A composition, ink, film, light emitting device, and display device

Abstract

This application belongs to the field of display technology and relates to a composition, ink, thin film, light-emitting device, and display apparatus. The composition comprises a polyhydroxy compound and a first metal oxide, wherein the polyhydroxy compounds are interconnected by hydrogen bonds, and the first metal oxide is coordinated with the polyhydroxy compounds. The polyhydroxy compounds can passivate surface defects of the first metal oxide, improving its conductivity, and, after coordination with the first metal oxide, can prevent uneven diffusion of the first metal oxide.

Description

Technical Field

[0001] This application relates to the field of display technology, and more specifically, to a composition, ink, thin film, light-emitting device, and display apparatus. Background Technology

[0002] Metal oxides have high electrical conductivity and are therefore often used to prepare carrier functional layers. However, existing metal oxides have a large number of oxygen dangling bonds on their surface, and these bonds are unevenly distributed within the carrier functional layer, resulting in an uneven surface morphology. Summary of the Invention

[0003] To address the aforementioned technical problems, this application provides a light-emitting device, which employs the following technical solution:

[0004] This application provides a composition comprising a polyhydroxy compound and a first metal oxide, wherein the plurality of polyhydroxy compounds are interconnected by hydrogen bonds, and the first metal oxide is coordinated with the polyhydroxy compounds.

[0005] Accordingly, this application also provides a film, the material of which includes the composition of any one of the above embodiments, or is prepared using the ink described in the above embodiments.

[0006] Accordingly, this application also provides a light-emitting device, which includes a first electrode, a light-emitting layer, a charge carrier functional layer and a second electrode stacked in sequence.

[0007] The charge carrier functional layer is the thin film described in any of the above embodiments.

[0008] Accordingly, this application also provides a display device, which includes the light-emitting device described in any of the above embodiments.

[0009] Compared with the prior art, the embodiments of this application have the following main advantages:

[0010] Polyhydroxy compounds can passivate surface defects of the first metal oxide, improve its conductivity, and after coordination with the first metal oxide, can prevent uneven diffusion of the first metal oxide. Attached Figure Description

[0011] To more clearly illustrate the solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of the structure of the thin film containing the first film layer and the second film layer according to an embodiment of this application;

[0013] Figure 2 These are the X-ray luminescent particle energy spectra of four control groups in the embodiments of this application;

[0014] Figure 3 This is a schematic diagram of the structure of the light-emitting device according to an embodiment of this application.

[0015] Figure label:

[0016] Thin film 10, first film layer 11, second film layer 12, light-emitting device 20, anode 100, hole injection layer 200, hole transport layer 300, light-emitting layer 400, first electron transport layer 500, second electron transport layer 600, cathode 700. Detailed Implementation

[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application.

[0018] In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operating state, specifically the orientation shown in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc., are used merely as illustrative purposes and do not impose numerical requirements or establish a numerical order.

[0019] In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0020] In this application, "at least one" means one or more, and "more than one" means two or more. "One or more", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can both mean: a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.

[0021] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0022] To address the aforementioned problems, this application provides a composition comprising a polyhydroxy compound and a first metal oxide, wherein the polyhydroxy compounds are interconnected by hydrogen bonds, and the first metal oxide is coordinated with the polyhydroxy compounds.

[0023] In this embodiment, firstly, when the polyhydroxy compound and the first metal are coordinated, the hydroxyl groups on the polyhydroxy compound can form hydrogen bonds with the undercoordinated oxygen atoms on the first metal oxide to passivate the surface defects of the first metal oxide, thereby improving the conductivity of the first metal oxide and thus improving the external quantum efficiency of the thin film containing the compound.

[0024] Secondly, the polyhydroxy compounds form a network structure through hydrogen bonding. This network structure can encapsulate the first metal oxide, allowing the polyhydroxy compounds to fully contact the first metal oxide, thereby improving the coordination efficiency between the polyhydroxy compounds and the first metal oxide, and thus increasing the passivation of defects. Simultaneously, during the preparation of the thin film, since the first metal oxide and polyhydroxy compounds are not connected, and the polyhydroxy compounds have a large molecular weight, uneven diffusion of the first metal oxide in the thin film can be avoided, thereby improving the morphological uniformity of the film containing the compound, and thus improving the carrier transport efficiency and lifetime of the film. In summary, the composition of this embodiment can improve the lifetime and external quantum efficiency of the thin film.

