Thin films and their preparation methods, light-emitting devices and their preparation methods, and electronic devices

Abstract

This application discloses a thin film and its preparation method, a light-emitting device and its preparation method, and an electronic device. The preparation method of the thin film includes the steps of: depositing a dispersion containing quantum dots and a crosslinking agent; performing a crosslinking induction treatment on the deposited dispersion; and performing a drying treatment on the dispersion after the crosslinking induction treatment to obtain a thin film. In this case, the surface of the quantum dots is connected with a plurality of first ligands, and the crosslinking agent contains at least two reactive groups. At least a portion of the first ligands can bond with the reactive groups of the crosslinking agent to form a second ligand, which can reduce the surface roughness of the thin film. Applying the preparation method of the thin film to the preparation of the light-emitting layer of a light-emitting device can improve the uniformity of the light-emitting layer, which is beneficial to improving the photoelectric performance and device lifespan of the light-emitting device.

Description

Technical Field

[0001] This application relates to the field of optoelectronic technology, specifically to a thin film and its preparation method, a light-emitting device and its preparation method, and an electronic device. Background Technology

[0002] Quantum dots (QDs), also known as semiconductor nanocrystals, are nanocrystals with radii smaller than or close to the exciton Bohr radius, typically ranging from 1 nm to 20 nm in size. Quantum dots exhibit unique fluorescent nanoeffects; their emission wavelength can be modulated by changing their size and composition. They possess advantages such as narrow full width at half maximum (FWHM) emission spectra, high color purity, good photostability, broad excitation spectra, and controllable emission spectra, making them promising for applications in photovoltaic power generation, optoelectronic displays, and biological probes.

[0003] Currently, solution-based methods are commonly used to prepare quantum dot thin films. However, because quantum dots are nanoparticles, they are prone to aggregation in solution, leading to uneven film formation and high surface roughness. This, in turn, degrades the performance of devices using quantum dot films. Therefore, improving the surface roughness of quantum dot films is of great significance for their application and development. Summary of the Invention

[0004] This application provides a thin film and its preparation method, a light-emitting device and its preparation method, and an electronic device to improve the surface roughness of quantum dot thin films, thereby improving the performance of devices using the quantum dot thin films.

[0005] The technical solution of this application is as follows:

[0006] In a first aspect, this application provides a method for preparing a thin film, comprising the following steps:

[0007] A deposition dispersion comprising quantum dots and a crosslinking agent;

[0008] The deposited dispersion is subjected to cross-linking induction treatment; and

[0009] The dispersion after the crosslinking induction treatment is dried to obtain a film;

[0010] The quantum dot has a plurality of first ligands attached to its surface, and the crosslinking agent contains at least two reactive groups, wherein at least a portion of the first ligands can bond with the reactive groups of the crosslinking agent to form a second ligand.

[0011] Optionally, the at least two reactive groups are the same reactive group; optionally, the crosslinking agent contains two identical reactive groups; and / or

[0012] The reactive groups of the crosslinking agent include one or more of the following: succinimide group, N-hydroxysuccinimide group, succinimide ester group, sulfosuccinimide ester group, and maleimide group; and / or

[0013] The quantum dots are selected from one or more of single-component quantum dots, core-shell structured quantum dots, inorganic perovskite quantum dots, organic perovskite quantum dots, and organic-inorganic hybrid perovskite quantum dots; and / or

[0014] The first ligand comprises one or more functional groups selected from hydroxyl, amino, thiol, and carboxyl groups; and / or

[0015] The dispersant in the dispersion is selected from one or more of alkane compounds, aromatic hydrocarbon compounds, alcohol compounds, and ester compounds.

[0016] Optionally, the crosslinking agent is selected from one or more of ethylene glycol-bis(N-hydroxysuccinimide succinate), bis(N-hydroxysuccinimide succinate) 3,3'-dithiodipropionate, bis(N-succinimide) sebacic acid, disuccinimide succinate, disuccinimide tartrate, bissuccinimide glutarate, and 3,3'-dithiobis(sulfonylsuccinimide propionate); and / or

[0017] The materials of the single-component quantum dots, the core of the core-shell quantum dots, and the shell of the core-shell quantum dots are independently selected from at least one of group II-VI, III-V, IV-VI, or I-III-VI compounds, wherein the group II-VI compounds are selected from CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, and HgSeTe. HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe, wherein the III-V compound is selected from 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, GaAlNA s, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs and InAlPSb One or more of the following compounds are selected from SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe; and one or more of the following compounds are selected from CuInS, CuInSe, and AgInS; and / or the inorganic perovskite quantum dots have the general structural formula AMX3, where A is Cs. + Ion, M is a divalent metal cation, M is selected from Pb 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+Fe 2+ 、Ge 2+ Yb 2+ and Eu 2+ One or more of the following, where X is a halide anion; and / or, the general structural formula of the organic perovskite quantum dot is CMX3, where C is formamidinyl; and / or, the general structural formula of the organic-inorganic hybrid perovskite quantum dot is BMX3, where B is selected from organic amine cations.

[0018] Optionally, the dispersion comprises, by mass percentage: 15%–20% quantum dots, 3%–5% crosslinking agent, and 75%–82% dispersant; and / or

[0019] In the dispersion, the mass ratio of the crosslinking agent to the quantum dots is 1:(3-6.67); and / or

[0020] The crosslinking induction treatment includes the step of subjecting the deposited dispersion to ultraviolet light treatment in an inert gas atmosphere.

[0021] In a second aspect, this application provides a thin film prepared by any of the thin film preparation methods described in the first aspect; or, the material of the thin film comprises a plurality of quantum dots, at least a portion of the surface of the quantum dots is connected to a second ligand, the second ligand being formed by bonding a first ligand to a reactive group of the crosslinking agent; at least a portion of two adjacent quantum dots are connected by the second ligand.

[0022] Optionally, the root mean square roughness of the thin film is 0.8 nm to 1.1 nm.

[0023] Thirdly, this application provides a light-emitting device, comprising:

[0024] The anode and cathode are arranged opposite each other; and

[0025] A light-emitting layer is disposed between the anode and the cathode;

[0026] The light-emitting layer is prepared by any of the thin film preparation methods described in the first aspect; or, the light-emitting layer comprises any of the thin films described in the second aspect.

[0027] Optionally, the light-emitting device further includes a hole-functional layer disposed between the anode and the light-emitting layer, wherein the material of the hole-functional layer comprises poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid), copper phthalocyanine, titanium phthalocyanine, 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene, 3-hexyl-substituted polythiophene, poly(9-vinylcarbazole), 4,4'-bis(9-carbazole)biphenyl, poly[bis(4-phenyl)(4-butylphenyl)amine], 4, 4'-Cyclohexylbis[N,N-di(4-methylphenyl)aniline], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)], poly(N,N'-di(4-butylphenyl)-N,N'-diphenyl-1,4-phenylenediamine-CO-9,9-dioctylfluorene), 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, 4,4',4”-tris( Carbazole-9-yl)triphenylamine, 4,4',4'-tris(2-naphthylphenylamino)triphenylamine, N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine, N,N'-diphenyl-N,N'-di(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine, N,N'-bis[4-(diphenylamino)phenyl]-N,N'-diphenylbenzidine, N,N'-bis(3-methylphenyl)-N,N'-diphenyl-9,9-spirodifluorene-2,7-diamine, N2,N7-di-1-naphthyl-N2,N7-diphenyl- 9,9'-spirodi[9H-fluorene]-2,7-diamine, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene, doped or undoped graphene, C60, doped or undoped nickel oxide, doped or undoped molybdenum oxide, doped or undoped tungsten oxide, doped or undoped vanadium oxide, doped or undoped p-type gallium nitride, doped or undoped chromium oxide, doped or undoped copper oxide, transition metal sulfides, and transition metal selenides, or one or more of these; and / or

[0028] The light-emitting device further includes an electronic functional layer disposed between the cathode and the light-emitting layer. The material of the electronic functional layer comprises one or more of a first metal oxide, lithium 8-hydroxyquinoline, cesium carbonate, cesium fluoride, cesium azide, lithium fluoride, organophosphorus oxide, organothiophosphine compound, and organoselenophosphine compound. The first metal oxide is selected from one or more of zinc oxide, titanium oxide, tin oxide, barium oxide, tantalum oxide, aluminum oxide, zirconium oxide, zinc magnesium oxide, zinc calcium oxide, zinc zirconium oxide, zinc gallium oxide, zinc aluminum oxide, lithium zinc oxide, zinc titanium oxide, yttrium zinc oxide, indium tin oxide, and lithium titanium oxide; and / or

[0029] The materials of the anode and the cathode are independently selected from one or more of metals, carbon materials, and a second metal oxide. The metal is selected from one or more of Al, Ag, Cu, Mo, Au, Ba, Pt, Ca, Ir, Ni, and Mg. The carbon material is selected from one or more of graphite, carbon nanotubes, graphene, and carbon fibers. The second metal oxide is selected from 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, aluminum-doped magnesium oxide, SnO2, ZnO, and In2O3.

