Optoelectronic device, method of manufacturing the same, and display device

Abstract

This application discloses an optoelectronic device, its fabrication method, and a display device. The optoelectronic device includes a stacked anode, a composite film layer, a light-emitting layer, and a cathode. The composite film layer is made of a composite material comprising a first metal oxide and an organic ligand attached to the surface of the first metal oxide. The organic ligand contains electron-withdrawing groups. In the technical solution proposed in this application, the composite film layer can serve as a hole-functional film layer, promoting hole transport and injection. It has a simple structure, is easy to fabricate, and the film material is stable and does not easily corrode adjacent film layers, thus contributing to the device's storage stability.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to an optoelectronic device, its fabrication method, and a display apparatus. Background Technology

[0002] Optoelectronic devices emit light by releasing energy through the recombination of electrons and holes, and are widely used in lighting, display technology, and other fields. Optoelectronic devices typically consist of an anode, a light-emitting layer, a cathode, and a hole-functional film layer located between the anode and the light-emitting layer. The hole-functional film layer usually consists of a hole transport layer and a hole injection layer, and the fabrication process of this dual-layer film is relatively complex. Summary of the Invention

[0003] In view of this, this application provides an optoelectronic device, a method for fabricating the same, and a display device.

[0004] The embodiments of this application are implemented as follows:

[0005] In a first aspect, embodiments of this application provide an optoelectronic device, including an anode, a composite film layer, a light-emitting layer, and a cathode stacked together, wherein the material of the composite film layer includes a composite material, the composite material including a first metal oxide and an organic ligand attached to the surface of the first metal oxide, the organic ligand containing an electron-withdrawing group.

[0006] Secondly, embodiments of this application provide a method for fabricating an optoelectronic device, comprising the following steps:

[0007] Provide anode;

[0008] A composite film layer is prepared on one side of the anode;

[0009] A light-emitting layer is disposed on the side of the composite film layer opposite to the anode;

[0010] A cathode is disposed on the side of the light-emitting layer opposite to the composite film layer;

[0011] The step of preparing a composite film layer on one side of the anode includes: providing a mixed solution comprising a metal salt, a fuel, and a solvent, wherein the metal salt contains electron-withdrawing groups; depositing the mixed solution on one side of the anode to form a liquid film; and heat-treating the liquid film to obtain the composite film layer.

[0012] Thirdly, embodiments of this application provide a display device, including the optoelectronic device described above, or the optoelectronic device prepared by the preparation method described above.

[0013] In the technical solution proposed in this application, the composite film layer can serve as a hole functional film layer, which promotes hole transport and injection. It has a simple structure, is easy to prepare, and the film layer material is stable and does not easily corrode adjacent film layers, which helps the device storage stability. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of an optoelectronic device provided in an embodiment of this application;

[0016] Figure 2 This is a schematic flowchart of a method for fabricating an optoelectronic device according to an embodiment of this application;

[0017] Figure 3 These are the AFM images of the thin films corresponding to Example 3 and Comparative Examples 1 to 3 in Experimental Example (I);

[0018] Figure 4 These are the external quantum efficiency-current density curves of the QLED devices in Examples 1 to 4 and Comparative Example 3;

[0019] Figure 5 These are voltage-time curves of the QLED devices in Examples 1 to 4 and Comparative Example 3;

[0020] Figure 6 These are the current density-voltage curves of the QLED devices in Examples 1 to 4 and Comparative Example 3;

[0021] Figure 7 These are the external quantum efficiency-current density curves of the QLED devices in Examples 3 and 5 to 7;

[0022] Figure 8 These are voltage-time curves of the QLED devices in Examples 3 and 5 to 7;

[0023] Figure 9 These are the current density-voltage curves of the QLED devices in Examples 3 and 5 to 7;

[0024] Figure 10 These are the external quantum efficiency-current density curves of the QLED devices in Examples 3 and 18 to 21;

[0025] Figure 11 These are voltage-time curves for the QLED devices in Examples 3 and 18 to 21;

[0026] Figure 12 These are the current density-voltage curves of the QLED devices in Examples 3 and 18 to 21;

[0027] Figure 13 These are the external quantum efficiency-current density curves of the QLED devices in Examples 24 to 25 and Comparative Examples 11 to 12;

[0028] Figure 14 These are voltage-time graphs of the QLED devices in Examples 24 to 25 and Comparative Examples 11 to 12;

[0029] Figure 15 These are current density-voltage curves of the QLED devices in Examples 24 to 25 and Comparative Examples 11 to 12;

[0030] Figure 16 These are external quantum efficiency-storage days curves for the QLED devices of Example 3, Comparative Example 3, and Comparative Example 13;

[0031] Figure 17 This is a schematic diagram of the energy level barrier formed between the anode, composite film layer and light-emitting layer in an optoelectronic device during the electro-driving process provided in the embodiments of this application.

[0032] Reference numerals: Optoelectronic device 100; Anode 10; Cathode 20; Light-emitting layer 30; Composite film layer 40; Second metal oxide 41; Composite material 42; Electron transport layer 50. Detailed Implementation

[0033] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, 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. In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. In addition, in the description of this application, the term "including" means "including but not limited to". 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 only for convenience and conciseness 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 values ​​within that range. For example, it should be assumed that the description of a range from 1 to 6 specifically discloses 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., as well as 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 range referred to.

[0034] 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.

[0035] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one," "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, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0036] In one aspect, embodiments of this application provide an optoelectronic device 100, such as a quantum dot light-emitting diode (LED), an organic light-emitting diode (OLED), etc. Please refer to... Figure 1The optoelectronic device 100 includes an anode 10, a composite film layer 40, a light-emitting layer 30, and a cathode 20 stacked together. The composite film layer 40 is made of a composite 42, which includes a first metal oxide and an organic ligand attached to the surface of the first metal oxide. The organic ligand contains an electron-withdrawing group.

[0037] In related technologies, hole-functional membranes typically consist of a hole transport layer and a hole injection layer. Fabrication of these membranes requires at least two steps, making the process quite complex. Furthermore, the selection of membrane materials must not only match the energy levels of adjacent membrane materials but also consider factors such as their film-forming properties and the availability of suitable solvents. Therefore, the requirements for material selection are stringent, and the two-layer design further complicates the process. Additionally, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS) is commonly used as the hole injection layer material. However, this acidic material can easily corrode the anode, affecting the device's storage stability.

[0038] In the technical solution proposed in this application, the composite film layer 40 promotes hole transport and injection, and can replace the traditional hole transport layer and hole injection layer as a hole functional film layer. The composite film layer 40 is a single film layer with a simple structure and is easy to prepare, which helps to simplify the preparation steps of the optoelectronic device 100; moreover, its material selection is less difficult, and common metal oxides can be used, reducing the difficulty of material selection; in addition, the film material of the composite film layer 40 is stable, non-acidic, and does not easily corrode adjacent film layers, which helps the device storage stability.

[0039] This composite film 40 can be formed by the combustion synthesis reaction of a metal salt containing electron-withdrawing groups with fuel. The preparation process is simple, and the self-assembled composite film 40 has better contact with the anode 10 and the light-emitting layer 30, which is beneficial to improving hole injection. In addition, the introduced electron-withdrawing groups can also increase the hole injection concentration of the device, improve the device conductivity, and thus improve the device efficiency and lifetime.

[0040] Organic ligands can consist of a single electron-withdrawing group, a combination of multiple electron-withdrawing groups, or a combination of electron-withdrawing groups with other common groups. It is understood that these other common groups can be selected from non-strong electron-donating groups (any group other than amine, amino, and oxonium groups), such as, but not limited to, alkyl, aryl, heteroaryl, etc.

[0041] The surface of the first metal oxide contains many defects, such as oxygen vacancies and uncoordinated metal atom defects. These defects are in an unstable, electron-deficient state and readily adsorb electron-withdrawing groups or structures containing electron-withdrawing groups. In the composite 42, the organic ligand is attached to the defects on the surface of the first metal oxide through chemisorption, electrostatic interaction, or bonding.

[0042] Electron-withdrawing groups are electrophilic chemical groups that attract surrounding electrons, drawing nearby electrons towards them. Electron-withdrawing groups typically possess lone pairs of electrons or partially filled electron shells, giving them high electron affinity. Specifically, these electron-withdrawing groups can include, but are not limited to, one or more of the following: sulfonic acid groups, halogen groups, cyano groups, nitro groups, carbonyl groups, alkynyl groups, and alkenyl groups.

