Composite material, thin film, preparation method of thin film, photoelectric device and display device

Abstract

The invention discloses a composite material, a thin film, a preparation method of the thin film, a photoelectric device and a display device.The composite material comprises nickel oxide particles, and the nickel oxide particles are doped with a copper element and a nitrogen element. The composite material disclosed by the invention has relatively high hole mobility.

Description

Technical Field

[0001] This application relates to the field of optoelectronic device technology, and in particular to a composite material, a thin film and its preparation method, an optoelectronic device and a display device. Background Technology

[0002] Nickel oxide nanoparticles, as a p-type semiconductor material, have high light transmittance in the ultraviolet, visible, and near-infrared regions. Their excellent chemical stability and unique optical, electrical, and magnetic properties make them widely used in electrochromic devices, light-emitting diodes, sensors, solar cells, and pn heterojunctions.

[0003] However, the hole mobility of existing nickel oxide nanoparticles is low and needs to be further improved. Summary of the Invention

[0004] In view of this, this application provides a composite material, a thin film, a method for preparing the same, an optoelectronic device, and a display device.

[0005] In a first aspect, this application provides a composite material comprising nickel oxide particles, wherein the nickel oxide particles are doped with copper and nitrogen.

[0006] Secondly, this application also provides a thin film, the thin film comprising a first film layer, wherein the first film layer comprises the composite material.

[0007] Thirdly, this application also provides a method for preparing a thin film, comprising the following steps:

[0008] A nickel oxide particle dispersion is deposited, the nickel oxide particle dispersion comprising nickel oxide particles and a solvent, to obtain a nickel oxide film; and

[0009] The nickel oxide film is placed in a nitrogen environment, and copper is used as the target material for the first magnetron sputtering to form the first film layer, thus obtaining a thin film.

[0010] Fourthly, an optoelectronic device includes an anode, a hole transport layer, and a cathode stacked sequentially, wherein the hole transport layer includes the composite material, or the hole transport layer is a first film layer in the thin film, or the hole transport layer is a first film layer prepared by the preparation method described above.

[0011] Fifthly, this application also provides a display device including the aforementioned optoelectronic device.

[0012] The composite material described in this application includes nickel oxide particles, and the nickel oxide particles are doped with copper and nitrogen elements, thus exhibiting a high hole mobility. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the structure of a thin film provided in an embodiment of this application;

[0015] Figure 2 This is a schematic diagram of another thin film structure provided in an embodiment of this application;

[0016] Figure 3 This is a flowchart of a thin film preparation method provided in an embodiment of this application;

[0017] Figure 4 This is a schematic diagram of the structure of an optoelectronic device provided in an embodiment of this application;

[0018] Figure 5 This is a schematic diagram of another optoelectronic device provided in an embodiment of this application;

[0019] Figure 6 This is a schematic diagram of the structure of another optoelectronic device provided in the embodiments of this application;

[0020] Figure 7 This is a flowchart of a method for fabricating an optoelectronic device provided in an embodiment of this application.

[0021] Figure Labels

[0022] Thin film 1; first film layer 11; second film layer 12; optoelectronic device 100; anode 10; hole transport layer 20; cathode 30; light-emitting layer 40; electron transport layer 50; hole injection layer 60; copper nitride layer 70. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application.

[0024] In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operating state, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc., are used merely as illustrative purposes and do not impose numerical requirements or establish a numerical order.

[0025] In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0026] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c," or "at least one of a, b, and c," can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0027] In this application, the term "on" forming another layer on a certain layer is a broad concept. It can mean that the formed other layer is adjacent to a certain layer, or it can mean that there are other spacer structures between the other layer and the certain layer. For example, when a second electrode is formed "on" a first charge carrier functional layer, the term "on" can mean that the formed second electrode is adjacent to the first charge carrier functional layer, or it can mean that there are other spacer structures between the second electrode and the first charge carrier functional layer, such as a light-emitting layer.

[0028] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0029] Currently, the lifespan and performance of red and green quantum dots have reached commercial standards, but the lifespan and performance of blue quantum dots are far from commercial application, which significantly limits the development of quantum dot optoelectronic devices. Experiments have shown that the Fermi level of red and green quantum dots is lower than that of the hole transport layer material, while the Fermi level of blue quantum dots is higher. This results in a larger contact potential difference (CPD) at the interface between the blue quantum dot layer and the hole transport layer during device fabrication, greatly increasing the difficulty of hole carrier transport. Conversely, the contact potential difference (CPD) between the quantum dot layer and the hole transport layer in red and green quantum dot devices is smaller, which reduces the difficulty of hole carrier transport to some extent. This is the main reason why the lifespan and performance of red and green quantum dots are far superior to those of blue quantum dots.

[0030] Nickel oxide (NiO), as a p-type semiconductor material, possesses a well-matched bandgap (3.8 eV, HOMO level -5.4 eV, LUMO level -1.6 eV), exhibiting high light transmittance in the ultraviolet, visible, and near-infrared regions. Its excellent chemical stability and unique optical, electrical, and magnetic properties make it widely used in electrochromic devices, light-emitting diodes (LEDs), sensors, solar cells, and pn heterojunctions. This invention primarily focuses on improving the hole functional layer, which incorporates nickel oxide material, to reduce the hole transport barrier in optoelectronic devices. This is of great significance for enhancing QLED performance.

[0031] The technical solution of this application is as follows:

[0032] In a first aspect, embodiments of this application provide a composite material comprising nickel oxide particles (NiO particles) doped with copper and nitrogen elements.

[0033] In some embodiments, the copper element is doped on the surface and / or inside the nickel oxide particles.

[0034] In some embodiments, the nitrogen element is doped on the surface and / or inside the nickel oxide particles.

[0035] It should be noted that oxygen vacancies are unavoidable during the synthesis of nickel oxide particles. The presence of oxygen vacancies has a significant impact on the electrical conductivity of nickel oxide particles. Within a certain range, an increase in oxygen vacancies leads to an increase in the conductivity of the nickel oxide material, while a decrease in oxygen vacancies leads to a decrease in conductivity. In metal oxides, oxygen vacancies are a common point defect. The electronegativity of other elements is generally lower than that of oxygen. When oxygen is lost from the crystal lattice, it is equivalent to losing one oxygen atom plus two positively charged electron-hole pairs. If these two electron-hole pairs are bound to the oxygen vacancy, the oxygen vacancy will generally be positively charged. Therefore, positively charged centers will form in regions rich in oxygen vacancies. These centers easily capture electrons, repel positively charged metal ions, and attract anions, resulting in a mismatch between positive and negative charge centers in the thin film and the generation of an electric dipole moment. When used in the hole transport layer of optoelectronic devices, it is similar to forming a high concentration of positron centers in nickel oxide particles and a low concentration in the light-emitting layer. This promotes the transport of holes to the light-emitting layer, thereby reducing the injection barrier between the nickel oxide particles and the light-emitting layer, increasing the Fermi level of the nickel oxide particles, and reducing the contact potential difference (CPD) between the nickel oxide particles and the light-emitting layer. This makes the energy levels of the light-emitting layer material and the hole terminals more matched, thereby improving the balance of charge carriers in the optoelectronic device and thus improving the efficiency, lifetime, and performance of the optoelectronic device.

