WO2023202146A1 - Hole transport thin film, photoelectric device and preparation method for photoelectric device - Google Patents

Abstract

Disclosed are a hole transport thin film, a photoelectric device and a preparation method for the photoelectric device. The material of the hole transport thin film comprises a conductive polymer and a first compound having a hole transport group; the content of the first compound in the thickness direction of the hole transport thin film is gradually increased or gradually decreased; the LUMO energy level of the first compound is greater than that of the conductive polymer, so that the aging rate of the thin film is reduced, and the service life of the photoelectric device is prolonged.

Description

Hole transport film, optoelectronic device and preparation method of optoelectronic device

This application claims priority to the Chinese patent application filed with the China Patent Office on April 20, 2022, with the application number 202210419130.3 and the application name "Hole transport film, optoelectronic device and preparation method of optoelectronic device", all of which The contents are incorporated into this application by reference.

Technical field

The present application relates to the field of display technology, and in particular to a hole transport film, an optoelectronic device, and a method for preparing an optoelectronic device.

Background technique

Optoelectronic devices have a wide range of applications in new energy, sensing, communications, display, lighting and other fields, such as solar cells, photodetectors, and organic electroluminescent devices (OLED or quantum dot electroluminescent devices (QLED)).

The structure of a traditional optoelectronic device mainly includes an anode, a hole injection layer, a hole transport film (i.e., a hole transport film), a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode. Under the action of the electric field, the holes generated by the anode and the electrons generated by the cathode of the optoelectronic device move and are injected into the hole transport film and electron transport layer respectively, and finally migrate to the light-emitting layer. When the two meet in the light-emitting layer, an Energy excitons, which excite light-emitting molecules and ultimately produce visible light.

Since hole transport is an organic material and electron transport is an inorganic material, the electron migration efficiency of inorganic nanoparticles is much greater than that of holes, which will cause a large amount of charge to accumulate at the interface between the hole transport film and the light-emitting layer, resulting in a small amount of electrons in the electric field. Under the action, it transitions to the hole transport film to form excitons, which in turn accelerates the aging of the hole transport material and affects the efficiency and life of the optoelectronic device.

Technical solutions

Therefore, this application provides a hole transport film, an optoelectronic device, and a method for preparing an optoelectronic device.

Embodiments of the present application provide a hole transport film. The material of the hole transport film includes a conductive polymer and a first compound. The first compound has a hole transport group. In the direction of film thickness, the content of the first compound gradually increases or decreases, wherein the LUMO energy level of the first compound is greater than the LUMO energy level of the conductive polymer.

Optionally, in some embodiments of the present application, the first compound contains one or more flexible alkyl groups, and the general formula of the first compound is R-A, where R is the flexible alkyl group. group, A is a hole-transporting group that does not contain the flexible alkyl group and correspondingly loses one or more hydrogen atoms, and R and A are connected through a chemical bond.

Optionally, in some embodiments of the present application, the flexible alkyl group is an alkyl group with 1 to 20 carbon atoms.

Optionally, in some embodiments of the present application, the hole transporting group is selected from 4,4'-bis(9-carbazole)biphenyl, N,N'-diphenyl-N, N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine group, 4,4',4"-tris(carbazol-9-yl)triphenylamine group, 9, One or more types of 9-diphenylfluorenyl.

Optionally, in some embodiments of the present application, the first compound is a fluorine-containing compound; and/or the first compound is soluble in aromatic hydrocarbons or aromatic hydrocarbon derivatives; and/or the first compound is The LUMO energy level is greater than -2.5eV.

Optionally, in some embodiments of the present application, the conductive polymer includes a homopolymer of any one of aniline monomer, thiophene monomer or fluorene monomer, or includes aniline monomer, thiophene monomer or A copolymer formed from one or more fluorene monomers.

Optionally, in some embodiments of the present application, the weight percentage of the conductive polymer is 60% to 95%, and the weight percentage of the first compound is 5% to 40%.

Optionally, in some embodiments of the present application, the conductive polymer is polyaniline, the first compound contains one or more flexible alkyl groups, and the general formula of the first compound is R-A , wherein R is the flexible alkyl group, A is 4,4'-bis(9-carbazole)biphenyl, R and A are connected through chemical bonds, wherein some of the hydrogen atoms in the first compound Replaced by fluorine atoms.

Optionally, in some embodiments of the present application, the weight percentage of the conductive polymer is 60%, and the weight percentage of the first compound is 40%; or the weight percentage of the conductive polymer is 95%, The weight percentage of the first compound is 5%; or the weight percentage of the conductive polymer is 20%, and the weight percentage of the first compound is 80%.

Correspondingly, the present application provides an optoelectronic device, including a stacked cathode, a luminescent layer, a hole transport film and an anode. The hole transport film is located between the luminescent layer and the anode. The hole transport film The film is the above-mentioned hole transport film, wherein the content of the first compound in the hole transport film gradually increases in the direction from the anode to the light-emitting layer.

Optionally, in some embodiments of the present application, the thickness of the hole transport film is 10 nm to 50 nm.

Optionally, in some embodiments of the present application, the material quantum dots of the light-emitting layer are selected from one or more of single structure quantum dots and core-shell structure quantum dots; the single structure quantum dots are selected from II -One or more of Group VI compounds, Group III-V compounds and Group I-III-VI compounds; the Group II-VI compound is selected from CdSe, CdS, CdTe, ZnSe, ZnS, CdTe, ZnTe, CdZnS , one or more of CdZnSe, CdZnTe, ZnSeS, ZnSeTe, ZnTeS, CdSeS, CdSeTe, CdTeS, CdZnSeS, CdZnSeTe and CdZnSTe; the III-V compound is selected from InP, InAs, GaP, GaAs, GaSb, AlN , AlP, InAsP, InNP, InNSb, GaAlNP and InAlNP; the I-III-VI group compound is selected from one or more of CuInS ₂ , CuInSe ₂ and AgInS ₂ ; and/or the cathode and the anode The material of the metal electrode is selected from one or more of metal electrodes, carbon electrodes, metal oxide electrodes or composite electrodes, and the material of the metal electrode is selected from Al, Ag, Cu, Mo, Au, Ba, Ca and Mg. One or more; the material of the carbon electrode is selected from one or more of graphite, carbon nanotubes, graphene and carbon fiber; the material of the metal oxide electrode is selected from doped or non-doped ITO , FTO, ATO, AZO, GZO, IZO, MZO and one or more of AMO; the composite electrode is selected from AZO/Ag/AZO, AZO/Al/AZO, ITO/Ag/ITO, ITO/Al/ ITO, ZnO/Ag/ZnO, ZnO/Al/ZnO, TiO ₂ /Ag/TiO ₂ , TiO ₂ /Al/TiO ₂ , ZnS/Ag/ZnS, ZnS/Al/ZnS, TiO ₂ /Ag/TiO ₂ and One or more of TiO ₂ /Al/TiO ₂ .