[0043] In this application, the sulfonic acid group refers to "-SO3H", the halogen group refers to -F, -Cl, -Br or -I, the cyano group refers to -C≡N, the nitro group refers to -NO2, and the carbonyl group refers to a group containing... The structural groups are alkynyl groups, which are groups containing a carbon-carbon triple bond (C≡C) and alkenyl groups, which are groups containing a carbon-carbon double bond (C=C).

[0044] Based on this, the organic ligands may include, but are not limited to, one or more of the following: sulfonic acid group, trifluoromethanesulfonate group, -F, -Cl, -Br, -I, cyano, acetocyano, isopentylcyano, nitro, carbonyl, pentanedione group, ethynyl, propynyl, vinyl, allyl, acetyl, acetylacetonate group, trifluoroacetylacetonate group, hexafluoroacetylacetonate group, trifluoroacetate group, fluoroborate group, trifluoromethanethio group, and trifluoropentanedione group. These organic ligands can connect well with defects on the surface of the first metal oxide and effectively exert electron-withdrawing properties, thereby increasing the hole injection concentration of the device.

[0045] The first metal oxide can be a common metal oxide in the art with hole transport or injection properties, such as, but not limited to, undoped metal oxides or boron-doped metal oxides. The metal oxide can be, but is not limited to, one or more of indium oxide, tin oxide, copper oxide, titanium oxide, zirconium oxide, tungsten oxide, manganese oxide, and chromium oxide. These metal oxides have superior hole transport characteristics and, as materials for the composite film layer 40, help promote hole transport and increase the hole injection concentration. The first metal oxide can also be a boron-doped metal oxide; boron replaces oxygen vacancies and is doped into the crystal structure of the metal oxide. The mass percentage of boron in the boron-doped metal oxide can be 0–3%, for example, 0.001%, 0.005%, 0.01%, 0.02%, 0.05%, 0.08%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, and values ​​between any two of the above, or values ​​less than 0.001% and greater than 0. Boron doping helps to further improve the performance of the device. Specifically, boron doping is a p-type doping, which can impart a reduction potential to the material, thereby enabling hole injection into the composite film layer 40. This doping mechanism can generate free holes in the metal oxide, which helps to increase the ohmic contact characteristics between the anode 10 and the metal oxide. In addition, the hole aggregation interface formed by p-type doping can cause the energy band of the p-type doped region to bend downward, which helps to increase the probability of holes at the anode 10 being injected into the metal oxide film through tunneling.

[0046] Furthermore, in some embodiments, the first metal oxide is selected from one or more of indium oxide, boron-doped indium oxide, tin oxide, and boron-doped tin oxide, and the electron-withdrawing group is selected from sulfonic acid groups and / or halogen groups.

[0047] The first metal oxide is a nanoparticle. In some embodiments, the average particle size of the first metal oxide is 5 to 10 nm; for example, it can be 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, or any two of the above values.

[0048] Electron-withdrawing groups are unevenly distributed in the composite film layer 40. In some embodiments, the content of electron-withdrawing groups on the side of the composite film layer 40 closer to the anode 10 is greater than the content on the side closer to the cathode 20; that is, electron-withdrawing groups are mainly distributed on the side of the composite film layer 40 closer to the anode 10, while the side of the composite film layer 40 closer to the light-emitting layer 30 contains relatively few or almost no electron-withdrawing groups. The introduction of electron-withdrawing groups can effectively adjust the conduction band energy level of the composite material 42, such as... Figure 17As shown, electrons on the side close to the light-emitting layer 30 tend to transfer out in the direction close to the anode 10 (indicated by a single arrow in the figure). In this way, a large number of holes will be left at the valence band position (indicated by a plus sign in the figure), thereby greatly increasing the hole concentration in the device and improving the conductivity of the device.

[0049] Specifically, the distribution of materials in the composite film layer 40 may be as follows:

[0050] In some embodiments, in the composite film layer 40, the content of the complex 42 on the side close to the anode 10 is greater than the content of the complex 42 on the side close to the cathode 20; that is, the complex 42 is concentrated on the side of the composite film layer 40 close to the anode 10, while the distribution on the side of the composite film layer 40 close to the light-emitting layer 30 is relatively less. In this way, the overall distribution state is as follows: the content of the electron-withdrawing group in the composite film layer 40 on the side close to the anode 10 is greater than the content of the electron-withdrawing group on the side close to the cathode 20.

[0051] In other embodiments, in the composite film layer 40, the content of the electron-withdrawing group in the complex 42 close to the anode 10 is greater than the content of the electron-withdrawing group in the complex 42 close to the cathode 20; there are many defects on the surface of the first metal oxide. Therefore, multiple organic ligands can be connected to its surface. In the composite film layer 40 of this embodiment, in the complex 42 distributed on the side close to the anode 10, the surface of the first metal oxide contains more electron-withdrawing groups, while in the complex 42 distributed on the side close to the light-emitting layer 30, the surface of the first metal oxide contains relatively fewer electron-withdrawing groups. Based on this, it also makes the content of the electron-withdrawing group in the complex 42 close to the anode 10 in the composite film layer 40 relatively more.

[0052] In some embodiments, the material of the composite film layer 40 further includes a second metal oxide 41, i.e., a metal oxide whose surface is not connected to the organic ligand. The second metal oxide 41 includes, but is not limited to, undoped or boron-doped metal oxides, wherein the metal oxide includes one or more of indium oxide, tin oxide, copper oxide, titanium oxide, zirconium oxide, tungsten oxide, manganese oxide, and chromium oxide; when the second metal oxide 41 is selected from boron-doped metal oxides, the mass percentage of boron in the boron-doped metal oxide can be 0 to 3%, for example, 0.001%, 0.005%, 0.01%, 0.02%, 0.05%, 0.08%, 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, and any two of the above values, or a value less than 0.001% and greater than 0. The second metal oxide 41 is a nanoparticle. In some embodiments, the average particle size of the second metal oxide 41 is 5 to 10 nm; for example, it can be 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, or any two of the above values.

[0053] In the composite film layer 40, the content of the second metal oxide 41 on the side near the anode 10 is less than the content of the second metal oxide 41 on the side near the cathode 20; the composite material 42 is mainly concentrated on the side of the composite film layer 40 near the anode 10, while the second metal oxide 41 is mainly concentrated on the side of the composite film layer 40 near the light-emitting layer 30. In this way, it is beneficial for the composite film layer 40 to generate more holes on the side near the light-emitting layer 30, thus forming a higher hole concentration.

[0054] Furthermore, in some embodiments, the distribution of electron-withdrawing groups in the composite film layer 40 exhibits a gradual trend. Specifically, in the direction from the cathode 20 to the anode 10, the content of electron-withdrawing groups in the composite film layer 40 gradually increases, thereby causing a gradient change in the conduction band energy level of the material in the composite film layer 40, which is more conducive to electron transfer and forms a higher hole concentration.

[0055] In some specific embodiments, the content of the composite 42 in the composite film layer 40 gradually increases in the direction from the cathode 20 to the anode 10; in other embodiments, the content of electron-withdrawing groups contained in the composite 42 in the composite film layer 40 gradually increases in the direction from the cathode 20 to the anode 10.

[0056] In some embodiments, the content of the second metal oxide 41 in the composite film layer 40 gradually decreases in the direction from the cathode 20 to the anode 10; further, on this basis, the content of the composite 42 gradually increases in the direction from the cathode 20 to the anode 10, and the content of electron-withdrawing groups contained in the composite 42 gradually increases.

[0057] In some embodiments, the thickness of the composite film layer 40 is 20 to 50 nm; for example, it can be 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, or any two of the above values.

[0058] In some embodiments, the material of the light-emitting layer 30 may include organic light-emitting materials or quantum dots.

[0059] The organic light-emitting material is a material known in the art for use in the organic light-emitting layer 30, for example, it may be selected from, but is not limited to, at least one of diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives or fluorene derivatives, TBPe fluorescent material emitting blue light, TTPA fluorescent material emitting green light, TBRb fluorescent material emitting orange light, and DBP fluorescent material emitting red light.

[0060] The quantum dot is a quantum dot known in the art for use in the quantum dot emitting layer 30. The quantum dot may be selected from, but is not limited to, at least one of single-structure quantum dots, core-shell quantum dots, and perovskite semiconductor materials. The shell of the core-shell quantum dot comprises one or more layers. The material of the single-structure quantum dot, the core material of the core-shell quantum dot, and the shell material of the core-shell quantum dot respectively include at least one 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, and CdSTe. At least one of the following: ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe; the IV-VI group compounds include SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, S At least one of nSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe; the III-V compound includes at least one of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, and GaAlNP. At least one of GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb; the I-III-VI group compounds include at least one of CuInS2, CuInSe2, and AgInS2; 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 Cs. + Ion, M is a divalent metal cation selected from Pb2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Eu 2+ At least one of them, where X is a halide anion selected from Cl. - ,Br - I - At least one of the following; the general structural formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, wherein B is an organic amine cation selected from CH3(CH2). n-2 NH3 + Or [NH3(CH2)] n NH3] 2+ Where n≥2, M is a divalent metal cation selected from Pb 2+ Sn 2+ Cu 2+ Ni 2 + Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Eu 2+ At least one of them, where X is a halide anion selected from Cl. - ,Br - I - At least one of them.

