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

Abstract

The embodiment of the invention provides a thin film and a preparation method thereof, a photoelectric device and a display device. The thin film comprises a modification material and an N-type semiconductor material, and the modification material comprises at least one of alginate and alginate derivatives. According to the thin film provided by the embodiment of the invention, the alginate and / or the alginate derivative are / is added, the alginate and the alginate derivative have relatively stable structures, and the alginate and the alginate derivative can be combined with the metal elements on the surface of the N-type semiconductor material to form a stable complex; the inorganic particles in the film can be connected to form a stable structure, so that the crack phenomenon of the film can be improved or eliminated.

Description

Technical Field

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

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

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

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

[0005] Exemplarily, the material of the thin film is composed of the N-type semiconductor material and the modifying material; and / or,

[0006] The thin film has a single-layer structure, and the mass ratio of the modifying material to the N-type semiconductor material is 1:(5 - 50);

[0007] Alternatively, the thin film includes a first sub-layer and a second sub-layer arranged in a stacked manner. The material of the first sub-layer includes the modifying material, and the material of the second sub-layer includes the N-type semiconductor material. The thickness ratio of the first sub-layer to the second sub-layer is 1:(5 - 50).

[0008] Exemplarily, the N-type semiconductor material is selected from at least one of metal oxides, doped metal oxides, II-VI group semiconductor materials, III-V group semiconductor materials, and I-III-VI group semiconductor materials; and / or

[0009] The metal oxide is selected from at least one of ZnO, BaO, TiO2, and SnO2; and / or

[0010] The metal oxide in the doped metal oxide is selected from at least one of ZnO, TiO2, and SnO2, and the doping element is selected from at least one of Al, Mg, Li, In, and Ga; and / or

[0011] The II-VI semiconductor group material is selected from at least one of ZnS, ZnSe, and CdS; and / or

[0012] The group III-V semiconductor material is selected from at least one of InP and GaP; and / or

[0013] The group I-III-VI semiconductor material is selected from at least one of CuInS and CuGaS.

[0014] In a second aspect, an embodiment of the present application provides a method for preparing a thin film, including:

[0015] Providing a composite material solution, the composite material solution includes a modifying material, an N-type semiconductor material, and a first solvent, and the modifying material includes at least one of alginate and alginate derivatives;

[0016] Depositing the composite material solution to obtain a first wet film layer, and annealing the first wet film layer to obtain a thin film.

[0017] Exemplarily, in the composite material solution, the concentration of the modifying material is 1 mg / ml to 5 mg / ml, and the concentration of the N-type semiconductor material is 10 mg / ml to 50 mg / ml; and / or

[0018] The first solvent in the composite material solution includes at least one of water, alcohol compounds, acetone, and tetrahydrofuran; and / or

[0019] When annealing the first wet film layer, the annealing temperature is 80°C to 120°C, and the annealing time is 5 minutes to 10 minutes.

[0020] In a third aspect, an embodiment of the present application provides a method for preparing a thin film, including:

[0021] Providing an N-type semiconductor material solution, the N-type semiconductor material solution includes an N-type semiconductor material and a second solvent, depositing the N-type semiconductor material solution to obtain a second wet film layer, and annealing the second wet film layer to obtain a second sub-layer;

[0022] Providing a modifying material solution, the modifying material solution includes a modifying material and a third solvent, the modifying material includes at least one of alginate and alginate derivatives, applying the modifying material solution onto the second sub-layer to obtain a third wet film layer, annealing the third wet film layer to obtain a first sub-layer, and forming a thin film, where the thin film includes a second sub-layer and a first sub-layer stacked on each other.

[0023] Exemplarily, in the N-type semiconductor material solution, the concentration of the N-type semiconductor material is 10 mg / ml to 50 mg / ml; and / or

[0024] The second solvent in the N-type semiconductor material solution includes at least one of methanol, ethanol, isobutanol, isopropanol, and butanol; and / or

[0025] In the modified material solution, the concentration of the modified material is 1 mg / ml to 5 mg / ml;

[0026] The third solvent in the modified material solution includes at least one of water, alcohol compounds, acetone, and tetrahydrofuran; and / or

[0027] The thickness ratio of the first sub-layer to the second sub-layer is 1:(5 - 50).

[0028] Fourthly, an embodiment of the present application provides an optoelectronic device, including an anode and a cathode arranged opposite to each other, and N light-emitting unit layers and N - 1 charge generation layers disposed between the anode and the cathode. One charge generation layer is arranged between every two adjacent light-emitting unit layers, where N is an integer greater than or equal to 2;

[0029] Each charge generation layer includes a stacked hole generation layer and an electron generation layer. In each charge generation layer, the hole generation layer is arranged on the side close to the cathode of the electron generation layer;

[0030] Wherein, at least one electron generation layer includes the thin film as described above or the thin film prepared by the preparation method of the thin film as described above.

[0031] Exemplarily, each light-emitting unit layer includes a stacked hole transport layer and a light-emitting layer, wherein the hole transport layer is located on the side close to the anode of the light-emitting layer; and / or

[0032] The optoelectronic device further includes an electron transport layer, and the electron transport layer is located between the light-emitting unit layer closest to the cathode and the cathode; and / or

[0033] The optoelectronic device further includes a hole injection layer, and the hole injection layer is located between the light-emitting unit layer closest to the anode and the anode.

[0034] Exemplarily, the anode and the cathode independently include a doped metal oxide particle electrode, a composite electrode, a graphene electrode, a carbon nanotube electrode, a metal elemental electrode or an alloy electrode respectively. The material of the doped metal oxide particle electrode includes one or more of indium-doped tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, magnesium-doped zinc oxide and aluminum-doped magnesium oxide. The composite electrode includes one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS or ZnS / Al / ZnS. The material of the metal elemental electrode includes one or more of Ag, Al, Cu, Mo, Au, Pt, Ca, Mg and Ba; and / or

[0035] The materials of each light-emitting layer independently include one or more of an organic light-emitting material and a quantum dot light-emitting material. The organic light-emitting material includes one or more of 4,4'-bis(N-carbazolyl)-1,1'-biphenyl: tris[2-(p-tolyl)pyridineiridium(III)], 4,4',4''-tris(carbazol-9-yl)triphenylamine: tris[2-(p-tolyl)pyridineiridium, diarylanthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent material, TTPX fluorescent material, TBRb fluorescent material, DBP fluorescent material, delayed fluorescence material, TTA material, thermally activated delayed material, polymer containing B-N covalent bond, hybrid local charge transfer excited state material, exciplex light-emitting material, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, polyfluorene and its derivatives;The quantum dot luminescent material includes one or more of single-structure quantum dots, core-shell structure quantum dots, and perovskite semiconductor materials. The materials of the single-structure quantum dots, the core materials of the core-shell structure quantum dots, and the shell materials of the core-shell structure quantum dots are each independently selected from one or more of II-VI group compounds, IV-VI group compounds, III-V group compounds, and I-III-VI group compounds. The II-VI group compounds include one or more of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe. The IV-VI group compounds include one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe. The III-V group compounds include one or more of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb. The I-III-VI group compounds include one or more of CuInS2, CuInSe2, and AgInS2. The perovskite semiconductor material includes doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors. The structural general formula of the inorganic perovskite semiconductor is AMX3, where A is Cs; + ion, M is a divalent metal cation, including Pb 2+ , Sn 2+ , Cu 2+ , Ni2+ , Cd 2+ , Cr 2+ , Mn 2+ , Co 2+ , Fe 2+ , Ge 2+ , Yb 2+ , Eu 2+ one or more of, X is a halogen anion, including Cl - , Br - , I - one or more of; the structural general formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, where B is an organic amine cation, including CH3(CH2) n-2 NH3 + or [NH3(CH2) n NH3] 2+ , where n≥2, M is a divalent metal cation, including Pb 2+ , Sn 2+ , Cu 2+ , Ni 2+ , Cd 2+ , Cr 2+ , Mn 2+ , Co 2+ , Fe 2+ , Ge 2+ , Yb 2+ , Eu 2+ one or more of, X is a halogen anion, including Cl - , Br - , I - one or more of; and / or

