Thin film and preparation method thereof, photoelectric device and display device

Abstract

The embodiment of the invention provides a thin film and a preparation method thereof, a photoelectric device and a display device. The thin film includes a first modification material and an N-type semiconductor material, the first modification material including fulvalene and / or fulvalene derivatives. The thin film provided by the embodiment of the invention contains the first modification material, the first modification material comprises fulvalene and / or fulvalene derivatives, and the fulvalene and the fulvalene derivatives can form stable chemical bonds with the N-type semiconductor material, so that the N-type semiconductor material in the thin film can be connected to form a stable structure; therefore, the crack phenomenon of the film can be improved or eliminated.

Description

Technical Field

[0001] The present application relates to the technical field of thin films, and particularly relates to a thin film, a preparation method thereof, an optoelectronic device, and a display device. Background Art

[0002] A thin film refers to a two-dimensional material formed by depositing at least one of atoms, molecules, or ions on the surface of a substrate, and the material of the thin film can be at least one of organic compounds and inorganic compounds. The types of thin films include, but are not limited to, optical thin films and semiconductor thin films, and thin films are widely used in the fields of electronics, machinery, printing, etc. Due to process reasons, problems such as cracks are likely to occur in thin films. Summary of the Invention

[0003] Based on this, embodiments of the present application provide a thin film, a preparation method thereof, an optoelectronic device, and a display device.

[0004] In a first aspect, embodiments of the present application provide a thin film, including a first modifying material and an N-type semiconductor material, where the first modifying material includes fulvalene and / or fulvalene derivatives.

[0005] In some embodiments, the fulvalene derivatives include at least one of tetrathiafulvalene, dimethyltetrathiafulvalene, formyltetrathiafulvalene, 4,4'-diphenyltetrathiafulvalene, tetramethyltetraselenafulvalene, bis(trimethylenedithio)tetrathiafulvalene, and tetrakis(methylthio)tetrathiafulvalene; and / or

[0006] The thickness of the thin film is 10 nm to 60 nm.

[0007] In some embodiments, the thin film is a single-layer structure, and the thin film includes a mixture of a first modifying material and an N-type semiconductor material, where the mass ratio of the first modifying material to the N-type semiconductor material is (1 - 5):30;

[0008] Alternatively, the thin film is a single-layer structure, and the thin film includes a mixture of a first modifying material, an N-type semiconductor material, and a second modifying material, where the mass ratio of the first modifying material, the N-type semiconductor material, and the second modifying material is (1 - 5):30:(1 - 5), and the second modifying material includes maleimide and / or maleimide derivatives.

[0009] In some embodiments, the maleimide derivative includes at least one of N-benzyl maleimide, N-phenyl maleimide, N-(1-pyrene) maleimide, 9-maleimide acridine, N-hydroxysuccinimide ester of 3-maleimide propionic acid, N-(4-nitrophenyl) maleimide, N-(4-fluorophenyl) maleimide, 3,4-dibromo maleimide, 6-maleimide hexanoic acid, and 4-maleimide butyric acid.

[0010] In some embodiments, the thin film includes a first sub-layer and a second sub-layer which are stacked, the first sub-layer includes the N-type semiconductor material, the second sub-layer includes the first modification material, and the thickness ratio of the second sub-layer to the first sub-layer is (1-5):30;

[0011] Alternatively, the thin film includes a third sub-layer, a first sub-layer, and a second sub-layer which are stacked in sequence, the first sub-layer includes the N-type semiconductor material, the second sub-layer includes the first modification material, the material of the third sub-layer includes a second modification material, the second modification material includes maleimide and / or maleimide derivative, and the thickness ratio of the third sub-layer, the first sub-layer, and the third sub-layer is (1-5):30:(1-5).

[0012] In some embodiments, the N-type semiconductor material is selected from at least one of metal oxides, doped metal oxides, II-VI group semiconductor materials, III-V group semiconductor materials, and I-III-VI group semiconductor materials; and / or

[0013] The metal oxide is selected from at least one of ZnO, BaO, TiO2, and SnO2; and / or

[0014] The metal oxide in the doped metal oxide is selected from at least one of ZnO, TiO2, and SnO2, and the doping element is selected from at least one of Al, Mg, Li, In, and Ga; and / or

[0015] The II-VI semiconductor group material is selected from at least one of ZnS, ZnSe, and CdS; and / or

[0016] The III-V semiconductor group material is selected from at least one of InP and GaP; and / or

[0017] The I-III-VI group semiconductor material is selected from at least one of CuInS and CuGaS.

[0018] In a second aspect, an embodiment of the present application further provides a method for preparing a thin film, including:

[0019] Provide a composite material solution, the composite material solution comprising a first modifying material, an N-type semiconductor material, and a first solvent, the first modifying material comprising fulvalene and / or a fulvalene derivative;

[0020] Deposit the composite material solution to obtain a thin film.

[0021] In some embodiments, in the composite material solution, the concentration of the first modifying material is 1 mg / ml to 5 mg / ml, and the concentration of the N-type semiconductor material is 10 mg / ml to 50 mg / ml; and / or

[0022] The first solvent in the composite material solution comprises at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropionamide, 1,2-dichloroethane, ethyl acetate, chloroform, dichloromethane, tetrahydrofuran, dinitrotoluene, ethanol, and acetone; and / or

[0023] The depositing the composite material solution to obtain a thin film comprises: depositing the composite material solution to obtain a first wet film layer, and performing a first annealing treatment on the first wet film layer to obtain a thin film, wherein the annealing temperature is 80°C to 120°C, and the annealing time is 5 minutes to 10 minutes.

[0024] In some embodiments, the composite material solution further comprises a second modifying material, the second modifying material comprising maleimide and / or a maleimide derivative, and the concentration of the second modifying material in the composite material solution is 1 mg / ml to 5 mg / ml.

[0025] In a third aspect, an embodiment of the present application further provides a method for preparing a thin film, comprising:

[0026] Provide an N-type semiconductor material solution, the N-type semiconductor material solution comprising an N-type semiconductor material and a second solvent, and deposit the N-type semiconductor material solution to obtain a first sub-layer;

[0027] Provide a first modifying material solution, the first modifying material solution comprising a first modifying material and a third solvent, the first modifying material comprising fulvalene and / or a fulvalene derivative, and deposit the first modifying material solution on the first sub-layer to obtain a second sub-layer, thereby forming a thin film, the thin film comprising the first sub-layer and the second sub-layer stacked.

[0028] In some embodiments, in the N-type semiconductor material solution, the concentration of the N-type semiconductor material is 10 mg / ml to 50 mg / ml; and / or

[0029] The second solvent in the N-type semiconductor material solution comprises at least one of methanol, ethanol, isobutanol, isopropanol, and butanol; and / or

[0030] In the first modifying material solution, the concentration of the first modifying material is 1 mg / ml to 5 mg / ml; and / or

[0031] The third solvent in the first modifying material solution includes at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropionamide, 1,2-dichloroethane, ethyl acetate, chloroform, dichloromethane, tetrahydrofuran, dinitrotoluene, ethanol, and acetone; and / or

[0032] Depositing the N-type semiconductor material solution to obtain the first sub-layer includes: depositing the N-type semiconductor material solution to obtain a second wet film layer, and performing a second annealing treatment on the second wet film layer to obtain the first sub-layer, wherein the annealing temperature is 80°C to 120°C, and the annealing time is 5 minutes to 10 minutes; and / or

[0033] Depositing the first modifying material solution on the first sub-layer to obtain the second sub-layer includes: depositing the first modifying material solution on the first sub-layer to obtain a third wet film layer, and performing a third annealing treatment on the third wet film layer to obtain the second sub-layer, wherein the annealing temperature is 80°C to 120°C, and the annealing time is 5 minutes to 10 minutes; and / or

[0034] The thickness ratio of the second sub-layer to the first sub-layer is (1 - 5):30.

[0035] In some embodiments, before providing the N-type semiconductor material solution, the method for preparing the thin film further includes:

[0036] Providing a second modifying material solution, the second modifying material solution includes a second modifying material and a fourth solvent, the second modifying material includes maleimide and / or maleimide derivatives, and depositing the second modifying material solution to obtain a third sub-layer;

[0037] Depositing the N-type semiconductor material solution includes: depositing the N-type semiconductor material solution on the third sub-layer;

[0038] The thin film includes a third sub-layer, a first sub-layer, and a second sub-layer which are stacked.

[0039] In some embodiments, in the second modifying material solution, the concentration of the second modifying material is 1 mg / ml to 5 mg / ml; and / or

[0040] The fourth solvent in the second modifying material solution includes at least one of methanol, ethanol, isopropanol, butanol, ether, acetone, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropionamide, and tetrahydrofuran; and / or

[0041] Depositing the second modified material solution to obtain a third sub-layer includes: depositing the second modified material solution to obtain a fourth wet film layer, and performing a fourth annealing treatment on the fourth wet film layer to obtain a third sub-layer, where the annealing temperature is 80°C to 120°C and the annealing time is 5 minutes to 10 minutes; and / or

[0042] The thickness ratio of the third sub-layer to the first sub-layer is (1 - 5):30.