[0061] As an example, the quantum dots of the core-shell structure can be selected from but not limited to at least one of CdZnSe / CdZnSe / ZnSe / CdZnS / ZnS, CdZnSe / CdZnSe / CdZnS / ZnS CdSe / CdSeS / CdS, InP / ZnSeS / ZnS, CdZnSe / ZnSe / ZnS, CdSeS / ZnSeS / ZnS, CdSe / ZnS, CdSe / ZnSe / ZnS, ZnSe / ZnS, ZnSeTe / ZnS, CdSe / CdZnSeS / ZnS and InP / ZnSe / ZnS. It should be noted that for the materials of the aforementioned single-structure quantum dots, or the core materials of the core-shell structure quantum dots, or the shell materials of the core-shell structure quantum dots, the provided chemical formulas only indicate the elemental composition and do not indicate the content of each element. For example, CdZnSe only indicates that it is composed of three elements, Cd, Zn, and Se. If the content of each element is to be expressed, it corresponds to Cd x Zn 1-x Se, 0 < x < 1. It can be understood that the core materials and each shell layer material of the core-shell structure quantum dots are expressed by connecting with " / ", and the order from left to right is the material types of the quantum dots from the inside out: core material / first shell layer material / Nth shell layer material, where N is an integer greater than or equal to 1. For example, CdSe / CdZnSeS / ZnS represents a core-shell structure quantum dot with two shell layers, whose core material is CdSe, the material of the first shell layer coated on the core is CdZnSeS, and the material of the second shell layer coated outside the first shell layer is ZnS.

[0062] The quantum dots can be any one of red quantum dots, green quantum dots, and blue quantum dots. Among them, red quantum dots refer to quantum dot luminescent materials with an emission peak wavelength in the range of 610 - 740 nm, green quantum dots refer to quantum dot luminescent materials with an emission peak wavelength in the range of 520 - 580 nm, and blue quantum dots refer to quantum dot luminescent materials with an emission peak wavelength in the range of 440 - 490 nm.

[0063] The quantum dot-based optoelectronic device 100 suffers from a carrier imbalance problem. Particularly in blue light-emitting devices based on blue quantum dots, the deeper energy levels and higher ionization potential of blue quantum dots create a significant hole injection barrier at the interface between the hole functional film and the light-emitting layer 30, making hole injection difficult while electron injection is relatively easy, resulting in a severe deficiency of hole concentration in the light-emitting layer 30. In red light-emitting devices based on red quantum dots and green light-emitting devices based on green quantum dots, the difference between hole and electron concentrations is relatively smaller. The problem in these two types of devices is more likely due to carrier injection imbalance caused by the weaker hole transport capability of the hole functional film. The composite film 40 proposed in this embodiment can effectively increase the hole injection concentration, reduce the difference between hole and electron concentrations, improve carrier balance, and thus enhance device performance. Since the difference between hole and electron concentrations is more pronounced in blue light-emitting devices, the improvement effect of the composite film 40 on carrier balance is particularly significant in blue light-emitting devices.

[0064] In addition, in some embodiments, the thickness of the light-emitting layer 30 is 20nm to 60nm; for example, it can be 20nm, 30nm, 40nm, 50nm, 60nm, or any two of the above values.

[0065] The anode 10 and the cathode 20 each independently include a doped metal oxide particle electrode, a metal-metal oxide composite electrode, a graphene electrode, a carbon nanotube electrode, a metal electrode, or an alloy electrode. The material of the doped metal oxide particle electrode is selected from one or more of indium-doped tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, magnesium-doped zinc oxide, and aluminum-doped magnesium oxide. The metal-metal oxide composite electrode is selected from AZO / Ag / AZO, AZO / Al / AZO, and ITO / Ag. The metal electrode material is selected from one or more of Ag, Al, Cu, Mo, Au, Pt, Si, Ca, Mg, and Ba; where " / " indicates a stacked structure. For example, the composite electrode AZO / Ag / AZO represents a three-layer stacked composite structure consisting of an AZO layer, an Ag layer, and an AZO layer.

[0066] In some embodiments, the optoelectronic device 100 may further include an electron transport layer 50 disposed between the light-emitting layer 30 and the cathode 20. The electron transport layer 50 may be made of materials commonly used in the art that possess electron transport properties, such as, but not limited to, at least one of N-type metal oxides and doped N-type metal oxides. Specifically, the N-type metal oxide may include, but is not limited to, one or more of ZnO, TiO2, and SnO2. The doped N-type metal oxide may include, but is not limited to, one or more of ZnO, TiO2, and SnO2. The doping element may include, but is not limited to, one or more of Al, Mg, Li, In, and Ga. In some embodiments, the thickness of the electron transport layer 50 is 20 nm to 60 nm; for example, it may be 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, or any two of the above values.

[0067] It is understood that the optoelectronic device 100 may also be provided with some functional layers that are conventionally used in optoelectronic devices 100 and help to improve device performance, such as electron blocking layer, hole blocking layer, interface modification layer, etc.

[0068] It is understood that the materials of each layer of the optoelectronic device 100 can be adjusted according to the optoelectronic requirements of the optoelectronic device 100.

[0069] It is understood that the optoelectronic device 100 can be an upright device or an inverted device.

[0070] In some embodiments, the optoelectronic device 100 further includes a substrate disposed on the surface of the anode 10 opposite to the composite film layer 40, or the substrate disposed on the surface of the cathode 20 opposite to the light-emitting layer 30. The substrate may be a rigid substrate or a flexible substrate. In some embodiments, the material of the substrate may include, but is not limited to, one or more of glass, silicon wafers, polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, polyamide, and polyethersulfone.

[0071] This application also proposes a method for fabricating an optoelectronic device 100, which can produce the optoelectronic device 100 described above. Please refer to [link to application]. Figure 2 The method for fabricating the optoelectronic device 100 includes the following steps:

[0072] S10 provides anode 10;

[0073] S20, a composite film layer 40 is prepared on one side of the anode 10;

[0074] S30, a light-emitting layer 30 is provided on the side of the composite film layer 40 away from the anode 10;

[0075] S40, a cathode 20 is disposed on the side of the light-emitting layer 30 opposite to the composite film layer 40.

[0076] Specifically, step S20 can be implemented through the following step S21: providing a mixed solution, the mixed solution including a metal salt, a fuel and a solvent, the metal salt containing electron-withdrawing groups; depositing the mixed solution on one side of the anode 10 to form a liquid film; and heat-treating the liquid film to obtain the composite film layer 40.

[0077] Metal salts are organometallic salts containing electron-withdrawing groups. In some embodiments, the metal salt may be a salt compound formed by the combination of a metal ion and the organic ligand described above.

[0078] Fuel refers to compounds that can undergo self-propagating high-temperature synthesis (SHS, or combustion synthesis) with metal salts, and can provide energy through combustion. Specifically, the fuel can be an oxygen-containing reducing agent that exhibits electron-accepting properties in the presence of metal ions.

[0079] Metal salts and fuels can undergo a combustion synthesis reaction to form a complex 42. The complex 42 comprises a first metal oxide and an organic ligand attached to the surface of the first metal oxide, the organic ligand containing an electron-withdrawing group. Specifically, metal ions in the metal salt react with the fuel to form the first metal oxide. Simultaneously, the organic ligands in the metal salt, which separate from the metal ions, adsorb onto the surface of the first metal oxide, thus forming the complex 42.

[0080] The preparation method proposed in this application utilizes a combustion synthesis method to synthesize a composite film layer 40 in one step. The composite film layer 40 comprises a composite 42, which includes a first metal oxide and an organic ligand attached to the surface of the first metal oxide. The organic ligand contains an electron-withdrawing group. The composite film layer 40 promotes hole transport and injection, and can replace traditional hole transport layers and hole injection layers as a hole-functional film layer. The preparation method is simple, simplifying the fabrication steps of the optoelectronic device 100.

