Composite film and application thereof

Abstract

The embodiment of the invention relates to the field of display, in particular to a composite film which comprises a first film layer and a second film layer which are stacked in sequence. The material of the first film layer comprises a metal compound, and the material of the second film layer comprises a sulfur-nitrogen compound. The invention further relates to application of the composite film. According to the technical scheme provided by the invention, the film layer stability of the first film layer can be improved.

Description

Technical Field

[0001] This application relates to the field of display technologies, and particularly to a composite film and its applications. Background Art

[0002] Currently, the widely used light-emitting device is a quantum dot light-emitting diode (QLED). QLEDs have advantages such as saturated emission light color, adjustable wavelength, low turn-on voltage, good solution processability, easy fine control of quantum dots, and high photoluminescence and electroluminescence quantum yields. However, the stability of the first film layer in existing QLED devices is poor and is easily dissolved and damaged by quantum dot solvents. Summary of the Invention

[0003] Based on this, embodiments of this application provide a composite film, a preparation method thereof, a light-emitting device, and a display device.

[0004] To solve the above technical problems, embodiments of this application provide a composite film, adopting the following technical solutions:

[0005] A composite film includes a first film layer and a second film layer stacked in sequence; the material of the first film layer includes a metal compound, and the material of the second film layer includes a sulfur nitride compound.

[0006] Further, the sulfur nitride compound is selected from at least one of polythiazyl, ammonium sulfide compound, and thiourea compound; and / or,

[0007] The metal compound is an N-type metal compound or a P-type metal compound; the N-type metal compound is selected from one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, aluminum zinc oxide, manganese zinc oxide, tin zinc oxide, lithium zinc oxide, magnesium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc stannide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, barium titanate, and the doping elements include at least one of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium; the P-type metal compound is selected from at least one of transition metal oxides, transition metal sulfides, transition metal tin compounds, nickel oxide, molybdenum oxide, tungsten oxide, and vanadium oxide; and / or,

[0008] The thickness of the first film layer is 30 - 40 nm; and / or,

[0009] The thickness of the second film layer is 10 - 40 nm.

[0010] Further, the ammonium sulfide compound is selected from at least one of ammonium hydrogen sulfide, ammonium sulfide, ammonium sulfate, and ammonium thiosulfate; and / or,

[0011] The general structural formula of the thiourea compound is shown in Formula I:

[0012]

[0013] Wherein, R1, R2, and R3 are each independently selected from at least one of a hydrogen atom, a hydroxyl group, an amino group, a carboxyl group, an ether bond, an ester group, an aldehyde group, a carbonyl group, a nitro group, a sulfonic acid group, an alkyl group, a methyl group, an ethyl group, a benzene ring, and a benzyl group; or are each independently selected from a C1-C20 hydrocarbon group, a C1-C20 hydrocarbon oxy group, a cycloalkyl group with 3 to 60 ring atoms, a heterocyclic hydrocarbon group with 3 to 60 ring atoms, an aryl group with 5 to 60 ring atoms, a heteroaryl group with 5 to 60 ring atoms, an aryloxy group with 5 to 60 ring atoms, and a heteroaryloxy group with 5 to 60 ring atoms, which are unsubstituted or substituted by an amino group, a halogen, a hydroxyl group, a carboxyl group, a nitro group, a sulfonic acid group, an aldehyde group, a mercapto group, and a cyano group, and the heteroatoms in the heteroaryl group or heteroaryloxy group are N, S, O, P, Si, and the number of heteroatoms is 1 to 20.

[0014] To solve the above technical problems, the embodiments of the present application also provide a method for preparing a composite film, and the following technical solutions are adopted:

[0015] A method for preparing a composite film, characterized by comprising the following steps:

[0016] Providing a first solution and a second solution, the first solution comprising a metal compound, and the second solution comprising a sulfur-nitrogen compound;

[0017] Depositing the first solution to form a first film layer;

[0018] Depositing the second solution on the first film layer to form a second film layer, obtaining a composite film.

[0019] Further, the step of forming the second film layer includes:

[0020] Performing ultraviolet treatment on the interface modification solution to obtain a second film layer.

[0021] Further, the light energy of the ultraviolet treatment is 130-160 mJ / cm 2 ; and / or,

[0022] The time of the ultraviolet treatment is 5-8 min.

[0023] The wavelength of the ultraviolet light for the ultraviolet treatment is 350-390 nm.

[0024] Further, the metal compound is an N-type metal compound or a P-type metal compound; the N-type metal compound is selected from one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, aluminum zinc oxide, manganese zinc oxide, tin zinc oxide, lithium zinc oxide, magnesium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc stannide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, barium titanate, and the doping elements include at least one of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, gadolinium; the P-type metal compound is selected from at least one of transition metal oxides, transition metal sulfides, transition metal stannides, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide; and / or,

[0025] The sulfur nitride compound is selected from at least one of polythiazyl, ammonium sulfate compound, thiourea compound; and / or,

[0026] The concentration of the metal compound in the first solution is 60-80 mg / mL; and / or,

[0027] The concentration of the sulfur nitride compound in the interface modification solution is 50-60 mg / mL.

[0028] To solve the above technical problems, the embodiments of the present application further provide a preparation method of a light-emitting device, adopting the following technical solutions:

[0029] A preparation method of a light-emitting device, comprising the following steps:

[0030] Providing a first electrode with a carrier functional layer, the carrier functional layer comprising the composite film as described above, or a composite film prepared by using the preparation method of the composite film as described above;

[0031] Depositing a quantum dot solution on the second film layer to form a quantum dot light-emitting layer;

[0032] Depositing a second electrode on the quantum dot light-emitting layer.

[0033] Further, before the step of depositing the quantum dot solution on the second film layer, it further includes:

[0034] Providing an initial quantum dot solution;

[0035] Performing phosphorylation treatment on the initial quantum dot solution to obtain a quantum dot solution, the quantum dot solution comprising a quantum dot material having a phosphate group.

[0036] Further, the step of performing phosphorylation treatment on the initial quantum dot solution to obtain a quantum dot solution includes:

[0037] Provide a phosphorylation reagent and a first solvent;

[0038] Mix the initial quantum dot solution and the phosphorylation reagent to obtain a first mixture;

[0039] Dry the first mixture to obtain a quantum dot material with phosphate groups;

[0040] Centrifuge the first mixture, and after removing the supernatant, obtain a separated liquid;

[0041] Mix the separated liquid with the first solvent to obtain a quantum dot solution.