[0036] The materials of each hole transport layer independently include one or more of 4,4'-N,N'-dicarbazolyl-biphenyl, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine), N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro, N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 4,4',4'-tris(N-carbazolyl)-triphenylamine, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(N-vinylcarbazole) and its derivatives, N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4-4'-diamine, spiro-NPB, poly(phenylene vinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene], 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene, 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline], 1,3-bis(carbazol-9-yl)benzene, polyaniline, polypyrrole, poly(p-)phenylene vinylene, aromatic tertiary amines, polynuclear aromatic tertiary amines, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, doped graphene, undoped graphene, C60, doped or undoped NiO, doped or undoped MoO3, doped or undoped WO3, doped or undoped V2O5, doped or undoped p-type gallium nitride, doped or undoped CrO3, doped or undoped CuO; and / or

[0037] The materials of each hole injection layer and the materials of each hole generation layer independently include one or more of 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, PEDOT, PEDOT:PSS, derivatives of PEDOT:PSS doped with s-MoO3, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, tetracyanoquinodimethane, copper phthalocyanine, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide, molybdenum sulfide, tungsten sulfide and copper oxide.

[0038] In a fifth aspect, an embodiment of the present application provides a display device, including the optoelectronic device as described above or an optoelectronic device prepared by the preparation method of the optoelectronic device as described above.

[0039] The thin film provided by the embodiment of the present application is obtained by adding a modifying material to the thin film. The modifying material includes at least one of alginate and alginate derivatives. Since alginate and alginate derivatives can form a cross-linked gel with a pseudo three-dimensional network structure under the attraction of intermolecular forces, that is to say, alginate and alginate derivatives themselves have a relatively stable structure, and alginate and alginate derivatives can combine with metal elements on the surface of the N-type semiconductor material to form a stable complex, so that the inorganic particles in the thin film can be connected to form a stable structure, thereby improving or eliminating the crack phenomenon of the thin film. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for the description of the embodiments.

[0041] Figure 1 FIG. 1 is a first schematic structural diagram of the thin film provided by the embodiment of the present application.

[0042] Figure 2 FIG. 2 is a second schematic structural diagram of the thin film provided by the embodiment of the present application.

[0043] Figure 3 FIG. 3 is a first flow chart of the preparation method of the thin film provided by the embodiment of the present application.

[0044] Figure 4 FIG. 4 is a second flow chart of the preparation method of the thin film provided by the embodiment of the present application.

[0045] Figure 5 FIG. 5 is a schematic structural diagram of the optoelectronic device provided by the embodiment of the present application.

[0046] Figure 6 FIG. 6 is a photo of the optoelectronic device prepared in Example 1 of the device of the present application.

[0047] Figure 7 FIG. 7 is a photo of the optoelectronic device prepared in Example 2 of the device of the present application.

[0048] Figure 8 FIG. 8 is a photo of the optoelectronic device prepared in Example 3 of the device of the present application.

[0049] Figure 9 FIG. 9 is a photo of the optoelectronic device prepared in Example 5 of the device of the present application.

[0050] Figure 10Photograph of the optoelectronic device prepared in Example 6 of the device of the present application.

[0051] Figure 11 Photograph of the optoelectronic device prepared in Comparative Example 1 of the device.

[0052] Reference numerals:

[0053] Optoelectronic device 100; thin film 61; first sublayer 611; second sublayer 612; anode 21; cathode 22; light-emitting unit layer 30; hole transport layer 31; light-emitting layer 32; charge generation layer 40; electron generation layer 41; hole generation layer 42; hole injection layer 50; electron transport layer 60. Detailed implementation manners

[0054] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present application.

[0055] In the present application, "and / or" describes the association relationship of associated objects and indicates that three relationships may exist. For example, A and / or B may indicate: A exists alone, A and B exist simultaneously, or B exists alone. Where A and B may be singular or plural.

[0056] In the present application, forming another layer "on" a certain layer, the so-called "on" is a broad concept, which may mean that the formed another layer is adjacent to a certain layer, or there may be other spacer structure layers between another layer and a certain layer. For example, forming a cathode "on" the first carrier functional layer, the so-called "on" may mean that the formed cathode is adjacent to the first carrier functional layer, or there may be other spacer structure layers between the cathode and the first carrier functional layer, such as a light-emitting layer.

[0057] It should be noted that electroluminescent devices can be divided into single-layer devices and stacked devices. In a single-layer device, only one light-emitting layer is provided, while in a stacked device, usually two or more light-emitting layers are provided. Among them, an electron generation layer and a hole generation layer are usually provided between two adjacent light-emitting layers. After the electron generation layer is prepared, other functional film layers usually need to be prepared above the electron generation layer. During the preparation process, the solvent of other functional film layers is likely to penetrate into the electron generation layer, resulting in cracking of the electron generation layer, thereby causing a decrease in the electrical properties of the electron generation layer and further causing a decrease in the performance of the stacked device. To solve this technical problem, the embodiments of the present application provide a thin film, which can be applied to a stacked device to replace the traditional electron generation layer, and this thin film is not prone to crack phenomenon, so the electrical properties of the stacked device can be improved.

[0058] Please refer to Figure 1 and Figure 2 , the embodiments of the present application provide a thin film 61, which includes a modifying material and an N-type semiconductor material, and the modifying material includes at least one of alginate and alginate derivatives.

[0059] Exemplarily, the alginate includes at least one of sodium alginate, calcium alginate, ammonium alginate, and calcium sodium alginate.

[0060] The alginate derivative includes at least one of propylene glycol alginate and sodium alginate sulfate.

[0061] Exemplarily, the material of the thin film is composed of the N-type semiconductor material and the modifying material.

[0062] Please combine Figure 1 , in some embodiments, the thin film is a single-layer structure. At this time, the material of the thin film 61 is a mixture of a modifying material and an N-type semiconductor material, wherein the mass ratio of the modifying material to the N-type semiconductor material is 1:(5 - 50), such as 1:5, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, etc.

[0063] It should be noted that when the material of the thin film 61 is a mixture, by mixing the modifying material and the N-type semiconductor material, the modifying material (alginate and / or alginate derivative) can be used to connect multiple N-type semiconductor materials together through the complexation with metal elements in the N-type semiconductor material, thereby improving the structural stability of the thin film 61 and avoiding phenomena such as cracks.