[0081] The formation of metal oxide films based on combustion synthesis reactions has been shown to follow a top-down crystallization process, starting with the evaporation of residual solvent from the top surface of the "wet" film and gradually crystallizing downwards. During the formation of the metal oxide, when metal ions combine with oxygen, the organic ligands break their bond. In this process, the metal salt and free organic ligands are gradually pushed downwards and concentrated on or near the surface of the anode 10. This results in a higher organic ligand content closer to the anode 10 and a lower content further away. Therefore, the further away from the anode 10, the higher the probability of metal ions combining with oxygen and the lower the probability of combining with organic ligands. The metal oxides that combine with organic ligands constitute complex 42, while the metal oxides that do not combine with organic ligands constitute the second metal oxide 41. As the reaction proceeds, the composite film layer 40 gradually forms, and the material in the composite film layer 40 is distributed in layers, mainly characterized by a higher content of electron-withdrawing groups on the side closer to the anode 10 than on the side closer to the cathode 20. Specifically, in the composite film layer 40, the content of the composite 42 on the side near the anode 10 is greater than the content of the composite 42 on the side near the cathode 20; the content of electron-withdrawing groups in the composite 42 near the anode 10 is greater than the content of electron-withdrawing groups in the composite 42 near the cathode 20; and the content of the second metal oxide 41 on the side near the anode 10 is less than the content of the second metal oxide 41 on the side near the cathode 20.

[0082] Divalent metal salts (denoted as M) 2+ Taking the reaction of ) and fuel (urea, CO(NH2)2) as an example, the reaction equation is:

[0083] M 2+ +CON2H 4(s) →MO (s) +N 2(g) +H2O (g) +CO 2(g) ΔH 298 K = -2320.4kJ.

[0084] Combustion synthesis is exothermic; once ignited, no external energy input is required. The self-generated heat of synthesis provides local energy supply, eliminating the need for high external processing temperatures (above 700°C). This allows metal salt solutions to be spin-coated into films and converted into metal oxide films at lower temperatures through a combustion reaction. The reaction temperature is low, energy consumption is low, and high-temperature damage to the substrate and anode is avoided.

[0085] The electron-withdrawing groups include one or more of the following: sulfonic acid group, halogen group, cyano group, nitro group, carbonyl group, alkynyl group, and alkenyl group.

[0086] Based on this, the organic ligand may include, but is not limited to, one or more of the following: sulfonic acid group, trifluoromethanesulfonate group, -F, -Cl, -Br, -I, cyano, acetocyano, isopentylcyano, nitro, carbonyl, pentanedionyl, ethynyl, propynyl, vinyl, allyl, acetyl, acetylacetone, trifluoroacetylacetone, hexafluoroacetylacetone, trifluoroacetate, fluoroborate, trifluoromethanethio, and trifluoropentanedione.

[0087] The metal salt may include, but is not limited to, one or more of indium salt, tin salt, copper salt, titanium salt, zirconium salt, tungsten salt, manganese salt, and chromium salt; correspondingly, it may react to generate one or more of indium oxide, tin oxide, copper oxide, titanium oxide, zirconium oxide, tungsten oxide, manganese oxide, and chromium oxide.

[0088] In some specific embodiments, the indium salt may include, but is not limited to, one or more of indium trifluoromethanesulfonate, indium acetylacetonate (III), indium trifluoroacetate (III), and indium trifluoroacetylacetonate (III); the tin salt may include, but is not limited to, one or more of tributyl(1-propynyl)tin, tetraallyltin, tin hexafluoroacetylacetonate (II), trifluorophenyltin, dibutyltin bis(trifluoromethanesulfonate), butyltin trichloride, stannous fluoroborate, tin trifluoromethanesulfonate, and tin methanesulfonate; the copper salt may include, but is not limited to, one or more of copper fluoroborate, copper acetylacetonate, copper trifluoroacetate, copper dichloro(1,10-phenanthroline)copper (II), copper trifluoromethanethiolate (I), copper tetraacetonitrile hexafluorophosphate (I), and copper bis(triphenylphosphine)nitrate; the titanium salt may include, but is not limited to, triisopropyltrimonium oxide. The zirconium salt may include, but is not limited to, ammonium fluorozirconate, zirconium dichlorodicarbonate, zirconium tetra(trifluoro-2,4-pentanedione) (IV), zirconium trichloride (IV), zirconium acetylacetonate, and zirconium trichloride (IV); the tungsten salt may include, but is not limited to, oxotungsten chloride (VI), mesitylenetricarbonyltungsten, pentacarbonyltungsten-N-pentylisocyanate, and bis(cyclopentanediyl)dichloride; the manganese salt may include, but is not limited to, decacarbonyldimanganese, manganese trifluoromethanesulfonate (II), manganese acetylacetonate, and 2-methylcyclopentadienetricarbonylmanganese; and the chromium salt may include, but is not limited to, chromium acetylacetonate and chromium benzenetricarbonyl. The aforementioned metal salts are commercially available. The organic ligands attached to the surface of the metal oxide prepared based on the aforementioned metal salts can be one or more of the following: sulfonic acid group, trifluoromethanesulfonate group, -F, -Cl, cyano group, ethyl cyano group, isopentyl cyano group, nitro group, carbonyl group, pentanedionyl group, ethynyl group, propynyl group, vinyl group, allyl group, acetyl group, acetylacetone group, trifluoroacetylacetone group, hexafluoroacetylacetone group, trifluoroacetate group, fluoroborate group, trifluoromethanethio group, and trifluoropentanedione group.

[0089] Furthermore, in some embodiments, the metal salt is selected from one or more of indium and tin salts, and the electron-withdrawing group is selected from sulfonic acid groups and / or halogen groups. For example, the metal salt may specifically be selected from one or more of indium trifluoromethanesulfonate, indium trifluoroacetate (III), indium trifluoroacetylacetonate (III), tin hexafluoroacetylacetonate (II), trifluorophenyltin, dibutyltin bis(trifluoromethanesulfonate), butyltin trichloride, stannous fluoroborate, tin trifluoromethanesulfonate, and tin methanesulfonate.

[0090] In some embodiments, the first metal oxide or the second metal oxide 41 may also be a boron-doped metal oxide. If the target product is a boron-doped metal oxide, a boron compound may be added to the mixed solution during step S21 to introduce boron into the crystal structure of the metal oxide during synthesis. In some embodiments, the mixed solution further includes a boron compound containing electron-withdrawing groups, which may include, but is not limited to, one or more of 2-cyanophenylboronic acid, 4-cyano-2-nitrophenylboronic acid, 2-cyano-4-fluorophenylboronic acid, 2-chloro-4-cyanophenylboronic acid, and 4-boronbenzenesulfonic acid.

[0091] In the mixed solution, the mass percentage of the boron compound containing electron-withdrawing groups to the total mass of the boron compound containing electron-withdrawing groups and the metal salt is 1% to 3%. For example, it can be 1%, 1.5%, 2%, 2.5%, 3%, or any two of the above values. This allows for the control of the boron doping level in the synthesized product, keeping the doping level within a suitable range, which contributes to improved device performance.

[0092] In some embodiments, the fuel may include an oxygen-containing reducing agent, which may include, but is not limited to, one or more of hydrogen peroxide, urea, glycine, citric acid, and tris(hydroxymethyl)aminomethane; the fuel may undergo a combustion synthesis reaction with the metal salt to generate metal oxide particles.

[0093] The mass ratio of the metal salt to the fuel is 100:2 to 8; for example, it can be 100:2, 100:3, 100:4, 100:5, 100:6, 100:7, 100:8, or any two of the above values. Controlling the mass ratio within this range allows for a complete combustion and synthesis reaction between the fuel and the metal salt, which helps to improve the feed conversion rate and increase the yield.

[0094] In some embodiments, the solvent includes one or more of methanol, ethanol, n-propanol, isopropanol, butanol, tert-butanol, pentanol, glycerol, methoxyethanol, N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO).

[0095] It is understood that there is no limit to the amount of solvent used, as long as it can fully dissolve the metal compound, fuel, and additives. In some embodiments, the amount of solvent added can meet the following conditions: 10 to 60 mg of the metal salt is added per mL of the solvent; for example, 10 mg, 20 mg, 30 mg, 40 mg, 50 mg, 60 mg of the metal salt, or any two of the above values, can be added per mL of solvent.

[0096] In some embodiments, the mixed solution further includes additives; during combustion synthesis, the additives can effectively prevent the aggregation of metal salts, thereby improving the film-forming ability of the metal salts. Specifically, the additives may include acetylacetone or 2,3-butanedione.