[0043] Fourthly, an embodiment of the present application further provides an optoelectronic device, including an anode and a cathode disposed opposite to each other, and N light-emitting unit layers and N - 1 charge generation layers disposed between the anode and the cathode, where one charge generation layer is disposed between every two adjacent light-emitting unit layers, and N is an integer greater than or equal to 2;

[0044] Each light-emitting unit layer includes a stacked light-emitting layer and an electron transport layer, where the electron transport layer is located on the side of the light-emitting layer close to the cathode;

[0045] Wherein, at least one electron transport layer located between the charge generation layer and the light-emitting layer includes the above-mentioned thin film or a thin film prepared by the preparation method of the above-mentioned thin film.

[0046] In some embodiments, the optoelectronic device further includes a stacked hole injection layer and a hole transport layer, the hole injection layer and the hole transport layer are located between the light-emitting unit layer closest to the anode and the anode, and the hole transport layer is located on the side of the hole injection layer close to the cathode; and / or

[0047] Each charge generation layer includes a stacked hole generation layer and an electron generation layer, and in each charge generation layer, the hole generation layer is disposed on the side of the electron generation layer close to the cathode.

[0048] In some embodiments, the anode and the cathode independently include a doped metal oxide particle electrode, a composite electrode, a graphene electrode, a carbon nanotube electrode, a metal elemental electrode, or an alloy electrode. The material of the doped metal oxide particle electrode includes one or more of 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 includes 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, or ZnS / Al / ZnS. The material of the metal elemental electrode includes one or more of Ag, Al, Cu, Mo, Au, Pt, Ca, Mg, and Ba; and / or

[0049] The materials of each light-emitting layer independently include one or more of an organic light-emitting material and a quantum dot light-emitting material. The organic light-emitting material includes one or more of 4,4'-bis(N-carbazolyl)-1,1'-biphenyl: tris[2-(p-tolyl)pyridineiridium(III)], 4,4',4''-tris(carbazol-9-yl)triphenylamine: tris[2-(p-tolyl)pyridineiridium], diarylanthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent material, TTPX fluorescent material, TBRb fluorescent material, DBP fluorescent material, delayed fluorescence material, TTA material, thermally activated delayed material, polymer containing B-N covalent bond, hybrid local charge transfer excited state material, exciplex light-emitting material, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, polyfluorene and its derivatives;The quantum dot luminescent material includes one or more of single-structure quantum dots, core-shell structure quantum dots, and perovskite semiconductor materials. The materials of the single-structure quantum dots, the core materials of the core-shell structure quantum dots, and the shell materials of the core-shell structure quantum dots are each independently selected from one or more of II-VI group compounds, IV-VI group compounds, III-V group compounds, and I-III-VI group compounds. The II-VI group compounds include 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 include 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 group compounds include 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 I-III-VI group compounds include one or more of CuInS2, CuInSe2, and AgInS2. The perovskite semiconductor material includes doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors. The structural general formula of the inorganic perovskite semiconductor is AMX3, where A is Cs; + ion, M is a divalent metal cation, including Pb 2+ , Sn 2+ , Cu 2+ , Ni2+ 、Cd 2+ Cr 2+ , Mn 2+ 、Co 2+ , Fe 2+ ,Ge 2+ , Yb 2+ 、Eu 2+ One or more of, X is a halogen anion, including Cl - Br - ,I - One or more of; the general structural formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, wherein 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, X is a halogen anion, including Cl - Br - ,I - One or more of; and / or

[0050] The materials of the hole transport layer include one or more of 4,4'-N,N'-dicarbazolyl-biphenyl, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], 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, poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine), 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(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(N-vinylcarbazole) and its derivatives, N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4-4'-diamine, spiro-NPB, poly(phenylene vinylene), poly[2-methoxy-5-(2-ethylhexoxy)-1,4-phenylene vinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene], 2,2',7,7'-tetra[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene, 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline], 1,3-bis(carbazol-9-yl)benzene, polyaniline, polypyrrole, poly(p-phenylene vinylene), aromatic tertiary amines, polynuclear aromatic tertiary amines, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, doped graphene, undoped graphene, C60, doped or undoped NiO, doped or undoped MoO3, doped or undoped WO3, doped or undoped V2O5, doped or undoped p-type gallium nitride, doped or undoped CrO3, doped or undoped CuO; and / or

[0051] The materials of the hole injection layer and the materials of each hole generation layer independently include one or more of 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, PEDOT, PEDOT:PSS, derivatives of PEDOT:PSS doped with s-MoO3, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, tetracyanoquinodimethane, copper phthalocyanine, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide, molybdenum sulfide, tungsten sulfide and copper oxide.

[0052] In a fifth aspect, an embodiment of the present application further provides a display device, including the optoelectronic device as described above.

[0053] The thin film in the embodiment of the present application contains a first modifying material, and the first modifying material includes fulvalene and / or fulvalene derivatives. Since both fulvalene and fulvalene derivatives can form stable chemical bonds with the N-type semiconductor material, the N-type semiconductor materials in the thin film can be connected to form a stable structure, thereby improving or eliminating the crack phenomenon of the thin film. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments.

[0055] Figure 1 FIG. 1 is a schematic diagram of the first structure of the thin film provided by the embodiment of the present application.

[0056] Figure 2 FIG. 2 is a schematic diagram of the second structure of the thin film provided by the embodiment of the present application.

[0057] Figure 3 FIG. 3 is a schematic diagram of the third structure of the thin film provided by the embodiment of the present application.

[0058] Figure 4 FIG. 4 is a first flowchart of the preparation method of the thin film provided by the embodiment of the present application.

[0059] Figure 5 FIG. 5 is a second flowchart of the preparation method of the thin film provided by the embodiment of the present application.

[0060] Figure 6 FIG. 6 is a schematic diagram of the structure of the optoelectronic device provided by the embodiment of the present application.

[0061] Figure 7 FIG. 7 is an electron microscope photograph of the optoelectronic device prepared in Example 1 of the device of the present application.

[0062] Figure 8 FIG. 8 is an electron microscope photograph of the optoelectronic device prepared in Comparative Example 1 of the device of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0063] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application.

[0064] In this application, "and / or" describes the relationship between associated objects and indicates that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, or B exists alone. Here, A and B can be singular or plural.

[0065] In this application, "at least one" means one or more, and "a plurality" means two or more. "At least one kind", "at least one of the following items" or similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can both represent: a, b, c, a + b, a + c, b + c, or a + b + c, where a, b, and c can be single or plural respectively.

[0066] In this application, forming another layer "on" a certain layer, the so-called "on" is a broad concept, which can mean that the formed another layer is adjacent to a certain layer, or there are other spacer structure layers between another layer and a certain layer. For example, forming a second electrode "on" the first carrier functional layer, the so-called "on" can mean that the formed second electrode is adjacent to the first carrier functional layer, or there are other spacer structure layers between the second electrode and the first carrier functional layer, such as a light-emitting layer.

[0067] "Parts by weight" refers to the basic measurement unit representing the mass ratio relationship of multiple components. 1 part can represent any unit mass, such as 1 g, 1 Kg, or it can also represent 2 g, 2 Kg, etc. Suppose we say that the parts by weight of component A is a parts, and the parts by weight of component B is b parts, then it represents the mass ratio of component A to component B as a:b. Or, it represents that the mass of component A is aK and the mass of component B is bK (K is any number representing a multiple factor). It should not be misunderstood that, different from the number of parts by weight, the sum of the parts by weight of all components is not limited to 100 parts.

[0068] Please refer to Figure 1 , an embodiment of this application provides a thin film 61, which includes a first modifying material and an N-type semiconductor material, and the first modifying material includes fulvalene and / or fulvalene derivatives.

[0069] Exemplarily, the fulvalene derivatives include at least one of tetrathiafulvalene, dimethyltetrathiafulvalene, formyltetrathiafulvalene, 4,4'-diphenyltetrathiafulvalene, tetramethyltetraselenafulvalene, bis(trimethylenedithio)tetrathiafulvalene, and tetrakis(methylthio)tetrathiafulvalene.

[0070] Exemplarily, the thickness of the thin film 61 is 10 nm to 60 nm, such as 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 60 nm, etc.

[0071] Please refer to Figure 1 , exemplarily, the thin film may be a single-layer structure, and the thin film includes a mixture of a first modifying material and an N-type semiconductor material, wherein the mass ratio of the first modifying material to the N-type semiconductor material is (1 - 5):30, such as 1:30, 2:30, 3:30, 4:30, 5:30, etc.

[0072] It can be understood that when the material of the thin film 61 is a composite material, it means that the first modifying material and the N-type semiconductor material are mixed with each other. At this time, the first modifying material (fulvalene and / or fulvalene derivative) can combine with the metal element on the surface of the N-type semiconductor material to form a stable chemical bond, so that the N-type semiconductor materials in the thin film 61 can be connected to form a stable structure, thereby improving the density of the thin film 61 and enhancing the solvent resistance of the thin film 61, and further improving or eliminating the crack phenomenon of the thin film 61.