[0030] Fourthly, this application provides a method for fabricating a light-emitting device, comprising the following steps:

[0031] A bottom electrode is provided, and a dispersion comprising quantum dots and a crosslinking agent is deposited on one side of the bottom electrode;

[0032] The deposited dispersion is subjected to cross-linking induction treatment;

[0033] The dispersion after the crosslinking induction treatment is dried to obtain a luminescent layer; and

[0034] A top electrode is formed on the side of the light-emitting layer away from the bottom electrode;

[0035] In this configuration, one of the bottom electrode and the top electrode is the anode, and the other is the cathode; the surface of the quantum dot is connected to a plurality of first ligands, and at least a portion of the first ligands can bond with the reactive groups of the crosslinking agent to form second ligands.

[0036] Optionally, the at least two reactive groups are the same reactive group; optionally, the crosslinking agent contains two identical reactive groups; and / or

[0037] The reactive groups of the crosslinking agent include one or more of succinimide groups, N-hydroxysuccinimide groups, succinimide ester groups, sulfosuccinimide ester groups, and maleimide groups. Optionally, the crosslinking agent is selected from one or more of ethylene glycol-bis(N-hydroxysuccinimide succinate), bis(N-hydroxysuccinimide succinate) 3,3'-dithiodipropionate bis(N-hydroxysuccinimide succinate), sebacic acid bis(N-succinimide) ester, octanoic acid bis(succinimide succinate), tartrate bis(succinimide) glutarate, and 3,3'-dithiobis(sulfosuccinimide propionate); and / or

[0038] The quantum dots are selected from one or more of single-component quantum dots, core-shell structured quantum dots, inorganic perovskite quantum dots, organic perovskite quantum dots, and organic-inorganic hybrid perovskite quantum dots; and / or

[0039] The first ligand comprises one or more functional groups selected from hydroxyl, amino, thiol and carboxyl groups.

[0040] Optionally, the dispersion comprises, by mass percentage: 15%–20% quantum dots, 3%–5% crosslinking agent, and 75%–82% dispersant; and / or

[0041] In the dispersion, the mass ratio of the crosslinking agent to the quantum dots is 1:(3-7); and / or

[0042] The crosslinking induction treatment includes the step of subjecting the deposited dispersion to ultraviolet light treatment in an inert gas atmosphere.

[0043] Fifthly, this application provides an electronic device comprising a light-emitting device as described in any of the third aspects, or a light-emitting device prepared by any of the preparation methods described in any of the fourth aspects.

[0044] This application provides a thin film and its preparation method, a light-emitting device and its preparation method, and an electronic device, which have the following technical advantages:

[0045] In the thin film preparation method of this application, the crosslinking agent plays a bridging role between quantum dots. Specifically, the reactive groups of the crosslinking agent can bond with the first ligand located on the surface of the quantum dots, so that the first ligands of different quantum dots undergo intramolecular crosslinking through the crosslinking reaction and bond with each other to form a network structure. This allows the quantum dots to be connected through the crosslinking agent, improving the binding force between the quantum dots and improving the "aggregation" phenomenon of quantum dots in solution. This increases the compactness of the quantum dot arrangement in the thin film, improves the film uniformity, and thus improves the film quality, current efficiency and device lifetime of the light-emitting device. Attached Figure Description

[0046] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0047] Figure 1 A schematic flowchart illustrating a method for preparing a thin film according to an embodiment of this application;

[0048] Figure 2 This is a schematic diagram of the structure of the first light-emitting device provided in the embodiments of this application;

[0049] Figure 3 A schematic flowchart illustrating a method for fabricating a light-emitting device according to an embodiment of this application;

[0050] Figure 4 This is a schematic diagram of the structure of the second type of light-emitting device provided in the embodiments of this application;

[0051] Figure 5 The image shows the surface morphology of the thin film obtained in Example 1.

[0052] Figure 6 This is a surface morphology diagram of the thin film prepared in Comparative Example 1.

[0053] The attached figures are labeled as follows:

[0054] 1: Light-emitting device, 10: Substrate, 11: Anode, 12: Cathode, 13: Light-emitting layer, 14: Electronic functional layer, 15: Hole functional layer, 151: Hole injection layer, 152: Hole transport layer. Detailed Implementation

[0055] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0057] It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of embodiments. Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0058] In the description of this application, the term "comprising" means "including but not limited to".

[0059] The term "at least one" means one or more, and "multiple" means two or more. The terms "at least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can be expressed as: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0060] In this application, the description of "layer A is formed on one side of layer B" or "layer A is formed on the side of layer B away from layer C" can mean that layer A is directly formed on one side of layer B or on the side of layer B away from layer C, that is, layer A and layer B are in direct contact; it can also mean that layer A is indirectly formed on one side of layer B or on the side of layer B away from layer C, that is, other film layers can be formed between layer A and layer B.

[0061] The term "and / or" encompasses any one of two or more of the listed items, as well as any and all combinations of the listed items. These combinations include any two listed items, any number of listed items, or a combination of all listed items. For example, "A and / or B" includes three parallel solutions: A, B, and A+B. Similarly, the technical solution "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (i.e., all connected by "logical OR"), any and all combinations of A, B, C, and D, including combinations of any two or three of A, B, C, and D, and combinations of all four of A, B, C, and D (i.e., all connected by "logical AND").

[0062] This application provides a method for preparing a thin film, such as... Figure 1 As shown, it includes the following steps:

[0063] S1, Depositional dispersion, which contains quantum dots and crosslinking agents;

[0064] S2. Perform cross-linking induction treatment on the deposited dispersion;

[0065] S3. The dispersion that has undergone crosslinking induction treatment is dried to obtain a film.

[0066] In this process, the surface of the quantum dot is connected with multiple first ligands, and the crosslinking agent contains at least two reactive groups. At least a portion of the first ligands can bond with the reactive groups of the crosslinking agent to form a second ligand.

[0067] In the preparation method of the thin film, the crosslinking agent plays a bridging role between quantum dots. Specifically, the reactive groups of the crosslinking agent can bond with the first ligands located on the surface of the quantum dots, so that the first ligands of different quantum dots undergo intramolecular crosslinking through the crosslinking reaction and bond with each other to form a network structure. Thus, the quantum dots are connected by the crosslinking agent, which improves the binding force between the quantum dots and can effectively improve the "aggregation" phenomenon of quantum dots in the solution. This effectively improves the compactness and order of the quantum dot arrangement in the thin film, improves the film uniformity, and reduces the surface roughness of the thin film, thereby effectively improving the film quality.

[0068] Specifically, in step S1, the deposition method of the dispersion includes, but is not limited to, one or more of the following: spin coating, printing, inkjet printing, blade coating, printing, dip coating, immersion, spraying, roller coating, casting, slot coating, strip coating, and solution electrodeposition.

[0069] In step S1, the dispersant of the dispersion is a compound in which both quantum dots and crosslinking agents have good dispersibility, including but not limited to one or more of alkane compounds, aromatic hydrocarbon compounds, alcohol compounds, and ester compounds. Among them, alkane compounds include haloalkanes, aromatic hydrocarbon compounds include haloaromatics, alcohol compounds include haloalcohols, and the alkyl groups in the ester compounds may be halogen-substituted. Alkane compounds may be, for example, alkanes having 1 to 20 carbon atoms, alkanes having 1 to 10 carbon atoms, or alkanes having 1 to 6 carbon atoms, such as one or more of n-octane, n-hexane, n-heptane, n-nonane, dichloromethane, chloroform, and carbon tetrachloride; aromatic hydrocarbon compounds may be aromatic hydrocarbons having 6 to 20 carbon atoms, aromatic hydrocarbons having 12 to 20 carbon atoms, aromatic hydrocarbons having 6 to 12 carbon atoms, or aromatic hydrocarbons having 8 to 18 carbon atoms, such as one or more of diethylbenzene, trimethylbenzene, propylbenzene, isopropylbenzene, p-toluene-isopropylbenzene, cyclohexylbenzene, butadiene, 1-methylnaphthalene, chlorobenzene, and indene; alcohol compounds may be, for example, carbon Alcohols having 1 to 20 atoms, alcohols having 1 to 10 carbon atoms, or alcohols having 1 to 6 carbon atoms, examples of which are one or more of methanol, ethanol, propanol, butanol, ethylene glycol, and glycerol; ester compounds having the general formula R1COOR2, wherein R1 and R2 are independently selected from alkyl groups having 1 to 20 carbon atoms, alkyl groups having 1 to 10 carbon atoms, or alkyl groups having 1 to 6 carbon atoms, for example, R1 and R2 are independently selected from methyl, ethyl, propyl, or butyl groups, examples of which are one or more of methyl formate, ethyl formate, propyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, and methyl propionate.

[0070] The quantum dots in step S1 include, but are not limited to, one or more of red quantum dots, green quantum dots, and blue quantum dots. The quantum dots include, but are not limited to, one or more of single-component quantum dots, core-shell structure quantum dots, inorganic perovskite quantum dots, organic perovskite quantum dots, and organic-inorganic hybrid perovskite quantum dots. The average particle size of the quantum dots can be, for example, 5 nm to 10 nm. Examples of the average particle size of the quantum dots are 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, or 10 nm.