[0042] Furthermore, the phosphorylation reagent includes at least one of trisodium phosphate, disodium hydrogen phosphate, sodium hexametaphosphate, diethylphosphoryl chloride, bis(2-diphenylphosphinophenyl) ether, dipotassium bis(p-sulfophenyl)phenylphosphine dihydrate; and / or,

[0043] The first solvent includes at least one of aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, halogenated hydrocarbon solvents, alcohol solvents, ether solvents, ester solvents, ketone solvents, diol derivative solvents, acetonitrile, pyridine; the aromatic hydrocarbon solvents include at least one of benzene, toluene, and xylene; the aliphatic hydrocarbon solvents include at least one of pentane, hexane, and octane; the alicyclic hydrocarbon solvents include at least one of cyclohexane, cyclohexanone, and toluene cyclohexanone; the halogenated hydrocarbon solvents include at least one of chlorobenzene, dichlorobenzene, and dichloromethane; the alcohol solvents include at least one of methanol, ethanol, and isopropanol; the ether solvents include at least one of diethyl ether and propylene oxide; the ester solvents include at least one of methyl acetate, ethyl acetate, and propyl acetate; the ketone solvents include at least one of acetone, methyl butyl ketone, and methyl isobutyl ketone; the diol derivative solvents include at least one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether; and / or,

[0044] The concentration of the phosphorylation reagent in the first mixture is 15 - 30 mg / mL.

[0045] Furthermore, the step of centrifuging the first mixture includes:

[0046] Provide a basic material;

[0047] Mix the first mixture and the basic material to obtain a second mixture;

[0048] Centrifuge the second mixture.

[0049] Furthermore, the basic material is selected from metal chlorides; the metal chlorides are selected from at least one of sodium chloride, potassium chloride, calcium chloride, and magnesium chloride; and / or,

[0050] The concentration of the basic material in the second mixed solution is 5-10 mg / mL.

[0051] To solve the above technical problems, the embodiments of the present application further provide a light-emitting device, adopting the following technical solutions:

[0052] A light-emitting device, characterized in that it includes a light-emitting device prepared by using the preparation method of the light-emitting device described above.

[0053] To solve the above technical problems, the embodiments of the present application further provide a display device, adopting the following technical solutions:

[0054] A display device includes the light-emitting device described above.

[0055] Compared with the prior art, the embodiments of the present application mainly have the following beneficial effects: By providing a second film layer containing a sulfur nitride compound on the first film layer, the film layer stability of the first film layer is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] To more clearly illustrate the solutions of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0057] Figure 1 It is a schematic structural diagram of an embodiment of the composite film of the present application;

[0058] Figure 2 It is a flowchart of an embodiment of the preparation method of the composite film of the present application;

[0059] Figure 3 It is a flowchart of an embodiment of the preparation method of the light-emitting device of the present application;

[0060] Figure 4 It is a schematic structural diagram of an embodiment of the light-emitting device of the present application;

[0061] Figure 5 It is a schematic structural diagram of another embodiment of the light-emitting device of the present application;

[0062] Reference Numerals:

[0063] 100, composite film; 110, first film layer; 120, second film layer; 200, light-emitting device; 210, first electrode; 220, quantum dot light-emitting layer; 230, second electrode; 240, electron transport layer; 250, hole transport layer; 260, hole injection layer. Detailed implementation manners

[0064] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs; the terms used in the description of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the description and claims of this application and the above drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the description and claims of this application or the above drawings are used to distinguish different objects and not to describe a specific order.

[0065] Reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of this application. The phrase does not necessarily refer to the same embodiment when it appears in various places in the specification, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0066] Refer to Figure 1 , an embodiment of this application provides a composite film, including a first film layer 110 and a second film layer 120 stacked in sequence, the material of the first film layer 110 includes a metal compound, and the material of the second film layer 120 includes a sulfur nitride compound.

[0067] In this embodiment, since the sulfur nitride compound has electrophilicity and nucleophilicity, a coordination bond is formed between the sulfur atom and the nitrogen atom in the sulfur nitride compound and the metal compound, so that the second film layer 120 forms a protective film on the first film layer 110, improving the stability of the first film layer 110 after film formation, and further improving the use stability of the composite film 100.

[0068] For example, when preparing a quantum dot light-emitting layer on the first film layer 110, the solvent of the quantum dot light-emitting layer will dissolve and damage the first film layer 110; based on this, this application prepares the second film layer 120 on the first film layer 110 to form a protective film on the first film layer 110, so as to avoid damage to the first film layer 110 caused by the solvent of the quantum dot light-emitting layer when preparing the quantum dot light-emitting layer on the first film layer 110, and further improve the stability of the first film layer 110.

[0069] In some embodiments, the sulfur nitride compound is selected from at least one of polythiazyl, ammonium sulfide compound, and thiourea compound.

[0070] In some embodiments, the ammonium sulfide compound is selected from at least one of ammonium hydrosulfide, ammonium sulfide, ammonium sulfate, and ammonium thiosulfate.

[0071] In some embodiments, the structural general formula of the thiourea compound is as shown in Formula I:

[0072]

[0073] Wherein, R1, R2, and R3 are each independently selected from at least one of a hydrogen atom, a hydroxyl group, an amino group, a carboxyl group, an ether bond, an ester group, an aldehyde group, a carbonyl group, a nitro group, a sulfonic acid group, an alkyl group, a methyl group, an ethyl group, a benzene ring, and a benzyl group; or are each independently selected from a C1-C20 hydrocarbon group, a C1-C20 hydrocarbon oxy group, a cycloalkyl group with 3 to 60 ring atoms, a heterocyclic hydrocarbon group with 3 to 60 ring atoms, an aryl group with 5 to 60 ring atoms, a heteroaryl group with 5 to 60 ring atoms, an aryloxy group with 5 to 60 ring atoms, and a heteroaryloxy group with 5 to 60 ring atoms, which are unsubstituted or substituted by an amino group, a halogen, a hydroxyl group, a carboxyl group, a nitro group, a sulfonic acid group, an aldehyde group, a mercapto group, or a cyano group, and one or more combinations thereof, wherein the heteroatoms in the heteroaryl group or heteroaryloxy group are N, S, O, P, Si, and the number of heteroatoms is 1 to 20

[0074] In some embodiments, the metal compound is an N-type metal compound or a P-type metal compound.