[0073] Please refer to Figure 1 , exemplarily, the thin film is a single-layer structure, and the thin film includes a mixture of a first modifying material, an N-type semiconductor material, and a second modifying material. The second modifying material includes maleimide and / or maleimide derivative, wherein the mass ratio of the first modifying material, the N-type semiconductor material, and the second modifying material is (1 - 5):30:(1 - 5), such as 1:30:1, 2:30:2, 3:30:3, 4:30:4, 5:30:5, 1:30:3, 2:30:5, 2:30:4, etc.

[0074] Exemplarily, the maleimide derivative includes at least one of N-benzyl maleimide, N-phenyl maleimide, N-(1-pyrene) maleimide, 9-maleimide acridine, N-hydroxysuccinimide ester of 3-maleimide propionic acid, N-(4-nitrophenyl) maleimide, N-(4-fluorophenyl) maleimide, 3,4-dibromo maleimide, 6-maleimide hexanoic acid, 4-maleimide butyric acid.

[0075] It can be understood that when the composite material further includes a second modifying material (maleimide and / or maleimide derivative), it means that the composite material simultaneously contains a first modifying material, an N-type semiconductor material, and a first modifying material (fulvalene and / or fulvalene derivative). Since the electron density in the first modifying material (fulvalene and / or fulvalene derivative) is relatively large (electron-rich), and the electron density in the second modifying material (maleimide and maleimide derivative) is relatively small (electron-deficient), electrons can easily flow between the first modifying material and the second modifying material. Therefore, the electron transport performance of the thin film 61 can be improved.

[0076] Please refer to Figure 2 , the thin film 61 includes a first sub-layer 611 and a second sub-layer 612 arranged in a stacked manner. The first sub-layer 611 includes the N-type semiconductor material, and the material of the second sub-layer 612 includes the first modifying material. The thickness ratio of the second sub-layer 612 to the first sub-layer 611 is (1 - 5):30, such as 1:30, 2:30, 3:30, 4:30, 5:30, etc.

[0077] It can be understood that when the thin film 61 includes a first sub-layer 611 and a second sub-layer 612 arranged in a stacked manner, it means that the first modifying material and the N-type semiconductor material respectively form film layers independently. At this time, at the interface between the second sub-layer 612 and the first sub-layer 611, the first modifying material (fulvalene and / or fulvalene derivative) can combine with the metal element on the surface of the N-type semiconductor material to form a stable chemical bond, enabling the N-type semiconductor materials in the thin film 61 to be connected to form a stable structure. Thus, the density of the thin film 61 can be increased, the solvent resistance of the thin film 61 can be improved, and the crack phenomenon of the thin film 61 can be improved or eliminated.

[0078] Please refer to Figure 3 , the thin film 61 further includes a third sub-layer 613, a first sub-layer 611, and a second sub-layer 612 arranged in a stacked manner in sequence. The first sub-layer 611 includes the N-type semiconductor material, the material of the second sub-layer 612 includes the first modifying material, and the material of the third sub-layer 613 includes a second modifying material. The second modifying material includes maleimide and / or maleimide derivative. The thickness ratio of the third sub-layer 613, the first sub-layer 611, and the second sub-layer 612 is (1 - 5):30:(1 - 5), such as 1:30:1, 2:30:2, 3:30:3, 4:30:4, 5:30:5, 1:30:3, 2:30:5, 2:30:4, etc.

[0079] It can be understood that when the thin film 61 includes a third sub-layer 613, a first sub-layer 611, and a second sub-layer 612 that are sequentially stacked, since the electron density in the material (fulvalene and / or fulvalene derivative) of the second sub-layer 612 is relatively large (electron-rich), and the electron density in the material (maleimide and maleimide derivative) of the third sub-layer 613 is relatively small (electron-deficient), electrons are prone to flow in the direction from the second sub-layer 612 to the third sub-layer 613, thereby improving the electron transport performance of the thin film 61.

[0080] Exemplarily, the N-type semiconductor material includes at least one of metal oxides, doped metal oxides, group II-VI semiconductor materials, group III-V semiconductor materials, and group I-III-VI semiconductor materials; the metal oxide is selected from at least one of ZnO, BaO, TiO2, and SnO2; the metal oxide in the doped metal oxide is selected from at least one of ZnO, TiO2, and SnO2, and the doping element is selected from at least one of Al, Mg, Li, In, and Ga; the group II-VI semiconductor material is selected from at least one of ZnS, ZnSe, and CdS; the group III-V semiconductor material is selected from at least one of InP and GaP; the group I-III-VI semiconductor material is selected from at least one of CuInS and CuGaS.

[0081] The thin film 61 provided by the embodiment of the present application contains a first modifying material, and the first modifying material includes fulvalene and / or fulvalene derivative. Since both fulvalene and fulvalene derivative can form stable chemical bonds with the metal elements on the surface of the N-type semiconductor material, the N-type semiconductor materials in the thin film 61 can be connected to form a stable structure, thereby improving the density of the thin film 61 and enhancing the solvent resistance of the thin film 61, and further improving or eliminating the crack phenomenon of the thin film 61. When the thin film 61 is applied to optoelectronic devices, the electrical performance of the optoelectronic devices can be improved.

[0082] It can be understood that when the density of the thin film 61 is increased, the electron transport performance of the thin film 61 can also be improved, thereby enhancing the light emission efficiency of the optoelectronic device.

[0083] Please refer to Figure 4 and, in combination with Figure 1 The embodiment of the present application provides a method for preparing a thin film, including:

[0084] S110, providing a composite material solution, the composite material solution including a first modifying material, an N-type semiconductor material, and a first solvent, and the first modifying material includes fulvalene and / or fulvalene derivative.

[0085] S120, depositing the composite material solution to obtain the thin film 61.

[0086] Exemplarily, in the composite material solution, the concentration of the first modification material is 1 mg / ml to 5 mg / ml (such as 1 mg / ml, 2 mg / ml, 3 mg / ml, 4 mg / ml, 5 mg / ml, etc.), and the concentration of the N-type semiconductor material is 10 mg / ml to 50 mg / ml (such as 10 mg / ml, 15 mg / ml, 20 mg / ml, 25 mg / ml, 30 mg / ml, 35 mg / ml, 40 mg / ml, 45 mg / ml, 50 mg / ml, etc.).

[0087] It should be noted that the reason for setting the concentration of the N-type semiconductor material in the composite material solution to 10 mg / ml to 50 mg / ml is as follows: when the concentration of the N-type semiconductor material is greater than 50 mg / ml, due to the too high concentration, the collision of the N-type semiconductor material in the solution will be accelerated, and the phenomenon of agglomeration of the N-type semiconductor material is more likely to occur. When the concentration of the N-type semiconductor material is less than 10 mg / ml, due to the low concentration, the thickness of the prepared thin film 61 will be too thin and the film thickness will be uneven.

[0088] Exemplarily, the first solvent in the composite material solution includes at least one of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMEAA), N,N-dimethylpropionamide (DMPA), 1,2-dichloroethane, ethyl acetate, chloroform, dichloromethane, tetrahydrofuran (THF), dinitrotoluene, ethanol, and acetone.

[0089] Exemplarily, depositing the composite material solution to obtain the thin film 61 includes: depositing the composite material solution to obtain a first wet film layer, and performing a first annealing treatment on the first wet film layer to obtain the thin film 61, wherein the annealing temperature is 80 °C to 120 °C (such as 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, etc.), and the annealing time is 5 minutes to 10 minutes (such as 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, etc.).

[0090] It should be noted that the reason for choosing the annealing temperature of 80 °C to 120 °C is as follows: when the annealing temperature is higher than 120 °C, the ligands on the surface of the N-type semiconductor material (such as zinc oxide nanoparticles) will be inactivated, increasing the steric hindrance and reducing the electron transport efficiency. When the annealing temperature is lower than 80 °C, the solvent in the thin film 61 cannot be completely removed, resulting in a low density of the thin film 61. Therefore, when preparing other functional thin films on the thin film 61 later, the material of the thin film 61 will be washed away.

[0091] Exemplarily, the composite material solution further includes a second modifying material, the second modifying material includes maleimide and / or maleimide derivatives, and the concentration of the second modifying material in the composite material solution is 1 mg / ml to 5 mg / ml (such as 1 mg / ml, 2 mg / ml, 3 mg / ml, 4 mg / ml, 5 mg / ml, etc.).

[0092] Please refer to Figure 5 , and at the same time in combination with Figure 2 , an embodiment of the present application provides a method for preparing a thin film, including:

[0093] S210, providing an N-type semiconductor material solution, the N-type semiconductor material solution includes an N-type semiconductor material and a second solvent, depositing the N-type semiconductor material solution to obtain a first sub-layer 611.

