Composite films and optoelectronic devices

Abstract

This application discloses a composite thin film and an optoelectronic device, relating to the field of display technology. The composite thin film includes a first thin film and a second thin film stacked together. The first thin film is made of inorganic nanoparticles, and the second thin film is made of metal hydroxide. The composite thin film provided by this application can significantly improve the efficiency of the device, etc.

Description

Technical Field

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

[0002] In related technologies, inorganic nanoparticles are commonly used as thin film materials. When the thin film is applied to optoelectronic devices, inorganic nanoparticles can easily cause exciton quenching, leading to a decrease in the efficiency of the optoelectronic devices. Summary of the Invention

[0003] In view of this, this application provides a composite thin film and an optoelectronic device.

[0004] The embodiments of this application are implemented as follows: a composite film, the composite film comprising a first film and a second film stacked together, wherein the material of the first film comprises inorganic nanoparticles and the material of the second film comprises metal hydroxide.

[0005] Accordingly, embodiments of this application also provide an optoelectronic device, which includes a first electrode, a functional layer, and a second electrode stacked together, wherein the functional layer includes the aforementioned composite thin film.

[0006] The composite thin film provided in this application can significantly improve the efficiency of devices, etc. Attached Figure Description

[0007] 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.

[0008] Figure 1 This is a schematic diagram of the structure of a composite film provided in an embodiment of this application;

[0009] Figure 2 This is a flowchart illustrating a method for preparing a composite thin film according to an embodiment of this application;

[0010] Figure 3 This is a schematic diagram of the structure of an optoelectronic device provided in an embodiment of this application;

[0011] Figure 4 This is a schematic diagram of the structure of another optoelectronic device provided in the embodiments of this application.

[0012] Figure label:

[0013] Composite film 10; First film 11; Second film 12;

[0014] Optoelectronic device 100; first electrode 20; active layer 30; second electrode 40. Detailed Implementation

[0015] 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.

[0016] 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 orientation shown 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.

[0017] 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.

[0018] In this application, "at least one" means one or more, and "more than one" means two or more. "One or more", "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.

[0019] 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.

[0020] The technical solution of this application is as follows:

[0021] Firstly, please refer to Figure 1 This application provides a composite film 10, which includes a first film 11 and a second film 12 stacked together. The material of the first film 11 includes inorganic nanoparticles, and the material of the second film 12 includes metal hydroxide.

[0022] The composite thin film 10 provided in this application includes a first thin film 11 and a second thin film 12 stacked together. The metal hydroxide in the second thin film 12 can passivate the defects in the inorganic nanoparticles in the first thin film 11, reduce the fluorescence quenching of excitons by the inorganic nanoparticles, improve the interfacial contact between the first thin film 11 and other adjacent film layers in the composite thin film 10, improve the quality of the composite thin film 10, and thus improve the luminous efficiency of the optoelectronic device when the composite thin film 10 is applied to the optoelectronic device 100.

[0023] In some embodiments, the inorganic nanoparticles contain metal ions, and at least one type of metal ion in the inorganic nanoparticles is the same as that in the metal hydroxide. The fact that some metal ions in the inorganic nanoparticles and some metal ions in the metal hydroxide are the same results in good energy level compatibility and high lattice fit between the first thin film 11 and the second thin film 12. This allows the metal hydroxide to effectively passivate defects in the inorganic nanoparticles, improving the quality of the composite thin film 10.

[0024] In some embodiments, when the inorganic nanoparticles contain several metal ions and / or the metal hydroxide contains several metal ions, at least one metal ion in the inorganic nanoparticles and at least one metal ion in the metal hydroxide are the same. In other words, the metal ions contained in the first film 11 and the second film 11 may be partially the same or completely identical.

[0025] In some embodiments, the metal ions include one or more of alkali metal ions, alkaline earth metal ions, transition metal ions, lanthanide metal ions, group IIIA metal ions, and group IVA metal ions.

[0026] Furthermore, the alkali metal ions include lithium ions.

[0027] The alkaline earth metal ions include magnesium ions.

[0028] The transition metal ions include one or more of the following: zinc ions, titanium ions, zirconium ions, tantalum ions, manganese ions, yttrium ions, copper ions, nickel ions, cadmium ions, molybdenum ions, tungsten ions, chromium ions, and vanadium ions.

[0029] The lanthanide metal ions include one or more of lanthanum ions and cerium ions.

[0030] The group IIIA metal ions include one or more of aluminum ions, gallium ions, and indium ions.

[0031] The group IVA metal ions include tin ions.

[0032] In some embodiments, the inorganic nanoparticles also contain non-metallic ions.

[0033] Furthermore, the non-metallic ions in the inorganic nanoparticles have a valence of x, where |x| > 1. It can be understood that |x| represents the absolute value of x. The non-metallic ion in the metal hydroxide is OH-. - The oxidation state of OH is -1. - Unlike the non-metallic ions in inorganic nanoparticles, the valence of OH groups at the interface between the first thin film 11 and the second thin film 12 is different. - By binding with metal ions in inorganic nanoparticles, the activity of inorganic nanoparticles can be reduced, thereby passivating the defects of inorganic nanoparticles.

[0034] In some embodiments, |x| = 2 or |x| = 3.

[0035] In some embodiments, the non-metallic ions in the inorganic nanoparticles include one or more of Group VA and Group VIA non-metallic ions.

[0036] Furthermore, the group VA nonmetallic ions include P 3- N 3- One or more of them.

[0037] The group VIA nonmetallic ions include O 2- S 2- Se 2- One or more of them.

[0038] In some embodiments, the average particle size of the inorganic nanoparticles is 2 nm to 50 nm, for example, it can be 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, or any range between two values. It should be noted that in this application, the particle size of the inorganic nanoparticles is measured by transmission electron microscopy (TEM).

[0039] Furthermore, the average particle size of the inorganic nanoparticles is 30 nm to 50 nm. Within this range of average particle size, the inorganic nanoparticles have a smaller specific surface area and a reduced number of surface atoms, thereby reducing surface defects.

[0040] In some embodiments, the inorganic nanoparticles include N-type inorganic nanoparticles or P-type inorganic nanoparticles. It should be noted that when the inorganic nanoparticles include N-type inorganic nanoparticles, the metal hydroxide has poor conductivity, which can reduce electron injection and promote an electron-hole balance.