[0075] Optionally, the N-type metal compound is selected from one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, aluminum zinc oxide, manganese zinc oxide, tin zinc oxide, lithium zinc oxide, magnesium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate, and the doping elements include at least one of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium.

[0076] Optionally, the P-type metal compound is selected from at least one of transition metal oxides, transition metal sulfides, transition metal tin compounds, nickel oxide, molybdenum oxide, tungsten oxide, and vanadium oxide.

[0077] In some embodiments, the first film layer is one of a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer.

[0078] In some embodiments, the thickness of the first film layer is 30 to 40 nm.

[0079] Optionally, the thickness of the first film layer is selected from any one of 30 nm, 32 nm, 34 nm, 36 nm, 38 nm, and 40 nm or a range formed by any two of them.

[0080] In some embodiments, the thickness of the second film layer is 10 to 40 nm.

[0081] Optionally, the thickness of the second film layer is selected from any one or any range formed by any two of 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, and 40 nm.

[0082] See Figure 2 , the embodiment of the present application also provides a method for preparing a composite film, including the following steps:

[0083] Step S110: Provide a first solution and a second solution, the first solution includes a metal compound, and the second solution includes a sulfur-nitrogen compound.

[0084] Step S120: Deposit the first solution to form a first film layer;

[0085] Step S130: Deposit the second solution on the first film layer to form a second film layer, obtaining a composite film.

[0086] In this embodiment, since the sulfur-nitrogen compound has electrophilicity and nucleophilicity, a coordination bond is formed between the sulfur atom and the nitrogen atom in the sulfur-nitrogen compound and the metal compound, so that a protective film is formed on the first film layer by the second film layer, improving the stability of the first film layer after film formation, and further improving the use stability of the composite film.

[0087] Secondly, since the sulfur-nitrogen compound has electrophilicity, it can produce an electrostatic adsorption effect on the quantum dot material, thereby reducing the particle spacing between the quantum dot material and the sulfur-nitrogen compound, making the quantum dot light-emitting layer formed on the second film layer dense and uniform, which is conducive to exciting the coupling resonance between quantum dot nanoparticles, and further reducing the non-radiative Auger recombination process and improving the light-emitting performance of the quantum dot light-emitting layer.

[0088] In step S110:

[0089] In some embodiments, the metal compound is an N-type metal compound or a P-type metal compound; the N-type metal compound is selected from one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, aluminum zinc oxide, manganese zinc oxide, tin zinc oxide, lithium zinc oxide, magnesium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc stannide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, barium titanate, and the doped elements include at least one of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium; the P-type metal compound is selected from at least one of transition metal oxides, transition metal sulfides, transition metal stannides, nickel oxide, molybdenum oxide, tungsten oxide, and vanadium oxide.

[0090] In some embodiments, the concentration of the metal compound in the first solution is 60-80 mg / mL.

[0091] Optionally, the concentration of the metal compound in the first solution is any one or the range formed by any two of 60 mg / mL, 65 mg / mL, 70 mg / mL, 75 mg / mL, and 80 mg / mL.

[0092] In some embodiments, the first solution includes an organic solvent, and the organic solvent includes at least one of aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, halogenated hydrocarbon solvents, alcohol solvents, ether solvents, ester solvents, ketone solvents, diol derivative solvents, acetonitrile, and pyridine.

[0093] Optionally, the aromatic hydrocarbon solvent includes at least one of benzene, toluene, and xylene.

[0094] Optionally, the aliphatic hydrocarbon solvent includes at least one of pentane, hexane, and octane.

[0095] Optionally, the alicyclic hydrocarbon solvent includes at least one of cyclohexane, cyclohexanone, and tolylcyclohexanone; the halogenated hydrocarbon solvent includes at least one of chlorobenzene, dichlorobenzene, and dichloromethane.

[0096] Optionally, the alcohol solvent includes at least one of methanol, ethanol, and isopropanol; the ether solvent includes at least one of diethyl ether and propylene oxide.

[0097] Optionally, the ester solvent includes at least one of methyl acetate, ethyl acetate, and propyl acetate.

[0098] Optionally, the ketone solvent includes at least one of acetone, methyl butyl ketone, and methyl isobutyl ketone.

[0099] Optionally, the diol derivative solvent includes at least one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether.

[0100] In some embodiments, the interface modification solution further includes a proton solvent.

[0101] In some embodiments, the proton solvent is selected from at least one of deionized water, water, liquid ammonia, methanol, ethanol, tert-butanol, benzyl alcohol, formic acid, and acetic acid.

[0102] In step S130:

[0103] In some embodiments, in the above step S130, the step of forming the second film layer includes:

[0104] Step S131, subject the interface modification solution to ultraviolet treatment to obtain the second film layer.

[0105] In this step, by subjecting the interface modification solution to ultraviolet treatment, sulfur atoms and nitrogen atoms are decomposed from the sulfur-nitrogen compound for forming coordination bonds with the metal compound.

[0106] In some embodiments, the light energy of the ultraviolet treatment is 130-160 mJ / cm 2 .

[0107] Optionally, the light energy of the ultraviolet treatment is selected from any one or any range formed by any two of 130 mJ / cm 2 , 132 mJ / cm 2 , 134 mJ / cm 2 , 136 mJ / cm 2 , 138 mJ / cm 2 , 140 mJ / cm 2 , 142 mJ / cm 2 , 144 mJ / cm 2 , 146 mJ / cm 2 , 148 mJ / cm 2 , 150 mJ / cm 2 , 152 mJ / cm 2 , 154 mJ / cm 2 , 156 mJ / cm 2 , 158 mJ / cm 2 , 160 mJ / cm 2 in any one or any range formed by any two of them.

[0108] In some embodiments, the time of the ultraviolet treatment is 5-8 min.

[0109] Optionally, the time of the ultraviolet treatment is selected from any one or any range formed by any two of 5 min, 6 min, 7 min, and 8 min.

[0110] In some embodiments, the ultraviolet light wavelength of the ultraviolet treatment is 350-390 nm.

[0111] Optionally, the ultraviolet light wavelength of the ultraviolet treatment is selected from any one or any range formed by any two of 350 nm, 355 nm, 360 nm, 365 nm, 370 nm, 375 nm, 380 nm, 385 nm, and 390 nm.

[0112] Referring to Figure 3 , the embodiment of the present application further provides a method for preparing a light-emitting device, including the following steps:

[0113] Step S210: Provide a first electrode with a carrier functional layer, where the carrier functional layer includes the composite film as described above, or a composite film prepared by using the preparation method of the composite film as described above.