[0025] Furthermore, the general structural formula of the composition is:

[0026]

[0027] Among them, at least two of R1, R2, R3, R4, R5, and R6 are selected from hydroxyl groups, and the rest are each independently selected from any one of hydrogen, halogen, cyano, nitro, hydroxyl, carboxyl, amino, cyano, isocyano, silyl, phosphoxy, substituted or unsubstituted alkyl, aryl, heterocyclic alkyl, and heterocyclic aryl groups, with substituents being S or O, heteroatoms, the number of heteroatoms being 1 to 2, and the number of main chain skeleton atoms being 1 to 6; A and B are independently selected from any one of C, O, S, N, P, Se, and Te; or,

[0028] When both A and B are selected from C atoms, and at least one of R5 and R6 is selected from hydroxyl groups, at least one of R1, R2, R3, and R4 is a group containing F, O, or N polar atoms.

[0029] In this embodiment, the weight ratio of the polyhydroxy compound to the first metal oxide ensures sufficient coordination between the polyhydroxy compound and the first metal oxide to passivate defects in the first metal oxide. Simultaneously, this weight ratio also allows the polyhydroxy compound to adequately connect to the first metal oxide, preventing uneven movement of the first metal oxide and thus improving the morphological uniformity of the film containing the compound. It should be understood that the weight ratio of the polyhydroxy compound to the first metal oxide can be any value or a range formed by any two of the following: 0.1 wt%, 1 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, and 30 wt%. Within this weight ratio range, the composition can adequately passivate defects in the first metal oxide and ensure sufficient encapsulation by the polyhydroxy compound while maintaining the conductivity of the composition. Optionally, when the weight ratio of the polyhydroxy compound to the first metal oxide is 10 wt% to 20 wt%, the polyhydroxy compound can further adequately encapsulate the first metal oxide.

[0030] Further, the first metal oxide includes one or more of the following, whether doped or undoped: zinc oxide, barium oxide, aluminum oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, zinc lithium oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin sulfide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate; and the doped element includes one or more of the following: aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium; and / or,

[0031] Polyhydroxy compounds include one or more of sorbitol, polyvinyl alcohol, polyethylene glycol, 2-(hydroxymethoxy)ethanol, and fructose. The types of these polyhydroxy compounds are shown in the table below:

[0032] The chemical structural formula of sorbitol is:

[0033]

[0034] The chemical structural formula of polyvinyl alcohol is:

[0035]

[0036] The chemical structural formula of polyethylene glycol is:

[0037]

[0038] The chemical structural formula of 2-(hydroxymethoxy)ethanol is:

[0039]

[0040] The chemical structural formula of fructose is:

[0041]

[0042] In this embodiment, the types of the first metal oxide and the polyhydroxy compound ensure that the compound has high conductivity; at the same time, the molecular weight of the polyhydroxy compound is large enough, and there are enough first metal oxides attached, so that it is not easy for it to move during the formation of the thin film.

[0043] Accordingly, this application also provides an ink comprising the composition of any of the above embodiments.

[0044] In this embodiment, since the ink includes the composition of any of the above embodiments, the film prepared by the ink has a low density and uniform distribution of the first metal oxide defect, uniform film morphology, high external quantum efficiency, and high service life.

[0045] Accordingly, please refer to Figure 1 This application also provides a thin film 10, the material of which includes the compounds of the above embodiments, or is prepared using the inks of the above embodiments.

[0046] In this embodiment, since the material of the thin film 10 includes the compound of the above embodiment, or the thin film 10 is prepared using the ink of the above embodiment, the first metal oxide defect density contained inside it is low and the distribution is uniform, and the thin film 10 has high morphological uniformity, external quantum efficiency and service life.

[0047] Furthermore, the thin film 10 includes a first film layer 11 and a second film layer 12 stacked sequentially. The first film layer 11 is prepared using the ink of the above embodiment. The materials of the first film layer 11 and the second film layer 12 each independently include a second metal oxide. Along the direction from the first film layer 11 to the second film layer 12, the concentration of the second metal oxide in the first film layer 11 gradually increases.