[0041] In some embodiments, the N-type inorganic nanoparticles include one or more of a first doped metal oxide particle, a first undoped metal oxide particle, a group IIB-VIA semiconductor material, a group IIIA-VA semiconductor material, and a group IB-IIIA-VIA semiconductor material. The first undoped metal oxide particle is made of one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The metal oxide in the first doped metal oxide particle is made of one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3. The doping element in the first doped metal oxide particle includes Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, and Ce. The semiconductor material comprises one or more of In, Ga, and the semiconductor material of group IIB-VIA includes one or more of ZnS, ZnSe, and CdS. The semiconductor material of group IIIA-VA includes one or more of InP and GaP. The semiconductor material of group IB-IIIA-VIA includes one or more of CuInS and CuGaS. The doping amount of the doping element in the first doped metal oxide particle is 0.1wt% to 15wt%, for example, it can be 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, or any range between two values.

[0042] In some embodiments, the p-type inorganic nanoparticles include one or more of a second doped metal oxide particle, a second undoped metal oxide particle, a metal sulfide, a metal selenide, and a metal nitride. The metal oxide in the second doped metal oxide particle and the metal oxide in the second undoped metal oxide particle each independently include one or more of MoO3, WO3, NiO, CrO3, CuO, and V2O5. The doping element in the second doped metal oxide particle includes one or more of Mo, W, Ni, Cr, Cu, and V. The sulfide includes one or more of CuS, MoS3, and WS3; the metal selenide includes one or more of MoSe3 and WSe3; and the metal nitride includes p-type gallium nitride. The doping amount of the dopant element in the second doped metal oxide particle is 0.1 wt% to 15 wt%, for example, it can be 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, or any range between two values.

[0043] In some embodiments, the metal hydroxide includes one or more of Zn(OH)2, Ti(OH)4, Sn(OH)2, Zr(OH)4, Ta(OH)5, Al(OH)3, Mg(OH)2, LiOH, Mn(OH)2, Y(OH)3, La(OH)3, Cu(OH)2, Ni(OH)2, Ce(OH)3, In(OH)3, Ga(OH)3, Cd(OH)2, Mo(OH)4, W(OH)6, Cr(OH)3, and V(OH)5.

[0044] For example, when the material of the first film 11 is ZnO, the material of the second film 12 is Zn(OH)2; when the material of the first film 11 is ZnMgO (magnesium-doped zinc oxide), the material of the second film 12 may also include Mg(OH)2.

[0045] In some embodiments, the thickness of the first thin film 11 is 10 nm to 70 nm, for example, it can be 20 nm, 30 nm, 40 nm, 50 nm, 60 nm or any range between two values. It should be noted that in this application, the thickness of the thin film is measured by a profilometer.

[0046] In some embodiments, the thickness of the second thin film 12 is 1 nm to 5 nm, for example, it can be 1.5 nm, 2 nm, 2.1 nm, 2.2 nm, 2.3 nm, 2.4 nm, 2.5 nm, 2.6 nm, 2.7 nm, 2.8 nm, 2.9 nm, 3 nm, 3.5 nm, 4 nm, 4.5 nm, or any range between two values. Within the aforementioned thickness range, it is beneficial for carrier (hole or electron) tunneling and has a relatively small impact on the conductivity of the composite thin film 10.

[0047] It should be noted that the materials of the first film 11 and the second film 12 contain some elements that are the same. Due to the manufacturing process, there may be a thin transition layer at the interface between the first film 11 and the second film 12. In the transition layer, there are inorganic nanoparticles of the first film 11 and metal hydroxides of the second film 12, as well as products of the reaction between the inorganic nanoparticles and the metal hydroxides.

[0048] In some embodiments, at least a portion of the metal hydroxide is chemically bonded to the inorganic nanoparticles at the interface between the first film 11 and the second film 12. The chemical bonds include one or more of ionic bonds and coordination bonds.

[0049] Specifically, the OH in the metal hydroxide - The inorganic nanoparticles are chemically bonded to the metal ions within them. This improves the bonding strength between the first film 11 and the second film 12, and is beneficial for OH groups. - After binding with metal ions, the activity of inorganic nanoparticles is reduced, thereby filling the vacancies in the inorganic nanoparticles.

[0050] Please see Figure 2 This application provides a method for preparing a composite thin film 10, comprising the following steps:

[0051] S11. A first thin film 11 is provided, wherein the material of the first thin film 11 includes inorganic nanoparticles;

[0052] S12. Provide an alkaline solution and a metal salt solution, wherein the alkaline solution includes an alkaline compound and the metal salt solution includes a metal salt. Deposit the alkaline solution and the metal salt solution on the first thin film 11 to form a second thin film 12, thereby obtaining a composite thin film 10.

[0053] It should be noted that during the deposition of the alkaline solution and the metal salt solution, the alkaline compound reacts with the metal salt to generate metal hydroxide, forming the second thin film 12.

[0054] In S11:

[0055] In some embodiments, the inorganic nanoparticles contain metal ions, and at least one type of metal ion in the inorganic nanoparticles is the same as that in the metal hydroxide.

[0056] The materials of the metal ions and the inorganic nanoparticles are described above and will not be repeated here.

[0057] The first thin film 11 can be achieved 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.

[0058] In S12:

[0059] In some embodiments, the alkaline compound is selected from one or more of alkali metal oxides, alkali metal hydroxides, alkali metal bicarbonates, alkali metal carbonates, alkaline earth metal oxides, alkaline earth metal hydroxides, alkaline earth metal bicarbonates, organic amines, ammonium salts, and ammonia water. Specifically, the alkali metal oxides include lithium oxide, sodium oxide, and potassium oxide; the alkali metal hydroxides include lithium hydroxide, sodium hydroxide, and potassium hydroxide; the alkali metal bicarbonates include sodium bicarbonate and potassium bicarbonate; the alkali metal carbonates include sodium carbonate and potassium carbonate; the alkaline earth metal oxides include magnesium oxide and calcium oxide; the alkaline earth metal hydroxides include magnesium hydroxide and calcium hydroxide; the alkaline earth metal bicarbonates include calcium bicarbonate; the organic amines include ethylenediamine, ethanolamine, diethanolamine, and triethanolamine; and the ammonium salts include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide.

[0060] In some embodiments, the non-metallic ions in the metal salt are selected from one or more of acetate ions, sulfate ions, halide ions, and nitrate ions.