[0094] Exemplarily, in the N-type semiconductor material solution, the concentration of the N-type semiconductor material is 10 mg / ml to 50 mg / ml, such as 10 mg / ml, 15 mg / ml, 20 mg / ml, 25 mg / ml, 30 mg / ml, 35 mg / ml, 40 mg / ml, 45 mg / ml, 50 mg / ml, etc.

[0095] It should be noted that the reason for setting the concentration of the N-type semiconductor material in the N-type semiconductor material solution to 10 mg / ml to 50 mg / ml is as follows: when the concentration of the N-type semiconductor material is greater than 50 mg / ml, due to the too high concentration, the collision of the N-type semiconductor material in the solution will be accelerated, and the phenomenon of agglomeration of the N-type semiconductor material is more likely to occur. When the concentration of the N-type semiconductor material is less than 10 mg / ml, due to the low concentration, the thickness of the obtained first sub-layer will be too thin and the film thickness will be uneven.

[0096] Exemplarily, the second solvent in the N-type semiconductor material solution includes at least one of methanol, ethanol, isobutanol, isopropanol, and butanol.

[0097] Exemplarily, depositing the N-type semiconductor material solution to obtain a first sub-layer includes: depositing the N-type semiconductor material solution to obtain a second wet film layer, and performing a second annealing treatment on the second wet film layer to obtain a first sub-layer, where the annealing temperature is 80°C to 120°C (such as 80°C, 90°C, 100°C, 110°C, 120°C, etc.), and the annealing time is 5 minutes to 10 minutes (such as 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, etc.).

[0098] It should be noted that the reason for selecting the annealing temperature of 80°C to 120°C is as follows: When the annealing temperature is higher than 120°C, the ligands on the surface of the N-type semiconductor material (such as zinc oxide nanoparticles) will be deactivated, increasing the steric hindrance and reducing the electron transport efficiency. When the annealing temperature is lower than 80°C, the solvent in the first sub-layer 611 cannot be completely removed, resulting in a lower density of the first sub-layer 611. Therefore, when preparing other functional thin films on the first sub-layer 611 later, the material of the first sub-layer 611 will be washed away.

[0099] S220, please combine Figure 2 , provide a first modifier material solution, the first modifier material solution includes a first modifier material and a third solvent, the first modifier material includes fulvalene and / or fulvalene derivatives, deposit the first modifier material solution on the first sub-layer 611 to obtain a third wet film layer, perform annealing treatment on the third wet film layer to obtain a second sub-layer 612, and form a thin film 61, the thin film 61 includes a first sub-layer 611 and a second sub-layer 612 arranged in a stacked manner.

[0100] Exemplarily, in the first modifier material solution, the concentration of the first modifier material is 1 mg / ml to 5 mg / ml, such as 1 mg / ml, 2 mg / ml, 3 mg / ml, 4 mg / ml, 5 mg / ml, etc.

[0101] Exemplarily, the third solvent in the first modifier material solution includes at least one of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMEAA), N,N-dimethylpropionamide (DMPA), 1,2-dichloroethane, ethyl acetate, chloroform, dichloromethane, tetrahydrofuran (THF), dinitrotoluene, ethanol, and acetone.

[0102] Exemplarily, the thickness ratio of the second sub-layer 612 to the first sub-layer 611 is (1 - 5):30, such as 1:30, 2:30, 3:30, 4:30, 5:30, etc.

[0103] Exemplarily, depositing the first modifier material solution on the first sub-layer to obtain the second sub-layer includes: depositing the first modifier material solution on the first sub-layer to obtain a third wet film layer, performing a third annealing treatment on the third wet film layer to obtain a second sub-layer, wherein the annealing temperature is 80°C to 120°C (such as 80°C, 90°C, 100°C, 110°C, 120°C, etc.), and the annealing time is 5 minutes to 10 minutes (such as 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, etc.).

[0104] Exemplarily, please combine Figure 3 , before providing the N-type semiconductor material solution, the method for preparing the thin film further includes:

[0105] A second modifying material solution is provided, the second modifying material solution includes a second modifying material and a fourth solvent, the second modifying material includes maleimide and / or maleimide derivatives, and the second modifying material solution is deposited to obtain a third sub-layer 613;

[0106] At this time, depositing the N-type semiconductor material solution includes: depositing the N-type semiconductor material solution on the third sub-layer 613;

[0107] The thin film 61 includes a third sub-layer 613, a first sub-layer 611, and a second sub-layer 612 which are stacked.

[0108] Exemplarily, in the second modifying material solution, the concentration of the second modifying material is 1 mg / ml to 5 mg / ml, such as 1 mg / ml, 2 mg / ml, 3 mg / ml, 4 mg / ml, 5 mg / ml, etc.

[0109] Exemplarily, the fourth solvent in the second modifying material solution includes at least one of methanol, ethanol, isopropanol, butanol, ether, acetone, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAC), N,N-dimethylpropionamide (DMPA), and tetrahydrofuran (THF).

[0110] Exemplarily, depositing the second modifying material solution to obtain a third sub-layer includes: depositing the second modifying material solution to obtain a fourth wet film layer, and performing a fourth annealing treatment on the fourth wet film layer to obtain a third sub-layer, wherein the annealing temperature is 80 °C to 120 °C (such as 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, etc.), and the annealing time is 5 minutes to 10 minutes (such as 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, etc.).

[0111] Exemplarily, the thickness ratio of the third sub-layer 613, the first sub-layer 611, and the second sub-layer 612 is (1 - 5):30:(1 - 5), such as 1:30:1, 2:30:2, 3:30:3, 4:30:4, 5:30:5, 1:30:3, 2:30:5, 2:30:4, etc.

[0112] Please refer to Figure 6 and at the same time combine with Figures 1 to 3 In addition, an optoelectronic device 100 is further provided in an embodiment of the present application, including an anode 21 and a cathode 22 which are oppositely arranged, and N light-emitting unit layers 30 and N - 1 charge generation layers 40 arranged between the anode 21 and the cathode 22. A charge generation layer 40 is arranged between every two adjacent light-emitting unit layers 30, wherein N is an integer greater than or equal to 2.

[0113] Each light-emitting unit layer 30 includes a stacked light-emitting layer 31 and an electron transport layer 32, wherein the electron transport layer 32 is located on a side of the light-emitting layer 31 close to the cathode 22.

[0114] Wherein, at least one electron transport layer 32 located between the charge generation layer 40 and the light-emitting layer 31 includes the thin film 61 in any of the above embodiments or the thin film 61 prepared by the preparation method of the thin film 61 in any of the above embodiments.

[0115] Please refer to Figure 6 , the optoelectronic device 100 further includes a stacked hole injection layer 50 and a hole transport layer 70. The hole injection layer 50 and the hole transport layer 70 are located between the anode 21 and a light-emitting unit layer 30 closest to the anode 21, and the hole transport layer 70 is located on a side of the hole injection layer 50 close to the cathode 22.

[0116] Please refer to Figure 6 , each charge generation layer 40 includes a stacked hole generation layer 42 and an electron generation layer 41. In each charge generation layer 40, the hole generation layer 42 is disposed on a side of the electron generation layer 41 close to the cathode 22.

[0117] It should be noted that in existing multi-light-emitting layer devices (stacked devices), the charge separation efficiency of the charge generation layer is usually low, resulting in carrier imbalance and low light-emitting efficiency inside the multi-light-emitting layer device (stacked device). In the embodiments of the present application, by providing at least one electron transport layer 32 located between the charge generation layer 40 and the light-emitting layer 31 to include the thin film 61, since the thin film 61 has good electron transport performance, the separation of electrons and holes in the charge generation layer 30 can be promoted, the charge separation efficiency can be improved, and thus the carrier balance inside the optoelectronic device 100 can be promoted.

[0118] Exemplarily, the anode 21 and the cathode 22 each independently include a doped metal oxide particle electrode, a composite electrode, a graphene electrode, a carbon nanotube electrode, a metal elemental electrode, or an alloy electrode. The material of the doped metal oxide particle electrode includes one or more of 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 includes 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, or ZnS / Al / ZnS. The material of the metal elemental electrode includes one or more of Ag, Al, Cu, Mo, Au, Pt, Ca, Mg, and Ba.