[0064] Please combine Figure 2, in some embodiments, the thin film 61 includes a second sub-layer 612 and a first sub-layer 611 arranged in a stacked manner. The material of the first sub-layer 611 includes the modifying material, and the material of the second sub-layer 612 includes the N-type semiconductor material. The thickness ratio of the first sub-layer 611 to the second sub-layer 612 is 1:(5 - 50), such as 1:5, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, etc.

[0065] It should be noted that when the thin film 61 includes a second sub-layer 612 and a first sub-layer 611 arranged in a stacked manner, when preparing the thin film 61, the second sub-layer 612 is usually prepared first and then the first sub-layer 611. The preparation method of the first sub-layer 611 is usually: coating the modifying material solution on the second sub-layer 612. At this time, some of the modifying materials in the modifying material solution will penetrate into the second sub-layer 612, so that the N-type semiconductor material in the second sub-layer 612 can still be connected by the modifying material. And at the interface between the second sub-layer 612 and the first sub-layer 611, the N-type semiconductor material on the surface of the second sub-layer 612 forms a stable connection with the first sub-layer 611 through complexation, so that the second sub-layer 612 is not prone to cracking, thereby improving the structural stability of the second sub-layer 612.

[0066] Exemplarily, the N-type semiconductor material includes at least one of metal oxides, doped metal oxides, II-VI group semiconductor materials, III-V group semiconductor materials, and I-III-VI group semiconductor materials; the metal oxide is selected from at least one of ZnO, BaO, TiO2, and SnO2; the metal oxide in the doped metal oxide is selected from at least one of ZnO, TiO2, and SnO2, and the doping element is selected from at least one of Al, Mg, Li, In, and Ga; the II-VI group semiconductor material is selected from at least one of ZnS, ZnSe, and CdS; the III-V group semiconductor material is selected from at least one of InP and GaP; the I-III-VI group semiconductor material is selected from at least one of CuInS and CuGaS.

[0067] Exemplarily, the thickness of the thin film 61 is 10nm - 50nm, such as 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, etc.

[0068] In summary, the thin film 61 provided in the embodiment of the present application can be used as an electron generation layer in a stacked device. By adding a modifying material to the thin film 61, the modifying material includes at least one of alginate and alginate derivatives. Since alginate and alginate derivatives can form a cross-linked gel with a quasi-three-dimensional network structure under the attraction of intermolecular forces, that is to say, alginate and alginate derivatives have a relatively stable structure themselves. Moreover, alginate and alginate derivatives can combine with metal elements on the surface of the N-type semiconductor material to form a stable complex, so that the inorganic particles in the thin film 61 can be connected to form a stable structure, which can improve the density of the thin film 61 and enhance the solvent resistance of the thin film 61, thereby improving or eliminating the crack phenomenon of the thin film 61. When the thin film 61 is applied to a stacked device, it can improve the electrical performance of the stacked device; and there is usually a problem of excessive electron injection in the light-emitting layer in the existing stacked devices. However, the thin film 61 in the embodiment of the present application by adding alginate and / or alginate derivatives, since the negative ions in alginate and alginate derivatives will form a local negative electric field with the injected electrons to block electron injection, thereby enabling the holes and electrons injected into the light-emitting layer to achieve electrical balance and improving the device efficiency.

[0069] It should be noted that "enhancing the solvent resistance of the thin film 61" means that when the thin film 61 is applied to an optoelectronic device, after the thin film 61 is formed into a film, when forming other functional film layers above the thin film 61 by the coating method, the crack phenomenon caused by the thin film 61 being dissolved by the solvent in other functional film layers can be avoided.

[0070] Please refer to Figure 3 , and at the same time combine Figure 1 , the embodiment of the present application also provides a method for preparing a thin film, including:

[0071] S110, providing a composite material solution, the composite material solution includes a modifying material, an N-type semiconductor material, and a first solvent, and the modifying material includes at least one of alginate and alginate derivatives.

[0072] Exemplarily, in the composite material solution, the concentration of the modifying material is 1 mg / ml to 5 mg / ml (such as 1 mg / ml, 2 mg / ml, 3 mg / ml, 4 mg / ml, 5 mg / ml, etc.), and the concentration of the N-type semiconductor material is 10 mg / ml to 50 mg / ml (such as 10 mg / ml, 15 mg / ml, 20 mg / ml, 25 mg / ml, 30 mg / ml, 35 mg / ml, 40 mg / ml, 45 mg / ml, 50 mg / ml, etc.).

[0073] It should be noted that the reason for setting the concentration of the N-type semiconductor material in the composite material solution to 10 mg / ml to 50 mg / ml is as follows: when the concentration of the N-type semiconductor material is greater than 50 mg / ml, due to the too high concentration, it will accelerate the collision of the N-type semiconductor material in the solution, and the phenomenon of agglomeration of the N-type semiconductor material is more likely to occur. When the concentration of the N-type semiconductor material is less than 10 mg / ml, due to the low concentration, the thickness of the second sub-layer 612 prepared will be too thin and the film thickness will be uneven.

[0074] It should be noted that the reason for setting the concentration of the modifying material in the composite material solution to 1 mg / ml to 5 mg / ml is as follows: when the concentration of the modifying material is greater than 5 mg / ml, due to the too high concentration of the modifying material and its poor electrical conductivity, it is easy to cause poor electrical conductivity of the prepared thin film 61; when the concentration of the modifying material is less than 1 mg / ml, due to the too low concentration, it is easy to cause the N-type semiconductor material to not be effectively connected, so that a stable structural system cannot be formed, and thus the effect of improving the structural stability of the thin film 61 cannot be achieved.

[0075] Exemplarily, the first solvent in the composite material solution includes at least one of water, alcohol compounds, acetone, and tetrahydrofuran; exemplarily, the alcohol compounds may include at least one of methanol, ethanol, isobutanol, isopropanol, and butanol; in some embodiments, the first solvent is a mixture of an alcohol compound and water, wherein the mass ratio of the alcohol compound to water is (3 to 19):1, such as 3:1, 5:1, 8:1, 10:1, 13:1, 15:1, 19:1, etc.

[0076] S120, deposit the composite material solution to obtain a first wet film layer, and perform annealing treatment on the first wet film layer to obtain the thin film 61.

[0077] Exemplarily, when performing annealing treatment on the first wet film layer, the annealing temperature is 80°C to 120°C (such as 80°C, 90°C, 100°C, 110°C, 120°C, etc.), and the annealing time is 5 minutes to 10 minutes (such as 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, etc.).

[0078] It should be noted that the reason for selecting the annealing temperature to be 80°C to 120°C is as follows: when the annealing temperature is higher than 120°C, the ligands on the surface of the N-type semiconductor material (such as zinc oxide nanoparticles) will be inactivated, increasing the steric hindrance and reducing the electron transport efficiency. When the annealing temperature is lower than 80°C, it will cause the solvent in the thin film 61 to not be completely removed, and when preparing other functional thin films on the thin film 61 later, the material of the thin film 61 will be washed away.

[0079] Please refer to Figure 4 and at the same time combineFigure 2 , The embodiments of the present application further provide a method for preparing a thin film, including:

[0080] S210, Provide an N-type semiconductor material solution, the N-type semiconductor material solution includes an N-type semiconductor material and a second solvent, deposit the N-type semiconductor material solution to obtain a second wet film layer, and perform annealing treatment on the second wet film layer to obtain a second sub-layer 612.