[0048] In this embodiment, the gradual increase in the concentration of the second metal oxide within the first film layer 11 can create a concentration gradient within the first film layer 11. This concentration gradient will ensure that the potential barrier within the first film layer 11 is continuous and unbroken, allowing electrons / holes to smoothly enter the first film layer from the second film layer until they reach the first metal oxide, thereby improving the electron / hole injection efficiency of the thin film 10.

[0049] It should be understood that, please refer to Figure 2 In this embodiment, four control groups are set up. The first control group has a zinc oxide film with a thickness of 30 nm. The second control group has a zinc oxide first film layer of 5 nm (with a concentration gradient) and a second film layer of 25 nm formed by magnetron sputtering. The third control group has a sorbitol-doped zinc oxide film with a thickness of 30 nm and a sorbitol doping ratio of 10%. The fourth control group has a zinc oxide first film layer of 5 nm (with a concentration gradient) and a second film layer of 25 nm formed by magnetron sputtering and a sorbitol doping ratio of 10%.

[0050] The vertical compositional distribution of the composite film was analyzed using depth-of-field X-ray luminescence spectroscopy (XPS). Based on their respective chemical structures, Zn2p and C1s were selected as characteristic elements representing ZnO and organic matter, respectively (characteristic elements of organic matter include not only doped organic molecules but also potentially organic ligands on the ZnO surface, which are not distinguished here). The Zn2p / C1s atomic percentage was measured to represent the distribution of ZnO and organic matter along the vertical gradient, and the results are shown below. Figure 2 As shown in the diagram. The two curves at the top, with atomic ratios close to 0.9 (green and orange), represent the zinc oxide concentration changes in the second and fourth control groups, respectively. This indicates that the zinc oxide concentration gradually increases within the 1–5 nm range (the first film layer), suggesting the formation of a concentration gradient within the first film layer. The two curves close to 0.7, from top to bottom, represent the zinc oxide concentrations in the first and third control groups, respectively. Due to the doping of sorbitol, the zinc oxide concentration in the third control group is lower. The two curves close to 0.3, from top to bottom, represent the organic matter concentrations in the third and first control groups, respectively. The green and orange curves close to 0.1 represent the organic matter concentrations in the second and fourth control groups, respectively.

[0051] Furthermore, the first metal oxide and the second metal oxide are made of the same material; and / or,

[0052] The second film layer 12 is deposited on the surface of the first film layer by magnetron sputtering; and / or,

[0053] The thickness of the first film layer 11 is 3 nm to 15 nm; and / or,

[0054] The thickness of the second film layer 12 is 1 nm to 100 nm.

[0055] In this embodiment, when the first metal oxide and the second metal oxide are the same material, an excessively large potential barrier between the first film layer and the second film layer 12 can be avoided, thereby improving the efficiency of holes / electrons entering the first film layer from the second film layer 12. When the second film layer 12 is deposited by magnetron sputtering, the film formed by magnetron sputtering has high density, thus improving the morphological uniformity of the film and improving the lifespan and external quantum efficiency of the film. At the same time, the first film layer can avoid the plasma impact generated by magnetron sputtering from damaging the underlying film layer (e.g., the light-emitting layer), and can also prevent the second metal oxide from entering the light-emitting layer, causing overcharging of the quantum material in the light-emitting layer, thereby avoiding Auger recombination and improving the lifespan of the light-emitting device. In this embodiment, the thickness of the first film layer 11 allows the second metal oxide to fully penetrate into the interior of the first film layer during the formation of the second film layer 12 by magnetron sputtering, thereby forming an effective concentration gradient. The thickness of the second film layer 12 enables the second film layer 12 to have good carrier transport performance.

[0056] It should be understood that the thickness of the first film layer can be any value or any two values ​​from 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 14nm, and 15nm. The thickness of the second film layer 12 can be any value or any two values ​​from 1nm, 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, and 100nm. The materials of the first film layer 11 and the second film layer 12 can be different, as long as both include metal oxides; for example, the second film layer 12 is tin oxide, and the first film layer 11 is zinc oxide.

[0057] Accordingly, please refer to Figure 3This application also provides a light-emitting device, which includes a light-emitting layer 400, a charge carrier functional layer, a first electrode (anode 100) and a second electrode (cathode 700) disposed opposite to each other, wherein the light-emitting layer is located between the first electrode and the second electrode, and the charge carrier functional layer is located between the light-emitting layer 400 and the second electrode;

[0058] The charge carrier functional layer is any one of the thin films 10 in the above embodiments.