[0071] For single-component quantum dots and core-shell quantum dots, the material of the single-component quantum dot, the material of the core of the core-shell quantum dot, or the material of the shell of the core-shell quantum dot includes, but is not limited to, at least one of group II-VI compounds, group III-V compounds, group IV-VI compounds, or group I-III-VI compounds, wherein the group II-VI compounds are selected from CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, Zn One or more of STe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe are selected, and the III-V compound is selected from GaN, GaP, GaAs, GaSb, AlN, AlP, and Al As, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, I nPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNA The chemical formulas are selected from one or more of SnS, InAlNSb, InAlPAs, and InAlPSb. Group IV-VI compounds are selected from one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe. Group I-III-VI compounds are selected from one or more of CuInS, CuInSe, and AgInS. It should be noted that for the aforementioned single-component quantum dot materials, or the core material of core-shell quantum dots, or the shell material of core-shell quantum dots, the provided chemical formulas only indicate the elemental composition and do not indicate the content of each element. For example, CdZnSe only indicates that it is composed of Cd, Zn, and Se. If the content of each element were indicated, it would correspond to Cd... x Zn 1-x Se, 0 <x<1。

[0072] For inorganic perovskite quantum dots, the general structural formula is AMX3, where A is Cs. + Ions, where M is a divalent metal cation, and M includes, but is not limited to, Pb. 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Or Eu 2+ X is a halide anion, including but not limited to Cl. - ,Br - or I - .

[0073] For organic perovskite quantum dots, the general structural formula is CMX3, where C is a formamidinyl group and M is a divalent metal cation, which may include, but is not limited to, Pb. 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Or Eu 2+ X is a halide anion, including but not limited to Cl. - ,Br - or I - .

[0074] For organic-inorganic hybrid perovskite quantum dots, the general structural formula is BMX3, where B is selected from organic amine cations, including but not limited to CH3(CH2). n-2 NH 3+ (n≥2) or NH3(CH2) n NH3 2+ (n≥2), M is a divalent metal cation, and M includes, but is not limited to, Pb. 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe2+ 、Ge 2+ Yb 2+ Or Eu 2+ X is a halide anion, including but not limited to Cl. - ,Br - Or I - .

[0075] In some embodiments of this application, the first ligand comprises one or more functional groups selected from hydroxyl, amino, thiol and carboxyl groups. The first ligand includes, but is not limited to, one or more of hydroxyl, carboxyl, amino, thiol, fatty acid ligands, aliphatic thiol ligands, aliphatic amine ligands and aromatic amine ligands.

[0076] Specifically, the fatty acid compounds may include cyclic or chain fatty acids with 4 to 30 carbon atoms, cyclic or chain fatty acids with 6 to 20 carbon atoms, or cyclic or chain fatty acids with 8 to 18 carbon atoms. More specifically, the fatty acid compounds are selected from one or more of the following: octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, eicosanoic acid, teicosanoic acid, docosahexaenoic acid, oleic acid, linoleic acid, arachidic acid, arachidonic acid, erucic acid, and docosahexaenoic acid.

[0077] The aliphatic thiols specifically include cyclic or chain aliphatic thiols with 4 to 30 carbon atoms, cyclic or chain aliphatic thiols with 6 to 20 carbon atoms, or cyclic or chain aliphatic thiols with 8 to 18 carbon atoms. More specifically, the aliphatic thiols include one or more of hexamethylenetetramine, octylthiol, nonylthiol, decanethiol, undecylthiol, dodecaylthiol, hexadecylthiol, and octadecylthiol.

[0078] The aliphatic amine compounds may specifically include cyclic or chain aliphatic amines with 6 to 20 carbon atoms, cyclic or chain aliphatic amines with 8 to 18 carbon atoms, or cyclic or chain aliphatic amines with 6 to 16 carbon atoms. More specifically, aliphatic amine compounds include one or more of hexylamine, octylamine, dioctylamine, trioctylamine, nonylamine, decylamine, dodecylamine, tridecanamine, tetradecanamine, pentadecylamine, hexadecylamine, heptadecanamine, octadecylamine, and oleylamine.

[0079] The aromatic amine compounds may specifically include aromatic amines with 6 to 20 carbon atoms, aromatic amines with 12 to 18 carbon atoms, or aromatic amines with 8 to 16 carbon atoms. More specifically, aromatic amine compounds include one or more of aniline, indolepropylamine, 4-octylaniline, and benzidine.

[0080] In order to improve the overall crosslinking speed and increase the density of the network structure, in some embodiments of this application, the at least two reactive groups are the same reactive groups to ensure that the reactive groups have the same priority and reduce the risk of multiple reactive groups bonding with the first ligand of the same quantum dot.

[0081] To enhance the crosslinking effect, in some embodiments of this application, the reactive groups of the crosslinking agent include one or more of the following: succinimide group, N-hydroxysuccinimide group, succinimide ester group, sulfosuccinimide ester group, and maleimide group. As an example, the crosslinking agent is selected from one or more of the following: ethylene glycol-bis(N-hydroxysuccinimide) (CAS No. 70539-42-3), bis(N-hydroxysuccinimide) 3,3'-dithiodipropionate (CAS No. 57757-57-0), sebacic acid di(N-succinimide) ester (CAS No. 23024-29-5), octanoic acid disuccinimide ester (CAS No. 68526-60-3), tartrate disuccinimide ester (CAS No. 77658-91-4), bissuccinimide glutarate (CAS No. 79642-50-5), and 3,3'-dithiobis(sulfonylsuccinimide) (CAS No. 81069-02-5).

[0082] To further improve the density of the cross-linked network structure and thus further reduce the surface roughness of the film, in some embodiments of this application, the dispersion comprises, by mass percentage: 15%–20% quantum dots, 3%–5% cross-linking agent, and 75%–82% dispersant. The mass percentage of quantum dots can be, for example, 15%, 16%, 17%, 18%, 19%, 20%, or any value between any two of the aforementioned percentages. The mass percentage of the cross-linking agent can be, for example, 3%, 4%, 5%, or any of the aforementioned percentages. The mass percentage of the dispersant can be, for example, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, or any of the aforementioned two percentages; and / or, in the dispersion, the mass ratio of the crosslinking agent to the quantum dots is 1:(3-7), for example, 1:3, 1:4, 1:5, 1:6, 1:7, or any of the aforementioned two values, to ensure that the amount of crosslinking agent is excessive relative to the first ligand, enabling all of the first ligand to undergo a crosslinking reaction.

[0083] In some embodiments of this application, step S2 includes: subjecting the deposited dispersion to ultraviolet light treatment in an inert gas atmosphere. Here, "inert gas atmosphere" refers to any chemically stable gas that does not chemically react with the components in the dispersion. In the embodiments of this application, the inert gas includes, but is not limited to, one or more of nitrogen, helium, neon, argon, krypton, xenon, and radon.

[0084] Furthermore, in order to balance improving the crosslinking effect and reducing manufacturing costs, in some embodiments of this application, the thickness of the deposited dispersion is 50 nm to 60 nm, and the light energy for ultraviolet irradiation is 120 mJ / cm². 2 Up to 160 mJ / cm 2 The ultraviolet light treatment time is 4 min to 6 min.

[0085] In step S3, "drying treatment" includes all processes that enable the deposited dispersion to acquire higher energy and solidify into a film, including but not limited to heat treatment or vacuum drying treatment, wherein the temperature of the heat treatment can be isothermal or non-isothermal (e.g., the temperature varies with gradient). As an example, the drying treatment is a heat treatment, and the temperature of the heat treatment is 60°C to 150°C.

[0086] This application also provides a thin film, wherein the thin film is at least one of the following conditions (a) and (b):

[0087] (a) Prepared by any of the thin film preparation methods described above;

[0088] (b) The material of the thin film contains a plurality of quantum dots, at least a portion of the surface of the quantum dots is connected to a second ligand, the second ligand being formed by the bonding of a first ligand with a reactive group of a crosslinking agent, and at least a portion of two adjacent quantum dots are connected by the second ligand.

[0089] For (b), the quantum dot, the first ligand, and the crosslinking agent are all described above.

[0090] In the thin film of this application embodiment, at least two adjacent quantum dots are connected by a second ligand, which improves the binding force between quantum dots, enhances the compactness and order of the quantum dot arrangement in the thin film, and reduces the surface roughness of the thin film. The root mean square roughness of the thin film is, for example, 0.8 nm to 1.1 nm.

[0091] This application also provides a light-emitting device, such as Figure 2As shown, the light-emitting device 1 includes an anode 11, a cathode 12, and a light-emitting layer 13. The anode 11 and the cathode 12 are disposed opposite to each other, and the light-emitting layer 13 is disposed between the anode 11 and the cathode 12. The light-emitting layer 13 is prepared by any of the thin film preparation methods described above, or the light-emitting layer 13 includes any of the thin films described above.

[0092] In the light-emitting device 1 of this application embodiment, the light-emitting layer 13 has good density and surface flatness, which can improve the current efficiency and device life of the light-emitting device 1.