[0081] Exemplarily, in the N-type semiconductor material solution, the concentration of the N-type semiconductor material is 10 mg / ml to 50 mg / ml (such as 10 mg / ml, 15 mg / ml, 20 mg / ml, 25 mg / ml, 30 mg / ml, 35 mg / ml, 40 mg / ml, 45 mg / ml, 50 mg / ml, etc.). It should be noted that when the concentration of the N-type semiconductor material is greater than 50 mg / ml, since the high concentration will accelerate the collision of the N-type semiconductor material in the solution, the phenomenon of agglomeration of the N-type semiconductor material is more likely to occur. When the concentration of the N-type semiconductor material is less than 10 mg / ml, due to the low concentration, the thickness of the obtained second sub-layer 612 will be too thin and the film thickness will be uneven.

[0082] Exemplarily, the second solvent in the N-type semiconductor material solution includes at least one of methanol, ethanol, isobutanol, isopropanol, and butanol.

[0083] Exemplarily, when performing annealing treatment on the second wet film layer, the annealing temperature is 80°C to 120°C (such as 80°C, 90°C, 100°C, 110°C, 120°C, etc.), and the annealing time is 5 minutes to 10 minutes (such as 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, etc.).

[0084] S220, Provide a modification material solution, the modification material solution includes a modification material and a third solvent, the modification material includes at least one of alginate and alginate derivatives, apply the modification material solution on the second sub-layer 612 to obtain a third wet film layer, and perform annealing treatment on the third wet film layer to obtain a first sub-layer, forming a thin film 61, and the thin film 61 includes a second sub-layer 612 and a first sub-layer 611 arranged in a stacked manner.

[0085] Exemplarily, in the modification material solution, the concentration of the modification material is 1 mg / ml to 5 mg / ml (such as 1 mg / ml, 2 mg / ml, 3 mg / ml, 4 mg / ml, 5 mg / ml, etc.).

[0086] Exemplarily, the third solvent in the modifying material solution includes at least one of water, alcohol compounds, acetone, and tetrahydrofuran; exemplarily, the alcohol compounds may include at least one of methanol, ethanol, isobutanol, isopropanol, and butanol; in some embodiments, the third solvent is a mixture of an alcohol compound and water, wherein the mass ratio of the alcohol compound to water is (3 to 19):1, such as 3:1, 5:1, 8:1, 10:1, 13:1, 15:1, 19:1, etc.

[0087] Exemplarily, when annealing the third wet film layer, the annealing temperature is 80°C to 120°C (such as 80°C, 90°C, 100°C, 110°C, 120°C, etc.), and the annealing time is 5 minutes to 10 minutes (such as 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, etc.).

[0088] It should be noted that when the modifying material solution is applied to the second sub-layer 612, part of the modifying material in the modifying material solution will penetrate into the second sub-layer 612, so that the N-type semiconductor material in the second sub-layer 612 can still be connected by the modifying material, and at the interface between the second sub-layer 612 and the first sub-layer 611, the N-type semiconductor material on the surface of the second sub-layer 612 and the modifying material in the first sub-layer 611 form a stable connection through complexation, so that the film 61 composed of the second sub-layer 612 and the first sub-layer 611 is not prone to cracking, and thus the structural stability of the film 61 can be improved.

[0089] Exemplarily, the thickness ratio of the first sub-layer 611 to the second sub-layer 612 is 1:(5 - 50), such as 1:5, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, etc.

[0090] Exemplarily, the thickness of the first sub-layer 611 is 0.1 nm to 5 nm, such as 0.1 nm, 0.5 nm, 1 nm, 1.5 nm, 2 nm, 2.5 nm, 3 nm, 3.5 nm, 4 nm, 4.5 nm, 5 nm, etc.

[0091] Exemplarily, the thickness of the second sub-layer 612 is 5 nm to 49.9 nm, such as 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 49.9 nm, etc.

[0092] Please refer to Figure 5, an embodiment of the present application further provides an optoelectronic device 100, including an anode 21 and a cathode 22 which are oppositely arranged, and N light-emitting unit layers 30 and N - 1 charge generation layers 40 disposed between the anode 21 and the cathode 22. One charge generation layer 40 is disposed between every two adjacent light-emitting unit layers 30, where N is an integer greater than or equal to 2.

[0093] Each charge generation layer 40 includes a stacked hole generation layer 42 and electron generation layer 41. In each charge generation layer 40, the hole generation layer 42 is disposed on the side of the electron generation layer 41 closer to the cathode 22.

[0094] Wherein, at least one electron generation layer 41 includes the thin film in any of the above embodiments or the thin film prepared by the preparation method of the thin film in any of the above embodiments.

[0095] Please refer to Figure 5 , each light-emitting unit layer 30 includes a stacked hole transport layer 31 and a light-emitting layer 32, wherein the hole transport layer 31 is located on the side of the light-emitting layer 32 closer to the anode 21.

[0096] Please refer to Figure 5 , the optoelectronic device 100 further includes an electron transport layer 60, and the electron transport layer 60 is located between the light-emitting unit layer 30 closest to the cathode 22 and the cathode 22.

[0097] Please refer to Figure 5 , the optoelectronic device 100 further includes a hole injection layer 50, and the hole injection layer 50 is located between the light-emitting unit layer 30 closest to the anode 21 and the anode 21.

[0098] Exemplarily, the anode 21 and the cathode 22 each independently include a doped metal oxide particle electrode, a composite electrode, a graphene electrode, a carbon nanotube electrode, a metal single electrode or an alloy electrode. The material of the doped metal oxide particle electrode includes one or more of indium-doped tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, magnesium-doped zinc oxide and aluminum-doped magnesium oxide. The composite electrode includes one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS or ZnS / Al / ZnS. The material of the metal single electrode includes one or more of Ag, Al, Cu, Mo, Au, Pt, Ca, Mg and Ba.