Optionally, in some embodiments of the present application, the optoelectronic device further includes a hole injection layer located between the hole transport film and the anode, and the hole injection layer The material is selected from one or more of PEDOT: PSS, MCC, CuPc, F4-TCNQ, HATCN, transition metal oxides, and transition metal chalcogenide compounds; and/or the optoelectronic device also includes an electron transport layer, so The electron transport layer is located between the cathode and the light-emitting layer, and the material of the electron transport layer is selected from ZnO, TiO ₂ , SnO ₂ , Ta ₂ O ₃ , ZrO2, NiO, TiLiO, ZnAlO, ZnMgO, ZnSnO, One or more of ZnLiO and InSnO.

Optionally, in some embodiments of the present application, when the optoelectronic device is a bottom-emitting device, the thickness of the cathode is 80 nm to 150 nm; the optoelectronic device is a top-emitting device, and the thickness of the anode is 5 nm to 5 nm. 40nm.

Correspondingly, the present application provides a method for preparing an optoelectronic device, including the following steps: providing a material solution including a conductive polymer and a first compound, the LUMO energy level of the first compound being greater than the LUMO energy level of the conductive polymer. ; Provide an anode, and place the material solution on the anode;

Performing a first heat treatment and a second heat treatment in sequence to obtain a hole transport film, the temperature of the first heat treatment being lower than the temperature of the second heat treatment; forming a luminescent layer on the hole transport film; forming a cathode on the luminescent layer .

Optionally, in some embodiments of the present application, the temperature of the first heat treatment is less than 100°C; and/or the temperature of the second heat treatment is greater than or equal to 100°C and less than or equal to 250°C.

Optionally, in some embodiments of the present application, the temperature of the first heat treatment is 40°C; and/or the temperature of the second heat treatment is 230°C.

Optionally, in some embodiments of the present application, the thickness of the hole transport film is 10 nm to 50 nm.

Optionally, in some embodiments of the present application, after providing the anode, the method includes: forming a hole injection layer on the anode; disposing the material solution on the hole injection layer; and/or Forming a cathode on the light-emitting layer includes: forming an electron transport layer and a cathode on the light-emitting layer.

Optionally, in some embodiments of the present application, the material quantum dots of the light-emitting layer are selected from one or more of single structure quantum dots and core-shell structure quantum dots; the single structure quantum dots are selected from II -One or more of Group VI compounds, Group III-V compounds and Group I-III-VI compounds; the Group II-VI compound is selected from CdSe, CdS, CdTe, ZnSe, ZnS, CdTe, ZnTe, CdZnS , one or more of CdZnSe, CdZnTe, ZnSeS, ZnSeTe, ZnTeS, CdSeS, CdSeTe, CdTeS, CdZnSeS, CdZnSeTe and CdZnSTe; the III-V compound is selected from InP, InAs, GaP, GaAs, GaSb, AlN , AlP, InAsP, InNP, InNSb, GaAlNP and InAlNP; the I-III-VI compound is selected from one or more of CuInS ₂ , CuInSe ₂ and AgInS ₂ ; and/or

The materials of the cathode and the anode are selected from one or more of metal electrodes, carbon electrodes, metal oxide electrodes or composite electrodes, and the materials of the metal electrode are selected from the group consisting of Al, Ag, Cu, Mo, Au, One or more of Ba, Ca and Mg; the material of the carbon electrode is selected from one or more of graphite, carbon nanotubes, graphene and carbon fiber; the material of the metal oxide electrode is selected from doped One or more of doped or non-doped ITO, FTO, ATO, AZO, GZO, IZO, MZO and AMO; the composite electrode is selected from AZO/Ag/AZO, AZO/Al/AZO, ITO/Ag /ITO, ITO/Al/ITO, ZnO/Ag/ZnO, ZnO/Al/ZnO, TiO ₂ /Ag/TiO ₂ , TiO ₂ /Al/TiO ₂ , ZnS/Ag/ZnS, ZnS/Al/ZnS, TiO ₂ /Ag/TiO ₂ and one or more of TiO ₂ /Al/TiO ₂ ; and/or the material of the hole injection layer is selected from PEDOT:PSS, MCC, CuPc, F4-TCNQ, HATCN, transition One or more of metal oxides and transition metal chalcogenide compounds; and/or the material of the electron transport layer is selected from ZnO, TiO ₂ , SnO ₂ , Ta ₂ O ₃ , ZrO2, NiO, TiLiO, ZnAlO, One or more of ZnMgO, ZnSnO, ZnLiO, and InSnO.

Description of the drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, other drawings can also be obtained based on these drawings without exerting creative efforts.

Figure 1 is a schematic structural diagram of an optoelectronic device provided by an embodiment of the present application;

Figure 2 is a schematic flow chart of a method for preparing an optoelectronic device provided by an embodiment of the present application;

Figure 3 is a schematic diagram of energy levels of each functional layer of an optoelectronic device provided by an embodiment of the present application;

Figure 4 is a schematic diagram of energy levels of each functional layer of an optoelectronic device provided by another embodiment of the present application;

Figure 5 is a schematic diagram of energy levels of each functional layer of an optoelectronic device provided by another embodiment of the present application;

FIG. 6 is a schematic diagram of energy levels of each functional layer of an optoelectronic device according to yet another embodiment of the present application.

Implementation Mode of this Application

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the scope of protection of this application.

In addition, it should be understood that the specific embodiments described here are only used to illustrate and explain the application, and are not used to limit the application. In this application, unless otherwise specified, the directional words used such as "upper" and "lower" specifically refer to the direction of the drawing in the drawings. In addition, in the description of this application, the term "including" means "including but not limited to." Various embodiments of the present application may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and simplicity and should not be understood as a hard limit to the scope of the present application; therefore, the described scope should be considered The description has specifically disclosed all possible subranges as well as the single numerical values within that range. For example, a description of a range from 1 to 6 should be considered to have specifically disclosed subranges, 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 A single number within the stated range, such as 1, 2, 3, 4, 5, and 6, applies regardless of the range. Additionally, whenever a numerical range is indicated herein, it is intended to include any cited number (fractional or whole) within the indicated range.

In this application, "and/or" describes the association of associated objects, indicating that there can be three relationships, for example, A and/or B, which can mean: A exists alone, A and B exist simultaneously, and B exists alone. Condition. Where A and B can be singular or plural.