[0061] In some embodiments, the metal ions in the metal salt include one or more of alkali metal ions, alkaline earth metal ions, transition metal ions, lanthanide metal ions, group IIIA metal ions, and group IVA metal ions.

[0062] Furthermore, the alkali metal ions include lithium ions.

[0063] The alkaline earth metal ions include magnesium ions.

[0064] The transition metal ions include one or more of the following: zinc ions, titanium ions, zirconium ions, tantalum ions, manganese ions, yttrium ions, copper ions, nickel ions, cadmium ions, molybdenum ions, tungsten ions, chromium ions, and vanadium ions.

[0065] The lanthanide metal ions include one or more of lanthanum ions and cerium ions.

[0066] The group IIIA metal ions include one or more of aluminum ions, gallium ions, and indium ions.

[0067] The group IVA metal ions include tin ions.

[0068] In some embodiments, the alkaline solution further includes a first solvent, which includes water.

[0069] In some embodiments, the metal salt solution further includes a second solvent, which includes water.

[0070] In some embodiments, the molar concentration of the alkaline compound in the alkaline solution is 0.05 mmol / L to 0.15 mmol / L, for example, it can be 0.06 mmol / L, 0.08 mmol / L, 0.1 mmol / L, 0.12 mmol / L, 0.14 mmol / L, or any range between two values. Within this molar concentration range, the dissolution and dispersion of the alkaline compound are beneficial.

[0071] In some embodiments, the molar concentration of the metal salt in the metal salt solution is 0.1 mmol / L to 0.5 mmol / L, for example, it can be 0.15 mmol / L, 0.2 mmol / L, 0.25 mmol / L, 0.3 mmol / L, 0.35 mmol / L, 0.4 mmol / L, or any range between two values. Within this molar concentration range, the dissolution and dispersion of the metal salt are beneficial.

[0072] In some embodiments, the molar ratio of the alkaline compound to the metal salt is 1:(1-20), for example, it can be 1:2, 1:5, 1:8, 1:10, 1:12, 1:15, 1:18, or any range between two values. It is understood that the alkaline compound ionizes in the alkaline solution to produce hydroxide ions, which react with the metal ions produced by the ionization of the metal salt in the solution to generate a metal hydroxide.

[0073] In some embodiments, the temperature for depositing the alkaline solution and the metal salt solution is 80°C to 150°C, for example, it can be 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, or any range between two values; the deposition time for the alkaline solution and the metal salt solution is 1 hour to 4 hours, for example, it can be 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, or any range between two values; the deposition pressure for the alkaline solution and the metal salt solution is 2 MPa to 6 MPa, for example, it can be 2.5 MPa, 3 MPa, 3.5 MPa, 4 MPa, 4.5 MPa, 5 MPa, 5.5 MPa, or any range between two values. This facilitates the sufficient reaction between the alkaline compound and the metal ions to generate metal hydroxide, forming the second thin film 12. It should be noted that within the pressure range provided in this application, the decomposition of the metal hydroxide into metal oxide is suppressed, ensuring that the second thin film 12 includes metal hydroxide.

[0074] Secondly, please refer to Figure 3 and Figure 4 This application also provides an optoelectronic device 100, which includes a first electrode 20, a functional layer and a second electrode 40 stacked together. The functional layer includes the composite film 10 described above, or the composite film 10 prepared by the above preparation method.

[0075] In some embodiments, the functional layer includes one or more of a hole functional layer, an active layer 30, and an electronic functional layer stacked sequentially, wherein the hole functional layer and / or the electronic functional layer includes the aforementioned composite film 10, and the second film 12 is disposed on the side close to the active layer 30.

[0076] It should be noted that in some embodiments, the first electrode 20 is the anode and the second electrode 40 is the cathode. In other embodiments, the first electrode 20 is the cathode and the second electrode 40 is the anode. The hole functional layer is located between the anode and the active layer 30, and the electron functional layer is located between the active layer 30 and the cathode.

[0077] The optoelectronic device 100 provided in this application uses metal hydroxide to passivate defects in the first thin film 11, and the second thin film 12 is disposed on the side close to the active layer 30, which can further block the fluorescence quenching caused by defects of inorganic nanoparticles to the active layer 30, thereby improving the luminous efficiency and service life of the optoelectronic device 100.

[0078] It is understood that when the hole functional layer includes the composite film 10, the inorganic nanoparticles are P-type inorganic nanoparticles. When the electronic functional layer includes the composite film 10, the inorganic nanoparticles are N-type inorganic nanoparticles.

[0079] The hole functional layer includes one or more of the following: a hole injection layer and a hole transport layer.

[0080] The electronic functional layer includes one or more of an electron injection layer and an electron transport layer.

[0081] It should be noted that when the hole functional layer includes the composite thin film 10, the material of the electronic functional layer includes N-type inorganic nanoparticles or N-type organic semiconductor materials. The N-type inorganic nanoparticles include one or more of the following: first doped metal oxide particles, first undoped metal oxide particles, IIB-VIA group semiconductor materials, IIIA-VA group semiconductor materials, and IB-IIIA-VIA group semiconductor materials. The material of the first undoped metal oxide particles includes one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The metal oxide in the first doped metal oxide particles includes one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3. The doping element in the first doped metal oxide particles includes... The semiconductor materials are selected from Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga, or more. The IIB-VIA group semiconductor materials include one or more of ZnS, ZnSe, and CdS. The IIIA-VA group semiconductor materials include one or more of InP and GaP. The IB-IIIA-VIA group semiconductor materials include one or more of CuInS and CuGaS. The doping amount of the doping element in the first doped metal oxide particle is 0.1wt% to 15wt%, for example, it can be 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, or any range between two values.The N-type organic semiconductor materials include 8-hydroxyquinoline aluminum (Alq3), 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi), 4,7-diphenyl-1,10-o-diazaphenanthroline (BPhen), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (DMBP), 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole (BT-1,2,4-Tz), bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum (BAlq2), and 2,2'-(1,3-phenyl)bis[5-(4-tert-butyl)] ... [2,4,6-trimethyl-3-(3-pyridyl)phenyl]borane (TM-3PB), tetra[(m-pyridyl)-phenyl-3-yl]biphenyl (m-PyBP), 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1”-terphenyl]-3,3”-diyl]dipyridine (TPD-Py), 1,3-bis(3,5-dipyridin-3-ylphenyl)benzene (DBP), n,n′-bis(naphthyl-1-yl)-n,n′-bis(phenyl)benzidine (NPB), and diphenyl[4-(triphenylsilyl)phenyl]phosphine oxide (TPDPS) are among the following.