[0114] Step S220: Deposit a quantum dot solution on the second film layer to form a quantum dot light-emitting layer.

[0115] Step S230: Deposit a second electrode on the quantum dot light-emitting layer.

[0116] In this embodiment, since the sulfur nitride compound has electrophilicity and nucleophilicity, a coordination bond is formed between the sulfur atom and the nitrogen atom in the sulfur nitride compound and the metal compound, so that a protective film is formed on the first film layer by the second film layer, improving the anti-solubility of the first film layer to the quantum dot solvent.

[0117] Secondly, since the sulfur nitride compound has electrophilicity, it can generate an electrostatic adsorption effect on the quantum dot material, thereby reducing the particle spacing between the quantum dot material and the sulfur nitride compound, making the quantum dot light-emitting layer formed on the second film layer dense and uniform, which is beneficial to exciting the coupling resonance between quantum dot nanoparticles, and further reducing the non-radiative Auger recombination process, improving the light-emitting performance of the quantum dot light-emitting layer.

[0118] In step S220:

[0119] In some embodiments, before the step of disposing the quantum dot solution on the second film layer in the above step S220, the following steps are further included:

[0120] Step S221: Provide an initial quantum dot solution.

[0121] Step S222: Perform phosphorylation treatment on the initial quantum dot solution to obtain a quantum dot solution.

[0122] In this embodiment, by performing phosphorylation treatment on the quantum dot material, the surface of the quantum dot material is negatively charged, thereby increasing the negative charge density on the surface of the quantum dot material. In this way, on the one hand, due to the action of electrostatic attraction, the negatively charged quantum dot material can interact with positively charged ions or molecules in the quantum dot solution to prevent aggregation, so that the quantum dot material stably exists in the quantum dot solution; on the other hand, the electrostatic adsorption effect between the quantum dot material and the second film layer can be further enhanced, so that the quantum dot light-emitting layer prepared from the quantum dot solution is more compact and uniform.

[0123] In some embodiments, the initial quantum dot solution includes a quantum dot material and a quantum dot solvent.

[0124] Optionally, the quantum dot material includes at least one of single-structure quantum dots and core-shell structure quantum dots. The material of the single-structure quantum dots, the core material of the core-shell structure quantum dots, and the shell material of the core-shell structure quantum dots are each independently selected from at least one of II-VI group compounds, IV-VI group compounds, III-V group compounds, and I-III-VI group compounds. Among them, the II-VI group compounds are selected from at least one 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 are selected from at least one 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 are selected from at least one 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, or InAlPSb; and the I-III-VI group compounds are selected from at least one of CuInS2, CuInSe2, and AgInS2.

[0125] Optionally, the quantum dot solvent is selected from at least one of aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, halogenated hydrocarbon solvents, alcohol solvents, ether solvents, ester solvents, ketone solvents, diol derivative solvents, acetonitrile, and pyridine; the aromatic hydrocarbon solvents include at least one of benzene, toluene, and xylene; the aliphatic hydrocarbon solvents include at least one of pentane, hexane, and octane; the alicyclic hydrocarbon solvents include at least one of cyclohexane, cyclohexanone, and toluene cyclohexanone; the halogenated hydrocarbon solvents include at least one of chlorobenzene, dichlorobenzene, and dichloromethane; the alcohol solvents include at least one of methanol, ethanol, and isopropanol; the ether solvents include at least one of diethyl ether and propylene oxide; the ester solvents include at least one of methyl acetate, ethyl acetate, and propyl acetate; the ketone solvents include at least one of acetone, methyl butanone, and methyl isobutyl ketone; the diol derivative solvents include at least one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether.

[0126] In some embodiments, in the above step S222, the step of phosphorylating the initial quantum dot solution to obtain a quantum dot solution includes:

[0127] Step S2221, providing a phosphorylating reagent and a first solvent;

[0128] Step S2222, mixing the initial quantum dot solution and the phosphorylating reagent to obtain a first mixture;

[0129] Step S2223, centrifuging the first mixture, and after removing the supernatant, obtaining a separated liquid;

[0130] Step S2224, mixing the separated liquid with the first solvent to obtain a quantum dot solution.

[0131] In some embodiments, the phosphorylating reagent includes at least one of trisodium phosphate, disodium hydrogen phosphate, sodium hexametaphosphate, diethylphosphoryl chloride, bis(2-diphenylphosphinophenyl) ether, and dipotassium bis(p-sulfophenyl)phenylphosphine dihydrate.

[0132] In some embodiments, the selection range of the first solvent is the same as that of the quantum dot solvent, which will not be elaborated here.

[0133] In some embodiments, the concentration of the phosphorylating reagent in the first mixture is 15 - 30 mg / mL.

[0134] Optionally, the concentration of the phosphorylation reagent in the first mixture is selected from any one or any range formed by any two of 15 mg / mL, 16 mg / mL, 17 mg / mL, 18 mg / mL, 19 mg / mL, 20 mg / mL, 21 mg / mL, 22 mg / mL, 23 mg / mL, 24 mg / mL, 25 mg / mL, 26 mg / mL, 27 mg / mL, 28 mg / mL, 29 mg / mL, 30 mg / mL.

[0135] In some embodiments, in step S2223 above, the step of centrifuging the first mixture includes:

[0136] Providing an alkaline material;

[0137] Mixing the first mixture and the alkaline material to obtain a second mixture;

[0138] Centrifuging the second mixture.

[0139] In this embodiment, the acidic ions remaining in the first mixture from the phosphorylation reagent are neutralized by the alkaline material. On the one hand, it prevents acidic corrosion of the second film layer, and on the other hand, it ensures the luminescence effect of the quantum dot light-emitting layer after forming.

[0140] In some embodiments, the alkaline material is selected from metal chlorides.

[0141] Optionally, the metal chloride is at least one of sodium chloride, potassium chloride, calcium chloride, and magnesium chloride.

[0142] In some embodiments, the concentration of the alkaline material in the second mixture is 5 - 10 mg / mL.

[0143] Optionally, the concentration of the alkaline material in the second mixture is selected from any one or any range formed by any two of 5 mg / mL, 6 mg / mL, 7 mg / mL, 8 mg / mL, 9 mg / mL, 10 mg / mL.

[0144] Refer to Figure 4 and Figure 5 , this application embodiment also provides a light-emitting device, including a light-emitting device prepared by using the preparation method of the light-emitting device as described above.