[0093] In some embodiments of this application, the materials of the anode 11 and the cathode 12 are independently selected from one or more of metals, carbon materials, and second metal oxides. The metals include, but are not limited to, one or more of Al, Ag, Cu, Mo, Au, Ba, Pt, Ca, Ir, Ni, and Mg. The carbon materials include, but are not limited to, one or more of graphite, carbon nanotubes, graphene, and carbon fibers. The third metal oxide includes, but is not limited to, one or more of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), antimony tin oxide (ATO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), indium-doped zinc oxide (IZO), magnesium-doped zinc oxide (MZO), SnO2, ZnO, and In2O3. The anode 11 or cathode 12 can also be a composite electrode, which has a sandwich-like structure. The upper and lower layers are made of doped or undoped transparent metal oxides, respectively, and the middle layer is made of metal, such as 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, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2. The thickness of the middle layer does not exceed 35 nm. The thickness of the anode 11 can be, for example, 20 nm to 300 nm, and the thickness of the cathode 12 can be, for example, 20 nm to 300 nm.

[0094] To further improve the overall performance of the light-emitting device 1, further reference is made to some embodiments of this application. Figure 2The light-emitting device also includes an electronic functional layer 14, which is disposed between the cathode 12 and the light-emitting layer 13. The thickness of the electronic functional layer 14 is, for example, 10 nm to 200 nm. The electronic functional layer 14 can be a single-layer structure or a multi-layer structure. The electronic functional layer may include one or more of an electron injection layer, an electron transport layer, and a hole blocking layer. For the electronic functional layer 14 including an electron injection layer, an electron transport layer, and a hole blocking layer, the electron injection layer, the electron transport layer, and the hole blocking layer may be disposed sequentially, and the electron injection layer is closer to the cathode 12 than the hole blocking layer.

[0095] The material of the electronic functional layer 14 includes, but is not limited to, one or more of the following: a first metal oxide, group II-VI semiconductor materials, group III-V semiconductor materials, group I-III-VI semiconductor materials, lithium 8-hydroxyquinoline, cesium carbonate, cesium fluoride, cesium azide, lithium fluoride, organophosphorus oxides, organothiophosphine compounds, and organoseleniophosphine compounds. The first metal oxide can be doped or undoped. Undoped first metal oxides are selected from, for example, one or more of ZnO, TiO2, SnO2, BaO, Ta2O3, Al2O3, and ZrO2. Doped first metal oxides are selected from, for example, one or more of zinc magnesium oxide, zinc calcium oxide, zinc zirconium oxide, zinc gallium oxide, zinc aluminum oxide, zinc lithium oxide, zinc titanium oxide, yttrium zinc oxide, indium tin oxide, and lithium titanium oxide, with ZnO as an example. (1-x) Mg x O, Zn (1-x) Ca x O, Zn (1-x) Zr x O, Zn (1-x) Ga x O, Zn (1-x) Al x O, Zn (1-x) Li x O, Al (1-x) Zn x O, Zn (1-x) Ti x O, Zn (1-x) Y x O、In (1-x) Sn x O and Ti (1-x) Li x One or more of O, wherein 0 < x ≤ 0.5. II-VI group semiconductor materials are selected from one or more of ZnS, ZnSe, and CdS. III-V group semiconductor materials are selected from one or more of InP and GaP. I-III-VI group semiconductor materials are selected from one or more of CuInS and CuGaS.

[0096] To further improve the photoelectric performance and device lifetime of the light-emitting device 1, further reference is made to some embodiments of this application. Figure 1 The light-emitting device 1 further includes a hole functional layer 15 disposed between the anode 11 and the light-emitting layer 13. The hole functional layer 15 can be a single-layer or multi-layer structure. For example, the hole functional layer 15 includes one or more of a hole injection layer, a hole transport layer, and an electron blocking layer. For the electron functional layer 14, which includes a hole injection layer, a hole transport layer, and an electron blocking layer, the hole injection layer, hole transport layer, and electron blocking layer can be disposed sequentially, with the hole injection layer closer to the anode 11 than the electron blocking layer. The thickness of the hole functional layer 15 is, for example, 10 nm to 200 nm.

[0097] The hole functional layer 15 is made of materials including, but not limited to, poly(3,4-vinyldioxythiophene):poly(styrenesulfonic acid), copper phthalocyanine, titanium phthalocyanine, 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene, 3-hexyl-substituted polythiophene, poly(9-vinylcarbazole), 4,4'-bis(9-carbazole)biphenyl, poly[bis(4-phenyl)(4-butylphenyl)amine], 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl))] [9,9-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)], [N,N'-di(4-butylphenyl)-N,N'-diphenyl-1,4-phenylenediamine-CO-9,9-dioctylfluorene], 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, 4,4',4'-tris(carbazole-9-yl)triphenylamine, 4,4',4'-tris(2-naphthylphenylamino)triphenylamine, N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine, N,N'-diphenyl-N,N'-di(3-methylphenyl)-1,1'-biphenyl -4,4'-Diamine, N,N'-bis[4-(diphenylamino)phenyl]-N,N'-diphenylbenzidine, N,N'-bis(3-methylphenyl)-N,N'-diphenyl-9,9-spirodifluorene-2,7-diamine, N2,N7-di-1-naphthyl-N2,N7-diphenyl-9,9'-spirodi[9H-fluorene]-2,7-diamine, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene, doped or undoped graphene, C60, doped or undoped nickel oxide, doped or undoped molybdenum oxide, doped or undoped tungsten oxide, doped or undoped oxygen The alloy comprises one or more of vanadium oxide, doped or undoped p-type gallium nitride, doped or undoped chromium oxide, doped or undoped copper oxide, transition metal sulfides, and transition metal selenides. The transition metal sulfides include, but are not limited to, one or more of molybdenum sulfide, tungsten sulfide, and copper sulfide; the transition metal selenides include, but are not limited to, one or more of molybdenum selenide and tungsten selenide; examples of doped or undoped nickel oxide are NiO, examples of doped or undoped molybdenum oxide are MoO3, examples of doped or undoped tungsten oxide are WO3, examples of doped or undoped vanadium oxide are V2O5, examples of doped or undoped chromium oxide are CrO3, and examples of doped or undoped copper oxide are one or more of CuO and Cu2O.

[0098] This application also provides a method for fabricating a light-emitting device, which can be used to fabricate any of the light-emitting devices described above, such as... Figure 3 As shown, the fabrication method of the light-emitting device includes the following steps:

[0099] S11. Provide a bottom electrode, and deposit a dispersion on one side of the bottom electrode, the dispersion containing quantum dots and a crosslinking agent;

[0100] S12. Perform cross-linking induction treatment on the deposited dispersion;

[0101] S13. The dispersion after cross-linking induction treatment is dried to obtain the luminescent layer;

[0102] S14. A top electrode is formed on the side of the light-emitting layer away from the bottom electrode.

[0103] In this design, one of the bottom electrode and the top electrode is the anode, and the other is the cathode. Multiple first ligands are attached to the surface of the quantum dots, and at least some of these first ligands can bond with the reactive groups of the crosslinking agent to form second ligands. It should be noted that the dispersant, quantum dots, crosslinking agent, the proportions of each component in the dispersion, and the first ligands are all as described above; step S12 is described as described in step S2 above, and step S13 is described as described in step S3 above.

[0104] To further improve the overall performance of the light-emitting device, in some embodiments of this application, the fabrication method of the light-emitting device further includes the steps of: forming a hole functional layer between the anode and the light-emitting layer, and / or forming an electron functional layer between the cathode and the light-emitting layer. The structural composition of the hole functional layer and the electron functional layer are as described above.

[0105] It should be noted that, in addition to the light-emitting layer, the preparation methods for other functional films in the light-emitting device include, but are not limited to, chemical and / or physical methods. Chemical methods include, but are not limited to, one or more of chemical vapor deposition, continuous ion layer adsorption and reaction, anodic oxidation, electrolytic deposition, and co-precipitation. Physical methods include, but are not limited to, physical deposition and solution methods. Physical deposition methods include, but are not limited to, one or more of thermal evaporation deposition, electron beam evaporation deposition, magnetron sputtering, multi-arc ion deposition, physical vapor deposition, atomic layer deposition, and pulsed laser deposition. Solution methods include, but are not limited to, one or more of spin coating, printing, inkjet printing, blade coating, dip coating, immersion coating, spraying, roller coating, casting, slot coating, and strip coating. When forming functional films using a solution method, a drying process is required to transform the wet film into a cured film. This drying process includes, but is not limited to, heat treatment, vacuum drying, and air drying. For functional films located above the light-emitting layer (made of inorganic compounds, especially inorganic nanoparticles), after forming a cured film using low-temperature drying processes (temperature not exceeding 80°C) such as vacuum drying and air drying, further annealing processes with controllable annealing depth, such as pulsed laser annealing, electron beam annealing, atomic annealing, and infrared irradiation annealing, can be used to further improve the film quality.

