Thin film and preparation method thereof, light-emitting device and display device

Abstract

The invention relates to the field of display, in particular to a thin film, a preparation method thereof, a light-emitting device and a display device. The preparation method of the thin film comprises the steps that an initial thin film is provided, and the material of the initial thin film comprises quantum dots; and treating the initial film with a protonic acid solution to obtain the film. According to the technical scheme provided by the invention, the dissolution resistance of the film can be improved.

Description

Technical Field

[0001] The present application relates to the field of display technologies, and in particular, to a thin film, a preparation method thereof, a light-emitting device, and a display device. Background Art

[0002] At present, quantum dot light-emitting diodes (QLEDs) have the advantages of a wide color gamut, a narrow emission spectrum, adjustable wavelength, low turn-on voltage, good solution processability, and easy fine control of quantum dots. QLEDs have become one of the alternatives for future high-performance and wide-color gamut displays.

[0003] In a light-emitting device with a mixed color, there are multiple stacked light-emitting layers. However, during the preparation process, the solvent of the light-emitting layer prepared in the next layer is likely to dissolve and damage the light-emitting layer prepared in the previous layer, thereby affecting the light-emitting performance of the light-emitting layer. Summary of the Invention

[0004] Based on this, embodiments of the present application provide a thin film, a preparation method thereof, a light-emitting device, and a display device.

[0005] In order to solve the above technical problems, embodiments of the present application provide a preparation method of a thin film, and adopt the following technical solutions:

[0006] A preparation method of a thin film includes:

[0007] Providing an initial thin film, the material of the initial thin film including quantum dots;

[0008] Treating the initial thin film with a protonic acid solution to obtain a thin film.

[0009] Further, the protonic acid is selected from at least one of an oxyacid, a halogen acid, a carboxylic acid, and a sulfonic acid; and / or,

[0010] The concentration of the protonic acid in the protonic acid solution is 0.0001 - 0.1 mmol / L.

[0011] Further, the oxyacid is selected from at least one of nitric acid, sulfuric acid, phosphoric acid, phosphorous acid, carbonic acid, chloric acid, and hypochlorous acid; and / or,

[0012] The halogen acid is selected from at least one of hydrochloric acid, hydrobromic acid, hydroiodic acid, fluoboric acid, and hypochlorous acid; and / or,

[0013] The carboxylic acid is selected from at least one of aliphatic carboxylic acids, alicyclic carboxylic acids, and aromatic carboxylic acids; the aliphatic carboxylic acid is selected from at least one of formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, succinic acid, acrylic acid, maleic acid, citric acid, and malic acid; the alicyclic carboxylic acid is selected from at least one of cyclohexanecarboxylic acid, cyclopentanecarboxylic acid, 1,2-cyclopentanedicarboxylic acid, and cyclohexanepropionic acid; the aromatic carboxylic acid is selected from at least one of benzoic acid, phenylacetic acid, cinnamic acid, salicylic acid, terephthalic acid, 4-methylbenzoic acid, and benzoic acid; and / or,

[0014] The sulfonic acid is selected from at least one of methanesulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid; and / or,

[0015] The concentration of the protonic acid in the protonic acid solution is 0.01 - 0.1 mmol / L.

[0016] Further, before the step of providing the initial thin film, the following steps are further included:

[0017] Providing a dispersion liquid, the dispersion liquid including quantum dots;

[0018] Depositing the dispersion liquid, and after desolvation treatment, obtaining the initial thin film.

[0019] Further, the step of treating the initial thin film with the protonic acid solution includes:

[0020] Using a solution method to dispose the protonic acid solution on the initial thin film; or,

[0021] Placing the initial thin film in an acidic atmosphere for treatment, the acidic atmosphere including the vapor formed by the protonic acid solution.

[0022] Further, the step of using a solution method to dispose the protonic acid solution on the initial thin film includes:

[0023] Using a solution method to immerse the initial thin film in the protonic acid solution; wherein, the time for which the initial thin film is immersed in the protonic acid solution is 5 - 15 s;

[0024] And / or, after the step of using a solution method to dispose the protonic acid solution on the initial thin film and before the step of obtaining the thin film, the following steps are further included:

[0025] Performing a drying treatment on the initial thin film after being treated with the protonic acid solution; wherein, the temperature of the drying treatment is 60 - 90 °C; and / or, the time of the drying treatment is 30 - 60 s.

[0026] Further, the quantum dots are selected from at least one of single-structure quantum dots, core-shell structure quantum dots, and perovskite quantum dots; the materials of the single-structure quantum dots, the core materials of the core-shell structure quantum dots, and the shell materials of the core-shell structure quantum dots are each independently selected from at least one of II-VI group compounds, IV-VI group compounds, III-V group compounds, and I-III-VI group compounds. The shell of the core-shell structure quantum dots includes one or more layers. 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; the I-III-VI group compounds are selected from at least one of CuInS2, CuInSe2, and AgInS2; the structural general formula of the perovskite quantum dots is ABX3; where A is an organic cation and / or an inorganic cation, and the organic cation is selected from at least one of MA + , FA + ; the inorganic cation is selected from Cs + ; B is a divalent metal cation, and B is selected from Pb2+ , Sn 2+ , Cu 2+ , Ni 2+ , Cd 2+ , Cr 2+ , Mn 2+ , Co 2+ , Fe 2+ , Ge 2+ , Yb 2+ , Eu 2+ at least one of; X is a halogen anion.