[0145] In the composite film of the light-emitting device, since the sulfur nitride compound has electrophilicity and nucleophilicity, a coordination bond is formed between the sulfur atom and the nitrogen atom in the sulfur nitride compound and the metal compound, so that the second film layer forms a protective film on the first film layer, improving the anti-solubility of the first film layer to the quantum dot solvent, and further improving the use stability of the composite film.

[0146] In some embodiments, the sulfur nitride compound is selected from at least one of polythiazyl, ammonium sulfide compound, and thiourea compound.

[0147] In some embodiments, the ammonium sulfide compound is selected from at least one of ammonium hydrogen sulfide, ammonium sulfide, ammonium sulfate, and ammonium thiosulfate.

[0148] In some embodiments, the structural general formula of the thiourea compound is as shown in Formula I:

[0149]

[0150] Wherein, R1, R2, and R3 are each independently selected from at least one of a hydrogen atom, a hydroxyl group, an amino group, a carboxyl group, an ether bond, an ester group, an aldehyde group, a carbonyl group, a nitro group, a sulfonic acid group, an alkyl group, a methyl group, an ethyl group, a benzene ring, and a benzyl group.

[0151] In some embodiments, the concentration of the sulfur nitride compound in the interface modification solution is 50 - 60 mg / mL.

[0152] Optionally, the concentration of the sulfur nitride compound in the interface modification solution is selected from any one or any range formed by any two of 50 mg / mL, 51 mg / mL, 52 mg / mL, 53 mg / mL, 54 mg / mL, 55 mg / mL, 56 mg / mL, 57 mg / mL, 58 mg / mL, 59 mg / mL, and 60 mg / mL.

[0153] In some embodiments, referring to Figure 4 , when the composite film is the electron transport layer 240, the light-emitting device 200 further includes a hole injection layer 260 and / or a hole transport layer 250 disposed between the second electrode 210 and the quantum dot light-emitting layer 220. The hole injection layer 260 and the hole transport layer 250 each independently include at least one of TFB, CuPc, PVK, Poly-TPD, PFB, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, polyaniline, transition metal oxide, transition metal sulfide, transition metal stannide, doped graphene, undoped graphene, C60, copper polyester carbonate, and molybdenum trioxide.

[0154] In other embodiments, referring to Figure 5When the composite film is the hole transport layer 250, the light-emitting device 200 further includes an electron transport layer 240 and / or an electron injection layer disposed between the quantum dot light-emitting layer 220 and the second electrode 230. The materials of the electron transport layer 240 and the electron injection layer independently include an inorganic material and / or an organic material respectively; the inorganic material includes one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, aluminum zinc oxide, manganese zinc oxide, tin zinc oxide, lithium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc stannide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, barium titanate, and the doped elements include at least one of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, gadolinium; the organic material includes at least one of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene-containing compounds, hydroxyquinoline compounds, polythiophene compounds, perylene diimide compounds, fullerene compounds.

[0155] In some embodiments, the materials of the first electrode 210 and the second electrode 230 independently include at least one of a metal material, a carbon material, and a metal oxide. The metal material includes at least one of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon material includes at least one of graphite, carbon nanotubes, graphene, and carbon fibers; the metal oxide includes a doped or undoped metal oxide. The doped metal oxide includes at least one of ITO, FTO, ATO, AZO, GZO, IZO, MZO, and AMO, or includes a composite electrode with a metal sandwiched between doped or undoped transparent metal oxides. The composite electrode includes at least one of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2.

[0156] An embodiment of the present application further provides a display device including the light-emitting device as described above.

[0157] In this embodiment, since the sulfur-nitrogen compound has electrophilicity and nucleophilicity, a coordination bond is formed between the sulfur atom and nitrogen atom in the sulfur-nitrogen compound and the metal compound, so that a protective film is formed on the first film layer by the second film layer. When preparing the quantum dot light-emitting layer on the first film layer, the solvent of the quantum dot light-emitting layer is prevented from damaging the first film layer, and the stability of the first film layer after film formation is improved. Moreover, since the sulfur-nitrogen compound has electrophilicity, it can exert an electrostatic adsorption effect on the quantum dot material, thereby reducing the particle spacing between the quantum dot material and the sulfur-nitrogen compound, making the quantum dot light-emitting layer formed on the second film layer dense and uniform, which is conducive to exciting the coupling resonance between quantum dot nanoparticles, and further reducing the non-radiative Auger recombination process and improving the light-emitting performance of the quantum dot light-emitting layer. In this way, the display effect of the display device is improved.

[0158] The technical solutions and technical effects of this application will be described in detail below through specific examples and comparative examples. The following examples are only partial examples of this application and do not specifically limit this application.

[0159] Composite film Example 1:

[0160] Step 1: Provide a substrate;

[0161] Step 2: Set a first solution on the substrate to form a first film layer with a thickness of 30 nm. Among them, the first solution includes ZnO, and the concentration of ZnO in the first solution is 60 mg / mL;

[0162] Step 3: Print a second solution on the first film layer, perform ultraviolet treatment on the second solution with ultraviolet light having a wavelength of 365 nm and a light energy of 130 mJ / cm 2 for 5 min, and then dry the second solution at a rotation speed of 4000 rpm to form a second film layer with a thickness of 10 nm, obtaining a composite film. Among them, the second solution includes thiourea and deionized water, and the concentration of thiourea in the second solution is 50 mg / mL.

[0163] Composite film Example 2:

[0164] The difference from the above Composite film Example 1 is that in Step 1 of this embodiment, ZnO is changed to NiO.

[0165] Composite film Example 3:

[0166] The difference from the above Composite film Example 1 is that in Step 1 of this embodiment, the concentration of ZnO in the first solution is changed to 80 mg / mL; correspondingly, the thickness of the formed first film layer is 40 nm.

[0167] Composite film Example 4:

[0168] The difference from the above-mentioned Composite Film Example 1 is as follows: In Step 2 of this example, thiourea is changed to polythiazyl.

[0169] Composite Film Example 5:

[0170] The difference from the above-mentioned Composite Film Example 1 is as follows: In Step 2 of this example, thiourea is changed to ammonium sulfide.

[0171] Composite Film Example 6:

[0172] The difference from the above-mentioned Composite Film Example 1 is as follows: In Step 2 of this example, the concentration of thiourea in the second solution is changed to 60 mg / mL; correspondingly, the thickness of the formed second film layer is 40 nm.