[0106] It is understandable that in existing technologies, the preparation method of the light-emitting layer includes the steps of depositing a quantum dot solution (without a crosslinking agent) and then drying the deposited quantum dot solution to solidify it into a film. Because the quantum dot surface contains abundant ligands, the spacing between the quantum dots after film formation is relatively large, the quantum dots are loosely arranged, and the bonding between the light-emitting layer and the underlying functional layer is low. Therefore, when using a solution method to prepare the functional film layer above the light-emitting layer, the deposited quantum dots may be redissolved or washed away by the functional material solution above, resulting in increased surface roughness of the light-emitting layer. The light-emitting device preparation method in this application can improve the bonding force between quantum dots in the light-emitting layer, increase the density and order of the quantum dot arrangement in the light-emitting layer, and improve the bonding density between the light-emitting layer and the underlying functional layer, effectively improving the film uniformity of the light-emitting layer. The light-emitting device preparation method in this application is not only simple in process but also suitable for large-scale industrial production. The resulting light-emitting layer has a dense and uniform structure, high luminous brightness, better luminous effect, and higher luminous stability.

[0107] After the various functional film layers of the light-emitting device are prepared, an encapsulation process is required. The encapsulation process can be carried out by commonly used machine encapsulation or manual encapsulation. In the encapsulation environment, the oxygen content and water content are both below 0.1 ppm to ensure the stability of the light-emitting device.

[0108] This application also provides an electronic device, which includes any of the light-emitting devices described in the embodiments of this application, or the electronic device includes a light-emitting device prepared by any of the preparation methods described in the embodiments of this application. The electronic device can be any electronic product with display function, including but not limited to smartphones, tablets, laptops, digital cameras, digital camcorders, smart wearable devices, smart weighing scales, in-vehicle displays, televisions, or e-book readers. Smart wearable devices can be, for example, smart bracelets, smartwatches, virtual reality (VR) headsets, etc.

[0109] The technical solutions and effects of this application will be described in detail below through specific embodiments, comparative examples and experimental examples. The following embodiments are only some embodiments of this application and are not intended to limit this application.

[0110] Example 1

[0111] This embodiment provides a method for preparing a thin film and the thin film obtained therefrom. The thin film contains CdZnSe / ZnS quantum dots, and at least two adjacent CdZnSe / ZnS quantum dots are connected via bis(succinimide) glutarate. The method for preparing the thin film includes the following steps:

[0112] S1.1 Synthesis of CdZnSe / ZnS quantum dots with octyl mercaptan ligands on the surface: 10 mmol of zinc acetate, 0.12 mmol of cadmium oxide, 10 mL of oleic acid, and 20 mL of octadecene were mixed to obtain a cationic precursor solution. Selenium was dispersed in trioctylphosphine to obtain a selenium precursor, and sulfur was dispersed in trioctylphosphine to obtain a sulfur precursor. Then, at a reaction temperature of 300 °C, 1 mmol of the selenium precursor was injected into the cationic precursor to obtain a solution containing CdZnSe quantum dot cores. 10.94 mmol of sulfur precursor was added to the solution containing CdZnSe quantum dot cores, and the reaction was carried out for 30 min to obtain a solution containing CdZnSe / ZnS quantum dots. Finally, 2 mmol of octyl mercaptan was added for ligand replacement to obtain CdZnSe / ZnS quantum dots with octyl mercaptan ligands on the surface. The emission wavelength was 533 nm and the full width at half maximum (FWHM) was 23 nm.

[0113] S1.2 Preparation of dispersion: The CdZnSe / ZnS quantum dots and bis(succinimide) glutarate obtained in step S1.1 are dispersed in an organic solvent to obtain a dispersion. The organic solvent is obtained by mixing chlorobenzene and cyclohexylbenzene in a mass ratio of 1:1. The mass of CdZnSe / ZnS quantum dots accounts for 15% of the total mass of the dispersion, the mass of bis(succinimide) glutarate accounts for 3% of the total mass of the dispersion, the mass of chlorobenzene accounts for 41% of the total mass of the dispersion, and the mass of cyclohexylbenzene accounts for 41% of the total mass of the dispersion.

[0114] S1.3. Provide a substrate and spin-coat the dispersion obtained in step S1.2 on one side of the substrate to obtain a wet film of dispersion with a thickness of 55nm.

[0115] S1.4. The substrate containing the wet film of the dispersion is placed in a nitrogen atmosphere, and the wet film of the dispersion is subjected to ultraviolet light irradiation induction treatment, wherein the light energy of the ultraviolet light irradiation treatment is 150 mJ / cm². 2 The ultraviolet light treatment time is 5 minutes;

[0116] S1.5 Under a nitrogen atmosphere, the wet film of the dispersion that has undergone ultraviolet light treatment is placed at a constant temperature of 130°C for heat treatment to solidify it into a film, thereby obtaining a thin film.

[0117] Example 2

[0118] This embodiment provides a method for preparing a thin film and the thin film obtained therefrom. Compared with the method for preparing the thin film in Example 1, the difference in the method for preparing the thin film in this embodiment is that step S1.2 is replaced with "preparing a dispersion: dispersing the CdZnSe / ZnS quantum dots and bis(succinimide) glutarate obtained in step S1.1 in an organic solvent to obtain a dispersion, wherein the organic solvent is obtained by mixing chlorobenzene and cyclohexylbenzene in a mass ratio of 1:1, the mass of CdZnSe / ZnS quantum dots accounts for 15% of the total mass of the dispersion, the mass of bis(succinimide) glutarate accounts for 5% of the total mass of the dispersion, the mass of chlorobenzene accounts for 40% of the total mass of the dispersion, and the mass of cyclohexylbenzene accounts for 40% of the total mass of the dispersion".

[0119] Example 3

[0120] This embodiment provides a method for preparing a thin film and the thin film obtained therefrom. Compared with the method for preparing the thin film in Example 1, the difference in the method for preparing the thin film in this embodiment is that step S1.2 is replaced with "preparing a dispersion: dispersing the CdZnSe / ZnS quantum dots and bis(succinimide) glutarate obtained in step S1.1 in an organic solvent to obtain a dispersion, wherein the organic solvent is obtained by mixing chlorobenzene and cyclohexylbenzene in a mass ratio of 1:1, the mass of CdZnSe / ZnS quantum dots accounts for 20% of the total mass of the dispersion, the mass of bis(succinimide) glutarate accounts for 3% of the total mass of the dispersion, the mass of chlorobenzene accounts for 38.5% of the total mass of the dispersion, and the mass of cyclohexylbenzene accounts for 38.5% of the total mass of the dispersion".

[0121] Example 4

[0122] This embodiment provides a method for preparing a thin film and the thin film obtained therefrom. The thin film contains CdZnSe / ZnS quantum dots, and at least two adjacent CdZnSe / ZnS quantum dots are connected via ethylene glycol-bis(N-hydroxysuccinimide succinate). Compared with the thin film preparation method in Example 1, the difference in the preparation method of the thin film in this embodiment is that "bis(N-hydroxysuccinimide glutarate)" in step S1.2 is replaced with "ethylene glycol-bis(N-hydroxysuccinimide succinate)".

[0123] Example 5

[0124] This embodiment provides a method for preparing a thin film and the thin film obtained therefrom. The thin film contains CdZnSe / ZnS quantum dots, and at least two adjacent CdZnSe / ZnS quantum dots are connected via bis(N-hydroxysuccinimide) 3,3'-dithiodipropionate. Compared with the thin film preparation method in Example 1, the difference in the preparation method of the thin film in this embodiment is that "bis(succinimide) glutarate" in step S1.2 is replaced with "bis(N-hydroxysuccinimide) 3,3'-dithiodipropionate".

[0125] Example 6

[0126] This embodiment provides a method for preparing a thin film and the thin film obtained therefrom. The thin film contains CdZnSe / ZnS quantum dots, and at least two adjacent CdZnSe / ZnS quantum dots are connected via di(N-succinimidyl) sebacate. Compared with the thin film preparation method in Example 1, the difference in the preparation method of the thin film in this embodiment is that "bis(succinimidyl) glutarate" in step S1.2 is replaced with "di(N-succinimidyl) sebacate".

[0127] Example 7

[0128] This embodiment provides a method for preparing a thin film and the thin film obtained therefrom. The thin film contains CdZnSe / ZnS quantum dots, and at least two adjacent CdZnSe / ZnS quantum dots are connected via disuccinimide octanoate. Compared with the thin film preparation method in Example 1, the difference in the preparation method of the thin film in this embodiment is that "bissuccinimide glutarate" in step S1.2 is replaced with "disuccinimide octanoate".

[0129] Example 8

[0130] This embodiment provides a method for preparing a thin film and the thin film obtained therefrom. The thin film contains CdZnSe / ZnS quantum dots, and at least two adjacent CdZnSe / ZnS quantum dots are connected via bis(succinimide) tartrate. Compared with the thin film preparation method in Example 1, the difference in the preparation method of the thin film in this embodiment is that "bis(succinimide) glutarate" in step S1.2 is replaced with "bis(succinimide) tartrate".

[0131] Example 9

[0132] This embodiment provides a method for preparing a thin film and the thin film obtained therefrom. The thin film contains CdZnSe / ZnS quantum dots, and at least two adjacent CdZnSe / ZnS quantum dots are connected via 3,3'-dithiobis(propionic acid sulfosuccinimide). Compared with the thin film preparation method in Example 1, the difference in the preparation method of the thin film in this embodiment is that "bissuccinimide glutarate" in step S1.2 is replaced with "3,3'-dithiobis(propionic acid sulfosuccinimide)".