[0059] In this embodiment, because the carrier functional layer in the light-emitting device is the thin film of the above embodiment, its external quantum efficiency and lifetime are high. It should be understood that the carrier functional layer can include at least one of the following: hole injection layer 200, hole transport layer 300, electron injection layer, and electron transport layer. When the thin film 10 includes a first film layer 11 and a second film layer 12, it can also serve as a carrier functional layer; for example, when it serves as an electron transport layer, its structure is as follows... Figure 3 As shown, the light-emitting device includes an anode 100, a hole injection layer 200, a hole transport layer 300, a light-emitting layer 400, an electron transport layer, and a cathode, which are stacked sequentially. The electron transport layer includes a first electron transport layer 500 and a second electron transport layer 600. The first electron transport layer includes sorbitol and a metal oxide.

[0060] Furthermore, the light-emitting device also includes a hole functional layer located between the light-emitting layer 400 and the first electrode. The hole functional layer includes a hole injection layer 200 and / or a hole transport layer 300. The materials of the hole injection layer and the hole transport layer are independently selected from TFB, CuPc, PVK, Poly-TPD, PFB, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, polyaniline, transition metal oxides, transition metal sulfides, transition metal tin compounds, doped graphene, undoped graphene, and C 60 One or more of the following; the material of the hole transport layer is selected from one or more of TFB, PVK, Poly-TPD, PFB, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS and its derivatives, TAPC, MCC, C60; or,

[0061] The light-emitting device further includes an electronic functional layer disposed between the first electrode and the light-emitting layer. The electronic functional layer includes an electron injection layer and / or an electron transport layer, wherein the materials of the electron transport layer and the electron injection layer independently include at least one of inorganic materials and organic materials, respectively. The inorganic material is selected from one or more of the following: doped or undoped zinc oxide, barium oxide, aluminum oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, zinc lithium oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin sulfide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate. Multiple, including one or more of the following elements: aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium; and organic materials including one or more of the following: 4,6-bis(3,5-bis(pyridin-3-yl)phenyl)-2-methylpyrimidine, 2,9-dimethyl-4,7-biphenyl-1,10-o-diazaphenanthroline, 4,7-diphenyl-1,10-phenanthroline, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 8-hydroxyquinoline aluminum, 8-hydroxyquinoline lithium, bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum, and ion-conjugated polyelectrolytes; and / or,

[0062] The material of the light-emitting layer 400 is an organic light-emitting material or a quantum dot light-emitting material; the organic light-emitting materials include one or more of the following: TBPe fluorescent material, TTPX fluorescent material, TBRb fluorescent material, DBP fluorescent material, TADF material, TTA material, polymers containing BN covalent bonds, hybrid local charge transfer excited state materials, excitocomplex light-emitting materials, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, and polyfluorene and its derivatives; the quantum dot light-emitting materials include one or more of the following: single-structure quantum dots, core-shell structure quantum dots, and perovskite semiconductor materials, and the shell of the core-shell structure quantum dots includes one or more layers;The materials for single-structure quantum dots, the core materials for core-shell structure quantum dots, and the shell materials for core-shell structure quantum dots are each independently selected from one or more compounds in groups II-VI, IV-VI, III-V, and I-III-VI. Group II-VI compounds include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, and HgSeTe. One or more of the following compounds: HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe; and group IV-VI compounds including SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, and SnSeT. One or more of e, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe, and III-V compounds including GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, and AlP One or more of Sb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb, and one or more of Group I-III-VI compounds including CuInS2, CuInSe2, and AgInS2;Perovskite semiconductor materials include doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors. Perovskite quantum dot luminescent materials include doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors. The general structural formula of inorganic perovskite semiconductors is AMX3, where A is cesium, M includes one or more of lead, tin, copper, nickel, cadmium, manganese, cobalt, iron, chromium, ytterbium, and europium, and X is a halogen, including one or more of chlorine, bromine, and iodine. The general structural formula of organic-inorganic hybrid perovskite semiconductors is BM'X'3, where B includes CH3(CH2). n-2 NH3 or [NH3(CH2)] n [NH3], where n≥2, M' includes one or more of lead, tin, copper, nickel, cadmium, manganese, cobalt, iron, chromium, ytterbium, and europium, and X' is a halogen, including one or more of chlorine, bromine, and iodine; and / or,