[0027] To solve the above technical problems, the embodiments of the present application provide a light-emitting device, adopting the following technical solutions:

[0028] A light-emitting device includes a first electrode, a light-emitting layer, and a second electrode that are sequentially stacked.

[0029] Wherein, the light-emitting layer includes at least one light-emitting sub-layer, and at least one of the light-emitting sub-layers includes a thin film prepared by the method for preparing a thin film as described above, or at least one of the light-emitting sub-layers includes the thin film as described above.

[0030] Further, the number of the light-emitting sub-layers is 3, and each of the light-emitting sub-layers includes a thin film prepared by the method for preparing a thin film as described above, or at least one of the light-emitting sub-layers includes the thin film as described above; the 3 light-emitting sub-layers are a red light-emitting sub-layer, a green light-emitting sub-layer, and a blue light-emitting sub-layer respectively.

[0031] Further, the materials of the first electrode and the second electrode are independently selected from at least one of a metal material, a carbon material, and a metal oxide. The metal material includes one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon material includes one or more of graphite, carbon nanotubes, graphene, and carbon fibers; the metal oxide includes a doped or undoped metal oxide. The doped metal oxide includes one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, and AMO, or includes a composite electrode in which a doped or undoped transparent metal oxide sandwiches a metal. 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; and / or,

[0032] The light-emitting device further includes a hole injection layer disposed between the first electrode and the light-emitting layer, and the material of the hole injection layer is selected from at least one of PEDOT:PSS, HATCN, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, polyaniline, CuPc, transition metal oxides, transition metal sulfides, transition metal stannides, doped graphene, undoped graphene, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide; and / or,

[0033] The light-emitting device further includes a hole transport layer disposed between the first electrode and the light-emitting layer, and the material of the hole transport layer is selected from at least one of TFB, PVK, Poly-TPD, PFB, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS and its derivatives, TAPC, MCC, C60; and / or,

[0034] The light-emitting device further includes an electron transport layer disposed between the light-emitting layer and the second electrode; the material of the electron transport layer is selected from inorganic materials and / or organic materials; the inorganic materials include 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, 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; the doping elements include at least one of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, gadolinium; the organic materials include at least one of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene-containing compounds, hydroxyquinoline compounds, polythiophene compounds, perylene diimide compounds, fullerene compounds; and / or,

[0035] The light-emitting device further includes an electron injection layer disposed between the light-emitting layer and the second electrode, and the material of the electron injection layer is selected from at least one of Yb, yttrium fluoride, Li, LiF, NaF, CsCO3, Cs, KBH4 or KH.

[0036] To solve the above technical problems, the embodiments of the present application provide a display device, which adopts the following technical solutions:

[0037] A display device includes the light-emitting device as described above.

[0038] Compared with the prior art, the embodiments of the present application mainly have the following beneficial effects: The protonic acid solution of the present invention can not only reduce the corrosion damage to the initial film, but also perform ligand exchange with the initial film, thereby improving the anti-solubility of the initial film. Description of the Drawings

[0039] To more clearly illustrate the solution of the present application, the accompanying drawings required for the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other accompanying drawings can be obtained based on these drawings without creative efforts.

[0040] Figure 1 It is a flowchart of the method for preparing a thin film according to an embodiment of the present application;

[0041] Figure 2 It is a schematic structural diagram of a light-emitting device according to an embodiment of the present application.

[0042] Reference numerals:

[0043] 200, light-emitting device; 210, first electrode; 220, second electrode; 230, light-emitting layer; 231, light-emitting sublayer; 240, hole injection layer; 250, hole transport layer; 260, electron transport layer; 270, electron injection layer. Specific embodiments

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used in the specification 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 specification and claims of this application and the above accompanying drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification and claims of this application or the above accompanying drawings are used to distinguish different objects and not to describe a specific order.

[0045] Referring to

[0046] Referring to Figure 1 , an embodiment of the present application provides a method for preparing a thin film, including:

[0047] Step S11, providing an initial thin film, the material of the initial thin film including quantum dots.

[0048] In some embodiments, before the step S11 of providing the initial thin film, the following steps are further included:

[0049] Step S111: Provide a dispersion liquid, where the dispersion liquid includes quantum dots;

[0050] Step S112: Deposit the dispersion liquid, and after solvent removal treatment, obtain the initial thin film.

[0051] In this embodiment, the dispersion liquid is deposited on a carrier surface by a solution method, and then after drying, the solution in the dispersion liquid is removed, so that the quantum dots in the dispersion liquid are deposited on the carrier surface to obtain an initial thin film. Among them, the carrier surface can be the surface of a substrate, a hole functional layer, or an electron functional layer.

[0052] In some embodiments, the solution method is selected from one of the sol-gel method, printing, inkjet printing, spin coating, and coating.

[0053] In some embodiments, the quantum dots are selected from at least one of single-structure quantum dots, core-shell structure quantum dots, and perovskite quantum dots; the materials of the single-structure quantum dots, the core materials of the core-shell structure quantum dots, and the shell materials of the core-shell structure quantum dots are each independently selected from at least one of II-VI group compounds, IV-VI group compounds, III-V group compounds, and I-III-VI group compounds. The shell of the core-shell structure quantum dots includes one or more layers. 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; the I-III-VI group compounds are selected from at least one of CuInS2, CuInSe2, and AgInS2; the structural general formula of the perovskite quantum dots is ABX3; where A is an organic cation and / or an inorganic cation, and the organic cation is selected from at least one of MA + , FA + , and the inorganic cation is selected from Cs + ; B is a divalent metal cation, and B is selected from Pb2+ 、Sn 2+ 、Cu 2+ 、Ni 2+ 、Cd 2+ 、Cr 2+ 、Mn 2+ 、Co 2+ 、Fe 2+ 、Ge 2+ 、Yb 2+ 、Eu 2+ at least one of; X is a halogen anion.