[0133] Example 10

[0134] This embodiment provides a method for preparing a thin film and the thin film obtained therefrom. The thin film contains CdZnSe / ZnS quantum dots, and at least two adjacent CdZnSe / ZnS quantum dots are connected via N-(β-maleimidepropoxy)succinimide ester (CAS No. 55750-62-4). Compared with the thin film preparation method in Example 1, the difference in the preparation method of the thin film in this embodiment is that "bissuccinimide glutarate" in step S1.2 is replaced with "N-(β-maleimidepropoxy)succinimide ester".

[0135] Example 11

[0136] This embodiment provides a light-emitting device and its fabrication method. The light-emitting device is a quantum dot light-emitting diode with a positive-position structure, such as... Figure 4As shown, in the direction from bottom to top, the light-emitting device 1 includes a substrate 10, an anode 11, a hole functional layer 15, a light-emitting layer 13, an electronic functional layer 14, and a cathode 12 stacked sequentially. The hole functional layer 15 is composed of a hole injection layer 151 and a hole transport layer 152 stacked together. The hole injection layer 151 is closer to the anode 11 than the hole transport layer 152. The electronic functional layer 14 is a single-layer structure.

[0137] The materials and thicknesses of each layer in light-emitting device 1 are as follows:

[0138] The substrate 10 is made of glass and has a thickness of 2 mm.

[0139] The anode 11 is made of ITO and has a thickness of 100 nm.

[0140] The cathode 12 is made of Ag and has a thickness of 25 nm.

[0141] The light-emitting layer 13 is the thin film prepared in Example 1;

[0142] The electronic functional layer 14 is made of nano-ZnO (average particle size of 6nm) and has a thickness of 30nm;

[0143] The hole injection layer 151 is made of PEDOT:PSS and has a thickness of 70nm.

[0144] The hole transport layer 152 is made of TFB material and has a thickness of 20 nm.

[0145] The fabrication method of the light-emitting device in this embodiment includes the following steps:

[0146] S11.1 Provide a substrate, sputter ITO on one side of the substrate to obtain an ITO layer, wipe the surface of the ITO layer with a small amount of soapy water using a cotton swab to remove visible impurities, and then sequentially ultrasonically clean the substrate containing ITO with deionized water for 15 min, acetone for 15 min, ethanol for 15 min, and isopropanol for 15 min, and after drying, perform ultraviolet-ozone surface treatment for 20 min to obtain a substrate containing an anode.

[0147] S11.2 Under normal temperature and pressure air environment, spin-coat a 2.8% PEDOT:PSS aqueous solution on the side of the anode away from the substrate, and then place it under constant temperature heat treatment at 150℃ to solidify into a film to obtain a hole injection layer.

[0148] S11.3 Under a nitrogen atmosphere at normal temperature and pressure, spin-coat a TFB-chlorobenzene solution with a concentration of 8 mg / mL onto the side of the hole injection layer away from the anode, and then place it under constant temperature heat treatment at 150℃ to solidify it into a film to obtain a hole transport layer.

[0149] S11.4 Under a nitrogen atmosphere at normal temperature and pressure, a light-emitting layer is formed on the side of the hole transport layer away from the hole injection layer, following the thin film preparation method in Example 1.

[0150] S11.5 Under a nitrogen atmosphere at normal temperature and pressure, a nano ZnO-ethanol solution with a concentration of 30 mg / mL is spin-coated onto the side of the light-emitting layer away from the hole transport layer, and then placed at 80°C for constant temperature heat treatment to solidify into a film to obtain an electronic functional layer.

[0151] S11.6. Place the laminated structure obtained after step S1.7 in a vacuum environment with a vacuum level not exceeding 3 × 10⁻⁶. -4 In the vapor deposition chamber of Pa, Ag is thermally vaporized on the side of the electronic functional layer away from the light-emitting layer through a mask to obtain the cathode, and then packaged to obtain the light-emitting device.

[0152] Example 12

[0153] This embodiment provides a light-emitting device and its preparation method. Compared with the light-emitting device in Example 11, the difference of the light-emitting device in this embodiment is that the light-emitting layer is the thin film obtained in Example 2.

[0154] Compared with the method for preparing the light-emitting device in Example 11, the method for preparing the light-emitting device in this example differs in that step S11.4 is replaced with "forming a light-emitting layer on the side of the hole transport layer away from the hole injection layer in a nitrogen atmosphere at room temperature and pressure, referring to the thin film preparation method in Example 2".

[0155] Example 13

[0156] This embodiment provides a light-emitting device and its preparation method. Compared with the light-emitting device in Example 11, the difference of the light-emitting device in this embodiment is that the light-emitting layer is the thin film obtained in Example 3.

[0157] Compared with the method for preparing the light-emitting device in Example 11, the method for preparing the light-emitting device in this example differs in that step S11.4 is replaced with "forming a light-emitting layer on the side of the hole transport layer away from the hole injection layer in a nitrogen atmosphere at room temperature and pressure, referring to the thin film preparation method in Example 3".

[0158] Example 14

[0159] This embodiment provides a light-emitting device and its preparation method. Compared with the light-emitting device in Example 11, the difference of the light-emitting device in this embodiment is that the light-emitting layer is the thin film obtained in Example 4.

[0160] Compared with the method for preparing the light-emitting device in Example 11, the method for preparing the light-emitting device in this example differs in that step S11.4 is replaced with "forming a light-emitting layer on the side of the hole transport layer away from the hole injection layer in a nitrogen atmosphere at room temperature and pressure, referring to the thin film preparation method in Example 4".

[0161] Example 15

[0162] This embodiment provides a light-emitting device and its preparation method. Compared with the light-emitting device in Example 11, the difference of the light-emitting device in this embodiment is that the light-emitting layer is the thin film obtained in Example 5.

[0163] Compared with the method for preparing the light-emitting device in Example 11, the method for preparing the light-emitting device in this example differs in that step S11.4 is replaced with "forming a light-emitting layer on the side of the hole transport layer away from the hole injection layer in a nitrogen atmosphere at room temperature and pressure, referring to the thin film preparation method in Example 5".

[0164] Example 16

[0165] This embodiment provides a light-emitting device and its preparation method. Compared with the light-emitting device in Example 11, the difference of the light-emitting device in this embodiment is that the light-emitting layer is the thin film obtained in Example 6.

[0166] Compared with the method for preparing the light-emitting device in Example 11, the method for preparing the light-emitting device in this example differs in that step S11.4 is replaced with "forming a light-emitting layer on the side of the hole transport layer away from the hole injection layer in a nitrogen atmosphere at room temperature and pressure, referring to the thin film preparation method in Example 6".

[0167] Example 17

[0168] This embodiment provides a light-emitting device and its preparation method. Compared with the light-emitting device in Example 11, the difference of the light-emitting device in this embodiment is that the light-emitting layer is the thin film obtained in Example 7.

[0169] Compared with the method for preparing the light-emitting device in Example 11, the method for preparing the light-emitting device in this example differs in that step S11.4 is replaced with "forming a light-emitting layer on the side of the hole transport layer away from the hole injection layer in a nitrogen atmosphere at room temperature and pressure, referring to the thin film preparation method in Example 7".

[0170] Example 18

[0171] This embodiment provides a light-emitting device and its preparation method. Compared with the light-emitting device in Example 11, the difference of the light-emitting device in this embodiment is that the light-emitting layer is the thin film obtained in Example 8.

[0172] Compared with the method for preparing the light-emitting device in Example 11, the method for preparing the light-emitting device in this example differs in that step S11.4 is replaced with "forming a light-emitting layer on the side of the hole transport layer away from the hole injection layer in a nitrogen atmosphere at room temperature and pressure, referring to the thin film preparation method in Example 8".

[0173] Example 19

[0174] This embodiment provides a light-emitting device and its preparation method. Compared with the light-emitting device in Example 11, the difference of the light-emitting device in this embodiment is that the light-emitting layer is the thin film obtained in Example 9.

[0175] Compared with the method for preparing the light-emitting device in Example 11, the method for preparing the light-emitting device in this example differs in that step S11.4 is replaced with "forming a light-emitting layer on the side of the hole transport layer away from the hole injection layer in a nitrogen atmosphere at room temperature and pressure, referring to the thin film preparation method in Example 9".

[0176] Example 20

[0177] This embodiment provides a light-emitting device and its preparation method. Compared with the light-emitting device in Example 11, the difference of the light-emitting device in this embodiment is that the light-emitting layer is a thin film obtained in Example 10.

[0178] Compared with the method for preparing the light-emitting device in Example 11, the method for preparing the light-emitting device in this example differs in that step S11.4 is replaced with "forming a light-emitting layer on the side of the hole transport layer away from the hole injection layer in a nitrogen atmosphere at room temperature and pressure, referring to the thin film preparation method in Example 10".