[0063] The first and second electrodes independently comprise doped metal oxide electrodes, composite electrodes, graphene electrodes, carbon nanotube electrodes, elemental metal electrodes, or alloy electrodes. The materials for the doped metal oxide electrodes include one or more of the following: indium-doped tin oxide, zinc-doped tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, magnesium-doped zinc oxide, aluminum-doped magnesium oxide, and cadmium-doped zinc oxide. The composite electrodes include AZO / Ag / AZO, AZO / APC / AZO, ITO / Ag / ITO, ITO / APC / ITO, IZO / Ag / IZO, IZO / APC / IZO, ZnO / Ag / ZnO, ZnO / APC / ZnO, TiO2 / Ag / TiO2, TiO2 / APC / TiO2, ZnS / Ag / ZnS, ZnS / Al / ZnS, Ca / Al, LiF / Ca, LiF / Al, and BaF2 / Al. The materials for the elemental metal electrodes include one or more of Ag, Ni, Pt, Au, Ir, Cu, Mo, Al, Ca, Mg, and Ba, and the alloy electrodes include Au:Mg alloy electrodes or Ag:Mg alloy electrodes.

[0064] Furthermore, the light-emitting device includes an anode 100, a hole injection layer 200, a hole transport layer 300, a light-emitting layer 400, an electron transport layer, an electron injection layer, and a cathode 700, which are sequentially stacked; or,

[0065] The light-emitting device includes a cathode 700, an electron injection layer, an electron transport layer, a light-emitting layer 400, a hole transport layer 300, a hole injection layer 200, and an anode 100, which are stacked in sequence.

[0066] In this embodiment, the carrier functional layer can serve as an electron functional layer and / or a hole functional layer to improve the electron transport efficiency and / or hole transport efficiency of the light-emitting device, thereby improving the external quantum efficiency of the light-emitting device. It should be understood that when the carrier functional layer serves as an electron functional layer, it can include an electron transport layer and / or an electron injection layer; when it serves as a hole functional layer, it can include a hole transport layer 300 and / or a hole injection layer 200. Furthermore, the carrier functional layer can be used in both upright and inverted devices.

[0067] Accordingly, this application also provides a display device, which includes the light-emitting device of any of the above embodiments. In this embodiment, since the light-emitting device in the display device is the light-emitting device of the above embodiments, it has higher external quantum efficiency and lifespan as per the principle of the above embodiments.

[0068] The present application will be specifically described below through specific embodiments. The following embodiments are only some embodiments of the present application and are not intended to limit the present application.

[0069] Example 1

[0070] This application provides a method for fabricating a light-emitting device, the method of which is as follows:

[0071] Step 1, Anode preparation. A substrate with ITO glass is provided. The ITO glass is cleaned and further organic contaminants on the surface of the ITO glass are removed using an ultraviolet ozone cleaner to improve the wettability of the ITO surface. Then, the preform is placed on a 230°C hot plate for drying to form a 50nm thick anode.

[0072] Step 2, preparation of the hole transport layer. A hole transport layer liquid film is formed on the anode. The substrate is transferred to a VCD device (high vacuum circulating drying equipment) for drying. Then, the substrate is placed on a 230°C hot stage for annealing for 30 minutes to form a 50nm thick hole transport layer. The hole transport layer material includes sorbitol molecules and molybdenum oxide. Sorbitol molecules form a network structure, and molybdenum oxide is located in the network structure and coordinated with sorbitol molecules.

[0073] Step 3, Prepare the light-emitting layer. Coat the light-emitting layer solution onto the hole transport layer described above, transfer the substrate to a VCD device for drying, and then anneal it for 10 minutes using a 100°C hot stage to form a 30nm thick light-emitting layer;

[0074] Step 4: Fabrication of the electron transport layer. An electron transport layer liquid film is formed on the above-mentioned light-emitting layer. The substrate is transferred to a VCD device (high vacuum circulating drying equipment) for drying. Then, the substrate is placed on a 230°C hot stage for annealing for 30 minutes to form a 30nm thick electron transport layer. The electron transport layer includes a first electron transport layer and a second electron transport layer stacked sequentially. The first electron transport layer contains sorbitol molecules and zinc oxide, with zinc oxide coordinated to sorbitol molecules. The thickness of the first electron transport layer is 10nm. The second electron transport layer is zinc oxide and is formed by magnetron sputtering to create a concentration gradient in the first electron transport layer.