[0097] In the mixed solution, the mass ratio of the metal salt to the additive is 100:1 to 4; for example, it can be 100:1, 100:1.5, 100:2, 100:2.5, 100:3, 100:3.5, 100:4, or any two of the above values. Controlling the additive ratio within this range can effectively improve the aggregation problem and enhance the film-forming effect.

[0098] The heat treatment temperature can be between 150 and 230°C; for example, it can be 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, or any two of the above values. Controlling the heat treatment temperature within this range provides a suitable temperature environment for the combustion reaction, promoting the reaction between the fuel and the metal salt. This method uses a relatively low heat treatment temperature, consumes little energy, and is less likely to damage the anode 10 and the substrate.

[0099] The heat treatment time can be 20 to 40 minutes; for example, it can be 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, or any two of the above values. Controlling the heat treatment time within this range ensures that the reaction proceeds fully; in addition, this method requires less time, has high production efficiency, and reduces the time that the anode 10 and the substrate are exposed to high temperatures, making it less likely to damage the anode 10 and the substrate.

[0100] It is understood that when the optoelectronic device 100 to be prepared also includes an electron transport layer 50, step S40 can be implemented as follows: an electron transport layer 50 is provided on the side of the light-emitting layer 30 away from the composite film layer 40, and a cathode 20 is provided on the side of the electron transport layer 50 away from the light-emitting layer 30.

[0101] When the optoelectronic device 100 also includes other films such as an electron blocking layer, a hole blocking layer, and an interface modification layer, the film can be prepared at the location of the target film. Specifically, the target film can be prepared on the surface of the film below the target film after the film below the target film is prepared.

[0102] The methods for forming the films such as the anode 10, cathode 20, light-emitting layer 30, and electron transport layer 50 can be chemical or physical methods. Chemical methods can include chemical vapor deposition, continuous ion layer adsorption and reaction, anodic oxidation, electrolytic deposition, and co-precipitation. Physical methods can include physical deposition or solution processing. Physical deposition methods include thermal evaporation deposition (CVD), electron beam evaporation deposition, magnetron sputtering, multi-arc ion deposition, physical vapor deposition (PVD), atomic layer deposition, and pulsed laser deposition. Solution processing methods include spin coating, printing, inkjet printing, blade coating, dip coating, immersion coating, spraying, roller coating, casting, slot coating, and strip coating. Those skilled in the art can prepare the various films of the optoelectronic device 100 of this application embodiment according to the known methods for preparing optoelectronic devices 100, which will not be elaborated further here.

[0103] This application also relates to a display device, which includes the optoelectronic device 100 provided in this application, or the optoelectronic device 100 prepared by the preparation method described above. The display device can be any electronic product with display functionality, including but not limited to smartphones, tablets, laptops, digital cameras, digital camcorders, smart wearable devices, smart weighing scales, in-vehicle displays, televisions, or e-book readers. Smart wearable devices can be, for example, smart bracelets, smartwatches, virtual reality (VR) headsets, etc.

[0104] The present application will be specifically described below through specific embodiments. These embodiments are only some embodiments of the present application and are not intended to limit the present application. Unless otherwise specified, the raw materials used in the following embodiments are all commercially available products.

[0105] Example 1

[0106] This embodiment provides a QLED and its preparation method. The QLED structure is ITO / composite film / B-QD / ZMO / Ag, and the composite film is made of indium oxide and indium oxide with trifluoromethanesulfonic acid groups attached to their surfaces.

[0107] Specifically, the steps include the following:

[0108] Step S1: Place the glass substrate with ITO anode (thickness 50nm) into a glass dish, and sonicate it for 20 minutes each with detergent, acetone, deionized water and ethanol in sequence. Then place it in an oven to dry it thoroughly. Then place the cleaned ITO glass sheet in oxygen plasma for 10 minutes to continue cleaning. Finally, treat the substrate surface with ultraviolet-ozone for 15 minutes.

[0109] Step S2: Indium trifluoromethanesulfonate (metal salt) and N,N-dimethylformamide (solvent) are mixed to prepare a chromium tricarbonyl trioxide metal salt solution with a concentration of 30 mg / mL. Citric acid (fuel) and 2,3-butanedione (additive) are added to the metal salt solution, wherein the mass ratio of fuel to metal salt is 2:100, and the mass ratio of additive to metal salt is 2:100. The mixture is then stirred continuously at room temperature for 3 hours to obtain a mixture. The mixture is spin-coated onto ITO at a speed of 1500 r / min for 30 s, followed by heat treatment in air at 200 °C for 30 min to obtain a composite film layer with a thickness of approximately 40 nm. After annealing, the surface of the obtained ITO / composite film layer semi-finished device is treated with ultraviolet-ozone for 20 min.

[0110] Step S3: Spin-coat a hexane solution containing blue quantum dots onto the composite film at a spin speed of 3000 r / min for 30 s. The blue quantum dots are Cd. 0.2 Zn 0.8 Se / Cd 0.4 Zn 0.6 Se / Cd 0.2 Zn 0.8 S / ZnSe / ZnS, with an emission peak wavelength of 471nm; after spin coating, annealing was performed at 100℃ in a glove box for 5 minutes to obtain a light-emitting layer with a thickness of approximately 30nm.

[0111] Step S4: Spin-coat ZMO ethanol solution onto the luminescent layer at a speed of 6000 r / min for 30 s to obtain a 35 nm thick electron transport layer.

[0112] Step S5: In a vacuum chamber, a 100nm thick Ag-cathode is vacuum-deposited on the electron transport layer; then the device is sealed with epoxy resin to obtain a QLED device.

[0113] Example 2

[0114] The scheme in this embodiment is basically the same as that in embodiment 1, except that in step S2 of this embodiment, the mass ratio of fuel to metal salt is adjusted from 2:100 to 4:100.

[0115] Example 3

[0116] The scheme in this embodiment is basically the same as that in embodiment 1, except that in step S2 of this embodiment, the mass ratio of fuel to metal salt is adjusted from 2:100 to 6:100.

[0117] Example 4

[0118] The scheme in this embodiment is basically the same as that in embodiment 1, except that in step S2 of this embodiment, the mass ratio of fuel to metal salt is adjusted from 2:100 to 8:100.

[0119] Example 5

[0120] The scheme in this embodiment is basically the same as that in embodiment 3, except that in step S2 of this embodiment, the mass ratio of additive to metal salt is adjusted from 2:100 to 1:100.

[0121] Example 6

[0122] The scheme in this embodiment is basically the same as that in embodiment 3, except that in step S2 of this embodiment, the mass ratio of additive to metal salt is adjusted from 2:100 to 4:100.

[0123] Example 7

[0124] The scheme in this embodiment is basically the same as that in embodiment 3, except that in this embodiment, in step S2, the fuel is changed from citric acid to urea and the additive is changed from 2,3-butanedione to acetylacetone.

[0125] Example 8

[0126] The scheme in this embodiment is basically the same as that in embodiment 7, except that the composite film material in this embodiment is tin oxide and tin oxide with trifluorophenyl groups attached to the surface. Correspondingly, in step S2, the metal salt is changed from indium trifluoromethanesulfonate to tin trifluorophenyl, and the solvent is changed from N,N-dimethylformamide to isopropanol.

[0127] Example 9

[0128] The scheme in this embodiment is basically the same as that in embodiment 7, except that the composite film material in this embodiment is copper oxide and copper oxide with trifluoroacetate ions attached to its surface. Correspondingly, in step S2, the metal salt is changed from indium trifluoromethanesulfonate to copper trifluoroacetate, and the solvent is changed from N,N-dimethylformamide to glycerol.

[0129] Example 10

[0130] The scheme of this embodiment is basically the same as that of embodiment 7, except that the material of the composite film layer in this embodiment is copper oxide and copper oxide with cyano groups and / or fluorine atoms connected on the surface. Correspondingly, in step S2, the metal salt is changed from indium trifluoromethanesulfonate to copper tetraacetonitrile hexafluorophosphate (I), and the solvent is changed from N,N-dimethylformamide to glycerol.

[0131] Example 11

[0132] The scheme in this embodiment is basically the same as that in embodiment 7, except that the composite film material in this embodiment is titanium oxide and titanium oxide with chlorine atoms bonded to its surface. Correspondingly, in step S2, the metal salt is changed from indium trifluoromethanesulfonate to titanium triisopropyl chloride, and the solvent is changed from N,N-dimethylformamide to butanol.

[0133] Example 12

[0134] The scheme of this embodiment is basically the same as that of embodiment 7, except that in this embodiment, the material of the composite film layer is zirconium oxide and zirconium oxide with chlorine atoms attached to its surface. Correspondingly, in step S2, the metal salt is changed from indium trifluoromethanesulfonate to zirconium dichlorodicyclopentadiene, and the solvent is changed from N,N-dimethylformamide to dimethyl sulfoxide.