[0036] In the composite material described in this application, the nickel oxide particles are doped with nitrogen. Nitrogen atoms replace some oxygen atoms, increasing the number of oxygen vacancies on the surface of the nickel oxide particles. The presence of these oxygen vacancies disrupts the surrounding electrons to some extent, causing lattice distortion in the crystal structure, thus effectively regulating the electronic structure, chemical properties, and conductivity of the nickel oxide particles. Since oxygen atoms have six valence electrons, when they are replaced by nitrogen atoms with only five valence electrons, it's equivalent to losing a valence electron at the nitrogen atom doping site, creating an extra hole. Therefore, when a certain amount of nitrogen atoms are incorporated, a certain number of holes are generated. Thus, when the composite material is used to prepare a hole-functional layer in contact with the quantum dot light-emitting layer, it can enhance the carrier transport capability at the hole end to some extent, effectively reducing the injection barrier between the nickel oxide particles and the quantum dots. This results in a more balanced electron-hole transport efficiency in the optoelectronic device, thereby improving the luminous efficiency and lifetime of the optoelectronic device. Furthermore, nitrogen doping can increase oxygen vacancies on the surface of nickel oxide particles. These oxygen vacancies can serve as charge trapping centers and adsorption sites for light generation, preventing the recombination of electrons and holes. This reduces the probability of non-radiative Auger recombination of charge carriers, thereby further improving the luminous efficiency and lifetime of optoelectronic devices including the thin film.

[0037] In the composite material described in this application, the nickel oxide particles are doped with copper. The atomic size of copper is comparable to that of nickel in the nickel oxide particles, and a small amount of copper incorporated into the nickel oxide lattice will not cause lattice distortion or even collapse. Furthermore, copper, as a transition metal, can fully utilize its excellent conductivity when incorporated into the nickel oxide particles. Copper has better conductivity than nickel, and appropriate doping can improve the conductivity of the composite material and increase the carrier mobility of the hole functional layer. In addition, copper has good corrosion resistance, effectively preventing other layers, such as the hole injection layer PEDOT:PSS, from eroding the nickel oxide film. Moreover, copper has better thermal conductivity than nickel; doping nickel oxide with copper can effectively and evenly distribute the heat generated during device operation, preventing localized overheating that could lead to device malfunction.

[0038] In some embodiments, the mass ratio of copper to nickel oxide particles in the composite material ranges from (0.01 to 0.06):1, for example, 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1, 0.06:1, and any range between these two values. Within this ratio range, the composite material can possess higher electrical conductivity, carrier mobility, and corrosion resistance.

[0039] In some embodiments, the mass ratio of nitrogen to nickel oxide particles in the composite material ranges from (0.01 to 0.05):1, for example, 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1, and any range between these two values. Within this ratio range, the composite material can possess higher electrical conductivity and carrier mobility.

[0040] In some embodiments, the average particle size of the nickel oxide particles ranges from 10 to 30 nm, for example, 10 nm, 12 nm, 15 nm, 16 nm, 18 nm, 20 nm, 22 nm, 25 nm, 26 nm, 28 nm, 30 nm, and any range between any two of the stated values.

[0041] In some embodiments, the composite material further includes copper nitride (Cu3N), which is a P-type semiconductor material (hole transport material), which is beneficial for improving the hole transport performance of the composite material.

[0042] In some embodiments, the mass ratio of the nickel oxide particles to the copper nitride in the composite material is in the range of (5 to 20):1, for example, 5:1, 6:1, 8:1, 10:1, 12:1, 13:1, 15:1, 16:1, 18:1, 20:1, and any range between any two of the above values.

[0043] Secondly, please refer to Figure 1 This application also provides a thin film 1, which includes a first film layer 11, and the first film layer 11 includes the composite material.

[0044] In some embodiments, the thin film 1 includes only the first film layer 11; in other words, the thin film 1 is a single-layer thin film.

[0045] Please see Figure 2 In some other embodiments, the thin film 1 further includes a second film layer 12 disposed on at least one surface of the first film layer 11; in other words, the thin film 1 is a composite film.

[0046] In some embodiments, the second film layer 12 is a copper nitride layer.

[0047] In some embodiments, the thickness of the first film layer 11 is 20 to 60 nm, for example, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, and any range between any two of the stated values.

[0048] In some embodiments, the thickness of the second film layer 12 is 3 to 8 nm, for example, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, and any range between any two of the stated values.

[0049] Thirdly, please refer to Figure 3 This application provides a method for preparing a thin film, comprising the following steps:

[0050] Step S11: Deposit the nickel oxide particle dispersion to obtain a nickel oxide film;

[0051] Step S12: Place the nickel oxide film in a nitrogen environment and perform a first magnetron sputtering with copper as the target to form a first film layer 11, thereby obtaining the thin film 1.

[0052] The thin film prepared by the aforementioned method includes the composite material described above.

[0053] The method for preparing the thin film involves sputtering Cu in a nitrogen atmosphere. This creates an oxygen-deficient environment within the cavity, facilitating the formation of oxygen vacancies on the surface of the nickel oxide particles. Furthermore, during sputtering, nitrogen atoms can replace some oxygen atoms, generating a large number of oxygen vacancies. These vacancies disrupt surrounding electrons, causing lattice distortion in the crystal structure, thus effectively regulating the material's electronic structure, chemical properties, and conductivity. Since oxygen atoms have six valence electrons, when replaced by nitrogen (which has only five valence electrons), the nitrogen atom doping site lacks a valence electron for coordination, creating an extra hole. Therefore, the incorporation of a certain amount of nitrogen atoms generates a certain number of holes. When this thin film is used as a hole-functional layer in contact with the quantum dot luminescent layer, it can enhance the carrier transport capability at the hole end, effectively reducing the injection barrier between the nickel oxide particles and the quantum dots. This results in a more balanced electron-hole transport efficiency in the optoelectronic device, thereby improving its luminous efficiency and lifetime. Furthermore, nitrogen doping can increase oxygen vacancies on the surface of nickel oxide particles. These oxygen vacancies can serve as charge trapping centers and adsorption sites for light generation, preventing the recombination of electrons and holes. This reduces the probability of non-radiative Auger recombination of charge carriers, thereby further improving the luminous efficiency and lifetime of optoelectronic devices including the thin film.

[0054] Furthermore, the preparation method uses copper as the target material for magnetron sputtering, which can dope copper into nickel oxide particles. Since the atomic size of copper is comparable to that of nickel in nickel oxide particles, a small amount of copper doping into the nickel oxide lattice will not cause lattice distortion or even collapse. Furthermore, as a transition metal element, copper doping into nickel oxide particles can fully utilize its excellent conductivity. Copper has better conductivity than nickel, and appropriate doping can improve the conductivity of the composite material and increase the carrier mobility of the hole functional layer, including the composite material. In addition, copper has good corrosion resistance, which can effectively prevent other layers, such as the hole injection layer PEDOT:PSS, from eroding the nickel oxide film. Moreover, copper has better thermal conductivity than nickel; doping nickel oxide with copper can effectively and evenly distribute the heat generated during device operation, preventing localized overheating that could lead to device malfunction.

[0055] In step S11:

[0056] The nickel oxide particle dispersion includes nickel oxide particles and a solvent.

[0057] The nickel oxide particles are as described above and will not be repeated here.

[0058] The solvents include, but are not limited to, one or more of the following: propylene glycol methyl ether acetate, hexane, chloroform, dichloromethane, formamide, trifluoroacetic acid, dimethyl sulfoxide (DMSO), acetonitrile, N,N-dimethylformamide (DMF), hexamethylphosphoramide, methanol, acetic acid, ethanol, isopropanol, pyridine, tetramethylethylenediamine, acetone, triethylamine, n-butanol, tert-butanol, dioxane, tetrahydrofuran, methyl formate, tributylamine, methyl ethyl ketone, ethyl acetate, chloroform, trioctylamine, dimethyl carbonate, diethyl ether, isopropyl ether, n-butyl ether, trichloroethylene, diphenyl ether, dichloroethane, benzene, toluene, carbon tetrachloride, carbon disulfide, cyclohexane, and hexane.