[0179] Comparative Example 1

[0180] This comparative example provides a method for preparing a thin film and the thin film obtained therefrom, wherein the material of the thin film is CdZnSe / ZnS quantum dots.

[0181] The preparation method of the thin film in this comparative example includes the following steps:

[0182] S101, Refer to step S1.1;

[0183] S102. Preparation of dispersion: The CdZnSe / ZnS quantum dots obtained in step S1.1 are dispersed in an organic solvent to obtain a dispersion. The organic solvent is obtained by mixing chlorobenzene and cyclohexylbenzene in a mass ratio of 1:1. The mass of CdZnSe / ZnS quantum dots accounts for 15% of the total mass of the dispersion, the mass of chlorobenzene accounts for 42.5% of the total mass of the dispersion, and the mass of cyclohexylbenzene accounts for 42.5% of the total mass of the dispersion.

[0184] S103. Provide a substrate, spin-coat the dispersion obtained in step S102 on one side of the substrate to obtain a wet film of dispersion with a thickness of 55 nm, and then place it under constant temperature heat treatment at 130°C to cure it into a film (performed under nitrogen atmosphere) to obtain a thin film.

[0185] Comparative Example 2

[0186] This comparative example provides a method for preparing a thin film and the thin film obtained therefrom, wherein the material of the thin film is CdZnSe / ZnS quantum dots.

[0187] Compared to the thin film preparation method in Comparative Example 1, the difference in the thin film preparation method in this comparative example is that step S103 is replaced by "providing a substrate, spin-coating the dispersion obtained in step S102 onto one side of the substrate to obtain a wet film of dispersion with a thickness of 55 nm, and then placing the substrate containing the wet film of dispersion under a nitrogen atmosphere to perform ultraviolet light irradiation-induced treatment on the wet film of dispersion, wherein the light irradiation energy of the ultraviolet light treatment is 150 mJ / cm 2 The ultraviolet light treatment time is 5 minutes, and finally it is placed at a constant temperature of 130℃ for heat treatment to solidify into a film (under nitrogen atmosphere) to obtain a thin film.

[0188] Comparative Example 3

[0189] This comparative example provides a method for preparing a thin film and the thin film obtained therefrom. Compared with the method for preparing the thin film in Example 1, the difference in the method for preparing the thin film in this comparative example is that step S1.4 is omitted and step S1.5 is replaced with "under a nitrogen atmosphere, the wet film of the dispersion is placed at a constant temperature of 130°C for heat treatment to solidify it into a film, thereby obtaining the thin film".

[0190] Comparative Example 4

[0191] This comparative example provides a light-emitting device and its preparation method. Compared with the light-emitting device in Example 11, the difference of the light-emitting device in this comparative example is that the light-emitting layer is a thin film prepared in Comparative Example 1.

[0192] Compared with the method for preparing the light-emitting device in Example 11, the difference in the method for preparing the light-emitting device in this comparative example is that step S11.4 is replaced with "forming a light-emitting layer on the side of the hole transport layer away from the hole injection layer by referring to the thin film preparation method in Comparative Example 1".

[0193] Comparative Example 5

[0194] This comparative example provides a light-emitting device and its preparation method. Compared with the light-emitting device in Example 11, the difference of the light-emitting device in this comparative example is that the light-emitting layer is a thin film prepared in Comparative Example 2.

[0195] Compared with the method for preparing the light-emitting device in Example 11, the difference in the method for preparing the light-emitting device in this comparative example is that step S11.4 is replaced with "forming a light-emitting layer on the side of the hole transport layer away from the hole injection layer by referring to the thin film preparation method in Comparative Example 2".

[0196] Comparative Example 6

[0197] This comparative example provides a light-emitting device and its preparation method. Compared with the light-emitting device in Example 11, the difference of the light-emitting device in this comparative example is that the light-emitting layer is a thin film prepared in Comparative Example 3.

[0198] Compared with the method for preparing the light-emitting device in Example 11, the difference in the method for preparing the light-emitting device in this comparative example is that step S11.4 is replaced with "forming a light-emitting layer on the side of the hole transport layer away from the hole injection layer by referring to the thin film preparation method in Comparative Example 3".

[0199] Experimental Example 1

[0200] The surface morphology of the films prepared in Examples 1 to 10 and Comparative Example 1 was observed using an atomic force microscope (AFM). Figure 5 and Figure 6 The surface morphology of the films prepared in Example 1 and Comparative Example 1 are shown respectively. The root mean square (RMS) roughness of the films prepared in Examples 1 to 10 and Comparative Example 1 was measured, and the results are shown in Table 1 below:

[0201] Table 1. RMS values ​​of the films prepared in Examples 1 to 10 and Comparative Example 1.

[0202]

[0203] As shown in Table 1, compared to the films in Comparative Examples 1 to 3, the RMS values ​​of the films in Examples 1 to 10 indicate that the surface smoothness of the films in Examples 1 to 10 is better than that of the film in Comparative Example 1. Taking Example 1 and Comparative Example 1 as examples, the RMS value of the film in Example 1 is only 53.5% of the RMS value of the film in Example 1, and... Figure 5 and Figure 6 It can be seen that, compared with the film morphology of Comparative Example 1, the film morphology in Example 1 is more uniform, and there are fewer film pores and quantum dot aggregations.

[0204] In the film preparation methods of Examples 1 to 10, the reactive groups of the crosslinking agent can bond with the first ligand located on the surface of the quantum dots, allowing the first ligands of different quantum dots to undergo intramolecular crosslinking through the crosslinking reaction and bond with each other to form a network structure. This connects the quantum dots through the crosslinking agent, improving the bonding force between them and effectively mitigating the "agglomeration" phenomenon of quantum dots in solution. This effectively enhances the compactness and orderliness of the quantum dot arrangement in the film, improves film uniformity, and reduces the surface roughness of the film, thus effectively improving the film quality. In Comparative Examples 1 and 2, the film preparation methods do not involve crosslinking agents, and the quantum dots are prone to "agglomeration," resulting in poor film uniformity and a loose arrangement of quantum dots, leading to high surface roughness. Although the film preparation method in Comparative Example 3 involves a crosslinking agent, the wet film of the dispersion was not subjected to ultraviolet light treatment, thus failing to induce a crosslinking reaction, resulting in poor film quality.

[0205] Experiment Example 2

[0206] Performance testing was performed on the packaged light-emitting devices from Examples 11 to 20 and Comparative Examples 4 to 6. An efficiency testing system was constructed using a Fostar FPD optical characteristic measurement device (including an Ocean Optics USB2000, a LabVIEW-controlled QE-PRO spectrometer, a Keithley 2400, a high-precision digital source meter Keithley 6485, a 50μm inner diameter optical fiber, device test probes and fixtures, various connecting cables and data cards, an efficiency test cassette, and a data acquisition system). The system measured the turn-on voltage, current, and maximum brightness (L) of each light-emitting device. max The parameters such as nit (nit) and emission spectrum were measured, and the lifespan of each of the above-mentioned light-emitting devices was tested using a lifespan testing device.

[0207] The current efficiency test method is as follows: the light-emitting area is set to 2mm × 2mm = 4mm. 2The brightness values ​​of the light-emitting device are intermittently collected within the driving voltage range of 0V to 6V. The initial voltage value for collecting brightness is 3V, and a measurement is taken every 0.2V. The current efficiency of the light-emitting device under that sampling condition is obtained by dividing the brightness value collected each time by the corresponding current density. The maximum current efficiency (CE) is then obtained. max ,cd / m 2 ).

[0208] The lifespan test method is as follows: Under constant current (2mA) drive, a 128-channel QLED lifespan test system is used to perform electroluminescence lifespan analysis on each light-emitting device, and the time (T95,h) required for each light-emitting device to decay from maximum brightness to 95% is recorded.

[0209] The performance test data of each light-emitting device at 25℃ are detailed in Table 2 below:

[0210] Table 2. Summary of performance test data of the light-emitting devices in Examples 11 to 20 and Comparative Example 2 at 25°C.

[0211]

[0212]

[0213] As shown in Table 2, compared to the overall performance of the light-emitting devices in Comparative Examples 4 to 6, the light-emitting devices in Examples 11 to 20 have superior overall performance. Specifically, the light-emitting devices in Examples 11 to 20 exhibit better photoelectric performance and longer device lifetime. Taking the light-emitting devices in Example 11 and Comparative Example 2 as examples, the L of the light-emitting device in Example 11... max L of the light-emitting device in Comparative Example 2 max The T95 of the light-emitting device in Example 11 is 1.2 times that of the light-emitting device in Example 2, and the T95 of the light-emitting device in Example 11 is 1.5 times that of the light-emitting device in Example 2, and the CE of the light-emitting device in Example 11 is... max CE of the light-emitting device in Comparative Example 2 max 1.5 times.