[0054] Step S12, treating the initial film with a protonic acid solution to obtain a film.

[0055] In the present invention, the protonic acid in the protonic acid solution can undergo a protonation reaction with the organic ligand on the initial film to achieve ligand exchange, thereby enhancing the anti-solubility of the prepared film.

[0056] Understandably, the protonic acid can provide H + , H + ions have a small radius and large polarity and are very easy to gain electrons. When treating the initial film with the protonic acid solution, the protonic acid H + in the protonic acid solution undergoes a protonation reaction with the ligand on the initial film, desorbing the basic ligand on the surface of the initial film, so that the surface of the initial film has unoccupied binding sites. At this time, the other half of the ions coexisting with the protonic acid in the protonic acid solution fill in the unoccupied binding sites, thereby realizing ligand exchange between the initial film and the trace protonic acid in the protonic acid solution.

[0057] Thus, in one example, the initial film is a light-emitting layer. After treating the quantum dot light-emitting layer with the protonic acid solution of the present invention, the solvent for preparing the next light-emitting layer on the light-emitting layer has anti-solubility, thereby avoiding the solvent of the next-prepared light-emitting layer from dissolving and damaging the previous-prepared light-emitting layer, and enhancing the stability and light-emitting performance of the light-emitting layer.

[0058] In some embodiments, the concentration of the protonic acid in the protonic acid solution is 0.0001 - 0.1 mmol / L. Since the protonic acid solution contains a trace amount of protonic acid with a concentration of 0.0001 - 0.1 mmol / L, when treating the initial film with the protonic acid solution, the corrosion and damage of the initial film by the protonic acid in the protonic acid solution can be reduced, ensuring the use stability of the initial film.

[0059] In some embodiments, the concentration of the protonic acid may be selected from any one or any range formed by any two of 0.0001 mmol / L, 0.0003 mmol / L, 0.0005 mmol / L, 0.0007 mmol / L, 0.0009 mmol / L, 0.001 mmol / L, 0.003 mmol / L, 0.005 mmol / L, 0.007 mmol / L, 0.009 mmol / L, 0.01 mmol / L, 0.03 mmol / L, 0.05 mmol / L, 0.07 mmol / L, 0.09 mmol / L, 0.1 mmol / L.

[0060] In some embodiments, the protonic acid is selected from at least one of oxyacids, haloacids, carboxylic acids, and sulfonic acids.

[0061] Optionally, the oxyacid is selected from at least one of nitric acid, sulfuric acid, phosphoric acid, phosphorous acid, carbonic acid, chloric acid, and hypochlorous acid.

[0062] Optionally, the haloacid is selected from at least one of hydrochloric acid, hydrobromic acid, hydroiodic acid, fluoboric acid, and hypochlorous acid.

[0063] Optionally, the carboxylic acid is selected from at least one of aliphatic carboxylic acids, alicyclic carboxylic acids, and aromatic carboxylic acids; the aliphatic carboxylic acid is selected from at least one of formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, succinic acid, acrylic acid, maleic acid, citric acid, and malic acid; the alicyclic carboxylic acid is selected from at least one of cyclohexanecarboxylic acid, cyclopentanecarboxylic acid, 1,2-cyclopentanedicarboxylic acid, and cyclohexanepropionic acid; the aromatic carboxylic acid is selected from at least one of benzoic acid, phenylacetic acid, cinnamic acid, salicylic acid, terephthalic acid, 4-methylbenzoic acid, and benzoic acid.

[0064] Optionally, the sulfonic acid is selected from at least one of methanesulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid.

[0065] Preferably, the protonic acid is selected from haloacids. Compared with the protonic acids of oxyacids, carboxylic acids, and sulfonic acids, due to the relatively large electronegativity difference between the halogen atom and the hydrogen atom in the haloacid, where the halogen atom has a higher electronegativity and the hydrogen atom has a lower electronegativity, the halogen atom carries a negative charge and the hydrogen atom carries a positive charge, thus making the haloacid have a stronger polarity; therefore, after treating the initial film with a protonic acid solution containing trace amounts of haloacid, the halogen atoms in the trace amounts of haloacid replace some of the original organic ligands of the quantum dots to become new ligands, enhancing the polarity of the initial film and thus enhancing the anti-solubility of the initial film.

[0066] Understandably, in one example, the initial thin film is a light-emitting layer. After being treated with the hydrohalic acid of the present invention, the light-emitting layer has good anti-solubility, making the mutual repulsive force between the solvents in the quantum dot ink such as aliphatic hydrocarbons, aromatic hydrocarbons, and cycloalkanes stronger for the treated light-emitting layer. Thus, it avoids the dissolution and damage of the solvent of the light-emitting layer prepared in the next layer to the light-emitting layer prepared in the previous layer, thereby improving the stability and light-emitting performance of the light-emitting layer.

[0067] In some embodiments, the protonic acid solution includes the protonic acid and a solvent; wherein, the solvent includes at least one of an alcohol solvent, an aromatic hydrocarbon solvent, an aliphatic hydrocarbon solvent, a cycloaliphatic hydrocarbon solvent, a halogenated hydrocarbon solvent, an ether solvent, an ester solvent, a ketone solvent, a glycol derivative solvent, pyridine, or phenol.