[0059] In some embodiments, the nickel oxide film is a wet film, which is advantageous for doping the nickel oxide particles with Cu and N.

[0060] In some embodiments, the thickness of the nickel oxide film ranges from 20 to 60 nm, for example, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, and any range between any two of the stated values.

[0061] In step S12:

[0062] In some embodiments, the power range of the first magnetron sputtering is 1 to 2 kW, for example, 1 kW, 1.1 kW, 1.2 kW, 1.3 kW, 1.4 kW, 1.5 kW, 1.6 kW, 1.7 kW, 1.8 kW, 1.9 kW, 2 kW, and any range between any two of these values. The time range of the first magnetron sputtering is 1 to 5 min, for example, 1 min, 2 min, 3 min, 4 min, 5 min, and any range between any two of these values. Within these ranges, it is advantageous to prepare nickel oxide films with high conductivity and carrier mobility.

[0063] In some embodiments, placing the nickel oxide film in a nitrogen environment and performing a first magnetron sputtering with copper as the target material includes: placing the nickel oxide film in a sputtering cavity, introducing nitrogen gas, and performing a first magnetron sputtering with copper as the target material.

[0064] In some embodiments, the sputtering chamber is evacuated to 10°C before nitrogen is introduced. -5 Below Pa, it is beneficial to form more oxygen vacancies on the surface of the nickel oxide particles, which is beneficial to doping the nickel oxide particles with nitrogen.

[0065] In some embodiments, the nitrogen flow rate ranges from 0.5 to 1 mL / min, for example, 0.5 mL / min, 0.6 mL / min, 0.7 mL / min, 0.8 mL / min, 0.9 mL / min, 1 mL / min, and any range between two of these values. Within this range, it is beneficial to form more oxygen vacancies in nickel oxide, which is beneficial for doping nitrogen into nickel oxide particles.

[0066] In some embodiments, a ignition gas is introduced simultaneously with nitrogen, including but not limited to argon.

[0067] In some embodiments, the flow rate ratio of the ignition gas to the nitrogen gas is (2-10):1, for example, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, and any range between these two values. Within this range, it is beneficial for both magnetron sputtering and the formation of more oxygen vacancies on the surface of the nickel oxide particles, thus promoting nitrogen doping within the nickel oxide particles.

[0068] In some embodiments, during the first magnetron sputtering, the pressure in the sputtering cavity is 0.5–5 Pa, for example, 0.5 Pa, 1 Pa, 1.5 Pa, 2 Pa, 2.5 Pa, 3 Pa, 3.5 Pa, 4 Pa, 4.5 Pa, 5 Pa, and any range between any two of these values. This is beneficial for preparing a first film layer 11 with better film-forming properties.

[0069] It is understandable that heat is generated during the first magnetron sputtering process. This heat is beneficial for the formation of more oxygen vacancies on the surface of nickel oxide particles and for the doping of copper and nitrogen elements.

[0070] It should be noted that in this application, the sputtering cavity can be a magnetron sputtering cavity of a known magnetron sputtering device used for magnetron sputtering.

[0071] In some embodiments, after obtaining the first film layer and before obtaining the thin film, the method further includes: preparing a second film layer on at least one surface of the first film layer, wherein the second film layer is a copper nitride layer.

[0072] In some embodiments, the method for preparing the copper nitride layer includes: using copper as a target material, performing a second magnetron sputtering to obtain the copper nitride layer.

[0073] In some embodiments, the power range of the second magnetron sputtering is 1 to 2 kW, for example, 1 kW, 1.1 kW, 1.2 kW, 1.3 kW, 1.4 kW, 1.5 kW, 1.6 kW, 1.7 kW, 1.8 kW, 1.9 kW, 2 kW, and any range between two of these values, and the time range of the second magnetron sputtering is 1 to 5 minutes. Within this range, it is beneficial to prepare a copper nitride layer with better results.

[0074] In some embodiments, the second magnetron sputtering is performed in an inert atmosphere. Further, the inert gas in the inert atmosphere includes, but is not limited to, one or more of nitrogen, argon, helium, and neon.

[0075] In at least some embodiments, the second magnetron sputtering is performed in a nitrogen flow. Further, in some embodiments, the flow rate of the nitrogen flow ranges from 0.5 to 1 mL / min, for example, 0.5 mL / min, 0.6 mL / min, 0.7 mL / min, 0.8 mL / min, 0.9 mL / min, 1 mL / min, and any range between any two of these values.

[0076] In some embodiments, a ignition gas is introduced simultaneously with nitrogen, including but not limited to argon.

[0077] In some embodiments, the flow ratio of the ignition gas to the nitrogen gas is (2-10):1, for example, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, and any range between these two values. Within this range, magnetron sputtering is advantageous.

[0078] In some embodiments, the pressure of the second magnetron sputtering is 0.5–5 Pa, for example, 0.5 Pa, 1 Pa, 1.5 Pa, 2 Pa, 2.5 Pa, 3 Pa, 3.5 Pa, 4 Pa, 4.5 Pa, 5 Pa, and any range between any two of these values. This is beneficial for preparing a copper nitride layer with good film formation effect.

[0079] It is understandable that the copper nitride layer can be prepared directly by extending the first magnetron sputtering time, that is, after the first film layer is prepared, the first magnetron sputtering is continued, so that the copper nitride layer can be formed on the surface of the first film layer.

[0080] Fourthly, please refer to Figure 4This application provides an optoelectronic device 100, comprising an anode 10, a hole transport layer 20, and a cathode 30 stacked sequentially. The hole transport layer 20 comprises the composite material described above, or the hole transport layer 20 is the first film layer 11 described above, or the hole transport layer 20 is the first film layer 11 prepared by the preparation method described above.

[0081] The hole transport layer 20 of the optoelectronic device 100 described in this application includes the composite material and thus has properties such as long lifespan.

[0082] Please see Figure 5 In some embodiments, the optoelectronic device 100 further includes a light-emitting layer 40, which is located between the hole transport layer 20 and the cathode 30. The hole transport layer 20 of the optoelectronic device 100 described in this application includes the composite material, thus exhibiting high luminous efficiency and long lifetime.

[0083] In at least one embodiment, the light-emitting layer 40 includes blue quantum dots. When the light-emitting layer 40 includes blue quantum dots, the hole transport layer 20, which includes the composite material, is in contact with the light-emitting layer 40. This can enhance the carrier transport capability at the hole end to a certain extent, effectively reduce the injection barrier between the nickel oxide particles and the blue quantum dots, and make the electron-hole transport efficiency in the blue optoelectronic device more balanced, thereby effectively improving the luminous efficiency and lifetime of the blue optoelectronic device.

[0084] In some embodiments, the optoelectronic device 100 further includes an electron transport layer 50, which is located between the light-emitting layer 40 and the cathode 30.

[0085] In some embodiments, the optoelectronic device 100 further includes a hole injection layer 60 located between the anode 10 and the hole transport layer 20.