[0119] Exemplarily, the materials of each light-emitting layer 31 independently include one or more of an organic light-emitting material and a quantum dot light-emitting material. The organic light-emitting material includes one or more of 4,4'-bis(N-carbazolyl)-1,1'-biphenyl: tris[2-(p-tolyl)pyridineiridium(III)], 4,4',4''-tris(carbazol-9-yl)triphenylamine: tris[2-(p-tolyl)pyridineiridium, a diarylanthracene derivative, a stilbene aromatic derivative, a pyrene derivative, a fluorene derivative, a TBPe fluorescent material, a TTPX fluorescent material, a TBRb fluorescent material, a DBP fluorescent material, a delayed fluorescence material, a TTA material, a thermally activated delayed material, a polymer containing a B-N covalent bond, a hybrid locally charge transfer excited state material, an exciplex light-emitting material, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, polyfluorene and its derivatives;The quantum dot light-emitting material includes one or more of single-structure quantum dots, core-shell structure quantum dots, and perovskite semiconductor materials. The materials of the single-structure quantum dots, the core materials of the core-shell structure quantum dots, and the shell materials of the core-shell structure quantum dots are each independently selected from one or more of II-VI group compounds, IV-VI group compounds, III-V group compounds, and I-III-VI group compounds. The II-VI group compounds include 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 include 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 group compounds include 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 I-III-VI group compounds include one or more of CuInS2, CuInSe2, and AgInS2. The perovskite semiconductor material includes doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors. The structural general formula of the inorganic perovskite semiconductor is AMX3, where A is Cs; + ions, M is a divalent metal cation, including Pb 2+ , Sn 2+ , Cu 2+ , Ni2+ 、Cd 2+ 、Cr 2+ 、Mn 2+ 、Co 2+ 、Fe 2+ 、Ge 2+ 、Yb 2+ 、Eu 2+ One or more of Cd, Cr, Mn, Co, Fe, Ge, Yb, Eu, where X is a halogen anion including Cl - 、Br - 、I - One or more of Br, I; the structural general 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 Pb, Sn, Cu, Ni, Cd, Cr, Mn, Co, Fe, Ge, Yb, Eu, where X is a halogen anion including Cl - 、Br - 、I - One or more of Br, I.

[0120] Exemplarily, the material of the hole transport layer 70 includes one or more of 4,4'-N,N'-dicarbazolyl-biphenyl, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], 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, poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine), 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(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(N-vinylcarbazole) and its derivatives, N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4-4'-diamine, spiro-NPB, poly(phenylene vinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene], 2,2',7,7'-tetra[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene, 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline], 1,3-bis(carbazol-9-yl)benzene, polyaniline, polypyrrole, poly(p-phenylene vinylene), aromatic tertiary amines, polynuclear aromatic tertiary amines, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, doped graphene, undoped graphene, C60, doped or undoped NiO, doped or undoped MoO3, doped or undoped WO3, doped or undoped V2O5, doped or undoped p-type gallium nitride, doped or undoped CrO3, doped or undoped CuO.

[0121] Exemplarily, the material of the hole injection layer 50 and the material of each hole generation layer 42 independently include one or more of 2,3,6,7,10,11 - hexacyano - 1,4,5,8,9,12 - hexaazatriphenylene, PEDOT, PEDOT:PSS, derivatives of PEDOT:PSS doped with s - MoO3, 4,4',4' - tris(N - 3 - methylphenyl - N - phenylamino)triphenylamine, tetracyanoquinodimethane, copper phthalocyanine, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide, molybdenum sulfide, tungsten sulfide, and copper oxide.

[0122] Please refer to Figure 3 , when the thin film 61 includes a third sub - layer 613, a first sub - layer 611, and a second sub - layer 612 arranged in a stacked manner, the third sub - layer 613, the first sub - layer 611, and the second sub - layer 612 are sequentially stacked in the direction from the anode 21 to the cathode 22. It should be noted that, due to the relatively large electron density (electron - rich) in the material (fulvalene and / or fulvalene derivatives) of the second sub - layer 612 and the relatively small electron density (electron - deficient) in the material (maleimide and maleimide derivatives) of the third sub - layer 613, electrons are likely to flow in the direction from the second sub - layer 612 to the third sub - layer 613, thereby improving the electron transport performance of the thin film 61. Since the direction from the second sub - layer 612 to the third sub - layer 613 is the same as the direction from the cathode (the second electrode 22) to the first light - emitting layer 51, it is beneficial for electrons in the cathode to be transferred to the first light - emitting layer 51, and thus the light - emitting efficiency of the first light - emitting layer 51 can be improved.

[0123] Exemplarily, the material of one electron transport layer 32 closest to the cathode 22 may include at least one of metal oxides, doped metal oxides, group II - VI semiconductor materials, group III - V semiconductor materials, and group I - III - VI semiconductor materials; the metal oxides are selected from at least one of ZnO, BaO, TiO2, and SnO2; the metal oxides in the doped metal oxides are selected from at least one of ZnO, TiO2, and SnO2, and the doping elements are selected from at least one of Al, Mg, Li, In, and Ga; the group II - VI semiconductor materials are selected from at least one of ZnS, ZnSe, and CdS; the group III - V semiconductor materials are selected from at least one of InP and GaP; the group I - III - VI semiconductor materials are selected from at least one of CuInS and CuGaS.

[0124] Exemplarily, the material of the electron generation layer 31 (CGL - N) includes one or more of phosphomolybdic acid (PMA), molybdenum oxide (MoO3), phosphotungstic acid, and tungsten trioxide (WO3).

[0125] Exemplarily, the thickness of each of the anode 21 and the cathode 22 is 10 nm - 120 nm, such as 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, etc.

[0126] Exemplarily, the thickness of the hole injection layer 50 is 10 nm - 50 nm, such as 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, etc.

[0127] Exemplarily, the thickness of the hole transport layer 70 is 10 nm - 50 nm, such as 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, etc.

[0128] Exemplarily, the thickness of the light-emitting layer 31 is 10 nm - 50 nm, such as 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, etc.

[0129] Exemplarily, the thickness of the electron transport layer 32 is 10 nm - 50 nm, such as 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, etc.

[0130] Exemplarily, the thickness of the charge generation layer 40 is 20 nm - 70 nm, such as 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, etc.

[0131] Exemplarily, the thickness of the electron generation layer 41 is 10 nm - 20 nm, such as 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, etc.

[0132] Exemplarily, the thickness of the hole generation layer 42 is 10 nm - 50 nm, such as 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, etc.

[0133] The embodiment of the present application further provides a display device, including the optoelectronic device 100 in any of the above embodiments or the optoelectronic device 100 prepared by the preparation method of the optoelectronic device in any of the above embodiments.

[0134] Exemplarily, the display device can be a terminal such as a television, a mobile phone, a tablet computer, a display, an advertising display screen, etc., and can also be a device with a display screen such as a game device, an Augmented Reality (AR) device, a Virtual Reality (VR) device, a data storage device, an audio playback device, a video playback device, a wearable device, etc., where the wearable device can be a smart bracelet, smart glasses, a smart watch, a smart decoration, etc.

[0135] The thin films of the present application, their preparation methods, and optoelectronic devices will be described in detail below in the form of specific embodiments.

[0136] Thin Film Example 1

[0137] A thin film, the preparation method of which includes:

[0138] Step 11: Provide a composite material solution, the composite material solution includes a first modifying material (tetrathiafulvalene), an N-type semiconductor material (ZMO), and a first solvent (ethanol). The concentration of the first modifying material (tetrathiafulvalene) is 3 mg / ml, and the concentration of the N-type semiconductor material (ZMO) is 30 mg / ml. Among them, tetrathiafulvalene is purchased from Aladdin Reagent (Shanghai) Co., Ltd., with a CAS number of 31366-25-3, a molecular formula of C6H4S4, and a molecular weight of 204.36;

[0139] Step 12: Deposit the composite material solution to obtain a first wet film layer, and perform annealing treatment on the first wet film layer (heat at 80 °C for 10 minutes) to obtain a thin film. The thickness of the thin film is 40 nm. The thin film is a single-layer structure and includes a mixture of a first modifying material and an N-type semiconductor material. Among them, the mass ratio of the first modifying material to the N-type semiconductor material is 3:30.

[0140] Thin Film Example 2

[0141] A thin film, the difference in its preparation method compared with Thin Film Example 1 is that:

[0142] In Step 11, in the composite material solution, the concentration of the first modifying material (tetrathiafulvalene) is 1 mg / ml;

[0143] In Step 12, in the obtained thin film, the mass ratio of the first modifying material to the N-type semiconductor material is 1:30.

[0144] Thin Film Example 3

[0145] A thin film, the difference in its preparation method compared with Thin Film Example 1 is that:

[0146] In Step 11, in the composite material solution, the concentration of the first modifying material (tetrathiafulvalene) is 5 mg / ml;

[0147] In Step 12, in the obtained thin film, the mass ratio of the first modifying material to the N-type semiconductor material is 5:30.

[0148] Thin Film Example 4

[0149] A thin film, the difference in its preparation method compared with Thin Film Example 1 is that:

[0150] In Step 11, in the composite material solution, the first modifying material is dimethyltetrathiafulvalene, and the concentration of dimethyltetrathiafulvalene is 3 mg / ml; among them, dimethyltetrathiafulvalene is purchased from Aladdin Reagent (Shanghai) Co., Ltd., and the MDL number is MFCD00143230.