[0135] Example 13

[0136] The scheme in this embodiment is basically the same as that in embodiment 7, except that the composite film material in this embodiment is chromium oxide and chromium oxide with carbonyl groups attached to its surface. Correspondingly, in step S2, the metal salt is changed from indium trifluoromethanesulfonate to chromium benzenetricarbonyl, and the solvent is changed from N,N-dimethylformamide to dimethyl sulfoxide.

[0137] Example 14

[0138] The scheme of this embodiment is basically the same as that of embodiment 7, except that the material of the composite film layer in this embodiment is chromium oxide and chromium oxide with acetylacetone groups on the surface. Correspondingly, in step S2, the metal salt is changed from indium trifluoromethanesulfonate to chromium acetylacetone.

[0139] Example 15

[0140] The scheme of this embodiment is basically the same as that of embodiment 7, except that the composite film material in this embodiment is tungsten oxide and tungsten oxide with chlorine atoms attached to its surface. Correspondingly, in step S2, the metal salt is changed from indium trifluoromethanesulfonate to bis(cyclopentadienyl)tungsten dichloride, and the solvent is changed from N,N-dimethylformamide to dimethyl sulfoxide.

[0141] Example 16

[0142] The scheme of this embodiment is basically the same as that of embodiment 7, except that the material of the composite film layer in this embodiment is tungsten oxide and tungsten oxide with isopentane cyano groups and / or carbonyl groups attached to the surface. Correspondingly, in step S2, the metal salt is changed from indium trifluoromethanesulfonate to pentacarbonyltungsten-N-pentylisocyanate.

[0143] Example 17

[0144] The scheme of this embodiment is basically the same as that of embodiment 7, except that the material of the composite film layer in this embodiment is manganese oxide and manganese oxide with carbonyl groups attached to the surface. Correspondingly, in step S2, the metal salt is changed from indium trifluoromethanesulfonate to 2-methylcyclopentadiene tricarbonyl manganese.

[0145] Example 18

[0146] The scheme in this embodiment is basically the same as that in embodiment 3, except that the heat treatment temperature in step S2 is adjusted from 200℃ to 150℃.

[0147] Example 19

[0148] The scheme in this embodiment is basically the same as that in embodiment 3, except that the heat treatment temperature in step S2 is adjusted from 200℃ to 230℃.

[0149] Example 20

[0150] The scheme in this embodiment is basically the same as that in embodiment 19, except that in step S2, the concentration of the metal salt solution is adjusted from 30 mg / mL to 10 mg / mL, and the thickness of the resulting composite film is changed to 20 nm.

[0151] Example 21

[0152] The scheme in this embodiment is basically the same as that in embodiment 19, except that in step S2, the concentration of the metal salt solution is adjusted from 30 mg / mL to 60 mg / mL, and the thickness of the resulting composite film is 50 nm.

[0153] Example 22

[0154] The scheme in this embodiment is basically the same as that in embodiment 15, except that in step S2 of this embodiment, 2-cyanophenylboronic acid is added to the metal salt solution, and the mass ratio of 2-cyanophenylboronic acid to metal salt is 2:100.

[0155] Example 23

[0156] The scheme in this embodiment is basically the same as that in embodiment 16, except that in step S2 of this embodiment, 2-cyanophenylboronic acid is added to the metal salt solution, and the mass ratio of 2-cyanophenylboronic acid to metal salt is 2:100.

[0157] Example 24

[0158] This embodiment is basically the same as embodiment 3, except that in step S3 of this embodiment, the blue quantum dot is changed to a red quantum dot Cd. 0.8 Zn 0.2 Se / Cd 0.5 Zn0.5 Se / Cd 0.5 Zn 0.5 S / ZnS, with an emission peak wavelength of 623nm.

[0159] Example 25

[0160] This embodiment is basically the same as embodiment 3, except that in step S3 of this embodiment, the blue quantum dot is changed to a green quantum dot Cd. 0.5 Zn 0.5 Se / Cd 0.3 Zn 0.7 Se / ZnSe / Cd 0.1 Zn 0.9 Se / ZnS has an emission peak wavelength of 542nm.

[0161] Comparative Example 1

[0162] This comparative example is basically the same as Example 3, except that the additive 2,3-butanedione was not added in step S2 of this comparative example.

[0163] Comparative Example 2

[0164] This comparative example is basically the same as Example 3, except that fuel citric acid was not added in step S2 of this comparative example.

[0165] Comparative Example 3

[0166] This comparative example is basically the same as Example 3, except that the composite film material in this comparative example is indium oxide, and correspondingly, step S2 is changed to:

[0167] 0.2 g of InCl3 powder was dissolved in 10 mL of oleylamine. During sonication, 12 mL of anhydrous ethanol was added dropwise. After the solution became clear, the mixture was poured into a sealed reaction vessel and heated to react at 180 °C for 20 h. The reaction vessel was then allowed to cool naturally to room temperature. The product was centrifuged and washed with anhydrous ethanol to obtain indium oxide nanoparticles. The indium oxide nanoparticles were then dissolved in ethanol to obtain an indium oxide nanoparticle solution.

[0168] The indium oxide nanoparticle solution was spin-coated onto ITO at a speed of 2500 r / min for 30 s. Subsequently, it was heat-treated in air at 150 °C for 30 min to obtain a composite film with a thickness of approximately 40 nm. After annealing, the surface of the resulting ITO / composite film semi-finished device was treated with ultraviolet-ozone for 20 min.

[0169] Comparative Example 4

[0170] This comparative example is basically the same as Example 8, except that the composite film material in this comparative example is tin oxide, and correspondingly, step S2 is changed to:

[0171] 50 mL of a 0.1 mol / L SnCl4 solution was prepared and added to a three-necked flask. Different amounts of polyvinylpyrrolidone (PVP) dispersant were added. After stirring at a certain temperature for a period of time, an ammonia solution of the appropriate concentration was added dropwise at a controlled rate. The pH value was measured every 5 minutes after the reaction began. When the pH value reached the desired level, the addition of ammonia was stopped, and stirring was continued for 30 minutes before stopping, thus forming a uniformly dispersed Sn(OH)4 suspension. After the reaction was complete, the suspension was aged for a certain time to obtain the precursor Sn(OH)4. The dried precursor Sn(OH)4 was thoroughly ground in an agate mortar and pestle and placed in a dark enamel container, which was then covered. It was then placed in a box-type resistance furnace and heated to a certain temperature, held for a corresponding time, to decompose the precursor SnO2. Nano-SnO2 powder was then obtained and dispersed in DMSO solution to obtain a tin oxide nanoparticle solution.

[0172] The tin oxide nanoparticle solution was spin-coated onto ITO at a speed of 2500 r / min for 30 s. Subsequently, it was heat-treated in air at 150 °C for 30 min to obtain a composite film with a thickness of approximately 40 nm. After annealing, the surface of the resulting ITO / composite film semi-finished device was treated with ultraviolet-ozone for 20 min.

[0173] Comparative Example 5

[0174] This comparative example is basically the same as Example 9, except that the composite film material in this comparative example is copper oxide, and correspondingly, step S2 is changed to:

[0175] Add an appropriate amount of copper nitrate to 30 ml of methoxyethanol to prepare a copper nitrate solution with a total concentration of 1 mol / L. Add 0.015 mmol of sodium citrate to obtain mixed solution A. Weigh an appropriate amount of sodium hydroxide and dissolve it in 5 ml of ethanol solution to obtain an alkaline solution; according to OH... - An alkaline solution was added to mixed solution A at a molar ratio of 1.8:1 to copper ions to form a mixed solution with pH=13. The solution was then stirred at 80℃ for 1 hour. The reaction product was filtered, centrifuged, and washed to obtain a copper oxide nanoparticle solution.

[0176] The copper oxide nanoparticle solution was spin-coated onto ITO at a speed of 2500 r / min for 30 s. Subsequently, it was heat-treated in air at 150 °C for 30 min to obtain a composite film with a thickness of approximately 40 nm. After annealing, the surface of the resulting ITO / composite film semi-finished device was treated with ultraviolet-ozone for 20 min.