[0082] Accordingly, when the electronic functional layer includes the composite thin film 10, the material of the hole functional layer includes a p-type organic semiconductor material or p-type inorganic nanoparticles, wherein the p-type organic semiconductor material includes 4,4'-N,N'-dicarbazolyl-biphenyl, N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4'-diamine, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl) )-spiro, N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 4,4',4'-tris(N-carbazolyl)-triphenylamine, 4,4',4'-tris(carbazol-9-yl)triphenylamine, trichloroisocyanuric acid, terbium-doped phosphate-based green luminescent materials, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzphenanthrene, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)- [co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(4-butylphenyl-diphenylamine), poly[bis(4-phenyl)(4-butylphenyl)amine], polyaniline, polypyrrole, poly(p-)phenylenevinylene, poly(phenylenevinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene], copper phthalocyanine, aromatic tertiary amines, polynuclear aromatic tertiary amines, 4,4'-bis(p-carbazole) -1,1'-Biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT, PEDOT:PSS and its derivatives, PEDOT:PSS derivatives doped with s-MoO3, poly(N-vinylcarbazole) and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, N,N'-bis(naphthyl-1-yl)-N,N'-diphenylbenzidine, spiron NPB, nanocrystalline diamond, microcrystalline cellulose and tetracyanoquinone dimethane, doped graphene, undoped graphene;The p-type inorganic nanoparticles include one or more of the following: second-doped metal oxide particles, second-undoped metal oxide particles, metal sulfides, metal selenides, and metal nitrides. The metal oxides in the second-doped metal oxide particles and the second-undoped metal oxide particles each independently include one or more of MoO3, WO3, NiO, CrO3, CuO, and V2O5. The doping element in the second-doped metal oxide particles includes one or more of Mo, W, Ni, Cr, Cu, and V. The metal selenide includes one or more of CuS, MoS3, and WS3; the metal selenide includes one or more of MoSe3 and WSe3; and the metal nitride includes p-type gallium nitride. The doping amount of the dopant element in the second doped metal oxide particle is 0.1 wt% to 15 wt%, for example, it can be 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, or any range between two values.

[0083] In some embodiments, the active layer 30 includes a light-emitting layer, and the optoelectronic device 100 includes a light-emitting diode.

[0084] In some embodiments, the active layer 30 is made of a luminescent material, which may include an organic luminescent material or a quantum dot luminescent material.

[0085] The organic light-emitting material may be selected from, but is 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(III)]), 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, and Exciplex (excitoplex) light-emitting materials.

[0086] The quantum dot luminescent material may be selected from, but is not limited to, one or more of single-structure quantum dots, core-shell structure quantum dots, and perovskite quantum dots.

[0087] The materials for the single-structure quantum dots, the core material of the core-shell quantum dots, and the shell material of the core-shell quantum dots can be selected from, but are not limited to, one or more compounds from group II-VI, group IV-VI, group III-V, and group I-III-VI. The shell of the core-shell quantum dots may consist of one or more layers. The group II-VI compounds may be selected from, 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 be selected from, 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 be selected from, 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 be selected from, but are not limited to, one or more of CuInS2, CuInSe2, and AgInS2.

[0088] As an example, the core-shell structured quantum dots can be selected from, 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. In the above descriptions of CdSe / ZnS, etc., the " / " indicates that the material after the " / " (as the shell) covers the material before the " / " (as the core).

[0089] The materials used for the perovskite quantum dots can be selected from, but are not limited to, doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors. The general structural formula of the inorganic perovskite semiconductor is AMX3, where A is Cs. + Ion, M is a divalent metal cation selected from 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 the following, where X is a halide anion selected from 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 selected from CH3(CH2). n-2 NH3 + Or [NH3(CH2)] n NH3] 2+ Where n≥2, M is a divalent metal cation selected from 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 the following, where X is a halide anion selected from Cl... - ,Br - I- One or more of them.

[0090] In some embodiments, the first electrode 20 and the second electrode 40 are each independently selected from metal electrodes, carbon electrodes, doped or undoped metal oxide electrodes, and composite electrodes; wherein, the material of the metal electrode is selected from one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Ni, Ir, and Mg; the material of the carbon electrode is selected from one or more of graphite, carbon nanotubes, graphene, and carbon fibers; the material of the doped or undoped metal oxide electrode is selected from ITO, FTO, ATO, AZO, GZO, IZO, MZO, etc. The composite electrode material is selected from one or more of the following: ITZO, ICO, AMO, SnO2, In2O3, Cd:ZnO, F:SnO2, In:SnO2, and Ga:SnO2. The composite electrode material is selected from one or more of 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, and ZnS / Al / ZnS. Here, " / " indicates a stacked structure; for example, the composite electrode AZO / Ag / AZO represents a three-layer stacked composite electrode consisting of an AZO layer, an Ag layer, and an AZO layer.

[0091] This application embodiment also provides a display device, which includes the above-described optoelectronic device 100.

[0092] 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.

[0093] 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.

[0094] Composite Thin Film Example 1

[0095] This embodiment provides a composite thin film, the preparation method of which is as follows:

[0096] The first thin film was prepared by sputtering. The material of the first thin film included inorganic nanoparticles ZnO, and the thickness of the first thin film was 30 nm.

[0097] The first film was placed in a sealed reaction vessel, and 5 mL of 0.1 mmol / L ammonia solution and 15 mL of 0.33 mmol / L zinc acetate solution were added to the reaction vessel. The vessel was then placed in an oven at 100°C for 2 hours at a pressure of 5 MPa to form a second film on the first film. The material of the second film included Zn(OH)2, and the thickness of the second film was 2.5 nm. After cooling to room temperature, the reaction vessel was opened and the film was removed. The first and second films were then immersed in deionized water three times to remove impurities. After drying at room temperature, a composite film was obtained.

[0098] Composite film Example 2

[0099] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the reaction is carried out in a 150°C oven.

[0100] Composite film Example 3

[0101] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the reaction is carried out in an 80°C oven.

[0102] Composite film Example 4

[0103] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the reaction is carried out in a 100°C oven for 4 hours.