[0086] Please see Figure 6 In some embodiments, the optoelectronic device 100 further includes a copper nitride layer 70, which is located between the hole transport layer 20 and the light-emitting layer 40. When there is an excess of electrons, the copper nitride layer 70 can absorb the excess electrons migrating from the light-emitting layer 40, thereby blocking or even preventing electrons from entering the hole transport layer 20 and charging the nickel oxide particles. This avoids affecting the long-term normal operation and stability of the nickel oxide particles, improving the luminous efficiency and lifetime of the optoelectronic device. Furthermore, the copper nitride in the copper nitride layer 70 is a p-type semiconductor material (hole transport material), which is beneficial for improving the hole mobility of the device, thereby further improving the luminous efficiency and lifetime of the optoelectronic device 100.

[0087] In some embodiments, the thickness of the copper nitride layer 70 is 3 to 8 nm, for example, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, and any range between any two of these values.

[0088] The anode 10 and the cathode 30 are anodes and cathodes known in the art for use in optoelectronic devices. For example, they can be independently, but are not limited to, doped metal oxide particle electrodes, composite electrodes, graphene electrodes, carbon nanotube electrodes, elemental metal electrodes, or alloy electrodes. The material of the doped metal oxide particle electrode can be, but is not limited to, one or more of indium-doped tin oxide (ITO), fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), indium-doped zinc oxide (IZO), magnesium-doped zinc oxide (MZO), and aluminum-doped magnesium oxide (AMO). The composite electrode is a composite electrode in which a metal is sandwiched between doped or undoped transparent metal oxide particles, such as AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS, ZnS / Al / ZnS, etc., where " / " indicates a stacked structure. For example, AZO / Ag / AZO represents a composite electrode comprising sequentially stacked AZO, Ag, and AZO layers. The material of the elemental metal electrode may include, but is not limited to, one or more of Ag, Al, Cu, Mo, Au, Pt, Ca, Mg, and Ba.

[0089] The material of the light-emitting layer 40 can be any material known in the art for use as a light-emitting layer, such as, but not limited to, one or more of organic light-emitting materials and quantum dots.

[0090] The organic light-emitting materials may include, but are not limited to, one or more of the following: CBP:Ir(mppy)3(4,4'-bis(N-carbazole)-1,1'-biphenyl:tris[2-(p-tolyl)pyridinium(III)), TCTX:Ir(mmpy)(4,4',4”-tris(carbazole-9-yl)triphenylamine:tris[2-(p-tolyl)pyridinium), diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials, DBP fluorescent materials, delayed fluorescent materials, TTA materials, TADF (thermally activated delayed) materials, polymers containing BN covalent bonds, HLCT (hybrid local charge transfer excited state) materials, Exciplex (excitoplex) light-emitting materials, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, and polyfluorene and its derivatives.

[0091] In some embodiments, the quantum dot may include, but is not limited to, one or more of single-structure quantum dots, core-shell quantum dots, and perovskite quantum dots. The core-shell quantum dot comprises one or more shell layers.

[0092] The materials for the single-structure quantum dots, the core materials for the core-shell structure quantum dots, and the shell materials for the core-shell structure quantum dots may include, but are not limited to, one or more of group II-VI compounds, group IV-VI compounds, group III-V compounds, and group I-III-VI compounds. The group II-VI compounds may include, but are not limited to, one or more of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe. The IV-VI group compounds may include, but are not limited to, one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe. The group III-V compounds may include, but are not limited to, one or more of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb. The group I-III-VI compounds may include, but are not limited to, one or more of CuInS2, CuInSe2, and AgInS2.

[0093] As an example, the core-shell structured quantum dots may include, but are not limited to, one or more of CdSe / CdSeS / CdS, InP / ZnSeS / ZnS, CdZnSe / ZnSe / ZnS, CdSeS / ZnSeS / ZnS, CdSe / ZnS, CdSe / ZnSe / ZnS, ZnSe / ZnS, ZnSeTe / ZnS, CdSe / CdZnSeS / ZnS, and InP / ZnSe / ZnS.

[0094] The perovskite quantum dots may include, but are not limited to, doped or undoped inorganic perovskite quantum dots, or organic-inorganic hybrid perovskite quantum dots. The general structural formula of the inorganic perovskite quantum dots is AMX3, where A is Cs. + Ions, where M is a divalent metal cation, including Pb 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Eu 2+ One or more of them, where X is a halide anion, including Cl. - ,Br - I - One or more of the following. The general structural formula of the organic-inorganic hybrid perovskite quantum dots is BMX3, where B is an organic amine cation, including CH3(CH2). n-2 NH3 + Or [NH3(CH2)] n NH3] 2+ Where n≥2, M is a divalent metal cation, including Pb 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2 + Eu 2+ One or more of them, where X is a halide anion, including Cl. - ,Br - I - One or more of them.

[0095] In some embodiments, the average particle size of the quantum dots is 5 to 15 nm, for example, 5 nm, 6 nm, 8 nm, 10 nm, 12 nm, 13 nm, 15 nm, and any range between any two of the stated values.

[0096] The surface of the quantum dots also includes ligands, including but not limited to substituted or unsubstituted C6-C. 24 Fatty acids, substituted or unsubstituted C6-C 24 Fatty amines, substituted or unsubstituted C6-C 24 Aliphatic thiols, substituted or unsubstituted C6-C 24 Aliphatic sulfides, substituted or unsubstituted C6-C 24 Aliphatic phosphine, substituted or unsubstituted C6-C 24 Aliphatic phosphine oxides, substituted or unsubstituted C8-C8 phosphine oxides 20 Aliphatic phosphates, substituted or unsubstituted C6-C 24 Aliphatic phosphates, substituted or unsubstituted C6-C 24 Aliphatic phosphorous acid and substituted or unsubstituted C6-C 24 At least one of the fatty phosphites, wherein the substituent is selected from at least one of C1-C6 alkyl, C1-C6 alkoxy and halogen.

[0097] In some embodiments, the substituted or unsubstituted C6-C 24 Fatty acids include at least one of the following: decanoic acid, undecenoic acid, tetradecanoic acid, oleic acid, linoleic acid, and stearic acid.

[0098] In some embodiments, the substituted or unsubstituted C6-C 24 Aliphatic thiols include at least one of octylthiol, dodecylthiol, and octadecylthiol.

[0099] In some embodiments, the substituted or unsubstituted C6-C 24 Fatty amines include at least one of oleylamine, octadecylamine, octylamine, dioctylamine, and trioctylamine.

[0100] In some embodiments, the substituted or unsubstituted C6-C 24 Aliphatic phosphines include trioctylphosphine.

[0101] In some embodiments, the substituted or unsubstituted C6-C 24 Aliphatic phosphine oxides include trioctylphosphine oxides.

[0102] The material of the electron transport layer 50 is a material known in the art for use in electron transport layers, such as one or more selected from, but not limited to, inorganic and organic electron transport materials. The inorganic electron transport material includes, but is not limited to, one or more of doped metal oxide particles, undoped metal oxide particles, IIB-VIA group semiconductor materials, IIIA-VA group semiconductor materials, and IB-IIIA-VIA group semiconductor materials. The undoped metal oxide particles include, but are not limited to, one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The metal oxides in the doped metal oxide particles include, but are not limited to, one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3. The doping elements in the doped metal oxide particles include, but are not limited to, one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga. The IIB-VIA group semiconductor materials include, but are not limited to, one or more of ZnS, ZnSe, and CdS. The IIIA-VA group semiconductor materials include, but are not limited to, one or more of InP and GaP. The IB-IIIA-VIA group semiconductor materials include, but are not limited to, one or more of CuInS and CuGaS. The organic electron transport materials include, but are not limited to, one or more of the following: quinoxaline compounds, imidazole compounds, triazine compounds, fluorene-containing compounds, and hydroxyquinoline compounds.