[0068] Optionally, the alcohol solvent includes at least one of methanol, ethanol, isopropanol, n-propanol, and isobutanol.

[0069] Optionally, the aromatic hydrocarbon solvent includes at least one of benzene, toluene, and xylene.

[0070] Optionally, the aliphatic hydrocarbon solvent includes at least one of pentane, hexane, and octane.

[0071] Optionally, the cycloaliphatic hydrocarbon solvent includes at least one of cyclohexane, cyclohexanone, and toluene cyclohexanone.

[0072] Optionally, the halogenated hydrocarbon solvent includes at least one of chlorobenzene, dichlorobenzene, and dichloromethane. Optionally, the ether solvent includes at least one of diethyl ether and propylene oxide.

[0073] Optionally, the ester solvent includes at least one of methyl acetate, ethyl acetate, and propyl acetate.

[0074] Optionally, the ketone solvent includes at least one of acetone, methyl butanone, and methyl isobutyl ketone.

[0075] Optionally, the glycol derivative solvent includes at least one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monobutyl ether.

[0076] In some embodiments, for the above step S12, the step of treating the initial thin film with the protonic acid solution includes:

[0077] Step S121, disposing the protonic acid solution on the initial thin film by a solution method; or,

[0078] Step S122, placing the initial thin film in an acidic atmosphere for treatment, and the acidic atmosphere includes the vapor formed by the protonic acid solution.

[0079] The above steps S121 and S122 can also make multiple surfaces on the initial thin film come into contact with the protonic acid solution, with a large contact area. In this way, the protonic acid in the protonic acid solution can fully undergo a protonation reaction with the organic ligands on the initial thin film to achieve ligand exchange, further enhancing the anti-solubility of the initial thin film.

[0080] In some embodiments, for the above step S121, the step of disposing the protonic acid solution on the initial thin film by using the solution method includes:

[0081] Step S1211, immersing the initial thin film in the protonic acid solution by using the solution method.

[0082] In this embodiment, the initial thin film is processed by immersion so that the protonic acid in the protonic acid solution can fully undergo ligand exchange, ensuring the anti-solubility of the upper light-emitting layer.

[0083] In some embodiments, the time for which the initial thin film is immersed in the protonic acid solution is 5 to 15 s.

[0084] Optionally, the time for which the initial thin film is immersed in the protonic acid solution is selected from any one or any range formed by any two of 5 s, 6 s, 7 s, 8 s, 9 s, 10 s, 11 s, 12 s, 13 s, 14 s, 15 s.

[0085] In some embodiments, after the step S121 of disposing the protonic acid solution on the initial thin film by using the solution method and before the step S12 of obtaining the thin film, the method further includes:

[0086] Step S1212, drying the initial thin film after being treated with the protonic acid solution.

[0087] In this embodiment, the drying treatment is used to volatilize the solvent in the protonic acid solution to avoid the solvent affecting the performance of the initial thin film after molding.

[0088] In some embodiments, the temperature of the drying treatment is 60 to 90 °C.

[0089] Optionally, the temperature of the drying treatment is selected from any one or any range formed by any two of 60 °C, 62 °C, 64 °C, 66 °C, 68 °C, 70 °C, 72 °C, 74 °C, 76 °C, 78 °C, 80 °C, 82 °C, 84 °C, 86 °C, 88 °C, 90 °C.

[0090] In some embodiments, the time of the drying treatment is 30 to 60 s.

[0091] Optionally, the time of the drying treatment is any one or the range formed by any two of 30s, 32s, 34s, 36s, 38s, 40s, 42s, 44s, 46s, 48s, 50s, 52s, 54s, 56s, 58s, 60s.

[0092] An embodiment of the present application provides a thin film prepared by using the thin film preparation method as described above.

[0093] In this embodiment, the protonic acid in the protonic acid solution can undergo a protonation reaction with the organic ligand on the initial thin film to achieve ligand exchange, thereby enhancing the anti-solubility of the initial thin film.

[0094] Refer to Figure 2 , a light-emitting device, including a first electrode 210, a light-emitting layer 230, and a second electrode 220 which are sequentially stacked; wherein, the light-emitting layer 230 includes at least one light-emitting sub-layer 231, and at least one of the light-emitting sub-layers 231 includes a thin film prepared by the thin film preparation method as described above, or at least one of the light-emitting sub-layers 231 includes the thin film as described above.

[0095] In the present invention, the protonic acid in the protonic acid solution can undergo a protonation reaction with the organic ligand on the initial thin film to achieve ligand exchange, thereby enhancing the anti-solubility of the light-emitting sub-layer 231.

[0096] In some embodiments, the light-emitting layer 230 includes at least two light-emitting sub-layers 231. In this embodiment, before preparing the next light-emitting sub-layer 231, the light-emitting sub-layer 231 prepared in the previous layer is first treated with the protonic acid solution of the present invention. Since the protonic acid solution contains a trace amount of protonic acid and the concentration of the protonic acid in the protonic acid solution is 0.0001 - 0.1 mmol / L, it can not only reduce the corrosion and damage of the protonic acid in the protonic acid solution to the light-emitting sub-layer 231 prepared in the previous layer, ensure the use stability of the light-emitting sub-layer 231 prepared in the previous layer, and the protonic acid in the protonic acid solution can undergo a protonation reaction with the organic ligand on the light-emitting sub-layer 231 prepared in the previous layer to achieve ligand exchange, thereby enhancing the anti-solubility of the light-emitting sub-layer 231 prepared in the previous layer to solvents such as aliphatic hydrocarbons, aromatic hydrocarbons, and naphthenic hydrocarbons in the quantum dot ink, prevent the solvent used to prepare the next light-emitting sub-layer 231 from dissolving and damaging the light-emitting sub-layer 231 prepared in the previous layer, and further enhance the stability and light-emitting performance of the light-emitting layer 230.