[0104] Composite film Example 5

[0105] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the sample is placed in an 80°C oven for 1 hour.

[0106] Composite film Example 6

[0107] This embodiment is basically the same as Embodiment 1, except that the thickness of the second film in this embodiment is 3nm.

[0108] Composite film Example 7

[0109] This embodiment is basically the same as Embodiment 1, except that the thickness of the second film in this embodiment is 2nm.

[0110] Composite film Example 8

[0111] This embodiment is basically the same as Embodiment 1, except that the inorganic nanoparticles ZnO in the first film are replaced with ZnMgO (magnesium-doped zinc oxide, with Mg doping amount of 5wt%); 15 mL of 0.33 mmol / L zinc acetate aqueous solution is replaced with 10 mL of 0.33 mmol / L zinc acetate aqueous solution and 5 mL of 0.33 mmol / L magnesium acetate aqueous solution; and the material of the second film includes Zn(OH)2 and Mg(OH)2.

[0112] Composite film Example 9

[0113] This embodiment is basically the same as Embodiment 1, except that the inorganic nanoparticles ZnO in the first film are replaced with TiO2; the zinc acetate aqueous solution is replaced with titanium tetrabromide aqueous solution; and the material of the second film includes Ti(OH)4.

[0114] Composite Thin Film Example 10

[0115] This embodiment is basically the same as Embodiment 1, except that the inorganic nanoparticles ZnO in the first film are replaced with NiO; the zinc acetate aqueous solution is replaced with the nickel acetate aqueous solution; and the material of the second film includes Ni(OH)2.

[0116] Composite Thin Film Example 11

[0117] This embodiment is basically the same as Embodiment 1, except that the inorganic nanoparticles ZnO in the first film are replaced with CuO; the zinc acetate aqueous solution is replaced with the copper chloride aqueous solution; and the material of the second film includes Cu(OH)2.

[0118] Composite film Example 12

[0119] This embodiment is basically the same as Embodiment 1, except that the preparation method of the first thin film in this embodiment includes:

[0120] An ethanol dispersion of 20 mg / mL ZnO was spin-coated onto a substrate and annealed at 80 °C for 30 min to remove the ethanol, thus obtaining the first film.

[0121] Composite film comparative example 1

[0122] This comparative example provides a thin film, prepared by the following method:

[0123] Thin films were prepared using the sputtering method described in Example 1. The materials of the thin films included inorganic nanoparticles ZnO, and the thickness of the thin films was 30 nm.

[0124] Composite film comparative example 2

[0125] This comparative example is basically the same as Example 1, except that the zinc acetate aqueous solution is replaced with the nickel acetate aqueous solution, and the material of the second film includes Ni(OH)2.

[0126] Composite film comparative example 3

[0127] This comparative example provides a thin film, prepared by the following method:

[0128] A mixture of 5 mL of 0.1 mmol / L ammonia solution and 15 mL of 0.33 mmol / L zinc acetate solution was deposited on a glass substrate and annealed at 180 °C to form a thin film containing both ZnO and Zn(OH)2.

[0129] Composite film comparative example 4

[0130] This comparative example is basically the same as Comparative Example 1, except that the inorganic nanoparticles ZnO in the film are replaced with ZnMgO (magnesium-doped zinc oxide, with Mg doping amount of 5wt%).

[0131] Composite film comparative example 5

[0132] This comparative example is basically the same as Comparative Example 1, except that the inorganic nanoparticles ZnO in the thin film are replaced with TiO2 in this comparative example.

[0133] Composite film comparative example 6

[0134] This comparative example is basically the same as Comparative Example 1, except that the inorganic nanoparticles ZnO in the thin film are replaced with NiO in this comparative example.

[0135] Composite film comparative example 7

[0136] This comparative example is basically the same as Comparative Example 1, except that the inorganic nanoparticles ZnO in the thin film are replaced with CuO in this comparative example.

[0137] Composite film comparative example 8

[0138] This comparative example provides a thin film, prepared by the following method:

[0139] An ethanol dispersion of 20 mg / mL ZnO was spin-coated onto a substrate and annealed at 80 °C for 30 min to remove the ethanol, thus obtaining a thin film.

[0140] On the composite films of Examples 1-12 and Comparative Examples 1-8, a CdSe / ZnS n-octane dispersion was spin-coated at a speed of 3000 rpm for 30 s, followed by annealing at 150 °C for 10 min to form a quantum dot luminescent layer. The composite film and the quantum dot luminescent layer were tested to obtain the fluorescence lifetime of the quantum dots in the quantum dot luminescent layer. The results are shown in Table 1.

[0141] Fluorescence lifetime refers to the time required for the fluorescence intensity of a fluorescent substance to decay to 1 / e (approximately 36.8%) of its initial intensity after excitation has ceased. Also known as fluorescence decay time, fluorescence lifetime is a crucial characteristic of fluorescent substances, reflecting the duration of their excited state and the persistence of fluorescence emission. A longer fluorescence lifetime indicates less exciton quenching.

[0142] The fluorescence lifetime was measured using a fluorescence lifetime spectrometer (FluoTime 300, PicoQuant). Time-resolved fluorescence lifetime decay and spectra were obtained through time-correlated single-photon counting data acquisition. A femtosecond pulsed diode laser (LDH-P-FA-530B, PicoQuant) with a repetition rate of 800 kHz was used to excite the sample. The collected photons were acquired using a multiplier tube (PMA-C-192, PicoQuant) connected to a time-correlated single-photon counting plate (TimeHarp 260Pico, PicoQuant). The overall instrument response function was approximately 200 ps (full width at half maximum). To reconstruct the time-resolved fluorescence lifetime spectrum, fluorescence decay curves dependent on the detection wavelength were obtained at 5 nm wavelength intervals. All fluorescence decay curves were collected at fixed acquisition times. The obtained curves were fitted with single-natural-exponential or multi-natural-exponential decay to obtain the corresponding decay ratio α. i and fluorescence lifetime τ i Then, calculate the average fluorescence lifetime using the following formula.