[0103] The material of the hole injection layer 60 can be any material known in the art for hole injection layers, such as, but not limited to, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzphenanthrene (HAT-CN), PEDOT, PEDOT:PSS, a derivative of PEDOT:PSS doped with s-MoO3 (PEDOT:PSS:s-MoO3), 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA), tetracyanoquinone dimethyl ether (F4-TCQN), copper phthalocyanine, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide, molybdenum sulfide, tungsten sulfide, and copper oxide.

[0104] In some embodiments, the thickness of the anode 10 is 100–200 nm; the thickness of the cathode 30 is 30–80 nm; the thickness of the light-emitting layer 40 is 30–80 nm; the thickness of the electron transport layer 50 is 20–60 nm; and the thickness of the hole injection layer 60 is 20–50 nm.

[0105] It is understood that the optoelectronic device 100 may also be provided with some functional layers that are conventionally used in optoelectronic devices and help to improve the performance of optoelectronic devices, such as electron blocking layer, hole blocking layer, electron injection layer, interface modification layer, etc.

[0106] It is understood that the materials of each layer of the optoelectronic device 100 can be adjusted according to the light emission requirements of the optoelectronic device 100.

[0107] In some embodiments, the optoelectronic device 100 further includes a substrate disposed on the side of the anode 10 away from the light-emitting layer 40, or the substrate disposed on the side of the cathode 30 away from the light-emitting layer 40.

[0108] The substrate can be a rigid substrate or a flexible substrate. In some embodiments, the substrate material may include, but is not limited to, one or more of glass, silicon wafer, polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, polyamide, and polyethersulfone.

[0109] It is understood that the optoelectronic device 100 can be an upright optoelectronic device or an inverted optoelectronic device. The optoelectronic device 100 can be a quantum dot optoelectronic device or an organic optoelectronic device.

[0110] Fifthly, please refer to Figures 4-7 This application also provides a method for fabricating an optoelectronic device, comprising the following steps:

[0111] Step S21: Provide the first electrode;

[0112] Step S22: Prepare a hole transport layer 20 on the first electrode using the thin film preparation method described above;

[0113] Step S23: Prepare a second electrode on the hole transport layer 20 to obtain the optoelectronic device 100.

[0114] In some embodiments, the first electrode is an anode 10 and the second electrode is a cathode 30. In other embodiments, the first electrode is a cathode 30 and the second electrode is an anode 10.

[0115] In some embodiments, the first electrode is an anode 10 and the second electrode is a cathode 30. The preparation of the hole transport layer 20 on the first electrode includes: sequentially preparing a stacked hole injection layer 60 and a hole transport layer 20 on the first electrode.

[0116] In some embodiments, the first electrode is an anode 10 and the second electrode is a cathode 30. The fabrication of the second electrode on the hole transport layer 20 includes: sequentially fabricating a light-emitting layer 40 and a second electrode on the hole transport layer 20.

[0117] In some embodiments, the first electrode is an anode 10 and the second electrode is a cathode 30. The fabrication of the second electrode on the hole transport layer 20 includes: sequentially fabricating a light-emitting layer 40, an electron transport layer 50, and a second electrode on the hole transport layer 20.

[0118] In some embodiments, the first electrode is a cathode 30 and the second electrode is an anode 10. The preparation of the hole transport layer 20 on the first electrode includes: sequentially preparing a light-emitting layer 40 and a hole transport layer 20 on the first electrode.

[0119] In some embodiments, the first electrode is a cathode 30 and the second electrode is an anode 10. Fabricating a hole transport layer 20 on the first electrode includes: sequentially fabricating an electron transport layer 50, a light-emitting layer 40, and a second electrode on the first electrode.

[0120] In some embodiments, the first electrode is a cathode 30 and the second electrode is an anode 10. The fabrication of the second electrode on the hole transport layer 20 includes: sequentially fabricating a stacked hole injection layer and a second electrode on the hole transport layer 20.

[0121] In some embodiments, the first electrode is an anode 10, the second electrode is a cathode 30, and after the hole transport layer 20 is prepared, a copper nitride layer 70 is prepared on the hole transport layer 20.

[0122] In other embodiments, the first electrode is a cathode 30 and the second electrode is an anode 10. The preparation of the hole transport layer 20 on the first electrode includes: sequentially preparing a stacked copper nitride layer 70 and a hole transport layer 20 on the first electrode.

[0123] In some embodiments, the preparation method of the copper nitride layer 70 is as described above and will not be repeated here.

[0124] The methods for preparing the second electrode, the light-emitting layer 40, the electron transport layer 50, and the hole injection layer 60, as well as the method for depositing the composite material described in this application, can be implemented using conventional techniques in the art, such as chemical or physical methods. Chemical methods include chemical vapor deposition, continuous ion layer adsorption and reaction, anodic oxidation, electrolytic deposition, and co-precipitation. Physical methods include physical deposition and solution methods. Physical deposition methods include thermal evaporation deposition, electron beam evaporation deposition, magnetron sputtering, multi-arc ion deposition, physical vapor deposition, atomic layer deposition, pulsed laser deposition, etc.; solution methods can include spin coating, printing, inkjet printing, blade coating, dip coating, immersion coating, spraying, roller coating, casting, slot coating, and strip coating, etc.

[0125] It is understood that when the optoelectronic device 100 further includes functional layers that are conventionally used in optoelectronic devices to help improve the performance of the optoelectronic device, such as an electron injection layer, an electron blocking layer, a hole blocking layer, an interface modification layer, etc., the method of fabricating the optoelectronic device 100 may also include the step of fabricating the above-mentioned functional layers using conventional techniques in the art.

[0126] Sixthly, embodiments of this application also provide a display device, the display device including the optoelectronic device 100.

[0127] The display device can be any electronic product with display function, including but not limited to smartphones, tablets, laptops, digital cameras, digital camcorders, smart wearable devices, smart weighing scales, in-vehicle displays, televisions, or e-book readers. Among them, smart wearable devices can be, for example, smart bracelets, smartwatches, virtual reality (VR) headsets, etc.

[0128] The present application will be specifically described below through specific embodiments. The following embodiments are only some embodiments of the present application and are not intended to limit the present application.

[0129] Example 1

[0130] The method for fabricating the optoelectronic device in this embodiment includes:

[0131] Step 1: Provide an ITO anode 10 glass substrate. Use a cotton swab dipped in a small amount of soapy water to wipe the ITO surface to remove visible impurities. Then, use deionized water, acetone, ethanol, and isopropanol for ultrasonic cleaning for 15 minutes. Finally, dry it with nitrogen gas for later use.

[0132] Step 2: Spin-coat PEDOT:PSS material onto the anode 10 at a speed of 4000 rpm for 45 seconds, and anneal at 160°C for 15 minutes to obtain a hole injection layer 60 with a thickness of 30 nm.

[0133] Step 3: Mix nickel acetylacetone with tert-butanol and stir evenly in a water bath at 60°C for 50 min. Then transfer to a polytetrafluoroethylene reactor and solvothermal react at 170°C in a forced-air drying oven for 30 h. After natural cooling to room temperature, centrifuge to separate the precipitate, wash with deionized water and anhydrous ethanol four times, and then dry at 110°C for 7 h. Dissolve the dried powder in ethanol to prepare a 10 mg / mL nickel oxide particle dispersion. Spin-coat the nickel oxide particle dispersion onto the hole injection layer 60 at a speed of 4000 rpm for 30 seconds to obtain a 40 nm thick nickel oxide wet film. Transfer the film to a magnetron sputtering chamber and evacuate to a vacuum level of 10.-5 After Pa, ignition gases argon and nitrogen are introduced, with the flow rate ratio of argon to nitrogen controlled at 6:1 and the flow rate of nitrogen at 0.7 mL / min. Sputtering begins when the working pressure in the chamber reaches 1 Pa. The target material used for magnetron sputtering is a 99.99% pure copper target. The magnetron sputtering power is 1.5 kW, and the magnetron sputtering time is 3 min. After natural cooling, a hole transport layer 20 with a thickness of 50 nm is obtained.