[0173] Composite Film Example 7:

[0174] The difference from the above-mentioned Composite Film Example 1 is as follows: In Step 2 of this example, the illumination energy of ultraviolet light is 160 mJ / cm 2 .

[0175] Composite Film Example 8:

[0176] The difference from the above-mentioned Composite Film Example 1 is as follows: In Step 2 of this example, the ultraviolet treatment time of ultraviolet light is 8 min.

[0177] Composite Film Comparative Example 1:

[0178] The difference from the above-mentioned Composite Film Example 1 is as follows: In this comparative example, Step 3 is omitted; correspondingly, the first film layer is used as the film.

[0179] Composite Film Comparative Example 2:

[0180] The difference from the above-mentioned Composite Film Example 2 is as follows: In this comparative example, Step 3 is omitted; correspondingly, the first film layer is used as the film.

[0181] Experimental Test Analysis 1: The composite films obtained from Composite Film Examples 1 to 8 and the films obtained from Composite Film Comparative Examples 1 and 2 were respectively subjected to a solubility resistance test, and the test results are shown in Table 1. Among them:

[0182] For the solubility resistance test, the side of the second film layer of the composite films obtained from Composite Film Examples 1 to 8 that is far from the first film layer was cleaned with chlorobenzene; or, the films obtained from Composite Film Comparative Examples 1 and 2 were cleaned with chlorobenzene.

[0183] Table 1

[0184] Film thickness before cleaning (nm) Film thickness after cleaning (nm) Example 1 of composite film 40 39.5 Example 2 of composite film 40 39.6 Example 3 of composite film 50 49.9 Example 4 of composite film 40 39.6 Example 5 of composite film 40 39.5 Example 6 of composite film 70 69.7 Example 7 of composite film 40 39.8 Example 8 of composite film 40 39.7 Comparative Example 1 of composite film 30 23.4 Comparative Example 2 of composite film 30 22.6

[0185] As can be seen from Table 1, by comparing Examples 1 to 8 of the composite film and Comparative Examples 1 and 2 of the composite film, it can be known that under the cleaning of chlorobenzene, the film thickness of Examples 1 to 7 of the composite film has no obvious change, indicating that by setting the second film layer on the first film layer, since a coordination bond is formed between the sulfur atom and nitrogen atom in the sulfur nitride compound in the second film layer and the metal compound in the first film layer, the second film layer forms a protective film on the first film layer, thereby improving the chloroform resistance of the composite film.

[0186] Light-emitting device Example 1:

[0187] Step 1: Provide an ITO substrate as the anode.

[0188] Step 2: Use the method of Example 1 of the above composite film to prepare a composite film on the anode as the electron transport layer.

[0189] Step 3: Mix 10 g of CdZnSe / ZnS quantum dot material and 100 mL of chlorobenzene evenly to obtain a quantum dot solution, and print the quantum dot solution on the electron transport layer to obtain a quantum dot light-emitting layer with a thickness of 40 nm.

[0190] Step 4: Print a NiO solution on the quantum dot light-emitting layer to obtain a hole transport layer with a thickness of 40 nm;

[0191] Step 5: Print a PEDOT:PSS solution on the hole transport layer to obtain a hole injection layer with a thickness of 20 nm;

[0192] Step 6: Evaporate Al on the hole injection layer to obtain a cathode with a thickness of 60 nm, and a light-emitting device is fabricated.

[0193] Light-emitting device Examples 2 to 7:

[0194] The difference from the above Light-emitting device Example 1 is that in Step 2 of Light-emitting device Example n, the composite film is prepared by the method in Composite film Example n + 1, where n is any one of 2 to 7.

[0195] Light-emitting device Example 8:

[0196] The difference from the above-mentioned Light-emitting device Example 1 is as follows: In Step 3 of this example, before the step of printing the quantum dot solution on the electron transport layer, 50 mL of the quantum dot solution is taken and mixed with 1500 mg of dipotassium bis(p-sulfonatophenyl)phenylphosphine dihydrate to obtain a mixed solution, which is mixed under strong magnetic stirring at 2000 rad / m for 2 h to obtain a first mixed solution, and then centrifuged at a rotation speed of 4000 rad / m for 30 min. The supernatant is removed with a pipette and repeated 3 times. The precipitate obtained by centrifugation is redissolved in 80 wt% chlorobenzene to obtain a phosphorylated quantum dot solution; correspondingly, in Step 3, the phosphorylated quantum dot solution is printed on the electron transport layer.

[0197] Among them, the concentration of dipotassium bis(p-sulfonatophenyl)phenylphosphine dihydrate in the mixed solution is 30 mg / mL.

[0198] Light-emitting device Example 9:

[0199] The difference from the above-mentioned Light-emitting device Example 8 is as follows: In Step 3 of this example, the mass of dipotassium bis(p-sulfonatophenyl)phenylphosphine dihydrate is changed to 750 mg; correspondingly, the concentration of dipotassium bis(p-sulfonatophenyl)phenylphosphine dihydrate in the first mixed solution is 15 mg / mL.

[0200] Light-emitting device Example 10:

[0201] The difference from the above-mentioned Light-emitting device Example 8 is as follows: In Step 3 of this example, dipotassium bis(p-sulfonatophenyl)phenylphosphine dihydrate is changed to trisodium phosphate.

[0202] Light-emitting device Example 11:

[0203] The difference from the above-mentioned Light-emitting device Example 11 is as follows: In Step 3 of this example, before the step of centrifuging at a rotation speed of 4000 rad / m for 30 min, 500 mg of NaCl is slowly added to the mixed solution to change the color of the solution from dark purple to light purple; correspondingly, the concentration of NaCl in the first mixed solution is 10 mg / mL.

[0204] Light-emitting device Example 12:

[0205] The difference from the above-mentioned Light-emitting device Example 11 is as follows: In Step 3 of this example, the mass of NaCl is changed to 250 mg; correspondingly, the concentration of NaCl in the mixed solution is 5 mg / mL.

[0206] Light-emitting device Example 13:

[0207] The difference from the above-mentioned Light-emitting device Example 11 is as follows: In Step 3 of this example, NaCl is changed to KCl.

[0208] Light-emitting device Example 14:

[0209] The difference from the above-mentioned Light-emitting device Example 1 is that before Step 2 of this example, a PEDOT:PSS solution is printed on the positive electrode to obtain a 20-nm-thick hole injection layer;

[0210] Step 2 of this example is: using the method of the above-mentioned Composite film Example 2 to prepare a composite film on the positive electrode as the hole transport layer; correspondingly, in Step 3, a quantum dot solution is printed on the hole transport layer.