In this application, "at least one" means one or more, and "plurality" means two or more. "At least one", "at least one of the following" or similar expressions thereof refers to any combination of these items, including any combination of a single item (items) or a plurality of items (items). For example, "at least one of a, b, or c", or "at least one of a, b, and c" can mean: a, b, c, a-b ( That is, a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple respectively.

Among them, the present application provides a hole transport film 10, which is mainly used in an optoelectronic device 100. Please refer to Figure 1. Figure 1 is a schematic structural diagram of an optoelectronic device 100 provided by an embodiment of the present application. The optoelectronic device 100 includes layers stacked in sequence. The cathode 20, the light-emitting layer 30, the hole transport film 10 and the anode 40.

Among them, the material of the hole transport film 10 includes a conductive polymer and a first compound. The LUMO (Lowest Unoccupied Molecular Orbital, lowest unoccupied molecular orbital) energy level of the first compound is greater than the LUMO energy level of the conductive polymer. During hole transport, In the direction of the film thickness of the film 10, the content of the first compound gradually increases or decreases.

In the example of FIG. 1 , the content of the first compound gradually increases in the thickness direction of the hole transport film 10 from bottom to top.

The above-mentioned hole transport film 10, the material of the hole transport film 10 includes a conductive polymer and a first compound, the first compound has a hole transport group, in the direction of the film thickness of the hole transport film 10, the first compound The content gradually increases or decreases, wherein the LUMO energy level of the first compound is greater than the LUMO energy level of the conductive polymer, because the LUMO energy level of the first compound is greater than the LUMO energy level of the conductive polymer, and In the direction of the film thickness of the hole transport film 10, the content of the first compound gradually increases or decreases, so that after further heat treatment of the hole transport film 10 as a whole, the hole transport film 10 as a whole becomes smaller along the thickness direction due to The content of the first compound contained is relatively high, so the energy level on this side is higher and has a shallow energy level. At the same time, the other side of the entire hole transport film 10 along the thickness direction contains a relatively low content of the first compound. Therefore, the energy level corresponding to this side is lower and has a deep energy level, that is, the energy level of the hole transport film 10 as a whole along the thickness direction changes to a gradient state. Therefore, when electrons move from the shallow energy level side of the hole transport film 10 When entering, due to the energy level difference between the two sides of the hole transport film 10 along the thickness direction, electrons cannot enter the hole transport film 10 , that is, they cannot make a transition to the other side of the hole transport film 10 , thus causing the above-mentioned holes to enter. When the hole transport film 10 is used in the hole transport film 10 of an optoelectronic device, it can greatly reduce the number of electrons that jump to the hole transport film 10 to form excitons under the action of an electric field, thereby reducing the aging rate of the hole transport film 10. The life of the optoelectronic device 100 is improved.

Among them, in some embodiments of the present application, the first compound contains a flexible alkyl group. The number of flexible alkyl groups contained in the first compound may be one or multiple. By adding a flexible alkyl group to the first compound The group can greatly enhance the solubility of the first compound, laying the foundation for subsequent preparation of the hole transport film 10 using a solution method.

Among them, the above-mentioned first compound belongs to a small molecule compound, and the conductive polymer belongs to a high molecular polymer.

Among them, the soluble first compound is obtained by converting insoluble small molecules and adding flexible groups. The flexible groups usually include multi-carbon chain groups and double bond groups.

In this embodiment, the first compound contains a flexible alkyl group.

In one embodiment, the general formula of the first compound is R-A, where R is a flexible alkyl group, and A is a hole transporting group that does not contain a flexible alkyl group and correspondingly loses one or more hydrogen atoms, R and A are connected through chemical bonds, wherein the corresponding position in A that loses one or more hydrogen atoms is used to connect the corresponding flexible alkyl group.

In one embodiment, the above-mentioned A is 4,4'-bis(9-carbazole)biphenyl, and the position marked "*" in the following corresponding structural formula is used to connect the corresponding flexible alkyl group, The corresponding structural formula is as follows:

Or for:

In another embodiment, the above-mentioned A is N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine, and the corresponding structure is The site marked with "*" in the formula is used to connect the corresponding flexible alkyl group, and the corresponding structural formula is as follows:

Or for:

Also available for:

In yet another embodiment, the above-mentioned A is 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline], and the position marked "*" in the corresponding structural formula is used Connect the corresponding flexible alkyl group, and the corresponding structural formula is as follows:

Furthermore, the above-mentioned A can also use 4,4',4"-tris(carbazol-9-yl)triphenylamine, and the position marked "*" in the corresponding structural formula is used to connect the corresponding flexible alkyl group Group, the corresponding general structural formula is as follows:

In addition, the above-mentioned A can also use 9,9-diphenylfluorene, and the corresponding general structural formula is as follows:

Or for:

Among them, in the above embodiments, the above-mentioned flexible alkyl group is usually placed at a position where a hydrogen atom is lost in the para-position or meta-position of any benzene ring in the above-mentioned general structural formula. For simplicity of explanation, the above-mentioned general structural formulas only shows the corresponding general structural formula when the site in A loses only one hydrogen atom. When the first compound has multiple corresponding flexible alkyl groups, A corresponds to the loss of multiple hydrogen atoms. For multiple sites, the corresponding principle can be referred to the situation when only one hydrogen atom is lost in the site in A, which will not be described again here.

Wherein, in some embodiments of the present application, the flexible alkyl group is an alkyl group with 1 to 20 carbon atoms.

Among them, the number of carbon atoms should not be too many, otherwise the molecular weight of the flexible alkyl group will be too large, which will lead to the molecular weight of the first compound being larger.

In some embodiments of the present application, the first compound is a fluorine-containing compound.

Among them, due to the large electronegativity of fluorine atoms, small atomic radius, short C-F bond, and bond energy as high as 500kJ/mol, adjacent fluorine atoms repel each other, so that the fluorine atoms are not in the same plane, but are distributed in a spiral along the carbon chain. Especially in a perfluorocarbon chain, the sum of the van der Waals radii of two fluorine atoms is about 0.27nm, basically surrounding and filling the C-C-C bond. This almost void-free space barrier prevents any atoms or groups from entering and destroying the C-C bond. Therefore, during the film formation process, the fluorine-containing compound tends to be enriched at the interface between the hole transport film 10 and the air (the side close to the light-emitting layer), and stretches into the air, so the hole transport film 10 is formed from the bottom layer (closer to the light-emitting layer). Gradient molecular structure from the side of the hole injection layer) to the top layer (the side close to the light-emitting layer). The closer to the bottom layer, the greater the content of the conductive polymer, and the closer to the top layer, the greater the content of the first compound.