[0099] Exemplarily, the materials of each light-emitting layer 32 independently include one or more of an organic light-emitting material and a quantum dot light-emitting material. The organic light-emitting material includes one or more of 4,4'-bis(N-carbazolyl)-1,1'-biphenyl: tris[2-(p-tolyl)pyridineiridium(III)], 4,4',4''-tris(carbazol-9-yl)triphenylamine: tris[2-(p-tolyl)pyridineiridium, a diarylanthracene derivative, a stilbene aromatic derivative, a pyrene derivative, a fluorene derivative, a TBPe fluorescent material, a TTPX fluorescent material, a TBRb fluorescent material, a DBP fluorescent material, a delayed fluorescence material, a TTA material, a thermally activated delayed material, a polymer containing a B-N covalent bond, a hybrid local charge transfer excited state material, an exciplex light-emitting material, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, and polyfluorene and its derivatives;The quantum dot light-emitting material includes one or more of single-structure quantum dots, core-shell structure quantum dots, and perovskite semiconductor materials. The materials of the single-structure quantum dots, the core materials of the core-shell structure quantum dots, and the shell materials of the core-shell structure quantum dots are each independently selected from one or more of II-VI group compounds, IV-VI group compounds, III-V group compounds, and I-III-VI group compounds. The II-VI group compounds include one or more of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe. The IV-VI group compounds include one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe. The III-V group compounds include one or more of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb. The I-III-VI group compounds include one or more of CuInS2, CuInSe2, and AgInS2. The perovskite semiconductor material includes doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors. The structural general formula of the inorganic perovskite semiconductor is AMX3, where A is Cs; + ions, M is a divalent metal cation, including Pb 2+ , Sn 2+ , Cu 2+ , Ni2+ 、Cd 2+ 、Cr 2+ 、Mn 2+ 、Co 2+ 、Fe 2+ 、Ge 2+ 、Yb 2+ 、Eu 2+ One or more of Cd, Cr, Mn, Co, Fe, Ge, Yb, Eu, X is a halogen anion, including one or more of Cl, Br, I; the structural general formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, where B is an organic amine cation, including CH3(CH2)NH3 or [NH3(CH2)NH3] where n≥2, M is a divalent metal cation, including one or more of Pb, Sn, Cu, Ni, Cd, Cr, Mn, Co, Fe, Ge, Yb, Eu, and X is a halogen anion, including one or more of Cl, Br, I. - 、Br - 、I - One or more of Cl, Br, I; the structural general formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, where B is an organic amine cation, including CH3(CH2)NH3 or [NH3(CH2)NH3] where n≥2, M is a divalent metal cation, including one or more of Pb, Sn, Cu, Ni, Cd, Cr, Mn, Co, Fe, Ge, Yb, Eu, and X is a halogen anion, including one or more of Cl, Br, I. n-2 NH3 + or [NH3(CH2) n NH3] 2+ , where n≥2, M is a divalent metal cation, including one or more of Pb, Sn, Cu, Ni, Cd, Cr, Mn, Co, Fe, Ge, Yb, Eu, and X is a halogen anion, including one or more of Cl, Br, I. 2+ 、Sn 2+ 、Cu 2+ 、Ni 2+ 、Cd 2+ 、Cr 2+ 、Mn 2+ 、Co 2+ 、Fe 2+ 、Ge 2+ 、Yb 2+ 、Eu 2+ One or more of Pb, Sn, Cu, Ni, Cd, Cr, Mn, Co, Fe, Ge, Yb, Eu, X is a halogen anion, including one or more of Cl, Br, I. - 、Br - 、I - One or more of Cl, Br, I.

[0100] Exemplarily, the materials of each hole transport layer 31 independently include one or more of 4,4'-N,N'-dicarbazolyl-biphenyl, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine), N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro, N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 4,4',4'-tris(N-carbazolyl)-triphenylamine, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(N-vinylcarbazole) and its derivatives, N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4-4'-diamine, spiro-NPB, poly(phenylene vinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene], 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene, 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline], 1,3-bis(carbazol-9-yl)benzene, polyaniline, polypyrrole, poly(p-)phenylene vinylene, aromatic tertiary amine, polynuclear aromatic tertiary amine, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compound, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, doped graphene, undoped graphene, C60, doped or undoped NiO, doped or undoped MoO3, doped or undoped WO3, doped or undoped V2O5, doped or undoped p-type gallium nitride, doped or undoped CrO3, doped or undoped CuO.

[0101] Exemplarily, the material of each hole injection layer 50 and the material of each hole generation layer 42 each independently include one or more of 2,3,6,7,10,11 - hexacyano - 1,4,5,8,9,12 - hexaazatriphenylene, PEDOT, PEDOT:PSS, a derivative of PEDOT:PSS doped with s - MoO3, 4,4',4' - tris(N - 3 - methylphenyl - N - phenylamino)triphenylamine, tetracyanoquinodimethane, copper phthalocyanine, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide, molybdenum sulfide, tungsten sulfide, and copper oxide.

[0102] Exemplarily, the optoelectronic device 100 can be an OLED (Organic Light - Emitting Diode) or a QLED (Quantum Dot Light Emitting Diodes).

[0103] Exemplarily, the thickness of the thin film 61 is 10 nm - 50 nm, such as 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, etc.

[0104] Exemplarily, when the thin film 61 includes a second sub - layer 612 and a first sub - layer 611 arranged in a stacked manner, the thickness ratio of the first sub - layer 611 to the second sub - layer 612 is 1:(5 - 50), such as 1:5, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, etc.

[0105] Exemplarily, the thickness of each of the anode 21 and the cathode 22 is 10 nm - 120 nm, such as 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, etc.

[0106] Exemplarily, the thickness of the hole injection layer 50 is 10 nm - 50 nm, such as 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, etc.

[0107] Exemplarily, the thickness of the hole generation layer 42 is 10 nm - 20 nm, such as 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, etc.

[0108] Exemplarily, the thickness of the hole transport layer 31 is 10 nm - 50 nm, such as 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, etc.

[0109] Exemplarily, the thickness of the light - emitting layer 32 is 10 nm - 50 nm, such as 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, etc.

[0110] Exemplarily, the thickness of the electron transport layer 60 is 10 nm - 50 nm, such as 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, etc.

[0111] An embodiment of the present application further provides a display device, including the optoelectronic device 100 in any of the above embodiments or the optoelectronic device 100 prepared by the preparation method of the optoelectronic device in any of the above embodiments.

[0112] Exemplarily, the display device may be a terminal such as a television, a mobile phone, a tablet computer, a display, an advertising display screen, etc., and may also be a device with a display screen such as a game device, an Augmented Reality (AR) device, a Virtual Reality (VR) device, a data storage device, an audio playback device, a video playback device, a wearable device, etc., where the wearable device may be a smart bracelet, smart glasses, a smart watch, smart decoration, etc.

[0113] The thin film of the present application, its preparation method, the optoelectronic device and its preparation method will be described in detail below in the form of specific embodiments.

[0114] Thin Film Embodiment 1

[0115] A thin film, its preparation method includes:

[0116] Step 11: Provide a composite material solution, the composite material solution includes ZMO (magnesium-doped zinc oxide) nanoparticles, a modifying material (sodium alginate) and a solvent (a mixture of butanol and acetone), wherein the concentration of the modifying material (sodium alginate) is 1 mg / ml, and the concentration of the ZMO nanoparticles is 30 mg / ml;

[0117] Step 12: Deposit the composite material solution by spin coating to form a wet film layer, and perform annealing treatment on the wet film layer. The annealing temperature is 80 °C and the annealing time is 10 minutes to obtain a thin film. The thickness of the thin film is 40 nm, and the mass ratio of the modifying material (sodium alginate) to the ZMO nanoparticles in the thin film is 1:30.

[0118] Thin Film Embodiment 2

[0119] A thin film, the difference between its preparation method and that of Thin Film Embodiment 1 is that:

[0120] In Step 11, the concentration of the modifying material (sodium alginate) in the composite material solution is different. In this Thin Film Embodiment 2, the concentration of the modifying material (sodium alginate) is 3 mg / ml;

[0121] In Step 12, the mass ratio of the modifying material (sodium alginate) to the ZMO nanoparticles in the obtained thin film is 1:10.

[0122] Film Example 3

[0123] A film, compared with Film Example 1 in its preparation method, the differences are as follows:

[0124] In Step 11, the concentration of the modifying material (sodium alginate) in the composite material solution is different. In this Film Example 3, the concentration of the modifying material (sodium alginate) is 6 mg / ml;

[0125] In Step 12, the mass ratio of the modifying material (sodium alginate) to the ZMO nanoparticles in the obtained film is 1:5.