[0134] Step 4: Spin-coat a CdZnSeS / ZnS quantum dot solution (solvent is n-hexane) with a concentration of 15 mg / mL onto the hole transport layer 20. The spin-coating speed is 4000 rpm and the time is 50 seconds. Then anneal at 130°C for 15 min to obtain a light-emitting layer 40 with a thickness of 40 nm.

[0135] Step 5: Spin-coat an ethanol solution of ZnO onto the light-emitting layer 40 at a speed of 4000 rpm for 30 seconds, followed by annealing at 140°C for 15 minutes to obtain an electron transport layer 50 with a thickness of 30 nm.

[0136] Step 6: In the vacuum coating machine, evacuate the vacuum to 4×10⁻⁶. -6 mbar, a Mg layer with a thickness of 20 nm and an Ag layer with a thickness of 35 nm are sequentially deposited on the electron transport layer 50, with the Mg deposition rate being mbar. The evaporation rate of Ag is Cathode 30 was obtained;

[0137] Step 7: Package the device to obtain optoelectronic device 100, which is a quantum dot light-emitting diode.

[0138] Example 2

[0139] This embodiment is basically the same as Embodiment 1, except that the magnetron sputtering power in this embodiment is 1kW.

[0140] Example 3

[0141] This embodiment is basically the same as Embodiment 1, except that the magnetron sputtering power in this embodiment is 2kW.

[0142] Example 4

[0143] This embodiment is basically the same as Embodiment 1, except that the magnetron sputtering time in this embodiment is 1 minute.

[0144] Example 5

[0145] This embodiment is basically the same as Embodiment 1, except that the magnetron sputtering time in this embodiment is 5 minutes.

[0146] Example 6

[0147] This embodiment is basically the same as Embodiment 1, except that the flow rate of nitrogen in this embodiment is 0.5 mL / min.

[0148] Example 7

[0149] This embodiment is basically the same as Embodiment 1, except that the flow rate of nitrogen in this embodiment is 1 mL / min.

[0150] Example 8

[0151] This embodiment is basically the same as Embodiment 1, except that the flow ratio of the ignition gas to the nitrogen gas is 2:1 in this embodiment.

[0152] Example 9

[0153] This embodiment is basically the same as Embodiment 1, except that the flow ratio of the ignition gas to the nitrogen gas is 10:1 in this embodiment.

[0154] Example 10

[0155] This embodiment is basically the same as Embodiment 1, except that in this embodiment, after the hole transport layer 20 is prepared, the first magnetron sputtering is performed to prepare a copper nitride layer 70 on the surface of the hole transport layer 20. The thickness of the copper nitride layer 70 in this embodiment is 3 nm.

[0156] Example 11

[0157] This embodiment is basically the same as embodiment 10, except that the thickness of the copper nitride layer 70 is 5.5 nm in this embodiment.

[0158] Example 12

[0159] This embodiment is basically the same as that of embodiment 10, except that the thickness of the copper nitride layer 70 is 8 nm in this embodiment.

[0160] Example 13

[0161] The method for fabricating the optoelectronic device in this embodiment includes:

[0162] Step 1: Provide a glass substrate and, in a vacuum coating machine, evacuate the vacuum to 4×10⁻⁶. -6 mbar, a Mg layer with a thickness of 20 nm and an Ag layer with a thickness of 35 nm are sequentially deposited on the substrate, with the Mg deposition rate being [missing information]. The evaporation rate of Ag is Cathode 30 was obtained;

[0163] Step 2: Spin-coat an ethanol solution of ZnO onto the cathode 30 at a speed of 4000 rpm for 30 seconds, followed by annealing at 140°C for 15 min to obtain an electron transport layer 50 with a thickness of 30 nm.

[0164] Step 3: Spin-coat a CdZnSeS / ZnS quantum dot solution (solvent is n-hexane) with a concentration of 15 mg / mL onto the electron transport layer 50. The spin-coating speed is 4000 rpm and the time is 50 seconds. Then anneal at 130°C for 15 min to obtain a light-emitting layer 40 with a thickness of 40 nm.

[0165] Step 4: Within the magnetron sputtering cavity, evacuate the vacuum level to 10. -5 After Pa, ignition gases argon and nitrogen are introduced, with the flow rate ratio of argon to nitrogen controlled at 6:1 and the flow rate of nitrogen at 0.7 mL / min. When the working pressure in the chamber is 1 Pa, sputtering begins on the light-emitting layer 40. The target material selected for magnetron sputtering is a copper target with a purity of 99.99%. The magnetron sputtering power is 1.5 kW, and the magnetron sputtering time is 3 min. After natural cooling, a copper nitride layer 70 with a thickness of 5.5 nm is obtained.

[0166] Step 5: Mix nickel acetylacetone with tert-butanol and stir evenly in a water bath at 60°C for 50 min. Then transfer to a polytetrafluoroethylene reactor and solvothermal react at 170°C for 30 h in a forced-air drying oven. After natural cooling to room temperature, centrifuge to separate the precipitate, wash with deionized water and anhydrous ethanol four times, and then dry at 110°C for 7 h. Dissolve the dried powder in ethanol to prepare a 10 mg / mL nickel oxide particle dispersion. Spin-coat the nickel oxide particle dispersion onto the copper nitride layer 70 at a speed of 4000 rpm for 30 seconds to obtain a 40 nm thick nickel oxide wet film. Transfer the film to a magnetron sputtering chamber and evacuate to a vacuum level of 10. -5 After Pa, ignition gases argon and nitrogen are introduced, with the flow rate ratio of argon to nitrogen controlled at 6:1 and the flow rate of nitrogen at 0.7 mL / min. Sputtering begins when the working pressure in the chamber reaches 1 Pa. The target material used for magnetron sputtering is a 99.99% pure copper target. The magnetron sputtering power is 1.5 kW, and the magnetron sputtering time is 3 min. After natural cooling, a hole transport layer 20 with a thickness of 50 nm is obtained.

[0167] Step 6: Spin-coat PEDOT:PSS material onto the hole transport layer 20 at a spin speed of 4000 rpm for 45 seconds, and anneal at 160°C for 15 minutes to obtain a hole injection layer 60 with a thickness of 30 nm.

[0168] Step 7: Prepare an ITO anode 10 on the hole injection layer 60;

[0169] Step 8: Packaging to obtain optoelectronic device 100, wherein optoelectronic device 100 is a quantum dot light-emitting diode.

[0170] Comparative Example 1

[0171] This comparative example is basically the same as Example 1, except that the method for preparing the hole transport layer in this comparative example includes:

[0172] Nickel acetylacetone was mixed with tert-butanol and stirred uniformly in a water bath at 60°C for 50 min. The mixture was then transferred to a polytetrafluoroethylene (PTFE) reactor and subjected to a solvothermal reaction at 170°C for 30 h in a forced-air drying oven. After natural cooling to room temperature, the precipitate was separated by centrifugation and washed four times with deionized water and anhydrous ethanol, respectively. The precipitate was then dried at 110°C for 7 h. The dried powder was dissolved in ethanol to prepare a 10 mg / mL nickel oxide particle dispersion. The nickel oxide particle dispersion was then spin-coated onto the hole injection layer at 4000 rpm for 30 seconds, followed by annealing at 140°C for 15 min to obtain a hole transport layer with a thickness of 50 nm.