[0211] Step 4 of this example is: printing ZnO on the quantum dot light-emitting layer to obtain an electron transport layer with a thickness of 30 nm; Step 5 is omitted, and correspondingly, in Step 6 of this example, Al is evaporated on the electron transport layer.

[0212] Light-emitting device Comparative Example 1:

[0213] The difference from the above-mentioned Light-emitting device Example 1 is that Step 2 of this comparative example is: using the method of the above-mentioned Composite film Comparative Example 1 to prepare a film on the positive electrode as the electron transport layer.

[0214] Light-emitting device Comparative Example 2:

[0215] The difference from the above-mentioned Light-emitting device Example 9 is that Step 2 of this comparative example is: using the method of the above-mentioned Composite film Comparative Example 2 to prepare a film on the positive electrode as the hole transport layer.

[0216] Experimental test analysis: The external quantum efficiency (EQE) and the lifetime LT95@1000 nit of the light-emitting devices prepared in Light-emitting device Examples 1 to 14 and Comparative Examples 1 and 2 are respectively tested using an IVL test system, and the test results are shown in Table 2.

[0217] Table 2

[0218]

[0219]

[0220] Referring to Table 1, it can be seen that in Embodiments 1 to 7 and 14 of the light-emitting device of the present application, a first film layer and a second film layer are included on the electron transport layer / hole transport layer. The sulfur atoms and nitrogen atoms in the second film layer form coordination bonds with the first film layer, making the second film layer serve as a protective film for the first film layer, which can avoid the dissolution and damage of the underlying electron transport layer / hole transport layer by the solvent in the quantum dot solution, improve the service stability on the electron transport layer / hole transport layer, and further improve the service life of the fabricated device. Moreover, the second film layer made of thiourea material has electrophilicity, which can produce an electrostatic adsorption effect on the quantum dot material in the quantum dot solution, thereby reducing the particle spacing between the quantum dot material and the thiourea material, making the quantum dot light-emitting layer formed on the second film layer dense and uniform, which is beneficial to exciting the coupling resonance between quantum dot nanoparticles, and further reducing the non-radiative Auger recombination process and improving the light-emitting performance of the light-emitting device. Thus, compared with Comparative Examples 1 and 2 of the light-emitting device, Embodiments 1 to 7 and 14 of the light-emitting device of the present application have higher LT95@1000nit and EQE.

[0221] Further, by comparing Embodiments 1, 8 to 10 of the light-emitting device, it can be seen that dipotassium bis(p-sulfophenyl)phenylphosphate dihydrate / trisodium phosphate is added to the quantum dot solution to increase the negative charge density of the quantum dot material, so that the electrostatic adsorption effect between the quantum dot material and the second film layer is enhanced, and the formed quantum dot light-emitting layer is more compact and uniform. Therefore, compared with Embodiment 1 of the light-emitting device, Embodiments 8 to 10 of the light-emitting device have higher LT95@1000nit and EQE.

[0222] Further, by comparing Embodiments 1, 11 to 13 of the light-emitting device, it can be seen that by using NaCl / KCl to neutralize the acidic ions remaining in the first mixed solution, on the one hand, it prevents the second film layer from being acid-corroded, and on the other hand, it ensures the light-emitting effect of the quantum dot light-emitting layer after molding. Therefore, compared with Embodiment 1 of the light-emitting device, Embodiments 8 to 10 of the light-emitting device have higher LT95@1000nit and EQE.

[0223] Obviously, the above-described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The preferred embodiments of the present application are given in the drawings, but they do not limit the patent scope of the present application. The present application can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosed content of the present application more thorough and comprehensive. Although the present application has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing specific embodiments, or perform equivalent replacements for some of the technical features. Any equivalent structures directly or indirectly using the content of the specification and drawings of the present application in other related technical fields are equally within the scope of the patent protection of the present application.

Claims

1. A composite film, characterized in that, Comprising a stacked first film layer and a second film layer; the material of the first film layer includes a metal compound, and the material of the second film layer includes a sulfur nitride compound.

2. The composite film according to claim 1, characterized in that, The sulfur nitride compound is selected from at least one of polythiazyl, ammonium sulfide compound, and thiourea compound; and / or, The metal compound is an N-type metal compound or a P-type metal compound; the N-type metal compound is selected from one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanate oxide, aluminum zinc oxide, manganese zinc oxide, tin zinc oxide, lithium zinc oxide, magnesium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc stannide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, barium titanate, and the doping elements include at least one of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium; the P-type metal compound is selected from at least one of transition metal oxides, transition metal sulfides, transition metal stannides, nickel oxide, molybdenum oxide, tungsten oxide, and vanadium oxide; and / or, The thickness of the first film layer is 30 - 40 nm; and / or, The thickness of the second film layer is 10 - 40 nm.

3. The composite film according to claim 2, characterized in that, The ammonium sulfide compound is selected from at least one of ammonium hydrosulfide, ammonium sulfide, ammonium sulfate, and ammonium thiosulfate; and / or, The structural general formula of the thiourea compound is shown as Formula I: Wherein, R1, R2, and R3 are each independently selected from at least one of a hydrogen atom, a hydroxyl group, an amino group, a carboxyl group, an ether bond, an ester group, an aldehyde group, a carbonyl group, a nitro group, and a sulfonic acid group; or are each independently selected from a C1 - C20 linear hydrocarbon group, a C1 - C20 linear hydrocarbon oxy group, a cycloalkane group with 3 - 60 ring atoms, a heterocycloalkane group with 3 - 60 ring atoms, an aryl group with 5 - 60 ring atoms, a heteroaryl group with 5 - 60 ring atoms, an aryloxy group with 5 - 60 ring atoms, and a heteroaryloxy group with 5 - 60 ring atoms that are unsubstituted or substituted by an amino group, a halogen, a hydroxyl group, a carboxyl group, a nitro group, a sulfonic acid group, an aldehyde group, a mercapto group, and a cyano group, and the heteroatoms in the heteroaryl group or heteroaryloxy group are N, S, O, P, Si, and the number of heteroatoms is 1 - 20.

4. A method for preparing a composite film, characterized in that, Comprising the following steps: Providing a first solution and a second solution, the first solution comprising a metal compound, and the second solution comprising a sulfur nitride compound; Depositing the first solution to form a first film layer; Depositing the second solution on the first film layer to form a second film layer, obtaining a composite film.