[0214] In Comparative Example 4, the light-emitting layer of the light-emitting device exhibits problems such as loose quantum dot arrangement and high surface roughness. This is due to two main reasons: firstly, the surface of the quantum dots is rich in octylthiol ligands, resulting in a certain spacing between the quantum dots and low inter-quantum dot bonding, leading to a loose arrangement; secondly, quantum dots are prone to aggregation in solution, causing uneven film formation. Furthermore, when preparing the film layer (e.g., the electronic functional layer) above the light-emitting layer using a solution method, the deposited quantum dots may be redissolved or washed away by the above nano-ZnO-ethanol solution, exacerbating the surface unevenness of the light-emitting layer and thus reducing the overall performance of the light-emitting device. The film quality of the light-emitting layer in Comparative Example 5 is not significantly different from that in Comparative Example 4. This may be because, although an ultraviolet light treatment step was added to the preparation method of the light-emitting layer, the dispersion containing quantum dots does not contain a crosslinking agent, resulting in poor film quality. Therefore, the overall performance of the light-emitting devices in Comparative Example 4 and Comparative Example 5 is not significantly different. The overall performance of the light-emitting device in Comparative Example 6 is not as good as that of the light-emitting devices in Examples 11 to 20, and the difference from the overall performance of the light-emitting devices in Comparative Examples 4 and 5 is not significant. This may be because, although a crosslinking agent was added to the dispersion containing quantum dots in the preparation method of the light-emitting layer, no ultraviolet light treatment step was added, resulting in poor film quality of the light-emitting layer. The light-emitting layers of the light-emitting devices in Examples 11 to 20 have the advantages of compact structure, high uniformity, and low surface roughness. This is because the reactive groups of the crosslinking agent can bond with the first ligand located on the surface of the quantum dots, allowing the ligands of different quantum dots to undergo intramolecular crosslinking through the crosslinking reaction and bond with each other to form a network structure. Thus, the quantum dots are connected by the crosslinking agent, improving the bonding force between quantum dots and effectively improving the "aggregation" phenomenon of quantum dots in solution. This enhances the compactness and orderliness of the quantum dot arrangement in the light-emitting layer, promotes film uniformity, reduces the surface roughness of the light-emitting layer, and is beneficial to improving the photoelectric performance and device lifespan of the light-emitting device.

[0215] The foregoing has provided a detailed description of a light-emitting device, a method for fabricating the light-emitting device, and an electronic device provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for preparing a thin film, characterized in that, Includes the following steps: A dispersion is provided, the dispersion comprising quantum dots and a crosslinking agent; The dispersion is subjected to crosslinking induction treatment; and The dispersion subjected to crosslinking induction treatment is dried to obtain the film; The quantum dot is connected to a plurality of first ligands, and the crosslinking agent is selected from one or more of the following: ethylene glycol-bis(N-hydroxysuccinimide succinate), bis(N-hydroxysuccinimide succinate) 3,3'-dithiodipropionate bis(N-hydroxysuccinimide succinate), sebacic acid bis(N-succinimide) ester, octanoic acid bis(succinimide succinate) ester, tartrate bis(succinimide) glutarate, and 3,3'-dithiobis(sulfonylsuccinimide succinate). The first ligand comprises one or more functional groups selected from hydroxyl, amino, mercapto, and carboxyl groups; In the dispersion, the mass ratio of the crosslinking agent to the quantum dots is 1:(3-6.67).

2. The preparation method according to claim 1, characterized in that, The quantum dots are selected from one or more of single-component quantum dots, core-shell structured quantum dots, inorganic perovskite quantum dots, organic perovskite quantum dots, and organic-inorganic hybrid perovskite quantum dots.

3. The preparation method according to claim 2, characterized in that, The materials of the single-component quantum dots, the core of the core-shell quantum dots, and the shell of the core-shell quantum dots are independently selected from at least one of group II-VI, III-V, IV-VI, or I-III-VI compounds, wherein the group II-VI compounds are selected from CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, and HgSeTe. HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe, wherein the III-V compound is selected from 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, GaAlNA s, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs and InAlPSb One or more of the following compounds are selected from SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe; and one or more of the following compounds are selected from CuInS, CuInSe, and AgInS; and / or the inorganic perovskite quantum dots have the general structural formula AMX3, where A is Cs. + Ion, M is a divalent metal cation, M is selected from Pb 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ and Eu 2+ One or more of the following, where X is a halide anion; and / or, the general structural formula of the organic perovskite quantum dot is CMX3, where C is formamidinyl; and / or, the general structural formula of the organic-inorganic hybrid perovskite quantum dot is BMX3, where B is selected from organic amine cations.

4. The preparation method according to any one of claims 1 to 3, characterized in that, The dispersion comprises, by weight percentage: 15%–20% quantum dots, 3%–5% crosslinking agent, and 75%–82% dispersant; and / or The crosslinking induction treatment includes the step of subjecting the deposited dispersion to ultraviolet light treatment in an inert gas atmosphere.

5. The preparation method according to claim 4, characterized in that, The dispersant is selected from one or more of alkane compounds, aromatic hydrocarbon compounds, alcohol compounds, and ester compounds.

6. A thin film, characterized in that, The thin film is prepared by the method for preparing the thin film as described in any one of claims 1 to 5; The thin film material contains a plurality of quantum dots, at least some of the quantum dots have a second ligand attached to their surface, the second ligand being formed by the bonding of the first ligand with the reactive group of the crosslinking agent, and at least some of the adjacent quantum dots are connected by the second ligand.

7. The thin film according to claim 6, characterized in that, The root mean square roughness of the film is 0.8 nm to 1.1 nm.

8. A light-emitting device, characterized in that, include: The anode and cathode are positioned opposite each other; as well as A light-emitting layer is disposed between the anode and the cathode; The light-emitting layer is prepared by the method for preparing the thin film as described in any one of claims 1 to 5; or the light-emitting layer comprises the thin film as described in claim 6 or 7.

9. The light-emitting device according to claim 8, characterized in that, The light-emitting device further includes a hole-functional layer disposed between the anode and the light-emitting layer. The hole-functional layer is made of materials comprising poly(3,4-vinyldioxythiophene):poly(styrenesulfonic acid), copper phthalocyanine, titanium phthalocyanine, 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene, 3-hexyl-substituted polythiophene, poly(9-vinylcarbazole), 4,4'-bis(9-carbazole)biphenyl, poly[bis(4-phenyl)(4-butylphenyl)amine], 4,4'- Cyclohexylbis[N,N-di(4-methylphenyl)aniline], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine)], poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)], poly(N,N'-di(4-butylphenyl)-N,N'-diphenyl-1,4-phenylenediamine-CO-9,9-dioctylfluorene), 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, 4,4',4''-tris(carbohydrate) 4,4',4'-tris(2-naphthylphenylamino)triphenylamine, N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine, N,N'-diphenyl-N,N'-di(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine, N,N'-bis[4-(diphenylamino)phenyl]-N,N'-diphenylbenzidine, N,N'-bis(3-methylphenyl)-N,N'-diphenyl-9,9-spirodifluorene-2,7-diamine, N2,N7-di-1-naphthyl-N2,N7-diphenyl- 9,9'-spirodi[9H-fluorene]-2,7-diamine, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene, doped or undoped graphene, C60, doped or undoped nickel oxide, doped or undoped molybdenum oxide, doped or undoped tungsten oxide, doped or undoped vanadium oxide, doped or undoped p-type gallium nitride, doped or undoped chromium oxide, doped or undoped copper oxide, transition metal sulfides, and transition metal selenides, or one or more of these; and / or The light-emitting device further includes an electronic functional layer disposed between the cathode and the light-emitting layer. The material of the electronic functional layer comprises one or more of a first metal oxide, lithium 8-hydroxyquinoline, cesium carbonate, cesium fluoride, cesium azide, lithium fluoride, organophosphorus oxide, organothiophosphine compound, and organoselenophosphine compound. The first metal oxide is selected from one or more of zinc oxide, titanium oxide, tin oxide, barium oxide, tantalum oxide, aluminum oxide, zirconium oxide, zinc magnesium oxide, zinc calcium oxide, zinc zirconium oxide, zinc gallium oxide, zinc aluminum oxide, lithium zinc oxide, zinc titanium oxide, yttrium zinc oxide, indium tin oxide, and lithium titanium oxide; and / or The materials of the anode and the cathode are independently selected from one or more of metals, carbon materials, and a second metal oxide. The metal is selected from one or more of Al, Ag, Cu, Mo, Au, Ba, Pt, Ca, Ir, Ni, and Mg. The carbon material is selected from one or more of graphite, carbon nanotubes, graphene, and carbon fibers. The second metal oxide is selected from 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, aluminum-doped magnesium oxide, SnO2, ZnO, and In2O3.

10. A method for fabricating a light-emitting device, characterized in that, The method for preparing the light-emitting device as described in claim 8 or 9 includes the following steps: A bottom electrode is provided, and a dispersion comprising quantum dots and a crosslinking agent is deposited on one side of the bottom electrode; The deposited dispersion is subjected to cross-linking induction treatment; The dispersion after the crosslinking induction treatment is dried to obtain a luminescent layer; and A top electrode is formed on the side of the light-emitting layer away from the bottom electrode; In this configuration, one of the bottom electrode and the top electrode is the anode, and the other is the cathode.

11. An electronic device, characterized in that, The electronic device includes the light-emitting device as described in claim 8 or 9, or the electronic device includes the light-emitting device prepared by the preparation method as described in claim 10.

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