[0143]

[0144] Table 1

[0145]

[0146] From Table 1, we can obtain:

[0147] As can be seen from Examples 1-9, 12 and Comparative Examples 1-5, 8, in the preparation of the quantum dot luminescent layer on the composite film provided in this application, the metal ions in the metal hydroxide in the second film are the same as the metal ions in the N-type inorganic nanoparticles in the first film, resulting in good energy level compatibility and lattice fit between the first and second films. This allows the metal hydroxide to fully passivate the defects of the N-type inorganic nanoparticles, reduce exciton quenching, and improve the fluorescence lifetime of the quantum dots. In Comparative Example 3, due to the high annealing temperature, the metal hydroxide content in the film is low, and the effect on improving the defects of the inorganic nanoparticles is limited. Moreover, it still cannot avoid the direct contact between the inorganic nanoparticles and the quantum dot luminescent layer, which would cause exciton quenching. Therefore, its effect is worse than that of the examples. The first film in the composite film provided in this application can be prepared by various methods, and the metal hydroxide in the second film can passivate the defects of the inorganic nanoparticles in the first film, thereby improving the performance of the composite film.

[0148] As can be seen from Examples 10-11 and Comparative Examples 6-7, metal hydroxides are also applicable to P-type inorganic nanoparticles. The second film is disposed between the first film and the quantum dot luminescent layer, which provides fluorescence lifetime for the quantum dots and avoids direct contact between the first film and the quantum dot luminescent layer, which would cause exciton quenching of the inorganic nanoparticles.

[0149] Device Example 1

[0150] This embodiment of the device provides an optoelectronic device, the fabrication method of which is as follows:

[0151] ITO conductive glass is provided. The ITO conductive glass is cleaned with a cleaning agent to initially remove the stains on the surface. Then, it is ultrasonically cleaned for 20 minutes each in deionized water, isopropanol, acetone and deionized water to remove the impurities on the surface. Finally, it is dried with high-purity nitrogen to form an ITO cathode.

[0152] In Example 1, a first film and a second film were sequentially prepared on an ITO cathode to form a composite film (electron transport layer).

[0153] A CdSe / ZnS n-octane dispersion was spin-coated onto the second film at a speed of 3000 rpm for 30 s, followed by annealing at 150 °C for 10 min to form a quantum dot luminescent layer.

[0154] A hole transport layer made of NiO was prepared on the quantum dot light-emitting layer by sputtering.

[0155] The anode is formed by thermally evaporating 100nm of silver through a mask in a vapor deposition chamber.

[0156] Packaging yields optoelectronic devices.

[0157] Device Examples 2-9

[0158] Device Examples 2-9 are basically the same as Device Example 1, except that the first thin film and the second thin film are prepared sequentially according to Composite Thin Film Examples 2-9 to form a composite thin film (electronic functional layer).

[0159] Device Example 10

[0160] This embodiment of the device provides an optoelectronic device, the fabrication method of which is as follows:

[0161] ITO conductive glass is provided. The ITO conductive glass is cleaned with a cleaning agent to initially remove the stains on the surface. Then, it is ultrasonically cleaned for 20 minutes each in deionized water, isopropanol, acetone and deionized water to remove the impurities on the surface. Finally, it is dried with high-purity nitrogen to form an ITO anode.

[0162] In Example 10, a first film and a second film were sequentially prepared on an ITO anode to form a composite film (hole transport layer).

[0163] A CdSe / ZnS n-octane dispersion was spin-coated onto the second film at a speed of 3000 rpm for 30 s, followed by annealing at 150 °C for 10 min to form a quantum dot luminescent layer.

[0164] A hole transport layer made of ZnO was prepared on the quantum dot light-emitting layer by sputtering.

[0165] A cathode is formed by thermally evaporating 100nm of silver through a mask in a vapor deposition chamber.

[0166] Packaging yields optoelectronic devices.

[0167] Device Example 11

[0168] Device Example 11 is basically the same as Device Example 10, except that, in the composite thin film Example 11, the first thin film and the second thin film are prepared sequentially to form a composite thin film (hole transport layer).

[0169] Device Example 12

[0170] Device Example 12 is basically the same as Device Example 1, except that the first thin film and the second thin film are prepared sequentially in the composite thin film Example 12 to form a composite thin film (electron transport layer).

[0171] Device Comparison Example 1

[0172] Device Comparative Example 1 is basically the same as Device Example 1, except that the composite thin film is prepared in Comparative Example 1 to form an electron transport layer.

[0173] Device Comparison Example 2

[0174] Device Comparative Example 2 is basically the same as Device Example 1, except that the first thin film and the second thin film are prepared sequentially in the composite thin film Comparative Example 2 to form a composite thin film (electron transport layer).

[0175] Device Comparison Example 3

[0176] Device Comparative Example 3 is basically the same as Device Example 1, except that a thin film is prepared in Comparative Example 3 to form an electron transport layer.

[0177] Device Comparison Examples 4-5

[0178] The devices in Comparative Examples 4 and 5 are basically the same as those in Device Example 1, except that the first thin film is prepared in Comparative Examples 4 and 5 to form an electron transport layer.

[0179] Device Comparison Example 6

[0180] Device Comparative Example 6 is basically the same as Device Example 10, except that a thin film is prepared using the composite thin film comparative example 6 to form a hole transport layer.

[0181] Device Comparison Example 7

[0182] Device Comparative Example 7 is basically the same as Device Example 10, except that the composite thin film is prepared in Comparative Example 7 to form a hole transport layer.

[0183] Device Comparison Example 8

[0184] Device Comparative Example 8 is basically the same as Device Example 1, except that a thin film is prepared using the composite thin film comparative example 8 to form an electron transport layer.

[0185] The external quantum efficiency (EQE) and lifetime (T95@1000nit) of the optoelectronic devices of Device Examples 1-12 and Device Comparative Examples 1-8 were tested, and the test results are shown in Table 2.

[0186] The external quantum efficiency (EQE) is measured as the ratio of electron-hole pairs injected into a quantum dot to emitted photons, expressed as a percentage (%). It is a crucial parameter for evaluating the quality of electroluminescent devices and can be obtained using an EQE optical testing instrument. The specific calculation formula is as follows:

[0187]

[0188] Where ηe is the optical output coupling efficiency, ηr is the ratio of recombination carriers to injected carriers, χ is the ratio of the number of excitons generating photons to the total number of excitons, and K R K is the radiation process rate. NRThis represents the rate of a non-radiative process. Test conditions: conducted at room temperature with an air humidity of 30–60%.