[0097] In some embodiments, the light-emitting layer 230 includes three light-emitting sub-layers 231. Each of the light-emitting sub-layers 231 includes a film prepared by the film preparation method described above, or at least one of the light-emitting sub-layers 231 includes the film described above. In this way, the light-emitting sub-layer 231 prepared in the upper layer is insoluble in the solvent of the light-emitting sub-layer 231 prepared in the lower layer, ensuring the stability and light-emitting performance of each light-emitting sub-layer 231, and further improving the stability and light-emitting performance of the light-emitting layer 230.

[0098] Secondly, when the three light-emitting sub-layers 231 are a red light-emitting sub-layer, a green light-emitting sub-layer, and a blue light-emitting sub-layer respectively, the light emitted by the red light-emitting sub-layer, the green light-emitting sub-layer, and the blue light-emitting sub-layer is mixed to form white light.

[0099] In some embodiments, the materials of the first electrode 210 and the second electrode 220 are independently selected from at least one of metal materials, carbon materials, and metal oxides. The metal materials include one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg. The carbon materials include one or more of graphite, carbon nanotubes, graphene, and carbon fibers. The metal oxides include doped or undoped metal oxides. The doped metal oxides include one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, and AMO, or include a composite electrode in which a doped or undoped transparent metal oxide sandwiches a metal. The composite electrodes include one or more 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.

[0100] In some embodiments, the light-emitting device 200 further includes a hole injection layer 240 disposed between the first electrode 210 and the light-emitting layer 230. The material of the hole injection layer 240 is selected from at least one of PEDOT:PSS, HATCN, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, polyaniline, CuPc, transition metal oxides, transition metal sulfides, transition metal stannides, doped graphene, undoped graphene, nickel oxide, molybdenum oxide, tungsten oxide, and vanadium oxide.

[0101] In some embodiments, the light-emitting device 200 further includes a hole transport layer 250 disposed between the first electrode 210 and the light-emitting layer 230, and the material of the hole transport layer 250 is selected from at least one of TFB, PVK, Poly-TPD, PFB, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS and its derivatives, TAPC, MCC, C60.

[0102] In some embodiments, the light-emitting device 200 further includes an electron transport layer 260 disposed between the light-emitting layer 230 and the second electrode 220; the material of the electron transport layer 260 is selected from inorganic materials and / or organic materials; the inorganic materials include 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 doping elements include at least one of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, gadolinium; the organic materials include at least one of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene-containing compounds, hydroxyquinoline compounds, polythiophene compounds, perylene diimide compounds, fullerene compounds.

[0103] In some embodiments, the light-emitting device 200 further includes an electron injection layer 270 disposed between the light-emitting layer 230 and the second electrode 220, and the material of the electron injection layer 270 is selected from one or more of Yb, yttrium fluoride, Li, LiF, NaF, CsCO3, Cs, KBH4 or KH.

[0104] The embodiment of the present application further provides a display device, including the light-emitting device as described above.

[0105] In the present invention, the protonic acid in the protonic acid solution can undergo a protonation reaction with the organic ligand on the initial film to achieve ligand exchange, thereby improving the anti-solubility of the light-emitting sublayer.

[0106] The technical solutions and technical effects of the present application are described in detail below through specific examples and comparative examples. The following examples are only partial examples of the present application and do not specifically limit the present application.

[0107] Film Example 1:

[0108] Step 1, spin-coat a 50-nm-thick red quantum dot ink on a substrate to obtain a red quantum dot layer as the initial film; wherein, the quantum dots of the red quantum dot ink are red CdSe, and the solvent is cyclohexane.

[0109] Step 2: Provide an HCl-EtOH solution with an HCl concentration of 0.0005 mmol / L. Drop 100 μL of the protonic acid solution onto the initial film, soak for 10 s, and then pre-bake at 80 °C for 1 min to obtain a film with a thickness of 51 nm.

[0110] Film Example 2:

[0111] The difference from Film Example 1 above is that in Step 2 of this example, the HCl concentration of the HCl-EtOH solution is 0.001 mmol / L; correspondingly, a film with a thickness of 53 nm is obtained.

[0112] Film Example 3:

[0113] The difference from Film Example 1 above is that in Step 2 of this example, the HCl concentration of the HCl-EtOH solution is 0.01 mmol / L; correspondingly, a film with a thickness of 48 nm is obtained.

[0114] Film Example 4:

[0115] The difference from Film Example 1 above is that in Step 2 of this example, the HCl concentration of the HCl-EtOH solution is 0.1 mmol / L; correspondingly, a film with a thickness of 45 nm is obtained.

[0116] Film Example 5:

[0117] The difference from Film Example 1 above is that in Step 2 of this example, the HCl-EtOH solution is changed to an HBr-EtOH solution; correspondingly, a film with a thickness of 56 nm is obtained.

[0118] Film Example 6:

[0119] The difference from Film Example 1 above is that in Step 2 of this example, the HCl-EtOH solution is changed to an HNO3-EtOH solution; correspondingly, a film with a thickness of 55 nm is obtained.

