides ZnO nanoparticles; The nanomaterial is prepared by depositing an In2O3 shell on the surface of the ZnO nanoparticles and loading Au atoms and / or Au microclusters onto the In2O3 shell.

2. The method for preparing nanomaterials according to claim 1, characterized in that, The preparation of the ZnO nanoparticles includes the following steps: Zinc salts are dissolved in an organic solvent to obtain a zinc salt solution; An alkaline solution was added to the zinc salt solution to prepare a ZnO nanoparticle solution; The ZnO nanoparticle solution was subjected to precipitation and drying treatment to obtain ZnO nanoparticles.

3. The method for preparing nanomaterials according to claim 2, characterized in that, The step of depositing an In2O3 shell on the surface of the ZnO nanoparticles includes: Indium salt is dissolved in an organic solvent to obtain an indium salt solution; The ZnO nanoparticles were dissolved in an organic alcohol to obtain an alcohol solution of ZnO nanoparticles. The ZnO nanoparticle alcohol solution was added to the indium salt solution, and then an alkaline solution was added and mixed to react and obtain a ZnO nanoparticle solution coated with an In2O3 shell. The solution of ZnO nanoparticles coated with the In2O3 shell was subjected to precipitation and drying treatment to obtain ZnO nanoparticles coated with the In2O3 shell.

4. The method for preparing nanomaterials according to claim 3, characterized in that, The steps for preparing nanomaterials by loading Au atoms and / or Au microclusters onto the In₂O₃ shell include: The ZnO nanoparticles coated with the In2O3 shell were dissolved in an organic alcohol to obtain an alcohol solution of ZnO nanoparticles coated with In2O3. Gold salt and ZnO nanoparticles coated with the In2O3 shell were added to a mixed solution of oleylamine and octadecene and mixed at 80-50°C. Au atoms and / or Au microclusters were loaded on the In2O3 shell to prepare nanomaterials.

5. The method for preparing nanomaterials according to claim 4, characterized in that, The gold salt is one or more of chloroauric acid, ammonium tetrachloroaurate hydrate, and (triphenylphosphine) gold chloride; and / or, the indium salt is one or more of indium nitrate, indium chloride, and indium acetate; and / or, the zinc salt is one or more of zinc chloride, zinc nitrate, and zinc acetate; and / or, the organic solvent is one or two of DMF and DMSO; and / or, the alkaline solution is one or more of sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, and ammonia.

6. A method for fabricating a light-emitting diode, characterized in that, Including the following steps: An electron transport layer is prepared on a cathode. The electron transport layer material is a nanomaterial, which includes ZnO nanoparticles and an In2O3 shell coating the surface of the ZnO nanoparticles. Au atoms and / or Au microclusters are loaded on the In2O3 shell. A light-emitting layer is fabricated on the electron transport layer; An anode is fabricated on the light-emitting layer to obtain the light-emitting diode; Alternatively, a light-emitting layer can be prepared on the anode; An electron transport layer is prepared on the light-emitting layer. The electron transport layer material is a nanomaterial, which includes ZnO nanoparticles and an In2O3 shell coating the surface of the ZnO nanoparticles. Au atoms and / or Au microclusters are loaded on the In2O3 shell. A cathode is fabricated on the electron transport layer to obtain the light-emitting diode.

7. A nanomaterial, characterized in that, It includes ZnO nanoparticles and an In2O3 shell coating the surface of the ZnO nanoparticles, wherein Au atoms and / or Au microclusters are loaded on the In2O3 shell.

8. A light-emitting diode device, characterized in that, It includes a cathode, an anode, a light-emitting layer disposed between the cathode and the anode, and an electron transport layer disposed between the cathode and the light-emitting layer, wherein the electron transport layer material is a nanomaterial prepared by any of the preparation methods of claims 1-5 or a nanomaterial as described in claim 7.

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