That is to say, since the fluorine-containing compound has a lower surface energy, when the conductive polymer and the first compound are used to prepare the hole transport film 10, the first compound can migrate to the upper side of the hole transport film 10 more easily. and aggregation. Naturally, the conductive polymer compound can easily migrate and aggregate to the lower side of the hole transport film 10, eventually causing the hole transport film 10 to form a layer, that is, one side of the hole transport film 10 is laminated with the first The other side of the hole transport film 10 is mainly composed of conductive polymers. In this way, both sides of the hole transport film 10 have different energy levels. One side has a shallow energy level, and the other side has a shallow energy level. One side has deep energy levels.

In this embodiment, by further replacing the hydrogen atoms in the first compound with fluorine atoms, the first compound becomes a fluorine-containing compound, which further helps the hole transport film 10 to form shallow energy on both sides of the film thickness. level and deep energy level, that is, there is an energy level difference on both sides of the hole transport film 10 in the thickness direction.

In some embodiments of the present application, the first compound is soluble in aromatic hydrocarbons or aromatic hydrocarbon derivatives.

Among them, aromatic hydrocarbons and aromatic hydrocarbon derivatives are polymer solvents with high boiling points. Select aromatic hydrocarbons and aromatic hydrocarbon derivatives as solvents, and select the first compound that is soluble in aromatic hydrocarbons or aromatic hydrocarbon derivatives to help with subsequent holes. The transmission film is prepared to avoid evaporation of aromatic hydrocarbon compounds at high temperatures.

In some embodiments of the present application, the LUMO energy level of the first compound is greater than -2.5 eV.

Among them, on the upper side of the hole transport film 10 mainly composed of the first compound, the LUMO energy level corresponding to the first compound usually has a shallow energy level, that is, the LUMO energy level is usually greater than -2.5eV, which can be used for conductive polymerization. A larger energy level difference is formed on the other side of the material-based hole transport film 10, which is more helpful to reduce the number of excitons formed by electrons jumping to the hole transport film under the action of the electric field.

Wherein, in some embodiments of the present application, the conductive polymer includes a homopolymer of any one of aniline monomer, thiophene monomer or fluorene monomer, or includes at least one of aniline monomer, thiophene monomer or fluorene monomer. A copolymer.

In some embodiments of the present application, the weight percentage of the conductive polymer is 60% to 95%, and the weight percentage of the first compound is 5% to 40%.

Among them, if the weight percentage of the first compound is too low, it will be difficult to form an energy level difference on both sides of the hole transport film 10 in the thickness direction, reducing the number of electrons that jump to the hole transport film to form excitons under the action of the electric field. The effect of reducing the aging rate of the hole transport film is not obvious. Usually, the minimum weight percentage of the first compound is 5%, and at this time, the weight percentage of the conductive polymer is 95%.

If the weight percentage of the first compound is too high, the conductive polymer content is too low, which will cause the hole mobility in the hole transport film 10 to be too low. Therefore, the minimum weight percentage of the conductive polymer is 60 %, at this time, the weight percentage of the first compound is 40%.

Referring to FIG. 1 , an embodiment of the present application also provides an optoelectronic device 100 . The optoelectronic device 100 includes a cathode 20 , a luminescent layer 30 , a hole transport film 10 and an anode 40 stacked in sequence.

The material of cathode 20 is a material known in the art for cathodes, and the material of anode 40 is a material known in the art for anodes. The materials of the cathode 20 and the anode 40 may be, for example, one or more of metals, carbon materials, and metal oxides. The metal may be, for example, one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, and Mg. A variety of; carbon materials can be, for example, one or more of graphite, carbon nanotubes, graphene, and carbon fibers; metal oxides can be doped or non-doped metal oxides, including ITO, FTO, ATO, AZO, One or more of GZO, IZO, MZO and AMO, including composite electrodes with metal sandwiched between doped or non-doped transparent metal oxides. Composite electrodes include but are not limited to AZO/Ag/AZO, AZO /Al/AZO, ITO/Ag/ITO, ITO/Al/ITO, ZnO/Ag/ZnO, ZnO/Al/ZnO, TiO ₂ /Ag/TiO ₂ , TiO ₂ /Al/TiO ₂ , ZnS/Ag/ZnS , one or more of ZnS/Al/ZnS, TiO ₂ /Ag/TiO ₂ and TiO ₂ /Al/TiO ₂ . The thickness of the cathode 20 is a cathode thickness known in the art, for example, it can be 10 nm to 200 nm, such as 10 nm, 35 nm, 50 nm, 80 nm, 120 nm, 150 nm, 200 nm, etc.; the thickness of the anode 40 is an anode thickness known in the art, for example It can be 10nm to 200nm, such as 10nm, 50nm, 80nm, 100nm, 120nm, 150nm, 200nm, etc.

The light-emitting layer 30 may be a quantum dot light-emitting layer, and in this case, the optoelectronic device 100 may be a quantum dot optoelectronic device. The thickness of the luminescent layer 30 can be within the thickness range of the luminescent layer in quantum dot optoelectronic devices known in the art, for example, it can be 5 nm to 100 nm, such as 5 nm, 10 nm, 20 nm, 50 nm, 80 nm, 100 nm, etc.; or it can be 60 nm to 100 nm. .

The material of the quantum dot light-emitting layer is the quantum dots known in the art to be used in the quantum dot light-emitting layer, for example, one of red quantum dots, green quantum dots and blue quantum dots. The quantum dots may be selected from, but are not limited to, at least one of single structure quantum dots and core-shell structure quantum dots. For example, the quantum dots can be selected from at least one of, but not limited to, II-VI compounds, III-V compounds and I-III-VI compounds; the II-VI compounds are selected from CdSe, CdS, CdTe, At least one of ZnSe, ZnS, CdTe, ZnTe, CdZnS, CdZnSe, CdZnTe, ZnSeS, ZnSeTe, ZnTeS, CdSeS, CdSeTe, CdTeS, CdZnSeS, CdZnSeTe and CdZnSTe; the III-V compound is selected from InP, InAs, GaP, GaAs, GaSb, AlN, AlP, InAsP, InNP, InNSb, GaAlNP and InAlNP; the I-III-VI compound is at least one selected from CuInS ₂ , CuInSe ₂ and AgInS ₂ .

For the hole transport film 10, reference can be made to the relevant descriptions above, which will not be repeated here. In the direction from the anode 40 to the light-emitting layer 30, the content of the first compound in the hole transport film 10 gradually increases.