[0120] Film Example 7:

[0121] The difference from Film Example 1 above is that in Step 2 of this example, the HCl-EtOH solution is changed to an HBF4-EtOH solution; correspondingly, a film with a thickness of 56 nm is obtained.

[0122] Film Example 8:

[0123] The difference from the above-mentioned Thin Film Example 1 is that in Step 2 of this example, the HCl-EtOH solution is changed to the TsOH-EtOH solution; correspondingly, a thin film with a thickness of 58 nm is obtained.

[0124] Thin Film Example 9:

[0125] The difference from the above-mentioned Thin Film Example 1 is that in Step 2 of this example, the HCl-EtOH solution is changed to the HCOOH-EtOH solution; correspondingly, a thin film with a thickness of 54 nm is obtained.

[0126] Thin Film Comparative Example 1:

[0127] The difference from the above-mentioned Thin Film Example 1 is that Step 2 is omitted; correspondingly, the initial thin film in Step 1 is annealed at 120 °C for 20 min to obtain a thin film with a thickness of 50 nm.

[0128] Function Test 1: The thin films obtained from Thin Film Examples 1 to 9 and Thin Film Comparative Example 1 are respectively subjected to a solubility resistance test: The thin films are cleaned with a quantum dot solvent, and the test results are shown in Table 1:

[0129] Table 1

[0130]

[0131]

[0132] Referring to Table 1, it can be seen that compared with Thin Film Comparative Example 1, after cleaning with the quantum dot solvent, the influence on Thin Film Examples 1 to 9 of the present invention is smaller, indicating that the thin films obtained after treatment with the protonic acid solution of the present invention have solubility resistance to the quantum dot solvent.

[0133] Continuing to refer to Table 1, comparing Thin Film Examples 1, 5 to 9, it can be seen that after ligand exchange, due to the relatively large polarity of the halogen, the difference in film thickness before and after cleaning of Thin Film Examples 1, 5, and 7 treated with the protonic acid solution containing halogen is smaller.

[0134] Light-Emitting Device Example 1:

[0135] Step 1: Provide an ITO substrate as the first electrode, and after cleaning the anode, perform ultraviolet ozone treatment for 15 min.

[0136] Step 2: Spin-coat a 50-nm-thick PEDOT:PSS on the anode, and then anneal at 150 °C for 20 min to obtain a hole injection layer.

[0137] Step 3: Spin-coat a 30-nm-thick TFB on the hole injection layer, and then anneal at 150 °C for 20 min to obtain a hole transport layer.

[0138] Step 4: Use the preparation method as in Film Example 1 to prepare a film on the hole transport layer to obtain a red light-emitting sub-layer; repeat using the preparation method as in Film Example 1 to prepare a film on the red light-emitting sub-layer to obtain a green light-emitting sub-layer, where the red quantum dot ink is changed to green quantum dot ink, and the quantum dots of the green quantum dot ink are green CdSe. Correspondingly, the initial film thickness obtained is 40 nm; finally, spin-coat 20 nm thick blue quantum dot ink on the green light-emitting sub-layer to obtain a blue light-emitting sub-layer, and then anneal at 120 °C for 20 min to obtain a light-emitting layer; among them, the materials of the blue quantum dot ink are all blue CdSe, and the solvent is cyclohexane.

[0139] Step 5: Spin-coat 25 nm thick ZnMgO on the light-emitting layer and then anneal at 100 °C for 15 min to obtain an electron transport layer.

[0140] Step 6: Place the ITO substrate after Step 5 in a vacuum evaporation chamber and evaporate 100 nm thick Ag on the electron transport layer as the second electrode to obtain a light-emitting device.

[0141] Light-emitting device Examples 2 to 9:

[0142] The difference from the above Light-emitting device Example 1 is that: in Step 4 of Light-emitting device Example n, the film in the light-emitting layer is prepared by the method as in Film Example n, where n is any one of 2 to 9.

[0143] Light-emitting device Comparative Example 1:

[0144] The difference from the above Light-emitting device Example 1 is that: Step 4 of this comparative example is to use the film prepared by the preparation method as in Film Comparative Example 1 as the red light-emitting sub-layer; correspondingly, in Step 5 of this comparative example, spin-coat 25 nm thick ZnMgO on the red light-emitting sub-layer.

[0145] Between Step 5 and Step 6 of this comparative example, the following steps are further included:

[0146] A 5-nm-thick PEI (polyetherimide) was spin-coated on the electron transport layer. After annealing at 100 °C for 15 min, a sacrificial layer was obtained. After spin-coating a 10-nm-thick PMA (phosphomolybdic acid) on the sacrificial layer, annealing treatment was carried out at 140 °C for 20 min to obtain a PMA layer, where the electron transport layer / sacrificial layer / PMA layer was a CGU unit; the steps three to five of this comparative example were repeated, where in step three, "spin-coat 30 nm thick TFB on the PMA layer", in step four, "the red quantum dot ink was changed to green quantum dot ink, and the quantum dots of the green quantum dot ink were green CdSe, and the correspondingly prepared thin film was used as the light-emitting sublayer of green light", in step five, "spin 25 nm thick ZnMgO on the light-emitting sublayer of green light", and then repeat the preparation of the CGU unit on the electron transport layer; repeat the steps three to five of this comparative example again, where in step three, "spin-coat 30 nm thick TFB on the PMA layer", in step four, "the red quantum dot ink was changed to blue quantum dot ink, and the quantum dots of the blue quantum dot ink were blue CdSe, and the correspondingly prepared thin film was used as the light-emitting sublayer of blue light", in step five, "spin 25 nm thick ZnMgO on the light-emitting sublayer of blue light".