[0151] Film Example 5

[0152] A film, compared with Film Example 1 in its preparation method, the difference lies in:

[0153] In Step 11, the composite material solution includes a first modifying material (tetrathiafulvalene), an N-type semiconductor material (ZMO), a first solvent (ethanol), and a second modifying material (N-phenylmaleimide). The concentration of the first modifying material (tetrathiafulvalene) is 3 mg / ml, the concentration of the N-type semiconductor material (ZMO) is 30 mg / ml, and the concentration of the second modifying material (N-phenylmaleimide) is 3 mg / ml; among them, N-phenylmaleimide is purchased from Aladdin Reagent (Shanghai) Co., Ltd., the CAS number is 941-69-5, and the molecular formula is C 10 H7NO2, and the molecular weight is 173.17;

[0154] In Step 12, the prepared film includes a mixture of the first modifying material, the N-type semiconductor material, and the second modifying material. Among them, the mass ratio of the first modifying material, the N-type semiconductor material, and the second modifying material is 3:30:3.

[0155] Film Example 6

[0156] A film, compared with Film Example 5 in its preparation method, the difference lies in:

[0157] In Step 11, in the composite material solution, the concentration of the second modifying material (N-phenylmaleimide) is 1 mg / ml;

[0158] In Step 12, in the prepared film, the mass ratio of the first modifying material, the N-type semiconductor material, and the second modifying material is 3:30:1.

[0159] Film Example 7

[0160] A film, compared with Film Example 5 in its preparation method, the difference lies in:

[0161] In Step 11, in the composite material solution, the concentration of the second modifying material (N-phenylmaleimide) is 5 mg / ml;

[0162] In Step 12, in the prepared film, the mass ratio of the first modifying material, the N-type semiconductor material, and the second modifying material is 3:30:5.

[0163] Thin Film Example 8

[0164] A thin film, the preparation method of which comprises:

[0165] Step 21: Provide an N-type semiconductor material solution, the N-type semiconductor material solution comprising an N-type semiconductor material (ZMO) and a second solvent (ethanol), deposit the N-type semiconductor material solution to obtain a second wet film layer, and perform annealing treatment on the second wet film layer (heat at 80 °C for 10 minutes) to obtain a first sub-layer (thickness 36.4 nm);

[0166] Step 22: Provide a first modification material solution, the first modification material solution comprising a first modification material (tetrathiafulvalene) and a third solvent (ethanol), deposit the first modification material solution on the first sub-layer to obtain a third wet film layer, and perform annealing treatment on the third wet film layer (heat at 80 °C for 10 minutes) to obtain a second sub-layer (thickness 3.6 nm), thereby forming a thin film, the thin film comprising the first sub-layer and the second sub-layer arranged in a stacked manner, and the thickness ratio of the second sub-layer to the first sub-layer is 3:30.

[0167] Thin Film Example 9

[0168] A thin film, the preparation method of which comprises:

[0169] Step 21: Provide a second modification material solution, the second modification material solution comprising a second modification material (N-phenylmaleimide) and a third solvent (ethanol), deposit the second modification material solution to obtain a fourth wet film layer, and perform annealing treatment on the fourth wet film layer (heat at 80 °C for 10 minutes) to obtain a third sub-layer (thickness 3.3 nm);

[0170] Step 22: Provide an N-type semiconductor material solution, the N-type semiconductor material solution comprising an N-type semiconductor material (ZMO) and a second solvent (ethanol), deposit the N-type semiconductor material solution on the third sub-layer to obtain a second wet film layer, and perform annealing treatment on the second wet film layer (heat at 80 °C for 10 minutes) to obtain a first sub-layer (thickness 33.4 nm);

[0171] Step 23: Provide a first modification material solution, the first modification material solution comprising a first modification material (tetrathiafulvalene) and a third solvent (ethanol), deposit the first modification material solution on the first sub-layer to obtain a third wet film layer, and perform annealing treatment on the third wet film layer (heat at 80 °C for 10 minutes) to obtain a second sub-layer (thickness 3.3 nm), thereby forming a thin film, the thin film comprising the third sub-layer, the first sub-layer and the second sub-layer arranged in a stacked manner in sequence, and the thickness ratio of the third sub-layer, the first sub-layer and the second sub-layer is 3:30:3.

[0172] It can be seen that, compared with Thin Film Example 8, the difference lies in that a third sub-layer is added below the first sub-layer in the thin film obtained in Thin Film Example 9.

[0173] Thin Film Example 10

[0174] A thin film, compared with Thin Film Example 1 in its preparation method, the differences are as follows:

[0175] In step 11, in the composite material solution, the concentration of the first modifier material (tetrathiafulvalene) is 10 mg / ml;

[0176] In step 12, in the obtained thin film, the mass ratio of the first modifier material to the N-type semiconductor material is 10:30.

[0177] Thin Film Example 11

[0178] A thin film, compared with Thin Film Example 5 in its preparation method, the differences are as follows:

[0179] In step 11, in the composite material solution, the concentration of the second modifier material (N-phenylmaleimide) is 10 mg / ml;

[0180] In step 12, in the obtained thin film, the mass ratio of the first modifier material, the N-type semiconductor material to the second modifier material is 3:30:10.

[0181] Thin Film Comparative Example 1

[0182] A thin film, its preparation method includes:

[0183] Providing an N-type semiconductor material solution, the N-type semiconductor material solution includes an N-type semiconductor material (ZMO) and a solvent (ethanol), and the concentration of the N-type semiconductor material (ZMO) is 30 mg / ml;

[0184] Depositing the N-type semiconductor material solution to obtain a wet film layer, and annealing the wet film layer (heating at 80 °C for 10 minutes) to obtain a thin film with a thickness of 40 nm.

[0185] Device Example 1

[0186] An optoelectronic device, its preparation method includes:

[0187] Step S1: Treat the cleaned anode (ITO) with UVO (ultraviolet ozone) for 15 minutes, spin-coat PEDOT:PSS on the anode, and heat at 150 °C for 15 minutes to obtain a hole injection layer with a thickness of 30 nm;

[0188] Step S2: Spin-coat TFB on the hole injection layer and heat at 150 °C for 15 minutes to obtain a hole transport layer with a thickness of 15 nm;

[0189] Step S3: Spin-coat core-shell structure quantum dots (ZnCdSe / ZnS, where ZnCdSe is the core and ZnS is the shell) on the hole transport layer, and heat at 100 °C for 8 minutes to obtain the first light-emitting layer with a thickness of 30 nm;

[0190] Step S4: Form a thin film (the first electron transport layer) on the first light-emitting layer by the method of Film Example 1;

[0191] Step S5: Spin-coat PMA on the thin film to obtain the electron generation layer, and heat at 120 °C for 10 minutes with a thickness of the electron generation layer being 10 nm;

[0192] Step S6: Spin-coat TFB on the electron generation layer to obtain the hole generation layer, and heat at 150 °C for 10 minutes with a thickness of the hole generation layer being 15 nm;

[0193] Step S7: Spin-coat core-shell structure quantum dots (ZnCdSe / ZnS, where ZnCdSe is the core and ZnS is the shell) on the hole generation layer, and heat at 100 °C for 8 minutes to obtain the second light-emitting layer with a thickness of 30 nm;

[0194] Step S8: Spin-coat ZMO nanoparticles on the second light-emitting layer, and heat at 80 °C for 10 minutes to obtain the second electron transport layer with a thickness of 40 nm;

[0195] Step S9: Evaporate Ag on the second electron transport layer to obtain the cathode with a thickness of 100 nm, thus obtaining the optoelectronic device.

[0196] Device Example 2

[0197] An optoelectronic device, the difference in its preparation method compared with Device Example 1 lies in:

[0198] In Step S4, a thin film (the first electron transport layer) is formed on the first light-emitting layer by the method of Film Example 2.

[0199] Device Example 3

[0200] An optoelectronic device, the difference in its preparation method compared with Device Example 1 lies in:

[0201] In Step S4, a thin film (the first electron transport layer) is formed on the first light-emitting layer by the method of Film Example 3.

[0202] Device Example 4

[0203] An optoelectronic device, the difference in its preparation method compared with Device Example 1 lies in:

[0204] In step S4, a thin film (the first electron transport layer) is formed on the first light-emitting layer by using the method of thin film embodiment 4.

[0205] Device Embodiment 5

[0206] An optoelectronic device, the difference in its preparation method compared with Device Embodiment 1 is that:

[0207] In step S4, a thin film (the first electron transport layer) is formed on the first light-emitting layer by using the method of thin film embodiment 5.

[0208] Device Embodiment 6

[0209] An optoelectronic device, the difference in its preparation method compared with Device Embodiment 1 is that:

[0210] In step S4, a thin film (the first electron transport layer) is formed on the first light-emitting layer by using the method of thin film embodiment 6.

[0211] Device Embodiment 7

[0212] An optoelectronic device, the difference in its preparation method compared with Device Embodiment 1 is that:

[0213] In step S4, a thin film (the first electron transport layer) is formed on the first light-emitting layer by using the method of thin film embodiment 7.

[0214] Device Embodiment 8

[0215] An optoelectronic device, the difference in its preparation method compared with Device Embodiment 1 is that:

[0216] In step S4, a thin film (the first electron transport layer) is formed on the first light-emitting layer by using the method of thin film embodiment 8.

[0217] Device Embodiment 9

[0218] An optoelectronic device, the difference in its preparation method compared with Device Embodiment 1 is that:

[0219] In step S4, a thin film (the first electron transport layer) is formed on the first light-emitting layer by using the method of thin film embodiment 9.