5. The preparation method of the composite film according to claim 4, characterized in that, The step of forming the second film layer includes: Performing ultraviolet treatment on the second solution to obtain a second film layer.

6. The method for preparing the composite film according to claim 5, characterized in that, The light energy of the ultraviolet treatment is 130-160 mJ / cm 2 ; and / or, The time of the ultraviolet treatment is 5 - 8 min. The wavelength of the ultraviolet light for the ultraviolet treatment is 350 - 390 nm.

7. The method for preparing the composite film according to any one of claims 4 to 6, characterized in that, The concentration of the metal compound in the first solution is 60 - 80 mg / mL; and / or, The concentration of the sulfur nitride compound in the second solution is 50 - 60 mg / mL.

8. A method for preparing a light-emitting device, characterized in that, Comprising the following steps: Provide a first electrode having a carrier functional layer, wherein the carrier functional layer includes a composite thin film as described in any one of claims 1 to 3, or a composite thin film prepared by using the preparation method of the composite thin film as described in any one of claims 4 to 7; Deposit a quantum dot solution on the second film layer to form a quantum dot light-emitting layer; Deposit a second electrode on the quantum dot light-emitting layer.

9. The method for preparing a light-emitting device according to claim 8, wherein, Before the step of depositing the quantum dot solution on the second film layer, it further includes: Provide an initial quantum dot solution; Perform phosphorylation treatment on the initial quantum dot solution to obtain a quantum dot solution.

10. The method for manufacturing a light-emitting device according to claim 9, characterized in that, The step of performing phosphorylation treatment on the initial quantum dot solution to obtain a quantum dot solution includes: Provide a phosphorylation reagent and a first solvent; Mix the initial quantum dot solution and the phosphorylation reagent to obtain a first mixture; Perform centrifugation on the first mixture, and after removing the supernatant, obtain a separated liquid; Mix the separated liquid with the first solvent to obtain a quantum dot solution. Mix the quantum dot material having a phosphate group and the first solvent to obtain a quantum dot solution.

11. The method for preparing a light-emitting device according to claim 10, characterized in that, The phosphorylation reagent includes at least one of trisodium phosphate, disodium hydrogen phosphate, sodium hexametaphosphate, diethylphosphoryl chloride, bis(2-diphenylphosphinophenyl) ether, dipotassium bis(p-sulfophenyl)phenylphosphine dihydrate; and / or, The first solvent includes at least one of aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, halogenated hydrocarbon solvents, alcohol solvents, ether solvents, ester solvents, ketone solvents, glycol derivative solvents, acetonitrile, pyridine; the aromatic hydrocarbon solvents include at least one of benzene, toluene and xylene; the aliphatic hydrocarbon solvents include at least one of pentane, hexane and octane; the alicyclic hydrocarbon solvents include at least one of cyclohexane, cyclohexanone and toluene cyclohexanone; the halogenated hydrocarbon solvents include at least one of chlorobenzene, dichlorobenzene and dichloromethane; the alcohol solvents include at least one of methanol, ethanol and isopropanol; the ether solvents include at least one of diethyl ether and propylene oxide; the ester solvents include at least one of methyl acetate, ethyl acetate and propyl acetate; the ketone solvents include at least one of acetone, methyl butanone and methyl isobutyl ketone; the glycol derivative solvents include at least one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether and ethylene glycol monobutyl ether; and / or, The concentration of the phosphorylation reagent in the first mixture is 15 to 30 mg / mL.

12. The manufacturing method of the light-emitting device according to claim 10, characterized in that, The step of performing centrifugation on the first mixture includes: Provide a basic material; Mix the first mixture and the basic material to obtain a second mixture; Perform centrifugation on the second mixture.

13. The manufacturing method of the light-emitting device according to claim 12, characterized in that, The basic material is selected from metal chlorides; the metal chlorides are selected from at least one of sodium chloride, potassium chloride, calcium chloride, magnesium chloride; and / or, The concentration of the basic material in the second mixture is 5 to 10 mg / mL.

14. A light-emitting device, characterized in that, Include a light-emitting device prepared by using the preparation method of the light-emitting device as described in any one of claims 8 to 13.

15. The light-emitting device according to claim 14, wherein The sulfur nitride compound is selected from at least one of polythiazyl, ammonium sulfate compound, thiourea compound; and / or, The metal compound is an N-type metal compound or a P-type metal compound; the N-type metal compound is selected from one or more of doped or undoped zinc oxide, barium oxide, aluminum oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, aluminum zinc oxide, manganese zinc oxide, tin zinc oxide, lithium zinc oxide, magnesium zinc oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc stannide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, barium titanate, and the doping elements include at least one of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, gadolinium; the P-type metal compound is selected from at least one of transition metal oxides, transition metal sulfides, transition metal stannides, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide.

16. The light-emitting device according to claim 15, wherein, The ammonium sulfate compound is selected from at least one of ammonium hydrogen sulfide, ammonium sulfide, ammonium sulfate, ammonium thiosulfate; and / or The structural general formula of the thiourea compound is shown in Formula I: Wherein, R1, R2, and R3 are each independently selected from at least one of a hydrogen atom, a hydroxyl group, an amino group, a carboxyl group, an ether bond, an ester group, an aldehyde group, a carbonyl group, a nitro group, a sulfonic acid group, an alkyl group, a methyl group, an ethyl group, a benzene ring, a benzyl group; or are each independently selected from a C1-C20 hydrocarbon group, a C1-C20 hydrocarbon oxy group, a cycloalkyl group with 3-60 ring atoms, a heterocyclic hydrocarbon group with 3-60 ring atoms, an aryl group with 5-60 ring atoms, a heteroaryl group with 5-60 ring atoms, an aryloxy group with 5-60 ring atoms, a heteroaryloxy group with 5-60 ring atoms, which are unsubstituted or substituted by an amino group, a halogen, a hydroxyl group, a carboxyl group, a nitro group, a sulfonic acid group, an aldehyde group, a mercapto group, a cyano group, and the combination of one or more of them, wherein the heteroatom in the heteroaryl group or heteroaryloxy group is N, S, O, P, Si, and the number of heteroatoms is 1-20.

17. A display device, characterized in that, Including a light-emitting device prepared by using the preparation method of the light-emitting device according to any one of claims 8 to 13, or being the light-emitting device according to any one of claims 14 to 16.

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