[0147] Comparative Example 2 of the light-emitting device:

[0148] The difference from the above Comparative Example 1 of the light-emitting device is that in step four of this comparative example, the material of the quantum dot ink was selected as CdSe, the solvent was cyclohexane, and the red quantum dot ink, green quantum dot ink, and blue quantum dot ink were mixed according to a volume ratio of 3:4:3 to obtain a mixed solution, and a 55-nm-thick mixed solution was spin-coated on the hole transport layer to obtain a light-emitting layer.

[0149] Comparative Example 3 of the light-emitting device:

[0150] The difference from the above Example 1 of the light-emitting device is that in step four of this comparative example, the concentration of HCl protonic acid in the protonic acid solution was 1 mmol / L.

[0151] Functional Test 2: Using an IVL test system, the external quantum efficiency (EQE), color coordinates, voltage, and lifetime test system of the light-emitting devices respectively prepared from Examples 1 to 12 and Comparative Examples 1 and 2 of the light-emitting device were used to test the LT95@1000 nit of the light-emitting device, and the test results are shown in Table 2.

[0152] Table 1

[0153]

[0154] Referring to Table 2, compared with Comparative Example 1 and Comparative Example 2 of the light-emitting device, the light-emitting devices of Embodiments 1 to 9 of the present invention, because before preparing the green quantum dot thin film and the blue quantum dot thin film, the quantum dot thin film prepared in the previous layer is respectively treated with a protonic acid solution, so that the protonic acid in the protonic acid solution can undergo a protonation reaction with the organic ligand on the initial thin film to achieve ligand exchange, thereby improving the anti-solubility of the initial thin film. The overlapping emission of quantum dots of red, green, and blue three colors makes the chromaticity coordinates of the light emitted by the light-emitting device of the embodiment of the present invention close to the standard white light chromaticity coordinates (0.333, 0.333), and at a lower driving voltage, the external quantum efficiency and LT95@1000n it(h) of the light-emitting device are improved, thereby improving the light-emitting performance of the light-emitting device and extending the service life.

[0155] Understandably, (1) Continuing to refer to Table 2, comparing Embodiments 1 to 4 of the light-emitting device, it can be seen that as the concentration of the protonic acid in the protonic acid solution increases, within a certain range, the anti-solubility of the thin film and the performance of the light-emitting device are similar. Compared with the tandem stacked white light device connected by the CGU unit in Comparative Example 1, the device structure of the embodiment is relatively simple, without additional voltage division and carrier injection problems; compared with the mixed three-color quantum dot scheme in Comparative Example 2, the embodiment avoids the Forster resonance energy transfer caused by the mixing of quantum dots with different bandgaps in Comparative Example 2. Embodiments 1-4 of the light-emitting device have certain advantages in performance compared with Comparative Examples 1-2.

[0156] Moreover, comparing Embodiments 1 to 4 of the light-emitting device with Comparative Example 3 of the light-emitting device, it can be seen that treating the quantum dot thin film with a protonic acid solution containing an excessive amount of protonic acid will cause serious corrosion damage to the quantum dot thin film, resulting in the light-emitting device prepared in Comparative Example 3 of the light-emitting device being unable to be lit.

[0157] (2) Continuing to refer to Table 2, comparing Embodiments 1, 5 to 9 of the light-emitting device, it can be seen that after ligand exchange, due to its relatively large polarity and relatively good orthogonality to the quantum dot ink solvent, the external quantum efficiency of the light-emitting device treated with hydrohalic acid is higher than that of other embodiments.

[0158] Obviously, the embodiments described above are only a part of the embodiments of this application, rather than all embodiments. The preferred embodiments of this application are given in the accompanying drawings, but they do not limit the patent scope of this application. This 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 this application more thorough and comprehensive. Although this 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 described in the foregoing specific embodiments, or perform equivalent replacements for some of the technical features. Any equivalent structure that makes use of the content of the specification and drawings of this application, directly or indirectly applied in other related technical fields, is similarly within the scope of patent protection of this application.

Claims

1. A method for preparing a thin film, characterized in that, Comprising: Providing an initial thin film, the material of the initial thin film comprising quantum dots; Treating the initial thin film with a protonic acid solution to obtain a thin film.

2. The method for preparing a thin film according to claim 1, characterized in that, The protonic acid is selected from at least one of oxyacids, haloacids, carboxylic acids, and sulfonic acids; and / or, The concentration of the protonic acid in the protonic acid solution is 0.0001 - 0.1 mmol / L.

3. The method for preparing a thin film according to claim 2, characterized in that, The oxyacid is selected from at least one of nitric acid, sulfuric acid, phosphoric acid, phosphorous acid, carbonic acid, chloric acid, and hypochlorous acid; and / or, The haloacid is selected from at least one of hydrochloric acid, hydrobromic acid, hydroiodic acid, and fluoboric acid; and / or, The carboxylic acid is selected from at least one of aliphatic carboxylic acids, alicyclic carboxylic acids, and aromatic carboxylic acids; the aliphatic carboxylic acid is selected from at least one of formic acid, acetic acid, propionic acid, butyric acid, oxalic acid, succinic acid, acrylic acid, maleic acid, citric acid, and malic acid; the alicyclic carboxylic acid is selected from at least one of cyclohexanecarboxylic acid, cyclopentanecarboxylic acid, 1,2 - cyclopentanedicarboxylic acid, and cyclohexanepropionic acid; the aromatic carboxylic acid is selected from at least one of benzoic acid, phenylacetic acid, cinnamic acid, salicylic acid, terephthalic acid, 4 - methylbenzoic acid, and benzoic acid; and / or, The sulfonic acid is selected from at least one of methanesulfonic acid, benzenesulfonic acid, and p - toluenesulfonic acid; and / or, The concentration of the protonic acid in the protonic acid solution is 0.01 - 0.1 mmol / L.