[0075] Step 5: Prepare the electron injection layer. Print zinc oxide solution onto the electron transport layer to form a 5 nm thick electron injection layer film.

[0076] Step 6, Cathode fabrication. The substrate is transferred to a vacuum evaporation machine, and Al is evaporated onto the light-emitting device to form a 70 nm thick aluminum cathode.

[0077] Example 2

[0078] This embodiment is basically the same as embodiment 1, except that the material of the hole transport layer in step 2 is replaced with oxide.

[0079] Example 3

[0080] This embodiment is basically the same as embodiment 1, except that the electron transport layer in step 4 is replaced with a separate film layer formed by zinc oxide.

[0081] Example 4

[0082] This embodiment is basically the same as Embodiment 1, except that the second electron transport layer in step 4 is omitted.

[0083] Example 5

[0084] This embodiment is basically the same as Embodiment 1, except that the method for forming the second electron transport layer in step 4 is replaced by solution deposition. In this case, the first electron transport layer cannot form a concentration gradient.

[0085] Example 6

[0086] This embodiment is basically the same as embodiment 1, except that the thickness of the first electron transport layer in step 4 is 15nm.

[0087] Example 7

[0088] This embodiment is basically the same as Embodiment 1, except that sorbitol in step 4 is replaced with polyvinyl alcohol.

[0089] Example 8

[0090] This embodiment is basically the same as Embodiment 1, except that the zinc oxide in the second electron transport layer in step 4 is replaced with tin oxide.

[0091] Comparative Example 1

[0092] This embodiment is basically the same as Embodiment 1, except that the material of the hole transport layer in step 2 is replaced with molybdenum oxide alone, and the material of the electron transport layer in step 5 is replaced with zinc oxide alone, and it is a single-layer structure.

[0093] External quantum efficiency and lifetime were tested for Examples 1-8 and Comparative Example 1, wherein:

[0094] The external quantum efficiency was tested using an IVL device to test the performance of the light-emitting devices in Examples 1-8 and Comparative Example 1. The voltage at a current density of 10 mA / cm2 (J10) was used as the driving voltage (gate-on voltage) index, and the external quantum efficiency at a brightness of 1000 cd / m2 was used as the external quantum efficiency index.

[0095] The lifespan test method is as follows: Under constant current (2mA) drive, a 128-channel QLED lifespan test system is used to perform electroluminescence lifespan analysis on each light-emitting device, record the time (T95,h) required for each light-emitting device to decay from maximum brightness to 95%, and calculate the time (T95@1000nit,h) required for each light-emitting device to decay from 100% brightness to 95% brightness at 1000nit using the decay fitting formula.

[0096] The test results are shown in Table 1.

[0097] Table 1:

[0098]

[0099]

[0100] As shown in Table 1:

[0101] As can be seen from Examples 1-3 and Comparative Example 1, firstly, the external quantum efficiency and lifetime of Example 3 are higher than those of Comparative Example 1, and the external quantum efficiency of Example 1 is higher than that of Example 2. This indicates that sorbitol can coordinate with metal oxides, thereby effectively improving the transport efficiency of electrons and holes, and improving the morphological uniformity of the hole transport layer and the electron transport layer, respectively, thereby improving the external quantum efficiency and lifetime of the light-emitting device.

[0102] As can be seen from Examples 1 and 4, the second electron transport layer can promote electron transport and thus eliminate the influence of polyhydroxy compounds, thereby improving the external quantum efficiency and lifespan of the light-emitting device.

[0103] As can be seen from Examples 1 and 5, the second electron transport layer formed by magnetron sputtering has high density, and the zinc oxide contained therein can penetrate into the first film layer to form a zinc oxide concentration gradient, thereby improving the efficiency of electrons entering the light-emitting layer from the second film layer, and thus improving the lifespan and external quantum efficiency of the film.