Referring further to FIG. 1 , in one embodiment, the optoelectronic device 100 may further include a hole injection layer (HIL) 50 . The hole injection layer 50 is located between the hole transport film 10 and the anode 40 . The material of the hole injection layer 50 can be selected from materials with hole injection capabilities, including but not limited to one of PEDOT: PSS, MCC, CuPc, F4-TCNQ, HATCN, transition metal oxides, and transition metal chalcogenide compounds. Kind or variety. PEDOT:PSS is a high molecular polymer, and its Chinese name is poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid).

Referring further to FIG. 1 , in an embodiment, the optoelectronic device 100 may further include an electron transport layer 60 , and the electron transport layer 60 is located between the cathode 20 and the light-emitting layer 30 . The electron transport layer 60 may be an oxide semiconductor nanomaterial with electron transport capability. The oxide semiconductor nanomaterial may be selected from, but not limited to, ZnO, TiO ₂ , SnO ₂ , Ta ₂ O ₃ , ZrO2, NiO, TiLiO, ZnAlO, and ZnMgO. , at least one of ZnSnO, ZnLiO and InSnO.

It can be understood that in addition to the above functional layers, the optoelectronic device 100 can also add some functional layers that are commonly used in optoelectronic devices and help improve the performance of the optoelectronic device, such as electron blocking layers, hole blocking layers, electron injection layers, and interface modifications. layer etc. It can be understood that the materials and thickness of each layer of the optoelectronic device 100 can be adjusted according to the lighting requirements of the optoelectronic device 100 .

In some embodiments of the present application, the optoelectronic device 100 is a quantum dot light-emitting diode, and the structure may be a glass substrate-anode-(hole injection layer)-hole transport film-quantum dot light-emitting layer-electron transport layer-cathode. Among them, the hole injection layer is optional, and the hole injection layer may or may not be included in the quantum dot light-emitting diode structure.

Optionally, in some embodiments of the present application, the thickness of the hole transport film 10 is 10 nm to 50 nm.

Correspondingly, this application also provides a method for manufacturing an optoelectronic device. Please refer to Figure 2. Figure 2 is a schematic flow chart of a method for manufacturing an optoelectronic device provided by an embodiment of the application. The preparation method includes the following steps:

Step S110: Provide a material solution including a conductive polymer and a first compound, where the LUMO energy level of the first compound is greater than the LUMO energy level of the conductive polymer.

Wherein, it is usually necessary to prepare a material solution of the conductive polymer and the first compound. For example, the conductive polymer and the first compound can be dissolved using a conventional organic solvent, such as toluene, chlorobenzene, cyclohexylbenzene, and methyl benzoate. , ethyl benzoate, anisole, aromatic hydrocarbons and aromatic hydrocarbon derivatives, etc., and the solvent can be a single type, or a mixed solvent formed by two or more different solvents.

In this embodiment, the order in which the conductive polymer, the first compound and the solvent are added is not limited, as long as the three can be fully mixed to obtain a polymer solution.

Step S120: Provide an anode and place the material solution on the anode.

The anode substrate can be a commonly used substrate, for example, it can be a rigid substrate made of glass; it can also be a flexible substrate made of polyimide. The material of the anode can be, for example, one or more of metals, carbon materials, and metal oxides. The metal can be, for example, one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, and Mg; carbon The material can be, for example, one or more of graphite, carbon nanotubes, graphene, and carbon fiber; the metal oxide can be doped or non-doped metal oxides, including ITO, FTO, ATO, AZO, GZO, IZO, One or more of MZO and AMO, including composite electrodes with metal sandwiched between doped or non-doped transparent metal oxides. Composite electrodes include but are not limited to AZO/Ag/AZO, AZO/Al/AZO , ITO/Ag/ITO, ITO/Al/ITO, ZnO/Ag/ZnO, ZnO/Al/ZnO, TiO ₂ /Ag/TiO ₂ , TiO ₂ /Al/TiO ₂ , ZnS/Ag/ZnS, ZnS/Al /ZnS, TiO ₂ /Ag/TiO ₂ and one or more of TiO ₂ /Al/TiO ₂ . In another embodiment, an anode and a hole injection layer are provided in a stacked arrangement, and a hole transport film including a conductive polymer and a first compound is arranged on the hole injection layer.

Among them, during the film formation process when the material solution including the conductive polymer and the first compound is placed on the anode, due to the lighter molecular weight of the first compound, the first compound can more easily migrate to the upper side of the hole transport film. and aggregation. Naturally, the conductive polymer compound can easily migrate and aggregate to the lower side of the hole transport film, eventually causing the hole transport film to form a layer, that is, one side of the hole transport film is dominated by the first compound. , the other side of the hole transport film is dominated by conductive polymer. In other words, in the direction of the thickness of the hole transport film finally formed, the content of the first compound gradually increases or decreases, and the LUMO of the first compound The energy level is greater than the LUMO energy level of the conductive polymer. The higher the content of the first compound, the higher the energy level at the corresponding position. In this way, both sides of the hole transport film have different energy levels, where One side has a shallow energy level, and the corresponding other side has a deep energy level.

For the conductive polymer and the first compound in this embodiment, reference can be made to the relevant descriptions in the above embodiments and will not be described again here.

Specifically, a solution method may be used to dispose the material solution including the conductive polymer and the first compound on the anode. The solution method includes but is not limited to spin coating, drip coating, coating, inkjet printing, blade coating, dipping and pulling, soaking, spray coating, roller coating, evaporation or casting, etc. The wet film is prepared by the solution method.

Step S130, perform first heat treatment and second heat treatment in sequence to obtain a hole transport film, and the temperature of the first heat treatment is lower than the temperature of the second heat treatment.

Among them, the wet film on the anode can be first subjected to a first heat treatment to volatilize the organic solvent in the wet film to form a hole transport film, and then the hole transport film can be subjected to a second heat treatment. The temperature of the first heat treatment is lower than that of the second heat treatment. temperature, the second heat treatment is used to eliminate the residual stress inside the hole transport film, thereby reducing the risk of layer deformation and cracks in the hole transport film. For example, the temperature of the first heat treatment can be less than 100°C, such as 95°C, 80°C, 70°C, 60°C, 50°C, 40°C, etc. The higher the temperature, the faster the wet film will dry. Vacuum can also be performed at normal temperature. dry. The temperature of the second heat treatment may be between 100°C and 250°C. For example, the temperature of the second heat treatment may be 100°C, 130°C, 160°C, 180°C, 200°C, 220°C, 240°C, 250°C, etc. It can be understood that the second heat treatment can be an annealing process, which includes sequential heating, holding and cooling processes. For example, the dry hole transport film is heated to 220°C and kept for 30 minutes, and then heated at a speed of 5°C/min. Cool to room temperature.

Step S140, forming a light-emitting layer on the hole transport film.