4. The method for preparing a thin film according to any one of claims 1 to 3, characterized in that, Before the step of providing the initial thin film, it further includes: Providing a dispersion, the dispersion comprising quantum dots; Depositing the dispersion, and after desolvation treatment, obtaining the initial thin film.

5. The method for preparing a thin film according to any one of claims 1 to 3, characterized in that, The step of treating the initial thin film with the protonic acid solution includes: Setting the protonic acid solution on the initial thin film by a solution method; or, Placing the initial thin film in an acidic atmosphere for treatment, the acidic atmosphere comprising vapor formed by the protonic acid solution.

6. The method for preparing a thin film according to claim 5, characterized in that, The step of setting the protonic acid solution on the initial thin film by a solution method includes: Soaking the initial thin film in the protonic acid solution by a solution method; wherein, the soaking time of the initial thin film in the protonic acid solution is 5 - 15 s; And / or, after the step of setting the protonic acid solution on the initial thin film by a solution method and before the step of obtaining the thin film, it further includes: Performing a drying treatment on the initial thin film after being treated with the protonic acid solution; wherein, the temperature of the drying treatment is 60 - 90 °C; and / or, the time of the drying treatment is 30 - 60 s.

7. The method for preparing a thin film according to any one of claims 1 to 3, characterized in that, The quantum dots are selected from at least one of single-structure quantum dots, core-shell structure quantum dots, and perovskite quantum dots; the materials of the single-structure quantum dots, the core materials of the core-shell structure quantum dots, and the shell materials of the core-shell structure quantum dots are each independently selected from at least one of II-VI group compounds, IV-VI group compounds, III-V group compounds, and I-III-VI group compounds. The shell layer of the core-shell structure quantum dots includes one or more layers. 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; the I-III-VI group compounds are selected from at least one of CuInS2, CuInSe2, and AgInS2; the structural general formula of the perovskite quantum dots is ABX3; where A is an organic cation and / or an inorganic cation, and the organic cation is selected from at least one of MA + , FA + ; the inorganic cation is selected from Cs + ; B is a divalent metal cation, and B 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+ 、Eu 2+ at least one of; X is a halogen anion.

8. A thin film, characterized in that, Prepared by using the method for preparing a thin film according to any one of claims 1 to 7.

9. A light-emitting device, characterized in that, Comprising a first electrode, a light - emitting layer, and a second electrode which are sequentially stacked; Wherein, the light - emitting layer comprises at least one light - emitting sub - layer, at least one of the light - emitting sub - layers comprises a thin film prepared by the method for preparing a thin film according to any one of claims 1 to 7, or at least one of the light - emitting sub - layers comprises the thin film according to claim 8.

10. The light-emitting device according to claim 9, characterized in that, The number of the light-emitting sub-layers is three, and each of the light-emitting sub-layers includes a thin film prepared by the method for preparing a thin film according to any one of claims 1 to 7, or at least one of the light-emitting sub-layers includes the thin film according to claim 8; the three light-emitting sub-layers are a red light-emitting sub-layer, a green light-emitting sub-layer, and a blue light-emitting sub-layer respectively.

11. The light-emitting device according to claim 9 or 10, characterized in that, The materials of the first electrode and the second electrode are independently selected from at least one of a metal material, a carbon material, and a metal oxide. The metal material includes one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon material includes one or more of graphite, carbon nanotubes, graphene, and carbon fibers; the metal oxide includes a doped or undoped metal oxide. The doped metal oxide includes one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, and AMO, or includes a composite electrode in which a doped or undoped transparent metal oxide sandwiches a metal. 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; and / or, The light-emitting device further includes a hole injection layer disposed between the first electrode and the light-emitting layer. The material of the hole injection layer is selected from at least one of PEDOT:PSS, HATCN, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, polyaniline, CuPc, transition metal oxides, transition metal sulfides, transition metal stannides, doped graphene, undoped graphene, nickel oxide, molybdenum oxide, tungsten oxide, and vanadium oxide; and / or, The light-emitting device further includes a hole transport layer disposed between the first electrode and the light-emitting layer. The material of the hole transport layer is selected from at least one of TFB, PVK, Poly-TPD, PFB, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS and its derivatives, TAPC, MCC, C60; and / or, The light-emitting device further includes an electron transport layer disposed between the light-emitting layer and the second electrode; the material of the electron transport layer is selected from inorganic materials and / or organic materials; the inorganic materials include 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, 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; the doped elements include at least one of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, gadolinium; the organic materials include at least one of quinoxaline compounds, imidazole compounds, triazine compounds, fluorene-containing compounds, hydroxyquinoline compounds, polythiophene compounds, perylene diimide compounds, fullerene compounds; and / or, The light-emitting device further includes an electron injection layer disposed between the light-emitting layer and the second electrode, and the material of the electron injection layer is selected from at least one of Yb, yttrium fluoride, Li, LiF, NaF, CsCO3, Cs, KBH4 or KH.

12. A display device, characterized in that, Comprising the light-emitting device according to any one of claims 8 to 11.

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