[0104] As can be seen from Examples 1 and 6, when the thickness of the first electron transport layer is within the thickness range provided in this application, it can ensure that the zinc oxide concentration gradient range within the first electron transport layer is distributed throughout the entire first electron transport layer, thereby improving the electron transport efficiency and thus improving the external quantum efficiency of the light-emitting device.

[0105] As can be seen from Examples 1 and 7-8, the polyhydroxy compounds and metal oxides provided in this application can be coordinated and linked, effectively improving the external quantum efficiency and lifespan of the light-emitting device.

[0106] The light-emitting device, its preparation method, and its display device provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A composition characterized in that, The composition comprises a polyhydroxy compound and a first metal oxide, wherein the polyhydroxy compounds are interconnected by hydrogen bonds and the first metal oxide is coordinated with the polyhydroxy compounds.

2. The composition of claim 1, wherein, The general structural formula of the composition is: Among them, at least two of R1, R2, R3, R4, R5, and R6 are selected from hydroxyl groups, and the rest are each independently selected from any one of hydrogen atom, halogen atom, cyano, nitro, hydroxyl, carboxyl, amino, cyano, isocyano, silyl, phosphoroxy, substituted or unsubstituted alkyl, aryl, heterocyclic alkyl, and heterocyclic aryl groups, the substituent group is S or O, the number of heteroatoms is 1 to 2, and the number of main chain skeleton atoms is 1 to 6; A and B are independently selected from any one of C, O, S, N, P, Se, and Te; or, When both A and B are selected from C atoms, and at least one of R5 and R6 is selected from hydroxyl groups, at least one of R1, R2, R3, and R4 is a group containing F, O, or N polar atoms.

3. The composition of claim 1, wherein, The weight ratio of the polyhydroxy compound to the first metal oxide is 0.1 wt% to 30 wt%, and optionally, the weight ratio of the polyhydroxy compound to the first metal oxide is 10 wt% to 20 wt%.

4. The composition of claim 1, wherein, The first metal oxide includes one or more of the following, whether doped or undoped: zinc oxide, barium oxide, aluminum oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, zinc lithium oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin sulfide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate. The doped element includes one or more of the following: aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium; and / or, The polyhydroxy compounds include one or more of sorbitol, polyvinyl alcohol, polyethylene glycol, 2-(hydroxymethoxy)ethanol, and fructose.

5. Ink, characterized by The ink comprises the composition of any one of claims 1 to 4.

6. A film characterized by, The material of the film includes the compound according to any one of claims 1-4, or is prepared using the ink according to claim 5.

7. The film of claim 6, wherein The thin film includes a first film layer and a second film layer stacked sequentially. The first film layer uses the ink described in claim 5. The materials of the first film layer and the second film layer each independently include a second metal oxide. Along the direction from the first film layer to the second film layer, the concentration of the second metal oxide in the first film layer gradually increases.

8. The film of claim 7, wherein The first metal oxide and the second metal oxide are made of the same material; and / or, The second film layer is deposited on the surface of the first film layer by magnetron sputtering; and / or, The thickness of the first film layer is 3 nm to 15 nm; and / or, The thickness of the second film layer is 1 nm to 100 nm.

9. A light-emitting device, characterized in that, The light-emitting device includes a light-emitting layer, a charge carrier functional layer, and a first electrode and a second electrode disposed opposite to each other, wherein the light-emitting layer is located between the first electrode and the second electrode, and the charge carrier functional layer is located between the light-emitting layer and the second electrode; Wherein, the charge carrier functional layer is the thin film of any one of claims 6 to 8.