[0189] The test method for lifetime T95@1000nit is as follows: Under constant current drive, the time required for the brightness of the device to decrease to a certain percentage of its maximum brightness is defined as T95. This lifetime is the measured lifetime. To shorten the testing cycle, device lifetime testing is usually performed at high brightness by accelerating device aging, and the lifetime at high brightness is obtained by fitting the extended exponential decay brightness decay formula. For example, the lifetime at 1000nit is measured as T95@1000nit. The specific calculation formula is as follows:

[0190]

[0191] Among them, T95 L For longer lifespan at low brightness, T95 H For the measured lifetime under high brightness, L H To accelerate the device to its maximum brightness, L L The value is 1000 nits, and A is the acceleration factor. In this experiment, the lifetime of several groups of QLED devices under rated brightness was measured, and the value of A was found to be 1.7.

[0192] Table 2

[0193]

[0194] From Table 2, we can obtain:

[0195] As can be seen from Device Examples 1-9, 12 and Device Comparative Examples 1-5, 8, the second thin film promotes the luminescence of the quantum dot luminescent layer by reducing exciton quenching, thereby improving the external quantum efficiency of the optoelectronic device. Furthermore, the metal hydroxide in the second thin film has poor conductivity; when the composite thin film acts as an electron transport layer, it suppresses electron injection, resulting in a more balanced injection of electrons and holes, promoting effective recombination of electrons and holes, and further improving the luminescence efficiency of the optoelectronic device. Device Examples 1-9 also effectively extend the lifespan of the optoelectronic device compared to Device Comparative Examples 1-5; Device Example 12 significantly improves the external quantum efficiency and extends the lifespan compared to Device Comparative Example 8.

[0196] As can be seen from device examples 10-11 and device comparative examples 6-7, when the composite thin film is used as a hole transport layer, the second thin film improves the interfacial contact between the first thin film and the quantum dot light-emitting layer, suppresses exciton quenching in the quantum dot light-emitting layer, improves the external quantum efficiency of the optoelectronic device, and improves the service life of the optoelectronic device.

[0197] 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 film, characterized in that, The composite film includes a first film and a second film stacked together. The material of the first film includes inorganic nanoparticles, and the material of the second film includes metal hydroxide.

2. The composite film as described in claim 1, characterized in that, The inorganic nanoparticles contain metal ions, and at least one type of metal ion in the inorganic nanoparticles is the same as that in the metal hydroxide; and / or At the interface between the first film and the second film, at least a portion of the metal hydroxide is connected to the inorganic nanoparticles by chemical bonds; the chemical bonds include one or more of ionic bonds and coordination bonds.

3. The composite film as described in claim 2, characterized in that, The metal ions include one or more of alkali metal ions, alkaline earth metal ions, transition metal ions, lanthanide metal ions, Group IIIA metal ions, and Group IVA metal ions; optionally, the alkali metal ions include lithium ions; the alkaline earth metal ions include magnesium ions; the transition metal ions include one or more of zinc ions, titanium ions, zirconium ions, tantalum ions, manganese ions, yttrium ions, copper ions, nickel ions, cadmium ions, molybdenum ions, tungsten ions, chromium ions, and vanadium ions; the lanthanide metal ions include one or more of lanthanum ions and cerium ions; the Group IIIA metal ions include one or more of aluminum ions, gallium ions, and indium ions; the Group IVA metal ions include tin ions; and / or The metal hydroxides include one or more of Zn(OH)2, Ti(OH)4, Sn(OH)2, Zr(OH)4, Ta(OH)5, Al(OH)3, Mg(OH)2, LiOH, Mn(OH)2, Y(OH)3, La(OH)3, Cu(OH)2, Ni(OH)2, Ce(OH)3, In(OH)3, Ga(OH)3, Cd(OH)2, Mo(OH)4, W(OH)6, Cr(OH)3, and V(OH)5.

4. The composite film as described in claim 2, characterized in that, The inorganic nanoparticles have an average particle size of 2 nm to 50 nm; and / or The inorganic nanoparticles also contain non-metallic ions, wherein the valence of the non-metallic ions in the inorganic nanoparticles is x, |x| > 1; and / or The inorganic nanoparticles include N-type inorganic nanoparticles or P-type inorganic nanoparticles.

5. The composite film as described in claim 4, characterized in that, The non-metallic ions in the inorganic nanoparticles include one or more of Group VA and Group VIA non-metallic ions; wherein, the Group VA non-metallic ions include P 3- N 3- One or more of the following; the group VIA nonmetallic ions include O 2- S 2- Se 2- One or more of the following; and / or The N-type inorganic nanoparticles include one or more of the following: first doped metal oxide particles, first undoped metal oxide particles, IIB-VIA group semiconductor materials, IIIA-VA group semiconductor materials, and IB-IIIA-VIA group semiconductor materials. The first undoped metal oxide particles are made of one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The metal oxide in the first doped metal oxide particles is made of one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3. The doping elements in the first-type doped metal oxide particles include one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga; the IIB-VIA group semiconductor materials include one or more of ZnS, ZnSe, and CdS; the IIIA-VA group semiconductor materials include one or more of InP and GaP; and the IB-IIIA-VIA group semiconductor materials include one or more of CuInS and CuGaS. The doping amount of the doping element in the first-type doped metal oxide particles is 0.1 wt% to 15 wt%; and / or The p-type inorganic nanoparticles include one or more of the following: second-doped metal oxide particles, second-undoped metal oxide particles, metal sulfides, metal selenides, and metal nitrides. The metal oxides in the second-doped metal oxide particles and the second-undoped metal oxide particles each independently include one or more of MoO3, WO3, NiO, CrO3, CuO, and V2O5. The doping element in the second-doped metal oxide particles includes one or more of Mo, W, Ni, Cr, Cu, and V. The metal sulfide includes one or more of CuS, MoS3, and WS3. The metal selenide includes one or more of MoSe3 and WSe3. The metal nitride includes p-type gallium nitride. The doping amount of the doping element in the second-doped metal oxide particles is 0.1 wt% to 15 wt%.

6. The composite film according to any one of claims 1 to 5, characterized in that, The thickness of the first thin film is 10 nm to 70 nm; and / or The thickness of the second thin film is 1 nm to 5 nm.

7. An optoelectronic device, characterized in that, The optoelectronic device includes a first electrode, a functional layer, and a second electrode stacked together, wherein the functional layer includes a composite thin film as described in any one of claims 1 to 6.