[0126] Film Example 4

[0127] A film, compared with Film Example 1 in its preparation method, the differences are as follows:

[0128] In Step 11, the concentration of the modifying material (sodium alginate) in the composite material solution is different. In this Film Example 3, the concentration of the modifying material (sodium alginate) is 0.6 mg / ml;

[0129] In Step 12, the mass ratio of the modifying material (sodium alginate) to the ZMO nanoparticles in the obtained film is 1:50.

[0130] Film Example 5

[0131] A film, compared with Film Example 1 in its preparation method, the differences are as follows:

[0132] In Step 11, the concentration of the modifying material (sodium alginate) in the composite material solution is different. In this Film Example 5, the concentration of the modifying material (sodium alginate) is 8 mg / ml;

[0133] In Step 12, the mass ratio of the modifying material (sodium alginate) to the ZMO nanoparticles in the obtained film is 1:3.75.

[0134] Film Example 6

[0135] A film, compared with Film Example 1 in its preparation method, the differences are as follows:

[0136] In Step 11, the type and concentration of the modifying material in the composite material solution are different. In this Film Example 6, the modifying material is ammonium alginate, and the concentration of the modifying material (ammonium alginate) is 3 mg / ml;

[0137] In Step 12, the mass ratio of the modifying material (ammonium alginate) to the ZMO nanoparticles in the obtained film is 1:10.

[0138] Film Example 7

[0139] A thin film, compared with the preparation method of thin film Example 1, the difference lies in:

[0140] In step 11, the types of modifying materials in the composite material solution are different. In this thin film Example 7, the modifying material is propylene glycol alginate, and the concentration of the modifying material (propylene glycol alginate) in the composite material solution is 3 mg / ml;

[0141] In step 12, the mass ratio of the modifying material (propylene glycol alginate) to the ZMO nanoparticles in the obtained thin film is 1:10.

[0142] Thin film Example 8

[0143] A thin film, its preparation method includes:

[0144] Step 21: Provide a ZMO nanoparticle solution. The ZMO nanoparticle solution includes ZMO nanoparticles and butanol. The concentration of the ZMO nanoparticles is 30 mg / ml. Apply the ZMO nanoparticle solution onto the first light-emitting layer and heat it at 80 °C for 5 minutes to obtain a second sub-layer, and the thickness of the second sub-layer is 38.7 nm;

[0145] Step 22: Provide a modifying material solution. The modifying material solution includes a modifying material (sodium alginate) and acetone. The concentration of the modifying material (sodium alginate) is 1 mg / ml. Apply the modifying material solution onto the ZMO nanoparticle layer and heat it at 80 °C for 5 minutes to obtain a first sub-layer, and the thickness of the first sub-layer is 1.3 nm, forming a thin film. The thin film is composed of a second sub-layer and a first sub-layer arranged in a stacked manner, and the thickness ratio of the first sub-layer to the second sub-layer is 1:30.

[0146] Thin film Example 9

[0147] A thin film, its preparation method includes:

[0148] A thin film, compared with the preparation method of thin film Example 1, the difference lies in:

[0149] In step 11, the thickness of the obtained second sub-layer is 33.3 nm;

[0150] In step 22, the thickness of the obtained first sub-layer is 6.7 nm. In the prepared thin film, the thickness ratio of the first sub-layer to the second sub-layer is 1:5.

[0151] Thin film Example 10

[0152] A thin film, its preparation method includes:

[0153] A thin film, compared with the preparation method of thin film Example 1, the difference lies in:

[0154] In step 11, the thickness of the obtained second sub-layer is 39.2 nm;

[0155] In step 22, the thickness of the obtained first sub-layer is 0.8 nm. In the prepared thin film, the thickness ratio of the first sub-layer to the second sub-layer is 1:49.

[0156] Thin film comparative example 1

[0157] A thin film, the preparation method thereof comprising:

[0158] Step 110: Provide a ZMO (magnesium-doped zinc oxide) nanoparticle solution, the ZMO nanoparticle solution comprising ZMO nanoparticles and a solvent (a mixture of butanol and acetone), wherein the concentration of the ZMO nanoparticles is 30 mg / ml;

[0159] Step 120: Deposit the ZMO nanoparticle solution by spin coating to form a wet film layer, and perform annealing treatment on the wet film layer. The annealing temperature is 80 °C and the annealing time is 10 minutes to obtain a thin film with a thickness of 40 nm.

[0160] Device example 1

[0161] An optoelectronic device, the preparation method thereof comprising:

[0162] Step 21: Subject the cleaned anode (ITO) to UVO treatment for 15 minutes, spin coat PEDOT:PSS on the anode, and heat at 150 °C for 15 minutes to obtain a hole injection layer with a thickness of 30 nm;

[0163] Step 22: Spin coat TFB on the hole injection layer and heat at 150 °C for 15 minutes to obtain a first hole transport layer with a thickness of 15 nm;

[0164] Step 23: Spin coat a core-shell structure quantum dot (ZnCdSe / ZnS, ZnCdSe is the core and ZnS is the shell) on the first hole transport layer and heat at 100 °C for 8 minutes to obtain a first light-emitting layer with a thickness of 30 nm;

[0165] Step 24: Prepare a thin film (electron generation layer) on the first light-emitting layer by the method of thin film example 1;

[0166] Step 25: Spin coat PEDOT on the thin film and heat at 150 °C for 15 minutes to obtain a hole generation layer with a thickness of 15 nm;

[0167] Step 26: Spin coat TFB on the hole generation layer and heat at 150 °C for 15 minutes to obtain a second hole transport layer with a thickness of 15 nm;

[0168] Step 27: Spin-coat core-shell structure quantum dots (ZnCdSe / ZnS, with ZnCdSe as the core and ZnS as the shell) on the second hole transport layer, and heat at 100 °C for 8 minutes to obtain the second light-emitting layer with a thickness of 30 nm;

[0169] Step 28: Spin-coat ZMO nanoparticles on the second light-emitting layer, and heat at 80 °C for 10 minutes to obtain the electron transport layer with a thickness of 40 nm;

[0170] Step 29: Evaporate Ag on the electron transport layer to obtain the cathode with a thickness of 100 nm, thus obtaining the optoelectronic device.

[0171] Device Example 2

[0172] An optoelectronic device, the difference in its preparation method from that of Device Example 1 lies in:

[0173] In Step 24, a thin film (electron generation layer) is prepared on the first light-emitting layer by using the method of Thin Film Example 2.

[0174] Device Example 3

[0175] An optoelectronic device, the difference in its preparation method from that of Device Example 1 lies in:

[0176] In Step 24, a thin film (electron generation layer) is prepared on the first light-emitting layer by using the method of Thin Film Example 3.

[0177] Device Example 4

[0178] An optoelectronic device, the difference in its preparation method from that of Device Example 1 lies in:

[0179] In Step 24, a thin film (electron generation layer) is prepared on the first light-emitting layer by using the method of Thin Film Example 4.

[0180] Device Example 5

[0181] An optoelectronic device, the difference in its preparation method from that of Device Example 1 lies in:

[0182] In Step 24, a thin film (electron generation layer) is prepared on the first light-emitting layer by using the method of Thin Film Example 5.