10. The light emitting device of claim 9, wherein, The light-emitting device further includes a hole functional layer located between the light-emitting layer and the first electrode. The hole functional layer includes a hole injection layer and / or a hole transport layer. The materials of the hole injection layer and the hole transport layer are independently selected from TFB, CuPc, PVK, Poly-TPD, PFB, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, polyaniline, transition metal oxides, transition metal sulfides, transition metal tin compounds, doped graphene, undoped graphene, and C. 60 One or more of the following; the material of the hole transport layer is selected from one or more of TFB, PVK, Poly-TPD, PFB, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS and its derivatives, TAPC, MCC, C60; or, The light-emitting device further includes an electronic functional layer disposed between the first electrode and the light-emitting layer. The electronic functional layer includes an electron injection layer and / or an electron transport layer, wherein the materials of the electron transport layer and the electron injection layer independently include at least one of inorganic and organic materials, respectively. The inorganic material is selected from doped or undoped zinc oxide, barium oxide, aluminum oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, zinc lithium oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin sulfide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and titanate. One or more of barium, doped with one or more of aluminum, magnesium, lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium; the organic material includes one or more of 4,6-bis(3,5-bis(pyridin-3-yl)phenyl)-2-methylpyrimidine, 2,9-dimethyl-4,7-biphenyl-1,10-o-diazaphenanthroline, 4,7-diphenyl-1,10-phenanthroline, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 8-hydroxyquinoline aluminum, 8-hydroxyquinoline lithium, bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum, and ion-conjugated polyelectrolytes; and / or, The material of the light-emitting layer is an organic light-emitting material or a quantum dot light-emitting material; the organic light-emitting material includes one or more of the following: TBPe fluorescent material, TTPX fluorescent material, TBRb fluorescent material, DBP fluorescent material, TADF material, TTA material, polymers containing BN covalent bonds, hybrid local charge transfer excited state materials, excitocomplex light-emitting materials, 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 the following: single-structure quantum dots, core-shell structure quantum dots, and perovskite semiconductor materials, wherein the shell of the core-shell structure quantum dots comprises one or more layers;The materials of the single-structure quantum dots, the core material of the core-shell structure quantum dots, and the shell material of the core-shell structure quantum dots are each independently selected from one or more of group II-VI compounds, group IV-VI compounds, group III-V compounds, and group I-III-VI compounds. The group II-VI compounds include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, and HgSeT. One or more of the following compounds: e, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe, wherein the group IV-VI compounds include SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, and SnSe. Te, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe, and SnPb, wherein the III-V compound comprises 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, and Al One or more of PSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb, wherein the group I-III-VI 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 perovskite semiconductor material includes doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors. The general structural formula of the inorganic perovskite semiconductor is AMX3, where A is cesium, M includes one or more of lead, tin, copper, nickel, cadmium, manganese, cobalt, iron, chromium, ytterbium, and europium, and X is a halogen, including one or more of chlorine, bromine, and iodine. The general structural formula of the organic-inorganic hybrid perovskite semiconductor is BM'X'3, where B includes CH3(CH2). n-2 NH3 or [NH3(CH2)] n [NH3], where n≥2, M' includes one or more of lead, tin, copper, nickel, cadmium, manganese, cobalt, iron, chromium, ytterbium, and europium, and X' is a halogen, including one or more of chlorine, bromine, and iodine; and / or, The first electrode and the second electrode each independently comprise a doped metal oxide electrode, a composite electrode, a graphene electrode, a carbon nanotube electrode, a metal element electrode, or an alloy electrode. The doped metal oxide electrode is made of one or more of the following materials: indium-doped tin oxide, zinc-doped tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, magnesium-doped zinc oxide, aluminum-doped magnesium oxide, and cadmium-doped zinc oxide. The composite electrode comprises AZO / Ag / AZO, AZO / APC / AZO, ITO / Ag / ITO, ITO / APC / ITO, IZO / Ag / IZO, and I... The electrode material includes one or more of Ag, Ni, Pt, Au, Ir, Cu, Mo, Al, Ca, Mg, and Ba, and the alloy electrode includes an Au:Mg alloy electrode or an Ag:Mg alloy electrode. The electrode material can be ZO / APC / IZO, ZnO / Ag / ZnO, ZnO / APC / ZnO, TiO2 / Ag / TiO2, TiO2 / APC / TiO2, ZnS / Ag / ZnS, ZnS / Al / ZnS, Ca / Al, LiF / Ca, LiF / Al, BaF2 / Al, CsF / Al, CaCO3 / Al, or BaF2 / Ca / Al.

11. The light emitting device of claim 9, wherein, The light-emitting device comprises an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode, which are stacked sequentially; or, The light-emitting device comprises a cathode, an electron injection layer, an electron transport layer, a light-emitting layer, a hole transport layer, a hole injection layer, and an anode, which are stacked in sequence.

12. A display device, characterized by comprising: The display device includes the light-emitting device as described in any one of claims 9 to 11.

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