8. The optoelectronic device as described in claim 7, characterized in that, The functional layer includes one or more of the following: a hole functional layer, an active layer, and an electronic functional layer, which are stacked sequentially. The hole functional layer and / or the electronic functional layer includes the composite film, and the second film is disposed on the side close to the active layer.

9. The optoelectronic device as described in claim 8, characterized in that, When the hole functional layer includes the composite thin film, the material of the electronic functional layer includes N-type inorganic nanoparticles or N-type organic semiconductor materials. The N-type inorganic nanoparticles include one or more of the following: first doped metal oxide particles, first undoped metal oxide particles, IIB-VIA group semiconductor materials, IIIA-VA group semiconductor materials, and IB-IIIA-VIA group semiconductor materials. The material of the first undoped metal oxide particles includes one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The metal oxide in the first doped metal oxide particles... The materials include one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3. The doping elements in the first doped metal oxide particles include one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga. The IIB-VIA group semiconductor materials include one or more of ZnS, ZnSe, and CdS. The IIIA-VA group semiconductor materials include one or more of InP and GaP. The IB-IIIA-VIA group semiconductor materials include one or more of CuInS and CuGaS. The doping amount of the doping element in the first doped metal oxide particle is 0.1 wt% to 15 wt%; the N-type organic semiconductor material includes 8-hydroxyquinoline aluminum, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 4,7-diphenyl-1,10-o-diazaphenanthroline, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole, bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum, 2 2'-(1,3-phenyl)bis[5-(4-tert-butylphenyl)-1,3,4-oxadiazole], tris[2,4,6-trimethyl-3-(3-pyridyl)phenyl]borane, tetra[(m-pyridyl)-phenyl-3-yl]biphenyl, 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1”-terphenyl]-3,3”-diyl]dipyridine, 1,3-bis(3,5-dipyridin-3-ylphenyl)benzene, n,n′-bis(naphthyl-1-yl)-n,n′-bis(phenyl)benzidine, diphenyl[4-(triphenylsilyl)phenyl]phosphine; or When the electronic functional layer includes the composite thin film, the material of the hole functional layer includes a p-type organic semiconductor material or p-type inorganic nanoparticles, wherein the p-type organic semiconductor material includes 4,4'-N,N'-dicarbazolyl-biphenyl, N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro, N N'-Di(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 4,4',4'-tris(N-carbazolyl)-triphenylamine, 4,4',4'-tris(carbazol-9-yl)triphenylamine, trichloroisocyanuric acid, terbium-doped phosphate-based green luminescent materials, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzphenanthrene, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)-co- (4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(4-butylphenyl-diphenylamine), poly[bis(4-phenyl)(4-butylphenyl)amine], polyaniline, polypyrrole, poly(p-)phenylenevinylene, poly(phenylenevinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene], copper phthalocyanine, aromatic tertiary amines, polynuclear aromatic tertiary amines, 4,4'-bis(p-carbazole)- 1,1'-Biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT, PEDOT:PSS and its derivatives, PEDOT:PSS derivatives doped with s-MoO3, poly(N-vinylcarbazole) and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, N,N'-di(naphthyl-1-yl)-N,N'-diphenylbenzidine, spironolactone (NPB), nanocrystalline diamond, microcrystalline cellulose and tetracyanoquinone dimethane, doped graphene, undoped graphene;The p-type inorganic nanoparticles include one or more of the following: second-doped metal oxide particles, second-undoped metal oxide particles, metal sulfides, metal selenides, and metal nitrides. The metal oxides in the second-doped and second-undoped metal oxide particles each independently include one or more of MoO3, WO3, NiO, CrO3, CuO, and V2O5. The doping element in the second-doped metal oxide particles includes one or more of Mo, W, Ni, Cr, Cu, and V. The metal sulfide includes one or more of CuS, MoS3, and WS3. The metal selenide includes one or more of MoSe3 and WSe3. The metal nitride includes p-type gallium nitride. The doping amount of the doping element in the second-doped metal oxide particles is 0.1 wt% to 15 wt%.

10. The optoelectronic device as described in claim 8, characterized in that, The active layer includes a light-emitting layer, the material of which includes organic light-emitting materials or quantum dot light-emitting materials; the organic light-emitting material is selected from 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(III)], 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, T The quantum dot luminescent material is selected from one or more of the following: TA material, TADF material, polymer containing BN covalent bonds, HLCT material, and Exciplex luminescent material; the quantum dot luminescent material is selected from one or more of the following: single-structure quantum dots, core-shell quantum dots, and perovskite quantum dots; the material of the single-structure quantum dot, the core material of the core-shell quantum dot, and the shell material of the core-shell quantum dot are respectively selected from one or more of the following: group II-VI compounds, group IV-VI compounds, group III-V compounds, and group I-III-VI compounds; the shell of the core-shell quantum dot is encapsulated... Includes one or more layers; the II-VI group compounds are selected from 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, CdZnSeT e, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe; wherein the IV-VI compound is selected from one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe;The III-V compounds are selected from 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. Multiple types; the I-III-VI group compounds are selected from one or more of CuInS2, CuInSe2, and AgInS2; the core-shell structured quantum dots are selected from 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; the perovskite quantum dots are made of doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors; the inorganic perovskite semiconductor has the general structural formula AMX3, where A is Cs; + Ion, M is a divalent metal cation selected from 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 the following, where X is a halide anion selected from 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 selected from CH3(CH2). n-2 NH3 + Or [NH3(CH2)] n NH3] 2+ Where n≥2, M is a divalent metal cation selected from 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 the following, where X is a halide anion selected from Cl... - ,Br - I - One or more of the following; and / or The first electrode and the second electrode are each independently selected from metal electrodes, carbon electrodes, doped or undoped metal oxide electrodes, and composite electrodes; wherein, the material of the metal electrode is selected from one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Ni, Ir, and Mg; the material of the carbon electrode is selected from one or more of graphite, carbon nanotubes, graphene, and carbon fibers; the material of the doped or undoped metal oxide electrode is selected from ITO, FTO, ATO, AZO, GZO, IZO, MZO, ITZO, and I The composite electrode material is selected from one or more of CO, AMO, SnO2, In2O3, Cd:ZnO, F:SnO2, In:SnO2, and Ga:SnO2; the composite electrode material is selected from one or more of 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, and ZnS / Al / ZnS.

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