[0183] Device Example 6

[0184] An optoelectronic device, the difference in its preparation method from that of Device Example 1 lies in:

[0185] In Step 24, a thin film (electron generation layer) is prepared on the first light-emitting layer by using the method of Thin Film Example 6.

[0186] Device Example 7

[0187] An optoelectronic device, the difference between its preparation method and that of Device Example 1 lies in that:

[0188] In step 24, a thin film (electron generation layer) is prepared on the first light-emitting layer by using the method of Thin Film Example 7.

[0189] Device Example 8

[0190] An optoelectronic device, the difference between its preparation method and that of Device Example 1 lies in that:

[0191] In step 24, a thin film (electron generation layer) is prepared on the first light-emitting layer by using the method of Thin Film Example 8.

[0192] Device Example 9

[0193] An optoelectronic device, the difference between its preparation method and that of Device Example 1 lies in that:

[0194] In step 24, a thin film (electron generation layer) is prepared on the first light-emitting layer by using the method of Thin Film Example 9.

[0195] Device Example 10

[0196] An optoelectronic device, the difference between its preparation method and that of Device Example 1 lies in that:

[0197] In step 24, a thin film (electron generation layer) is prepared on the first light-emitting layer by using the method of Thin Film Example 10.

[0198] Device Comparative Example 1

[0199] An optoelectronic device, the difference between its preparation method and that of Device Example 1 lies in that:

[0200] In step 24, a thin film (electron generation layer) is prepared on the first light-emitting layer by using the method of Thin Film Comparative Example 1.

[0201] The optoelectronic devices prepared in Device Examples 1, 2, 3, 5, 6 and Device Comparative Example 1 were photographed under an electron microscope, and the photos of the optoelectronic devices in Device Example 1 are as Figure 6 shown, the photos of the optoelectronic devices in Device Example 2 are as Figure 7 shown, the photos of the optoelectronic devices in Device Example 3 are as Figure 8 shown, the photos of the optoelectronic devices in Device Example 5 are as Figure 9 shown, the photos of the optoelectronic devices in Device Example 6 are as Figure 10 shown, the photos of the optoelectronic devices in Device Comparative Example 1 are as Figure 11 shown. It can be seen that Device Examples 1, 2, 3, 5, 6 ( Figures 6 to 10)The structure of each film layer of the optoelectronic device is complete, which indicates that the structure of the thin film (electron generation layer) is complete and no crack phenomenon appears. However, for the optoelectronic device in Comparative Example 1 of the device ( Figure 11 )serious cracks appear in the optoelectronic device, indicating that serious crack defects have occurred in the thin film (electron generation layer).

[0202] The optoelectronic devices prepared in Device Examples 1-10 and Device Comparative Example 1 were tested. Using the Fosida FPD optical property measurement equipment, an efficiency test system built by controlling a QE PRO spectrometer, a Keithley 2400, and a Keithley 6485 through LabView, parameters such as voltage, current, and brightness were measured, and the luminous efficiency CE was obtained through calculation. The test results are shown in Table 1.

[0203] Table 1

[0204]

[0205]

[0206] As can be seen from the above table, the morphologies of the optoelectronic devices in Device Examples 1-10 are normal, while cracks appear in the optoelectronic device of Device Comparative Example 1. Considering that the only difference between Device Examples 1-10 and Device Comparative Example 1 lies in the material and manufacturing method of the thin film (electron generation layer), the thin film (electron generation layer) in Device Examples 1-10 of the present application includes ZMO (magnesium-doped zinc oxide) nanoparticles and a modifying material (sodium alginate), while the thin film (electron generation layer) of Device Comparative Example 1 is only composed of ZMO (magnesium-doped zinc oxide) nanoparticles. This shows that the difference in the morphologies of the optoelectronic devices in Device Examples 1-10 and Device Comparative Example 1 lies in the difference in the morphology of the thin film (electron generation layer). From Figure 11 it can be clearly seen that there are many obvious cracks in the thin film (electron generation layer) of the optoelectronic device in Device Comparative Example 1. By comparing the luminous efficiencies of the optoelectronic devices in Device Examples 1-10 and Device Comparative Example 1, it can be seen that the luminous efficiency of the optoelectronic device in Device Comparative Example 1 is lower, indicating that the cracks on the thin film (electron generation layer) have a significant impact on the electrical performance of the optoelectronic device.

[0207] By comparing Device Example 1-4 with Device Example 5, it can be seen that although there is no obvious difference in the morphology of the optoelectronic devices between Device Example 5 and those of Device Example 1-4, and no crack phenomenon appears, however, the luminous efficiency of the optoelectronic device of Device Example 5 is significantly lower than that of the optoelectronic devices of Device Example 1-4. It is known that the difference between Device Example 1 and Device Example 5 lies in that: in Device Example 1-4, the mass ratio of the modifying material (sodium alginate) to the ZMO nanoparticles in the thin film (electron generation layer) is 1:(5-30), while in Device Example 5, the mass ratio of the modifying material (sodium alginate) to the ZMO nanoparticles in the thin film (electron generation layer) is 1:3.75. This shows that the content of the modifying material (sodium alginate) in the thin film (electron generation layer) prepared in Device Example 5 is too high. When the content of the modifying material (sodium alginate) in the thin film is too high, due to the poor conductivity of the modifying material (sodium alginate), the conductivity of the thin film (electron generation layer) will be poor, thereby affecting the luminous efficiency of the optoelectronic device. By controlling the mass ratio of the modifying material (sodium alginate) to the ZMO nanoparticles in the thin film (electron generation layer) within 1:(5-30) in this application, it is possible to improve the density and solvent resistance of the thin film (electron generation layer) while avoiding the influence on the electrical properties of the thin film (electron generation layer).

[0208] The thin film and its preparation method, optoelectronic device, and display device provided by the embodiments of the present application have been introduced in detail above. Specific examples are used herein to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the present application. At the same time, for those skilled in the art, based on the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A thin film, characterized in that, It includes a modifying material and an N-type semiconductor material, and the modifying material includes at least one of alginate and alginate derivatives.

2. The thin film according to claim 1, wherein The alginate includes at least one of sodium alginate, calcium alginate, ammonium alginate, and calcium sodium alginate; and / or The alginate derivative includes at least one of propylene glycol alginate and sodium alginate sulfate; and / or The thickness of the thin film is 10 nm to 50 nm.

3. The thin film according to claim 1 or 2, characterized in that, The material of the thin film is composed of the N-type semiconductor material and the modifying material; and / or, The thin film has a single-layer structure, and the mass ratio of the modifying material to the N-type semiconductor material is 1:(5 - 50); Alternatively, the thin film includes a first sub-layer and a second sub-layer arranged in a stacked manner. The material of the first sub-layer includes the modifying material, and the material of the second sub-layer includes the N-type semiconductor material. The thickness ratio of the first sub-layer to the second sub-layer is 1:(5 - 50).

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

5. A method for preparing a thin film, characterized in that, It includes: Providing a composite material solution, the composite material solution includes a modifying material, an N-type semiconductor material, and a first solvent, and the modifying material includes at least one of alginate and alginate derivatives; Depositing the composite material solution to obtain a first wet film layer, and annealing the first wet film layer to obtain a thin film.