Step S150, forming a cathode on the light-emitting layer.

In this embodiment, by providing a material solution including a conductive polymer and a first compound, the LUMO energy level of the first compound is greater than the LUMO energy level of the conductive polymer, an anode is provided, the material solution is placed on the anode, and the steps are performed in sequence The first heat treatment and the second heat treatment are to obtain a hole transport film. The temperature of the first heat treatment is lower than the temperature of the second heat treatment. Among them, due to the lighter molecular weight of the first compound, the first compound can more easily transfer to the hole transport film. Naturally, the conductive polymer compound can migrate and aggregate to the lower side of the hole transport film more easily, eventually causing the hole transport film to form layers, that is, one side of the hole transport film starts with the first The other side of the hole transport film is dominated by conductive polymers.

In other words, in the final optoelectronic device, the content of the first compound in the hole transport film gradually increases or decreases in the direction of the film thickness, and the LUMO energy level of the first compound is greater than the LUMO of the conductive polymer. Energy level. The higher the content of the first compound, the higher the energy level at the corresponding position. In this way, both sides of the hole transport film have different energy levels. One side has a shallow energy level, and the corresponding other side has a shallow energy level. One side has a deep energy level, and the increase in the LUMO energy level on the top layer of the hole transport film increases the difficulty for electrons to transition from the light-emitting layer to the hole transport film, thereby reducing the aging rate of the hole transport film and thereby improving the performance of optoelectronic devices. life.

It can be understood that when the optoelectronic device further includes a hole injection layer, step S120 is: providing an anode, sequentially forming stacked hole injection layers on the anode, and disposing the material solution on the hole injection layer. Further, when the optoelectronic device further includes an electron transport layer, step S150 is: forming an electron transport layer and a cathode on the light-emitting layer.

Among them, if the optoelectronic device is a bottom-emitting device, the thickness of the cathode electrode is 80nm~150nm, and if the optoelectronic device is a top-emitting device, the thickness of the anode electrode is 5nm~40nm.

It can be understood that when the optoelectronic device further includes other functional layers such as an electron blocking layer, a hole blocking layer, an electron injection layer, and/or an interface modification layer, the method for preparing the optoelectronic device further includes the step of forming each of the functional layers.

It should be noted that the anode, luminescent layer, cathode and other functional layers in this application can all be prepared using conventional techniques in the art, including but not limited to solution methods and deposition methods. The solution methods include but are not limited to spin coating, Coating, inkjet printing, scraping, dipping, soaking, spraying, roller coating or casting; deposition methods include chemical methods and physical methods. Chemical methods include but are not limited to chemical vapor deposition, continuous ion layer adsorption and reaction method, anodizing method, electrolytic deposition method or co-precipitation method. Physical methods include but are not limited to thermal evaporation coating method, electron beam evaporation coating method, magnetron sputtering method, multi-arc ion coating method, physical vapor deposition method, atomic layer deposition method or pulsed laser deposition method. When the solution method is used to prepare the anode 40, the luminescent layer, the cathode and other functional layers, a drying process needs to be added.

It can be understood that the preparation method of the optoelectronic device can also include a packaging step. The packaging material can be acrylic resin or epoxy resin. The packaging can be machine packaging or manual packaging. UV curing glue can be used. The environment in which the packaging step is performed contains oxygen. The concentrations of water and water are both lower than 0.1ppm to ensure the stability of photovoltaic devices.

Optionally, in some embodiments of the present application, the temperature of the first heat treatment is less than 100°C.

The temperature of the first heat treatment is less than 100° C., which helps the first compound to migrate and accumulate to the upper side of the hole transport film more easily.

Optionally, in some embodiments of the present application, the temperature of the second heat treatment is greater than or equal to 100°C and less than or equal to 250°C.

The temperature of the second heat treatment is set at 100°C to 250°C, which is helpful for thermal curing of the hole transport film.

In this embodiment, the thickness of the finally formed hole transport film can be controlled and adjusted by controlling and adjusting the solution concentration and other conditions used in the solution method. The thickness of the hole transport film may range from 10 to 50nm, such as 10nm, 15nm, 20nm, 25nm, 30nm, 40nm, 50nm, etc. Taking spin coating as an example, the thickness of the hole transport film can be controlled by adjusting the concentration of the solution, the spin coating speed and the spin coating time.

Correspondingly, embodiments of the present application also provide a display device, including the optoelectronic device 100 provided by the present application. The display device can be any electronic product with a display function. Electronic products include but are not limited to smartphones, tablets, laptops, digital cameras, digital camcorders, smart wearable devices, smart weighing scales, vehicle monitors, and televisions. Or an e-book reader, wherein the smart wearable device can be, for example, a smart bracelet, a smart watch, or a virtual reality (Virtual Reality). An embodiment of the present application also provides a method for preparing an optoelectronic device 100, including the step of preparing a hole transport film. , prepare a hole transport film using the preparation method shown in step S31 to step S33.

The technical solutions and technical effects of the present application will be described in detail below through specific examples, comparative examples and experimental examples. The following examples are only some examples of the present application and do not specifically limit the present application.

Example 1

This embodiment provides a quantum dot light-emitting diode and a preparation method thereof. The structural composition of the quantum dot light-emitting diode is shown in Figure 1. The quantum dot light-emitting diode of this embodiment includes a cathode 20 and an electron transport layer that are stacked sequentially from top to bottom. 60. Light-emitting layer 30, hole transport film 10, hole injection layer 50 and anode 40.

The materials of each layer structure in quantum dot light-emitting diodes are:

The material of the cathode 20 is Al.

The material of the electron transport layer 60 is Zn _0.7 Mg _0.3 O.

The material of the light-emitting layer 30 is nano-ZnS.

The material of the hole transport film 10 is: including the conductive polymer (95% wt) of the present application and the first compound (5% wt), wherein the conductive polymer is polyaniline and the first compound contains flexible alkyl groups. 4,4'-bis(9-carbazole)biphenyl, some H atoms are replaced by fluorine atoms.

The material of the hole injection layer 50 is PEDOT:PSS.

The anode 40 is made of ITO with a thickness of 100 nm, and a glass substrate is provided on one side of the anode 40 .

The preparation method of quantum dot light-emitting diodes in this embodiment includes the following steps:

Materials for preparing the hole transport film 10: The conductive polymer and the first compound are dissolved in aromatic hydrocarbons to obtain a hole transport material solution.

Anode 40 is prepared on a glass substrate.

PEDOT:PSS was spin-coated on the side of the anode 40 away from the glass substrate at a rotation speed of 5000 rpm for 30 seconds, and then annealed at 200° C. for 15 minutes to obtain the hole injection layer 50 .