[0173] Comparative Example 2

[0174] This comparative example is basically the same as Example 13, except that this comparative example does not include the preparation of the copper nitride layer, and the method for preparing the hole transport layer in this comparative example includes:

[0175] Nickel acetylacetone was mixed with tert-butanol and stirred uniformly in a water bath at 60°C for 50 min. The mixture was then transferred to a polytetrafluoroethylene (PTFE) reactor and subjected to a solvothermal reaction at 170°C for 30 h in a forced-air drying oven. After natural cooling to room temperature, the precipitate was separated by centrifugation and washed four times with deionized water and anhydrous ethanol, respectively. The precipitate was then dried at 110°C for 7 h. The dried powder was dissolved in ethanol to prepare a 10 mg / mL NiO particle dispersion. The NiO particle dispersion was then spin-coated onto the luminescent layer at 4000 rpm for 30 seconds, followed by annealing at 140°C for 15 min to obtain a hole transport layer with a thickness of 50 nm.

[0176] The hole mobility of the hole transport layer and the electron mobility of the electron transport layer in Examples 1-13 and Comparative Examples 1-2 were detected respectively, and the detection results are shown in Table 1.

[0177] The maximum brightness L of the optoelectronic devices in Examples 1-13 and Comparative Examples 1-2 max External quantum efficiency (EQE), lifetime T95, and lifetime T95@1000 nit were tested. The test results are shown in Table 1.

[0178] The carrier mobility test method is as follows: The current density-voltage curves of the optoelectronic devices (single carrier transport thin film devices HOD / EOD) of Examples 1-13 and Comparative Examples 1-2 are measured. The structure of EOD is anode / quantum dot emitting layer / electron transport layer / cathode, and the structure of HOD is anode / hole transport thin film / quantum dot emitting layer / cathode. The materials of each layer of the half-device are the same as the shell materials of the corresponding examples and comparative examples. The space charge confinement current (SCLC) region in the current density-voltage curve is obtained, and then the current density is calculated according to the formula J = (9 / 8)ε. r ε0μ e V 2 / d 3 Calculate the electron / hole mobility, where J represents the current density in mA / cm². -2 ;ε r ε₀ represents the relative permittivity, and μ represents the vacuum permittivity. e Electron / hole mobility is expressed in cm. 2 V -1 s -1 V represents the driving voltage, with units of V; d represents the film thickness, with units of m.

[0179] Maximum brightness L max The lifetime T95 and lifetime T95@1000nit test methods are as follows: In CDA gas, under a constant current drive of 2mA, the time it takes for the device brightness to decay to a certain percentage of its maximum brightness is measured. The time for the brightness to decay to 95% of the maximum brightness is defined as T95, and this lifetime is the measured lifetime. To shorten the lifetime testing cycle, device lifetime testing is usually performed at high brightness by accelerating device aging, and the lifetime at low brightness is obtained by fitting the decay fitting formula. For example, the lifetime at 1000 nits is denoted as T95@1000nits, and the calculation formula is:

[0180]

[0181] Among them, T95 L The lifespan at low brightness is typically taken as the lifespan at 1000 nits, T95. H The lifetime at high brightness, i.e., the measured lifetime, L H L is the maximum brightness that the device accelerates to. L The typical value is 1000 nits, where A is the acceleration factor, which is set to 1.7.

[0182] External quantum efficiency (EQE) is the ratio of electron-hole pairs injected into a quantum dot to emitted photons, expressed as a percentage (%). It is an important parameter for evaluating the quality of electroluminescent devices and can be measured using EQE optical testing instruments. The specific calculation formula is as follows:

[0183]

[0184] Where ηe is the optical output coupling efficiency, ηr is the ratio of the number of recombinated carriers to the number of injected carriers, χ is the ratio of the number of excitons that generate photons to the total number of excitons, KR is the radiative process rate, and KNR is the non-radiative process rate.

[0185] The above test conditions were: conducted at room temperature with an air humidity of 50%.

[0186] Table 1:

[0187]

[0188]

[0189] As shown in Table 1:

[0190] Compared to the optoelectronic device of Comparative Example 1, the optoelectronic devices of Examples 1-12 exhibit higher hole mobility, higher maximum brightness, higher luminous efficiency, and longer lifetime. Compared to the optoelectronic device of Comparative Example 2, the optoelectronic device of Example 13 exhibits higher hole mobility, higher maximum brightness, higher luminous efficiency, and longer lifetime. It is evident that doping with copper and nitrogen elements by sputtering copper and nitrogen in the hole transport layer 20 can effectively improve the hole mobility, maximum brightness, luminous efficiency, and lifetime of the optoelectronic device. This may be because: sputtering Cu in a nitrogen atmosphere facilitates the formation of oxygen vacancies on the surface of nickel oxide particles, thereby effectively regulating the electronic structure, chemical properties, and conductivity of the material; furthermore, nitrogen doping generates a certain amount of holes, which can enhance the carrier transport capability at the hole end to some extent; additionally, nitrogen doping can increase the oxygen vacancies on the surface of nickel oxide particles, and oxygen vacancies can reduce the probability of non-radiative Auger recombination of carriers; furthermore, copper doping does not cause lattice distortion or even collapse of nickel oxide and can also improve the conductivity of the composite material.

[0191] The technical solutions provided by the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A composite material, characterized in that, It includes nickel oxide particles, which are doped with copper and nitrogen.

2. The composite material as described in claim 1, characterized in that, The copper element is doped on the surface and / or inside the nickel oxide particles; and / or The nitrogen element is doped on the surface and / or inside the nickel oxide particles; and / or The average particle size of the nickel oxide particles ranges from 10 to 30 nm; and / or In the composite material, the mass ratio of copper to nickel oxide particles ranges from (0.01 to 0.06):1; and / or In the composite material, the mass ratio of nitrogen to nickel oxide particles ranges from (0.01 to 0.05):

1.

3. The composite material as described in claim 1, characterized in that, The composite material also includes copper nitride. Optionally, the mass ratio of the nickel oxide particles to the copper nitride is in the range of (5-20):

1.

4. A thin film, characterized in that, The film includes a first film layer, wherein the first film layer includes the composite material according to any one of claims 1 to 3.

5. The thin film as described in claim 4, characterized in that, The thickness of the first film layer is 20–60 nm; and / or The thin film further includes a second film layer disposed on at least one surface of the first film layer, the second film layer being a copper nitride layer, and optionally, the thickness of the second film layer being 3 to 8 nm.

6. A method for preparing a thin film, characterized in that, Includes the following steps: A nickel oxide particle dispersion is deposited, the nickel oxide particle dispersion comprising nickel oxide particles and a solvent, to obtain a nickel oxide film; and The nickel oxide film is placed in a nitrogen environment, and copper is used as the target material for the first magnetron sputtering to form the first film layer, thus obtaining a thin film.

7. The preparation method according to claim 6, characterized in that, Placing the nickel oxide film in a nitrogen environment and using copper as a target for first magnetron sputtering includes: placing the nickel oxide film in a sputtering cavity, introducing nitrogen gas, and using copper as a target for first magnetron sputtering.