[0177] Comparative Example 6

[0178] This comparative example is basically the same as Example 11, except that the composite film material in this comparative example is titanium oxide, and correspondingly, step S2 is changed to:

[0179] 0.5 ml of tetrabutyl titanate was added dropwise to 16 ml of 1,3-propanediol and stirred at 50 °C for 2 h until the mixture was homogeneous and no white precipitate was formed. Then, 0.147 g of sodium hypochlorite was added and stirring was continued for 1.5 h to obtain a transparent pale yellow solution. The transparent pale yellow solution was transferred to a 20 ml polytetrafluoroethylene-lined stainless steel high-pressure reactor and placed in an oven. The reactor was reacted at 180 °C for 20 h. After the reaction was completed, the mixture was cooled to room temperature to obtain the reaction product. The reaction product was filtered, centrifuged, and washed to obtain a titanium dioxide nanoparticle solution.

[0180] The titanium dioxide nanoparticle solution was spin-coated onto ITO at a speed of 2500 r / min for 30 s. Subsequently, it was heat-treated in air at 150 °C for 30 min to obtain a composite film with a thickness of approximately 40 nm. After annealing, the surface of the resulting ITO / composite film semi-finished device was treated with ultraviolet-ozone for 20 min.

[0181] Comparative Example 7

[0182] This comparative example is basically the same as Example 12, except that the composite film material in this comparative example is zirconium oxide, and correspondingly, step S2 is changed to:

[0183] 0.4 g of ZrCl2, 0.7 g of urea, and 0.2 g of citric acid were dispersed in 25 mL of anhydrous ethanol and stirred thoroughly to form a solution. The solution was then placed in a 40 mL reaction vessel, sealed, and reacted at 200 °C for 8 hours. The product solution was removed and centrifuged to remove the solvent components. The solution was washed with anhydrous ethanol to obtain zirconia nanoparticles. The zirconia nanoparticles were dissolved in ethanol to obtain a zirconia nanoparticle solution.

[0184] The tin oxide nanoparticle solution was spin-coated onto ITO at a speed of 2500 r / min for 30 s. Subsequently, it was heat-treated in air at 150 °C for 30 min to obtain a composite film with a thickness of approximately 40 nm. After annealing, the surface of the resulting ITO / composite film semi-finished device was treated with ultraviolet-ozone for 20 min.

[0185] Comparative Example 8

[0186] This comparative example is basically the same as Example 13, except that the composite film material in this comparative example is chromium oxide, and correspondingly, step S2 is changed to:

[0187] Cr(NO3)3·9H2O was dispersed in ethanol to obtain 100 mL of precursor solution (concentration 40 mmol / L), which was heated in a microwave oven at 800 W for 3 min. When the precursor solution boiled and a large number of uniform bubbles appeared, heating was stopped and the solution was removed. Immediately, 5 mL of sodium citrate in ethanol solution (concentration 40 mmol / L) was added to obtain a mixed solution. The mixed solution was then microwaved at 500 W for 2 min, removed, and cooled to room temperature in the dark. Subsequently, the mixture was centrifuged at 25,000 RCF for 15 min and washed twice with ethanol to obtain a chromium oxide nanoparticle solution.

[0188] The chromium oxide nanoparticle solution was spin-coated onto ITO at a speed of 2500 r / min for 30 s. Subsequently, it was heat-treated in air at 150 °C for 30 min to obtain a composite film with a thickness of approximately 40 nm. After annealing, the surface of the resulting ITO / composite film semi-finished device was treated with ultraviolet-ozone for 20 min.

[0189] Comparative Example 9

[0190] This comparative example is basically the same as Example 15, except that the composite film material in this comparative example is tungsten oxide, and correspondingly, step S2 is changed to:

[0191] Weigh 2 mmol of Na₂WO₄·2H₂O, dissolve it in deionized water, and stir at room temperature to form a Na₂WO₄ solution. Add 2 mmol of EDTA-2Na powder to the Na₂WO₄ solution, then add 4 mL of concentrated hydrochloric acid, followed by 2 mL of n-butanol to obtain a mixed solution. Pour the mixed solution into a high-pressure reactor, seal the reactor, and place it in an oven at 200°C for 12 h for heat treatment. After the high-pressure reactor cools naturally, the resulting product is centrifuged and washed with n-butanol three times to obtain a tungsten oxide nanoparticle solution.

[0192] The tungsten oxide nanoparticle solution was spin-coated onto ITO at a speed of 2500 r / min for 30 s. Subsequently, it was heat-treated in air at 150 °C for 30 min to obtain a composite film with a thickness of approximately 40 nm. After annealing, the surface of the resulting ITO / composite film semi-finished device was treated with ultraviolet-ozone for 20 min.

[0193] Comparative Example 10

[0194] This comparative example is basically the same as Example 17, except that the composite film material in this comparative example is manganese oxide, and correspondingly, step S2 is changed to:

[0195] 180 mg of potassium permanganate was weighed and mixed with 60 mL of chlorobenzene to obtain a precursor solution. 10 g of ammonium bicarbonate was weighed, and the precursor solution and ammonium bicarbonate were placed in a beaker and placed in a sealed environment (vacuum drying oven) for heating at 80 °C to carry out the reaction. After the reaction was completed, the mixture was centrifuged at 15000 rpm for 10 min to obtain a manganese oxide nanoparticle solution.

[0196] The manganese oxide particle solution was spin-coated onto ITO at a speed of 2500 r / min for 30 s. Subsequently, it was heat-treated in air at 150 °C for 30 min to obtain a composite film with a thickness of approximately 40 nm. After annealing, the surface of the resulting ITO / composite film semi-finished device was treated with ultraviolet-ozone for 20 min.

[0197] Comparative Example 11

[0198] This comparative example is basically the same as Comparative Example 3, except that in step S3 of this comparative example, the blue quantum dots are replaced with red quantum dots Cd. 0.8 Zn 0.2 Se / Cd 0.5 Zn 0.5 Se / Cd 0.5 Zn 0.5 S / ZnS, with an emission peak wavelength of 623nm.

[0199] Comparative Example 12

[0200] This comparative example is basically the same as Comparative Example 3, except that in step S3 of this comparative example, the blue quantum dots are replaced with green quantum dots Cd. 0.5 Zn 0.5 Se / Cd 0.3 Zn 0.7 Se / ZnSe / Cd 0.1 Zn 0.9 Se / ZnS has an emission peak wavelength of 542nm.

[0201] Comparative Example 13

[0202] This comparative example scheme is basically the same as that of Comparative Example 3, the only difference being that the device structure in this comparative example is ITO / PEDOT:PSS / TFB / QD / ZMO / Ag. Accordingly, step S2 is changed to:

[0203] A PEDOT:PSS aqueous solution was spin-coated onto a cleaned ITO glass slide in air at a spin speed of 3500 r / min for 30 s. After spin-coating, the slide was annealed in air at 150 °C for 30 min. After annealing, the glass slide was quickly transferred to a glove box under a nitrogen atmosphere to obtain a hole injection layer with a thickness of 20 nm. TFB material (concentration of 8 mg / mL, solvent of chlorobenzene) was then spin-coated onto the hole injection layer at a spin speed of 4000 r / min for 30 s. After spin-coating, the slide was annealed in a glove box at 180 °C for 30 min to obtain a hole transport layer with a thickness of 30 nm.

[0204] Experimental Example

[0205] (I) Comparison of film-forming effects

[0206] The mixture from step S2 of Examples 3 and Comparative Examples 1 to 3 was taken. The mixture was spin-coated onto a glass substrate at a rotation speed of 1500 r / min for 30 s, followed by heat treatment in air at 200°C for 30 min to obtain a thin film with a thickness of approximately 40 nm. The surface morphology was then observed using an atomic force microscope (AFM), and the results are as follows. Figure 3 As shown.

[0207] Results Analysis: The film prepared in Example 3 exhibited the best film uniformity, while Comparative Examples 1 to 3 showed poorer uniformity. Specifically, the film uniformity of Comparative Example 3 was relatively worse than that of Example 3. This may be because electron-withdrawing groups can improve the dispersibility of the metal salt solution and, during the heating and crystallization process of the metal salt, prevent the metal salt crystals from agglomerating, increasing the spacing between crystals and allowing the metal salt to form metal oxides in an orderly manner from top to bottom, thereby improving its film uniformity. The film uniformity of Comparative Example 1 was relatively worse than that of Example 3. This may be because the additives can effectively prevent the metal salt liquid from agglomerating into large clusters, thereby forming an amorphous and glassy state with improved film-forming ability, significantly improving the quality of the generated film. The film uniformity of Comparative Example 2 was relatively worse than that of Example 3. This may be because the addition of fuel can promote the combustion reaction, lower the required temperature, thereby improving the crystallinity of the metal salt and promoting crystallization film formation.

[0208] (II) Performance tests were conducted on the quantum dot light-emitting diodes of the embodiments and comparative examples. The test results are shown in Table 1 and Appendix. Figures 4 to 15 .