The hole transport material solution was spin-coated on the side of the hole injection layer 50 away from the anode 40 at a rotation speed of 3000 rpm for 30 seconds, followed by drying at 40°C and annealing at 230°C to obtain the hole transport film 10 .

CdZnSe quantum dots are spin-coated on the side of the hole transport film 10 away from the hole injection layer 50 , and then annealed to obtain the light-emitting layer 30 .

Zn _0.9 Mg _0.1 O is spin-coated on the side of the light-emitting layer 30 away from the hole transport film 10 , and then annealed to obtain the electron transport layer 60 .

The Al cathode 20 is prepared by evaporation on the side of the electron transport layer 60 away from the light-emitting layer 30 .

Among them, after the heat treatment of the hole transport film 10 is completed, the LUMO energy level becomes a gradient energy level, and on the side close to the light-emitting layer 30, the LUMO energy level of the hole transport film 10 can reach -2.1 eV. Please refer to Figure 3 for the energy level diagram.

Example 2

This embodiment provides a quantum dot light-emitting diode and a preparation method thereof. Compared with the quantum dot light-emitting diode of Embodiment 1, the only difference between the quantum dot light-emitting diode of this embodiment is the material of the hole transport film 10 It is: containing the conductive polymer of the present application (80% wt) and the first compound (20% wt).

Among them, after the heat treatment of the hole transport film 10 is completed, the LUMO energy level becomes a gradient energy level, and on the side close to the light-emitting layer 30, the LUMO energy level of the hole transport film 10 can reach -1.6 eV. Please refer to Figure 4 for the energy level diagram.

Example 3

This embodiment provides a quantum dot light-emitting diode and a preparation method thereof. Compared with the quantum dot light-emitting diode of Embodiment 1, the only difference between the quantum dot light-emitting diode of this embodiment is the material of the hole transport film 10 It is: containing the conductive polymer of the present application (60% wt) and the first compound (40% wt).

Among them, after the heat treatment of the hole transport film 10 is completed, the LUMO energy level becomes a gradient energy level, and on the side close to the light-emitting layer 30, the LUMO energy level of the hole transport film 10 can reach -1.3 eV. Please refer to Figure 5 for the energy level diagram.

Comparative ratio

This embodiment provides a quantum dot light-emitting diode and a preparation method thereof. Compared with the quantum dot light-emitting diode of Embodiment 1, the only difference between the quantum dot light-emitting diode of this embodiment is the material of the hole transport film 10 For: containing the conductive polymer of this application, please see Figure 6 for the energy level diagram.

Analyzing with reference to Figures 3 to 6, in Example 1, the LUMO energy level of the hole transport film 10 is increased from -3.7eV to -2.1eV, so that the LUMO energy level difference between the hole transport film 10 and the light-emitting layer increases to 2.0 eV; In Example 2, the LUMO energy level of the hole transport film 10 is increased from -3.7eV to -1.6eV, so that the LUMO energy level difference between the hole transport film 10 and the light-emitting layer is increased to 2.5eV; in Example 3, The LUMO energy level of the hole transport film 10 is increased from -3.7eV to -1.3eV, which increases the LUMO energy level difference between the hole transport film 10 and the light-emitting layer to 2.8eV.

Obviously, as the proportion of the first compound gradually increases, the LUMO energy level difference between the hole transport film 10 and the light-emitting layer increases, which increases the difficulty for electrons to transition from the light-emitting layer to the hole transport film, thereby reducing the aging of the hole transport film. rate, thereby improving the life of optoelectronic devices.

The hole transport films, optoelectronic devices, optoelectronic device preparation methods and display devices provided by the embodiments of the present application have been introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The above embodiments The description is only used to help understand the method and core ideas of the present application; at the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the ideas of the present application. In summary, , the content of this description should not be understood as a limitation of this application.

Claims (20)

1. A hole transport film, wherein the material of the hole transport film includes a conductive polymer and a first compound, the first compound has a hole transport group, where the film thickness of the hole transport film is direction, the content of the first compound gradually increases or gradually decreases, wherein the LUMO energy level of the first compound is greater than the LUMO energy level of the conductive polymer.
2. The hole transport film according to claim 1, wherein the first compound contains one or more flexible alkyl groups, the general formula of the first compound is R-A, wherein R is the flexible alkyl group Group, A is a hole-transporting group that does not contain the flexible alkyl group and correspondingly loses one or more hydrogen atoms, and R and A are connected through a chemical bond.
3. The hole transport film according to claim 2, wherein the flexible alkyl group is an alkyl group with 1 to 20 carbon atoms.
4. The hole transport film according to any one of claims 1 to 3, wherein the hole transport group is selected from the group consisting of 4,4'-bis(9-carbazole)biphenyl, N,N'- Diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamino, 4,4',4"-tris(carbazol-9-yl) One or more of triphenylamine group and 9,9-diphenylfluorenyl group.
5. The hole transport film according to any one of claims 1 to 4, wherein the first compound is a fluorine-containing compound; and/or

   The first compound is soluble in aromatic hydrocarbons or aromatic hydrocarbon derivatives; and/or

   The LUMO energy level of the first compound is greater than -2.5 eV.
6. The hole transport film according to any one of claims 1 to 5, wherein the conductive polymer includes a homopolymer of any one of aniline monomer, thiophene monomer or fluorene monomer, or includes an aniline monomer. A copolymer formed from one or more of monomers, thiophene monomers or fluorene monomers.
7. The hole transport film according to any one of claims 1 to 6, wherein the weight percentage of the conductive polymer is 60% to 95%, and the weight percentage of the first compound is 5% to 40%.
8. The hole transport film according to any one of claims 1 to 7, wherein the conductive polymer is polyaniline, the first compound contains one or more flexible alkyl groups, and the first The general formula of the compound is R-A, wherein R is the flexible alkyl group, A is 4,4'-bis(9-carbazole)biphenyl, R and A are connected through a chemical bond, wherein the first Some of the hydrogen atoms in the compound are replaced by fluorine atoms.
9. The hole transport film according to claim 8, wherein the weight percentage of the conductive polymer is 60% and the weight percentage of the first compound is 40%; or

   The weight percentage of the conductive polymer is 95%, and the weight percentage of the first compound is 5%; or

   The weight percentage of the conductive polymer is 20%, and the weight percentage of the first compound is 80%.
10. An optoelectronic device, which includes a stacked cathode, a luminescent layer, a hole transport film and an anode, the hole transport film is located between the luminescent layer and the anode, and the hole transport film is as claimed in the claim The hole transport film according to any one of 1 to 9, wherein the content of the first compound in the hole transport film gradually increases in the direction from the anode to the light-emitting layer.
11. The optoelectronic device according to claim 10, wherein the hole transport film has a thickness of 10 nm to 50 nm.
12. The optoelectronic device according to any one of claims 10-11, wherein,