[0220] Device Embodiment 10

[0221] An optoelectronic device, the difference in its preparation method compared with Device Embodiment 1 is that:

[0222] In step S4, a thin film (the first electron transport layer) is formed on the first light-emitting layer by using the method of thin film embodiment 10.

[0223] Device Embodiment 11

[0224] An optoelectronic device, compared with Device Example 1 in its preparation method, is characterized in that:

[0225] In step S4, a thin film (the first electron transport layer) is formed on the first light-emitting layer by using the method of Thin Film Example 11.

[0226] Device Comparative Example 1

[0227] An optoelectronic device, compared with Device Example 1 in its preparation method, is characterized in that:

[0228] In step S4, a thin film (the first electron transport layer) is formed on the first light-emitting layer by using the method of Thin Film Comparative Example 1.

[0229] Performance test:

[0230] The optoelectronic devices prepared in Device Examples 1-11 and Device Comparative Example 1 are photographed under an electron microscope;

[0231] The optoelectronic devices prepared in Device Examples 1-11 and Device Comparative Example 1 are tested. Using a Fosda FPD optical property measurement device, an efficiency test system built by controlling a QE PRO spectrometer, a Keithley 2400, and a Keithley 6485 through LabView, parameters such as voltage, current, and brightness are measured, and the luminous efficiency CE is obtained through calculation. The test results are shown in Table 1.

[0232] Table 1

[0233]

[0234]

[0235] Please combine Table 1 and Figures 7 to 8 , it can be seen that the morphologies of the optoelectronic devices in Device Examples 1-11 are normal, while the optoelectronic device in Device Comparative Example 1 has cracks. It is known that the only difference between Device Examples 1-11 and Device Comparative Example 1 lies in the material and manufacturing method of the thin film (the first electron transport layer). The thin films (the first electron transport layer) in Device Examples 1-11 of the present application all include ZMO (magnesium-doped zinc oxide) nanoparticles and a first modifier (tetrathiafulvalene), while the thin film (the first electron transport layer) in Device Comparative Example 1 is only composed of ZMO (magnesium-doped zinc oxide) nanoparticles. This shows that the difference in the morphologies of the optoelectronic devices prepared in Device Example 1 and Device Comparative Example 1 lies in the difference in the morphology of the thin film (the first electron transport layer). From Figure 8It can be clearly seen that there are many obvious cracks in the thin film (the first electron transport layer) of the optoelectronic device in Comparative Device Example 1. By comparing the luminous efficiency of the optoelectronic devices of Device Examples 1-11 with that of the optoelectronic device of Comparative Device Example 1, it can be seen that the luminous efficiency of the optoelectronic device of Comparative Device Example 1 is significantly reduced, indicating that the cracks on the thin film (the first electron transport layer) have a significant impact on the electrical performance of the optoelectronic device.

[0236] By comparing Device Examples 1-3 with Device Example 10, it can be seen that although there is no obvious difference in the morphology between the optoelectronic devices of Device Example 10 and those of Device Examples 1-3, and no crack phenomenon appears, however, the luminous efficiency of the optoelectronic device of Device Example 10 is significantly lower than that of the optoelectronic devices of Device Examples 1-3. It is known that the only difference between Device Examples 1-3 and Device Example 10 is that in the thin film (the first electron transport layer) prepared in Device Examples 1-3, the mass ratio of the first modifier material to the N-type semiconductor material is (1-5):30, while in the thin film (the first electron transport layer) prepared in Device Example 10, the mass ratio of the first modifier material to the N-type semiconductor material is 10:30. It can be seen that this is due to the excessive content of the first modifier material (tetrathiafulvalene) in the thin film (the first electron transport layer) prepared in Device Example 10. It is known that the first modifier material (tetrathiafulvalene) has good electrical conductivity. However, when the content of the first modifier material (tetrathiafulvalene) is too high, it will cause the electron concentration in the thin film (the first electron transport layer) to be too large. The high-concentration electrons accumulate at the interface between the hole transport layer and the first light-emitting layer, resulting in the electrochemical corrosion and damage of the organic material in the hole transport layer, thereby causing the luminous efficiency of the optoelectronic device to decrease. By controlling the mass ratio of the first modifier material to the N-type semiconductor material to be (1-5):30 in the present application, it is possible to ensure that the thin film (the first electron transport layer) does not have cracks while enabling the optoelectronic device to have a high luminous efficiency.

[0237] By comparing Device Examples 5 - 7 with Device Example 11, it can be seen that although there is no obvious difference in the morphology between the optoelectronic devices of Device Example 11 and those of Device Examples 5 - 7, and no crack phenomenon appears, the luminous efficiency of the optoelectronic devices of Device Example 11 is significantly lower than that of the optoelectronic devices of Device Examples 5 - 7. It is known that the only difference between Device Examples 5 - 7 and Device Example 11 is that in the thin film (the first electron transport layer) prepared in Device Examples 5 - 7, the mass ratio of the second modifier material to the N-type semiconductor material is (1 - 5):30, while in the thin film (the first electron transport layer) prepared in Device Example 11, the mass ratio of the second modifier material to the N-type semiconductor material is 10:30. It can be seen that this is because the content of the second modifier material (N-phenylmaleimide) in the thin film (the first electron transport layer) prepared in Device Example 11 is too high. It should be noted that when the content of the second modifier material (N-phenylmaleimide) in the thin film is too high, due to the poor conductivity of the second modifier material (N-phenylmaleimide), the conductivity of the thin film (the first electron transport layer) will be poor, thereby affecting the luminous efficiency of the optoelectronic device. By controlling the mass ratio of the second modifier material to the N-type semiconductor material to be (1 - 5):30 in this application, it is possible to ensure that the thin film (the first electron transport layer) has good conductivity, and thus ensure that the optoelectronic device has a high luminous efficiency.

[0238] The above has introduced in detail the thin film and its preparation method, optoelectronic device, and display device provided by the embodiments of the present application. Specific examples are used herein to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the present application. At the same time, for those skilled in the art, based on the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A thin film, characterized in that, It includes a first modifying material and an N-type semiconductor material, and the first modifying material includes fulvalene and / or fulvalene derivatives.

2. The thin film according to claim 1, characterized in that, The fulvalene derivatives include at least one of tetrathiafulvalene, dimethyltetrathiafulvalene, formyltetrathiafulvalene, 4,4'-diphenyltetrathiafulvalene, tetramethyltetraselenafulvalene, bis(trimethylenedithio)tetrathiafulvalene, and tetrakis(methylthio)tetrathiafulvalene; and / or The thickness of the thin film is 10 nm to 60 nm.

3. The thin film according to claim 1, characterized in that, The thin film has a single-layer structure, and the thin film includes a mixture of a first modifying material and an N-type semiconductor material, wherein the mass ratio of the first modifying material to the N-type semiconductor material is (1 - 5):30; Alternatively, the thin film has a single-layer structure, and the thin film includes a mixture of a first modifying material, an N-type semiconductor material, and a second modifying material, wherein the mass ratio of the first modifying material, the N-type semiconductor material, and the second modifying material is (1 - 5):30:(1 - 5), and the second modifying material includes maleimide and / or maleimide derivatives.

4. The thin film according to claim 3, wherein, The maleimide derivatives include at least one of N-benzylmaleimide, N-phenylmaleimide, N-(1-pyrene)maleimide, 9-maleimidoacridine, N-hydroxysuccinimide ester of 3-maleimidopropionic acid, N-(4-nitrophenyl)maleimide, N-(4-fluorophenyl)maleimide, 3,4-dibromomaleimide, 6-maleimidohexanoic acid, and 4-maleimidobutyric acid.

5. The thin film according to claim 1, characterized in that, The thin film includes a first sub-layer and a second sub-layer arranged in a stacked manner, the first sub-layer includes the N-type semiconductor material, the second sub-layer includes the first modifying material, and the thickness ratio of the second sub-layer to the first sub-layer is (1 - 5):30; Alternatively, the thin film includes a third sub-layer, a first sub-layer, and a second sub-layer arranged in a stacked manner in sequence, the first sub-layer includes the N-type semiconductor material, the second sub-layer includes the first modifying material, the material of the third sub-layer includes a second modifying material, the second modifying material includes maleimide and / or maleimide derivatives, and the thickness ratio of the third sub-layer, the first sub-layer, and the third sub-layer is (1 - 5):30:(1 - 5).

6. The thin film according to any one of claims 1-5, characterized in that, The N-type semiconductor material is selected from at least one of metal oxides, doped metal oxides, II-VI group semiconductor materials, III-V group semiconductor materials, and I-III-VI group semiconductor materials; and / or The metal oxides are selected from at least one of ZnO, BaO, TiO2, and SnO2; and / or The metal oxides in the doped metal oxides are selected from at least one of ZnO, TiO2, and SnO2, and the doping elements are selected from at least one of Al, Mg, Li, In, and Ga; and / or The II-VI semiconductor group materials are selected from at least one of ZnS, ZnSe, and CdS; and / or The III-V semiconductor group materials are selected from at least one of InP and GaP; and / or The I-III-VI group semiconductor materials are selected from at least one of CuInS and CuGaS.