8. The preparation method according to claim 7, characterized in that, The nickel oxide film is a wet film; and / or The average particle size of the nickel oxide particles ranges from 10 to 30 nm; and / or The thickness of the nickel oxide film ranges from 20 to 60 nm; and / or The power range of the first magnetron sputtering is 1–2 kW; and / or The first magnetron sputtering time ranges from 1 to 5 minutes; and / or The flow rate of the nitrogen gas is in the range of 0.5–1 mL / min; and / or Before introducing nitrogen, the process also includes: evacuating the sputtering chamber to a vacuum level of 10. -5 Below Pa; and / or A ignition gas, including argon, is introduced simultaneously with nitrogen gas, and the flow rate ratio of the ignition gas to the nitrogen gas is (2-10):1; and / or During the first magnetron sputtering, the pressure in the sputtering cavity is 0.5–5 Pa; and / or The solvent includes one or more of the following: propylene glycol methyl ether acetate, hexane, chloroform, dichloromethane, formamide, trifluoroacetic acid, dimethyl sulfoxide, acetonitrile, N,N-dimethylformamide, hexamethylphosphoramide, methanol, acetic acid, ethanol, isopropanol, pyridine, tetramethylethylenediamine, acetone, triethylamine, n-butanol, tert-butanol, dioxane, tetrahydrofuran, methyl formate, tributylamine, methyl ethyl ketone, ethyl acetate, chloroform, trioctylamine, dimethyl carbonate, diethyl ether, isopropyl ether, n-butyl ether, trichloroethylene, diphenyl ether, dichloroethane, benzene, toluene, carbon tetrachloride, carbon disulfide, cyclohexane, and hexane.

9. The preparation method according to claim 6, characterized in that, After obtaining the first film layer by first magnetron sputtering, and before obtaining the thin film, the method further includes: preparing a second film layer on at least one surface of the first film layer, wherein the second film layer is a copper nitride layer.

10. The preparation method according to claim 9, characterized in that, The method for preparing the copper nitride layer includes: using copper as a target material, performing a second magnetron sputtering to obtain the copper nitride layer; wherein... The power range of the second magnetron sputtering is 1–2 kW; and / or The second magnetron sputtering time range is 1–5 min; and / or The pressure of the second magnetron sputtering is 0.5–5 Pa; and / or The second magnetron sputtering is performed in an inert atmosphere, wherein the inert gas in the inert atmosphere includes one or more of nitrogen, argon, helium, and neon; and / or The second magnetron sputtering is carried out in a nitrogen flow, wherein the flow rate of the nitrogen flow ranges from 0.5 to 1 mL / min; optionally, a ignition gas, including argon, is also introduced during the second magnetron sputtering, and the flow rate ratio of the ignition gas to the nitrogen gas is (2 to 10):

1.

11. An optoelectronic device, characterized in that, The device comprises an anode, a hole transport layer, and a cathode stacked sequentially, wherein the hole transport layer comprises the composite material described in any one of claims 1 to 3, or the hole transport layer is the first film layer in the thin film described in claim 4, or the hole transport layer is the first film layer prepared by the preparation method described in any one of claims 6 to 8.

12. The optoelectronic device as described in claim 11, characterized in that, The optoelectronic device further includes a copper nitride layer, which is located between the hole transport layer and the cathode.

13. The optoelectronic device as described in claim 12, characterized in that, The thickness of the copper nitride layer is 3–8 nm; and / or The anode and the cathode each independently comprise a doped metal oxide particle electrode, a composite electrode, a graphene electrode, a carbon nanotube electrode, a metal element electrode, or an alloy electrode. The doped metal oxide particle electrode is made of one or more of the following materials: indium-doped tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, magnesium-doped zinc oxide, and aluminum-doped magnesium oxide. The composite electrode comprises one or more of the following: AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS, or ZnS / Al / ZnS. The metal element electrode is made of one or more of the following: Ag, Al, Cu, Mo, Au, Pt, Ca, Mg, and Ba; and / or The optoelectronic device further includes an electron transport layer located between the cathode and the hole transport layer. The electron transport layer is made of one or more inorganic and organic electron transport materials. The inorganic electron transport material includes one or more of second-doped metal oxide particles, second-undoped metal oxide particles, IIB-VIA group semiconductor materials, IIIA-VA group semiconductor materials, and IB-IIIA-VIA group semiconductor materials. The second-undoped metal oxide particles are made of one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The metal oxide in the second-doped metal oxide particles includes ZnO, TiO2, SnO2, and ZrO5. One or more of O2, Ta2O5, and Al2O3; the doping element in the second doped metal oxide particles includes one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga; the IIB-VIA group semiconductor material includes one or more of ZnS, ZnSe, and CdS; the IIIA-VA group semiconductor material includes one or more of InP and GaP; the IB-IIIA-VIA group semiconductor material includes one or more of CuInS and CuGaS; the organic electron transport material includes one or more of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene-containing compounds, and hydroxyquinoline compounds; and / or The optoelectronic device further includes a hole injection layer located between the anode and the hole transport layer. The hole injection layer is made of one or more of the following materials: 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene, PEDOT, PEDOT:PSS, PEDOT:PSS-doped s-MoO3 derivatives, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, tetracyanoquinone dimethylamine, copper phthalocyanine, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide, molybdenum sulfide, tungsten sulfide, and copper oxide; and / or The optoelectronic device further includes a light-emitting layer located between the cathode and the hole transport layer or between the cathode and the copper nitride layer. The material of the light-emitting layer includes one or more of organic light-emitting materials and quantum dots. The organic light-emitting materials include one or more of 4,4'-bis(N-carbazole)-1,1'-biphenyl:tris[2-(p-tolyl)pyridinium(III), 4,4',4”-tris(carbazole-9-yl)triphenylamine:tris[2-(p-tolyl)pyridinium, diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials, DBP fluorescent materials, delayed fluorescence materials, TTA materials, thermally activated delayed materials, polymers containing BN covalent bonds, hybrid local charge transfer excited state materials, excitopolymer light-emitting materials, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, and polyfluorene and its derivatives.The quantum dots include one or more of single-structure quantum dots, core-shell quantum dots, and perovskite semiconductor materials. The core-shell quantum dots comprise one or more shell layers. The materials of the single-structure quantum dots, the core material of the core-shell quantum dots, and the shell materials of the core-shell quantum dots are each independently selected from one or more of group II-VI compounds, group IV-VI compounds, group III-V compounds, and group I-III-VI compounds. The group II-VI compounds include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, and ZnS. One or more of the following compounds: SnS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe, wherein the group IV-VI compounds include SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, and SnSTe. e, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe, the III-V compound comprising one or more of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, G One or more of aAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb, wherein the I-III-VI group compounds include one or more of CuInS2, CuInSe2, and AgInS2; wherein the perovskite semiconductor material includes doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors, wherein the general structural formula of the inorganic perovskite semiconductor is AMX3, where A is Cs; + Ions, where M is a divalent metal cation, including Pb 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Eu 2+ One or more of them, where X is a halide anion, including Cl. - ,Br - I - One or more of the following; the general structural formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, where B is an organic amine cation, including CH3(CH2). n-2 NH3 + Or [NH3(CH2)] n NH3] 2+ Where n≥2, M is a divalent metal cation, including Pb 2+ Sn 2+ Cu 2+ Ni 2 + Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Eu 2+ One or more of them, where X is a halide anion, including Cl. - ,Br - I - One or more of them.

14. A display device, characterized in that, Includes the optoelectronic device according to any one of claims 11 to 13.

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