6. The method for preparing the thin film according to claim 5, wherein In the composite material solution, the concentration of the modifying material is 1 mg / ml to 5 mg / ml, and the concentration of the N-type semiconductor material is 10 mg / ml to 50 mg / ml; and / or The first solvent in the composite material solution includes at least one of water, alcohol compounds, acetone, and tetrahydrofuran; and / or When annealing the first wet film layer, the annealing temperature is 80 °C to 120 °C, and the annealing time is 5 minutes to 10 minutes.

7. A method for preparing a thin film, characterized in that, It includes: Providing an N-type semiconductor material solution, the N-type semiconductor material solution includes an N-type semiconductor material and a second solvent, depositing the N-type semiconductor material solution to obtain a second wet film layer, and annealing the second wet film layer to obtain a second sub-layer; A modified material solution is provided. The modified material solution includes a modified material and a third solvent. The modified material includes at least one of alginate and alginate derivatives. The modified material solution is applied onto the second sub-layer to obtain a third wet film layer, and the third wet film layer is annealed to obtain a first sub-layer, thereby forming a thin film which includes the second sub-layer and the first sub-layer stacked on each other.

8. The method for preparing a thin film according to claim 7, characterized in that, In the N-type semiconductor material solution, the concentration of the N-type semiconductor material is 10 mg / ml to 50 mg / ml; and / or The second solvent in the N-type semiconductor material solution includes at least one of methanol, ethanol, isobutanol, isopropanol, and butanol; and / or In the modified material solution, the concentration of the modified material is 1 mg / ml to 5 mg / ml; The third solvent in the modified material solution includes at least one of water, alcohol compounds, acetone, and tetrahydrofuran; and / or The thickness ratio of the first sub-layer to the second sub-layer is 1:(5 - 50).

9. An optoelectronic device, characterized in that, It includes an anode and a cathode which are oppositely arranged, and N light-emitting unit layers and N - 1 charge generation layers disposed between the anode and the cathode. One charge generation layer is provided between every two adjacent light-emitting unit layers, wherein N is an integer greater than or equal to 2; Each charge generation layer includes a hole generation layer and an electron generation layer stacked on each other. In each charge generation layer, the hole generation layer is disposed on the side closer to the cathode of the electron generation layer; Wherein, at least one electron generation layer includes a thin film as described in any one of claims 1 - 4 or a thin film prepared by the preparation method of the thin film as described in any one of claims 5 - 8.

10. The optoelectronic device according to claim 9, wherein, Each light-emitting unit layer includes a hole transport layer and a light-emitting layer stacked on each other. Wherein, the hole transport layer is located on the side closer to the anode of the light-emitting layer; and / or The optoelectronic device further includes an electron transport layer which is located between the light-emitting unit layer closest to the cathode and the cathode; and / or The optoelectronic device further includes a hole injection layer which is located between the light-emitting unit layer closest to the anode and the anode.

11. The optoelectronic device according to claim 10, wherein The anode and the cathode each independently include a doped metal oxide particle electrode, a composite electrode, a graphene electrode, a carbon nanotube electrode, a metal single-element electrode or an alloy electrode. The material of the doped metal oxide particle electrode includes one or more of indium-doped tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, magnesium-doped zinc oxide, and aluminum-doped magnesium oxide. The composite electrode includes one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS, or ZnS / Al / ZnS. The material of the metal single-element electrode includes one or more of Ag, Al, Cu, Mo, Au, Pt, Ca, Mg, and Ba; and / or The materials of each light-emitting layer independently include one or more of an organic light-emitting material and a quantum dot light-emitting material. The organic light-emitting material includes one or more of 4,4'-bis(N-carbazolyl)-1,1'-biphenyl: tris[2-(p-tolyl)pyridineiridium(III)], 4,4',4''-tris(carbazol-9-yl)triphenylamine: tris[2-(p-tolyl)pyridineiridium, diarylanthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent material, TTPX fluorescent material, TBRb fluorescent material, DBP fluorescent material, delayed fluorescence material, TTA material, thermally activated delayed material, polymer containing B-N covalent bond, hybrid local charge transfer excited state material, exciplex light-emitting material, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, polyfluorene and its derivatives;The quantum dot luminescent material includes one or more of single-structure quantum dots, core-shell structure quantum dots, and perovskite semiconductor materials. The materials of the single-structure quantum dots, the core materials of the core-shell structure quantum dots, and the shell materials of the core-shell structure quantum dots are each independently selected from one or more of II-VI group compounds, IV-VI group compounds, III-V group compounds, and I-III-VI group compounds. The II-VI group compounds include one or more of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe. The IV-VI group compounds include one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe. The III-V group compounds include one or more of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb. The I-III-VI group compounds include one or more of CuInS2, CuInSe2, and AgInS2. The perovskite semiconductor material includes doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors. The structural general formula of the inorganic perovskite semiconductor is AMX3, where A is Cs; + ion, M is a divalent metal cation, including Pb 2+ , Sn 2+ , Cu 2+ , Ni 2+ 、 Cd 2+ 、 Cr 2+ 、 Mn 2+ 、 Co 2+ 、 Fe 2+ 、 Ge 2+ 、 Yb 2+ 、 Eu 2+ one or more of, X is a halogen anion, including Cl - 、 Br - 、 I - one or more of; the structural general formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, where B is an organic amine cation, including CH3(CH2) n-2 NH3 + or [NH3(CH2) n NH3] 2+ , where n≥2, M is a divalent metal cation, including Pb 2+ 、 Sn 2+ 、 Cu 2+ 、 Ni 2+ 、 Cd 2+ 、 Cr 2+ 、 Mn 2+ 、 Co 2+ 、 Fe 2+ 、 Ge 2+ 、 Yb 2+ 、 Eu 2+ one or more of, X is a halogen anion, including Cl - 、 Br - 、 I - one or more of; and / or The materials of each hole transport layer independently include one or more of 4,4'-N,N'-dicarbazolyl-biphenyl, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine), N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro, N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 4,4',4'-tris(N-carbazolyl)-triphenylamine, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(N-vinylcarbazole) and its derivatives, N,N'-bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4-4'-diamine, spiro-NPB, poly(phenylene vinylene), poly[2-methoxy-5-(2-ethylhexoxy)-1,4-phenylene vinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene], 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene, 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline], 1,3-bis(carbazol-9-yl)benzene, polyaniline, polypyrrole, poly(p-phenylene vinylene), aromatic tertiary amines, polynuclear aromatic tertiary amines, 4,4'-bis(p-carbazolyl)-1,1'-biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, doped graphene, undoped graphene, C60, doped or undoped NiO, doped or undoped MoO3, doped or undoped WO3, doped or undoped V2O5, doped or undoped p-type gallium nitride, doped or undoped CrO3, doped or undoped CuO; and / or The materials of each hole injection layer and the materials of each hole generation layer independently include one or more of 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene, PEDOT, PEDOT:PSS, derivatives of PEDOT:PSS doped with s-MoO3, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, tetracyanoquinodimethane, copper phthalocyanine, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide, molybdenum sulfide, tungsten sulfide and copper oxide.

12. A display device, characterized in that, Including the optoelectronic device according to any one of claims 9-11.

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