7. A method for preparing a thin film, characterized in that, It includes: Provide a composite material solution, the composite material solution comprising a first modifying material, an N-type semiconductor material, and a first solvent, the first modifying material comprising fulvalene and / or a fulvalene derivative; Deposit the composite material solution to obtain a thin film.

8. The method for preparing the thin film according to claim 7, wherein In the composite material solution, the concentration of the first modifying material is 1 mg / ml to 5 mg / ml, and the concentration of the N-type semiconductor material is 10 mg / ml to 50 mg / ml; and / or The first solvent in the composite material solution comprises at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropanamide, 1,2-dichloroethane, ethyl acetate, chloroform, dichloromethane, tetrahydrofuran, dinitrotoluene, ethanol, and acetone; and / or The depositing the composite material solution to obtain a thin film comprises: depositing the composite material solution to obtain a first wet film layer, and performing a first annealing treatment on the first wet film layer to obtain a thin film, wherein the annealing temperature is 80°C to 120°C, and the annealing time is 5 minutes to 10 minutes.

9. The method for preparing a thin film according to claim 7, wherein The composite material solution further comprises a second modifying material, the second modifying material comprising maleimide and / or a maleimide derivative, and the concentration of the second modifying material in the composite material solution is 1 mg / ml to 5 mg / ml.

10. A method for preparing a thin film, characterized in that, Comprising: Provide an N-type semiconductor material solution, the N-type semiconductor material solution comprising an N-type semiconductor material and a second solvent, deposit the N-type semiconductor material solution to obtain a first sub-layer; Provide a first modifying material solution, the first modifying material solution comprising a first modifying material and a third solvent, the first modifying material comprising fulvalene and / or a fulvalene derivative, deposit the first modifying material solution on the first sub-layer to obtain a second sub-layer, and form a thin film, the thin film comprising the first sub-layer and the second sub-layer stacked.

11. The method for preparing the thin film according to claim 10, characterized in that, In the N-type semiconductor material solution, the concentration of the N-type semiconductor material is 10 mg / ml to 50 mg / ml; and / or The second solvent in the N-type semiconductor material solution comprises at least one of methanol, ethanol, isobutanol, isopropanol, and butanol; and / or In the first modifying material solution, the concentration of the first modifying material is 1 mg / ml to 5 mg / ml; and / or The third solvent in the first modifying material solution comprises at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropanamide, 1,2-dichloroethane, ethyl acetate, chloroform, dichloromethane, tetrahydrofuran, dinitrotoluene, ethanol, and acetone; and / or The depositing the N-type semiconductor material solution to obtain a first sub-layer comprises: depositing the N-type semiconductor material solution to obtain a second wet film layer, and performing a second annealing treatment on the second wet film layer to obtain a first sub-layer, wherein the annealing temperature is 80°C to 120°C, and the annealing time is 5 minutes to 10 minutes; and / or Depositing the first modifying material solution on the first sub-layer to obtain a second sub-layer includes: depositing the first modifying material solution on the first sub-layer to obtain a third wet film layer, and performing a third annealing treatment on the third wet film layer to obtain the second sub-layer, where the annealing temperature is 80°C to 120°C and the annealing time is 5 minutes to 10 minutes; and / or The thickness ratio of the second sub-layer to the first sub-layer is (1 - 5):

30.

12. The method for preparing the thin film according to claim 10, characterized in that, Before providing the N-type semiconductor material solution, the method for preparing the thin film further includes: Providing a second modifying material solution, the second modifying material solution including a second modifying material and a fourth solvent, the second modifying material including maleimide and / or maleimide derivatives, and depositing the second modifying material solution to obtain a third sub-layer; The depositing the N-type semiconductor material solution includes: depositing the N-type semiconductor material solution on the third sub-layer; The thin film includes a third sub-layer, a first sub-layer, and a second sub-layer which are stacked.

13. The method for preparing the thin film according to claim 12, wherein In the second modifying material solution, the concentration of the second modifying material is 1 mg / ml to 5 mg / ml; and / or The fourth solvent in the second modifying material solution includes at least one of methanol, ethanol, isopropanol, butanol, ether, acetone, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylpropionamide, and tetrahydrofuran; and / or The depositing the second modifying material solution to obtain a third sub-layer includes: depositing the second modifying material solution to obtain a fourth wet film layer, and performing a fourth annealing treatment on the fourth wet film layer to obtain the third sub-layer, where the annealing temperature is 80°C to 120°C and the annealing time is 5 minutes to 10 minutes; and / or The thickness ratio of the third sub-layer, the first sub-layer, and the third sub-layer is (1 - 5):30:(1 - 5).

14. An optoelectronic device, characterized in that, Including an anode and a cathode which are oppositely arranged, and N light-emitting unit layers and N - 1 charge generation layers provided between the anode and the cathode, with a charge generation layer provided between every two adjacent light-emitting unit layers, where N is an integer greater than or equal to 2; Each light-emitting unit layer includes a stacked light-emitting layer and an electron transport layer, where the electron transport layer is located on the side of the light-emitting layer close to the cathode; Wherein, at least one electron transport layer located between the charge generation layer and the light-emitting layer includes the thin film as described in any one of claims 1 - 6 or the thin film prepared by the method for preparing the thin film as described in any one of claims 7 - 13.

15. The optoelectronic device according to claim 14, characterized in that, The optoelectronic device further includes a stacked hole injection layer and a hole transport layer, the hole injection layer and the hole transport layer are located between the anode and the light-emitting unit layer closest to the anode, and the hole transport layer is located on the side of the hole injection layer close to the cathode; and / or Each charge generation layer includes a stacked hole generation layer and an electron generation layer, and in each charge generation layer, the hole generation layer is provided on the side of the electron generation layer close to the cathode.

16. The optoelectronic device according to claim 15, characterized in that, The anode and the cathode each independently include 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 material of the doped metal oxide particle electrode includes one or more of 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 includes 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, or ZnS / Al / ZnS. The material of the metal element electrode includes one or more of Ag, Al, Cu, Mo, Au, Pt, Ca, Mg, and Ba; and / or The materials of each light-emitting layer independently include one or more of an organic light-emitting material and a quantum dot light-emitting material. The organic light-emitting material includes one or more of 4,4'-bis(N-carbazolyl)-1,1'-biphenyl: tris[2-(p-tolyl)pyridineiridium(III)], 4,4',4''-tris(carbazol-9-yl)triphenylamine: tris[2-(p-tolyl)pyridineiridium, diarylanthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent material, TTPX fluorescent material, TBRb fluorescent material, DBP fluorescent material, delayed fluorescence material, TTA material, thermally activated delayed material, polymer containing B-N covalent bond, hybrid local charge transfer excited state material, exciplex light-emitting material, polyacetylene and its derivatives, poly(phenylene) and its derivatives, polythiophene and its derivatives, polyfluorene and its derivatives;The quantum dot luminescent material includes one or more of single-structure quantum dots, core-shell structure quantum dots, and perovskite semiconductor materials. The materials of the single-structure quantum dots, the core materials of the core-shell structure quantum dots, and the shell materials of the core-shell structure quantum dots are each independently selected from one or more of II-VI group compounds, IV-VI group compounds, III-V group compounds, and I-III-VI group compounds. The II-VI group compounds include 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 include 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 group compounds include 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 I-III-VI group compounds include one or more of CuInS2, CuInSe2, and AgInS2. The perovskite semiconductor material includes doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors. The structural general formula of the inorganic perovskite semiconductor is AMX3, where A is Cs; + ions, 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, X is a halogen anion, including Cl - , Br - , I - one or more of; the structural general 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, X is a halogen anion, including Cl - , Br - , I - one or more of; and / or The materials of the hole transport layer include one or more of 4,4'-N,N'-dicarbazolyl-biphenyl, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], 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, poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine), 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(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(N-vinylcarbazole) and its derivatives, N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4-4'-diamine, spiro-NPB, poly(phenylene vinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene], 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene, 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline], 1,3-bis(carbazol-9-yl)benzene, polyaniline, polypyrrole, poly(p-)phenylene vinylene, aromatic tertiary amines, polynuclear aromatic tertiary amines, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, doped graphene, undoped graphene, C60, doped or undoped NiO, doped or undoped MoO3, doped or undoped WO3, doped or undoped V2O5, doped or undoped p-type gallium nitride, doped or undoped CrO3, doped or undoped CuO; and / or The materials of the hole injection layer and the materials of each hole generation layer each independently include one or more of 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, PEDOT, PEDOT:PSS, derivatives of PEDOT:PSS doped with s-MoO3, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, tetracyanoquinodimethane, copper phthalocyanine, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide, molybdenum sulfide, tungsten sulfide and copper oxide.

17. A display device, characterized in that, It includes the optoelectronic device according to any one of claims 14-16.

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