    The material quantum dots of the light-emitting layer are selected from one or more of single structure quantum dots and core-shell structure quantum dots; the single structure quantum dots are selected from II-VI group compounds, III-V group compounds and I- One or more of III-VI compounds; the II-VI compound is selected from CdSe, CdS, CdTe, ZnSe, ZnS, CdTe, ZnTe, CdZnS, CdZnSe, CdZnTe, ZnSeS, ZnSeTe, ZnTeS, CdSeS, One or more of CdSeTe, CdTeS, CdZnSeS, CdZnSeTe and CdZnSTe; the III-V group compound is selected from InP, InAs, GaP, GaAs, GaSb, AlN, AlP, InAsP, InNP, InNSb, GaAlNP and InAlNP; The Group I-III-VI compound is selected from one or more of CuInS ₂ , CuInSe ₂ and AgInS ₂ ; and/or

    The materials of the cathode and the anode are selected from one or more of metal electrodes, carbon electrodes, metal oxide electrodes or composite electrodes, and the materials of the metal electrode are selected from the group consisting of Al, Ag, Cu, Mo, Au, One or more of Ba, Ca and Mg; the material of the carbon electrode is selected from one or more of graphite, carbon nanotubes, graphene and carbon fiber; the material of the metal oxide electrode is selected from doped One or more of doped or non-doped ITO, FTO, ATO, AZO, GZO, IZO, MZO and AMO; the composite electrode is selected from AZO/Ag/AZO, AZO/Al/AZO, ITO/Ag /ITO, ITO/Al/ITO, ZnO/Ag/ZnO, ZnO/Al/ZnO, TiO ₂ /Ag/TiO ₂ , TiO ₂ /Al/TiO ₂ , ZnS/Ag/ZnS, ZnS/Al/ZnS, TiO One or more of ₂ /Ag/TiO ₂ and TiO ₂ /Al/TiO ₂ .
13. The optoelectronic device according to any one of claims 10 to 12, wherein the optoelectronic device further includes a hole injection layer located between the hole transport film and the anode, The material of the hole injection layer is selected from one or more of PEDOT: PSS, MCC, CuPc, F4-TCNQ, HATCN, transition metal oxides, and transition metal chalcogenide compounds; and/or

    The optoelectronic device further includes an electron transport layer located between the cathode and the light-emitting layer. The material of the electron transport layer is selected from the group consisting of ZnO, TiO ₂ , SnO ₂ , Ta ₂ O ₃ , and ZrO2 , NiO, TiLiO, ZnAlO, ZnMgO, ZnSnO, ZnLiO, InSnO, one or more.
14. The optoelectronic device according to any one of claims 10 to 13, wherein when the optoelectronic device is a bottom emitting device, the thickness of the cathode is 80 nm to 150 nm; when the optoelectronic device is a top emitting device, the anode The thickness is 5nm~40nm.
15. A method for preparing an optoelectronic device, which includes the following steps:

    providing a material solution including a conductive polymer and a first compound, the first compound having a LUMO energy level greater than the LUMO energy level of the conductive polymer;

    providing an anode on which the material solution is disposed;

    Performing a first heat treatment and a second heat treatment in sequence to obtain a hole transport film, the temperature of the first heat treatment being lower than the temperature of the second heat treatment;

    forming a light-emitting layer on the hole transport film;

    A cathode is formed on the light emitting layer.
16. The preparation method according to claim 15, wherein the temperature of the first heat treatment is less than 100°C; and/or

    The temperature of the second heat treatment is greater than or equal to 100°C and less than or equal to 250°C.
17. The preparation method according to claim 16, wherein the temperature of the first heat treatment is 40°C; and/or

    The temperature of the second heat treatment is 230°C.
18. The preparation method according to any one of claims 15 to 17, wherein the thickness of the hole transport film is 10 nm to 50 nm.
19. The preparation method according to any one of claims 15 to 18, wherein, after providing the anode, it includes: forming a hole injection layer on the anode; the material solution is provided on the hole injection layer; and/ or

    Forming a cathode on the light-emitting layer includes forming an electron transport layer and a cathode on the light-emitting layer.
20. The preparation method according to claim 19, wherein,

    The material quantum dots of the light-emitting layer are selected from one or more of single structure quantum dots and core-shell structure quantum dots; the single structure quantum dots are selected from II-VI group compounds, III-V group compounds and I- One or more of III-VI compounds; the II-VI compound is selected from CdSe, CdS, CdTe, ZnSe, ZnS, CdTe, ZnTe, CdZnS, CdZnSe, CdZnTe, ZnSeS, ZnSeTe, ZnTeS, CdSeS, One or more of CdSeTe, CdTeS, CdZnSeS, CdZnSeTe and CdZnSTe; the III-V group compound is selected from InP, InAs, GaP, GaAs, GaSb, AlN, AlP, InAsP, InNP, InNSb, GaAlNP and InAlNP; The Group I-III-VI compound is selected from one or more of CuInS ₂ , CuInSe ₂ and AgInS ₂ ; and/or

    The materials of the cathode and the anode are selected from one or more of metal electrodes, carbon electrodes, metal oxide electrodes or composite electrodes, and the materials of the metal electrode are selected from the group consisting of Al, Ag, Cu, Mo, Au, One or more of Ba, Ca and Mg; the material of the carbon electrode is selected from one or more of graphite, carbon nanotubes, graphene and carbon fiber; the material of the metal oxide electrode is selected from doped One or more of doped or non-doped ITO, FTO, ATO, AZO, GZO, IZO, MZO and AMO; the composite electrode is selected from AZO/Ag/AZO, AZO/Al/AZO, ITO/Ag /ITO, ITO/Al/ITO, ZnO/Ag/ZnO, ZnO/Al/ZnO, TiO ₂ /Ag/TiO ₂ , TiO ₂ /Al/TiO ₂ , ZnS/Ag/ZnS, ZnS/Al/ZnS, TiO One or more of ₂ /Ag/TiO ₂ and TiO ₂ /Al/TiO ₂ ; and/or

    The material of the hole injection layer is selected from one or more of PEDOT: PSS, MCC, CuPc, F4-TCNQ, HATCN, transition metal oxides, and transition metal chalcogenide compounds; and/or

    The material of the electron transport layer is selected from one or more of ZnO, TiO ₂ , SnO ₂ , Ta ₂ O ₃ , ZrO2, NiO, TiLiO, ZnAlO, ZnMgO, ZnSnO, ZnLiO, and InSnO.

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