[0209] (1) The test method for external quantum efficiency (EQE) is as follows:

[0210] The ratio of electron-hole pairs injected into a quantum dot to emitted photons, expressed as a percentage (%), is an important parameter for evaluating the quality of electroluminescent devices. It can be measured using an EQE optical testing instrument. The specific calculation formula is as follows:

[0211]

[0212] Where ηe is the optical output coupling efficiency, ηr is the ratio of recombination carriers to injected carriers, χ is the ratio of the number of excitons generating photons to the total number of excitons, and K R K is the radiation process rate. NR This represents the rate of a non-radiative process.

[0213] Test conditions: Conducted at room temperature with an air humidity of 30-60%.

[0214] (2) The test method for lifespan T95@1000nit is as follows:

[0215] The time required for a device's brightness to decrease to a certain percentage of its maximum brightness under constant current or voltage drive, defined as T95, is the time it takes for the brightness to drop to 95% of its maximum brightness. This lifetime is the measured lifetime. To shorten the testing cycle, device lifetime testing is usually performed at high brightness by accelerating device aging, and the lifetime at high brightness is obtained by fitting an extended exponential decay brightness decay formula. For example, the lifetime at 1000 nits is measured as T95@1000nits. The specific calculation formula is as follows:

[0216]

[0217] Among them, T95 L For longer lifespan at low brightness, T95 H For the measured lifetime under high brightness, L H To accelerate the device to its maximum brightness, L L The value is 1000 nits, and A is the acceleration factor. In this experiment, the lifetime of several groups of QLED devices under rated brightness was measured, and the value of A was found to be 1.7.

[0218] (3) Device conductivity and hole injection performance testing: A QLED efficiency testing system was built using LabVIEW to control QE PRO and Keithley 2400. The system was used to test the current density and voltage relationship curves of complete devices to compare device conductivity. The system was also used to test the current density and voltage relationship curves of single-hole devices, and the current density at 8V was used for comparison. For single-hole devices driven by constant current or voltage, the operating voltage under stable conditions was used for comparison. The operating voltage under stable conditions refers to the operating voltage of the device in a relatively balanced stage after more than 12 hours of operation during the device lifetime test. The voltage at 10 hours was used for comparison.

[0219] The fabrication method of a single hole device (HOD) is basically the same as that of its corresponding complete QLED device, the only difference being the removal of the electron transport layer.

[0220] Table 1

[0221]

[0222]

[0223] As can be seen from the table above:

[0224] The devices in Examples 1 to 25 all exhibit high HOD device current density, EQE, and T95@1000nit, as well as low HOD device operating voltage, and Figures 4 to 15 The devices in each of the embodiments shown exhibited excellent performance curves, demonstrating that the devices with composite film layers proposed in this application can operate and function well and are feasible.

[0225] Devices in Examples 1 to 7 and Examples 18 to 23 have higher HOD device current density, EQE, and T95@1000nit, and lower HOD device operating voltage than device in Comparative Example 3; Device in Example 8 has higher HOD device current density, EQE, and T95@1000nit, and lower HOD device operating voltage than device in Comparative Example 4; Devices in Examples 9 and 10 have higher HOD device current density, EQE, and T95@1000nit, and lower HOD device operating voltage than device in Comparative Example 5; Device in Example 11 has higher HOD device current density, EQE, and T95@1000nit, and lower HOD device operating voltage than device in Comparative Example 6; Device in Example 12 has higher HOD device current density, EQE, and T95@1000nit, and lower HOD device operating voltage than device in Comparative Example 7; Devices in Examples 13 and 14 have higher HOD device current density, EQE, and T95@1000nit, and lower HOD device operating voltage than device in Comparative Example 8. T95@1000nit and a lower HOD device operating voltage; the devices of Examples 15-16 have higher HOD device current density, EQE and T95@1000nit than the device of Comparative Example 9, and a lower HOD device operating voltage; the device of Example 17 has higher HOD device current density, EQE and T95@1000nit than the device of Comparative Example 10, and a lower HOD device operating voltage; it is shown that by using metal oxides with electron-withdrawing groups on the surface as materials in the composite film layer proposed in this application, and by controlling the distribution ratio of electron-withdrawing groups, the hole concentration of the device is effectively increased, thereby significantly increasing the current density on the hole side of the device at 8V, reducing its operating voltage, and thus improving the overall luminous efficiency and lifetime of the device; at the same time, the comparison of the J-EQE curves of the HOD devices of various examples and comparative examples can further confirm that the solution of this application can effectively improve the hole injection concentration of the device, improve the conductivity of the device, and thus achieve the improvement of device efficiency and lifetime.

[0226] Furthermore, in Examples 7 to 17, the improvement in performance of Examples 13 to 17 is more significant, indicating that tungsten salts, manganese salts, and chromium salts are more conducive to improving device performance compared to other metal salts;

[0227] Meanwhile, compared to Example 3, Examples 22 and 23 show more significant improvements, indicating that doping boron into metal oxides is beneficial for further improving device performance.

[0228] Furthermore, comparing Example 3 with Comparative Example 3, Example 24 with Comparative Example 11, and Example 25 with Comparative Example 12, it can be seen that when red and green quantum dots are applied to this scheme, the device lifetime increases from 1326.78 hours to 2212.98 hours, an increase of 1.66 times (green quantum dots increase by 1.48 times), which is worse than the 2.94 times increase of blue quantum dots. This shows that the method of this application is particularly suitable for improving the performance of blue light devices. This also indirectly confirms that the device design and fabrication method of this scheme can effectively increase the hole concentration, so that its advantage in improving device performance is particularly prominent in blue light devices with severe hole concentration deficiency.

[0229] (III) Stability tests were conducted on the devices from Example 3, Comparative Example 3, and Comparative Example 13. The testing method was as follows: the devices were placed in an environment of 24°C and 8% humidity for 60 days, and the changes in EQE before and after the placement were examined. The results are as follows. Figure 16 As shown.

[0230] After 60 days of storage, the EQE of the device in Example 3 decreased by only about 1.13%, while the EQE of the device in Comparative Example 3 decreased by 10.15%, and the EQE of the device in Comparative Example 13 decreased by 12.43%. Moreover, in terms of the curve trend, the downward trend of Example 3 and Comparative Example 3 is relatively gentle, while Comparative Example 13 shows a more obvious downward trend. This indicates that the storage stability of the device in Example 3 is significantly better.

[0231] In summary, this approach utilizes the combustion reaction principle to directly form a composite film layer from metal salts containing electron-withdrawing groups in a one-step process, replacing the traditional hole transport and hole injection layers without damaging the anode. Furthermore, the introduction of fuel and additives lowers the combustion reaction temperature, preventing the aggregation of inorganic nanoparticles and improving the film quality. The resulting self-assembled composite film layer exhibits good film-forming properties, conductivity, and storage stability, while the hole injection concentration is increased, ultimately leading to a significant improvement in device efficiency and lifetime.

[0232] The technical solutions provided by 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 description of the above embodiments is only for the purpose of helping to understand the method 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. An optoelectronic device, characterized in that, The device includes an anode, a composite film layer, a light-emitting layer, and a cathode stacked together. The composite film layer is made of a composite material, which includes a first metal oxide and an organic ligand attached to the surface of the first metal oxide. The organic ligand contains an electron-withdrawing group.

2. The optoelectronic device according to claim 1, characterized in that, In the composite film, the content of electron-withdrawing groups on the side closer to the anode is greater than the content of electron-withdrawing groups on the side closer to the cathode; and / or, The composite film layer further includes a second metal oxide, which comprises an undoped or boron-doped metal oxide, wherein the metal oxide comprises one or more of indium oxide, tin oxide, copper oxide, titanium oxide, zirconium oxide, tungsten oxide, manganese oxide, and chromium oxide; optionally, the boron-doped metal oxide contains 0-3% boron by mass; and / or, The thickness of the composite film is 20–50 nm; and / or, The average particle size of the first metal oxide is 5–10 nm.

3. The optoelectronic device according to claim 2, characterized in that, In the composite film, the content of the second metal oxide on the side closer to the anode is less than the content of the second metal oxide on the side closer to the cathode; and / or, In the composite film layer, the content of the composite material on the side closer to the anode is greater than the content of the composite material on the side closer to the cathode; and / or, In the composite film, the composite near the anode contains a higher content of electron-withdrawing groups than the composite near the cathode; and / or, The average particle size of the second metal oxide is 5–10 nm.

4. The optoelectronic device according to claim 3, characterized in that, In the direction from the cathode to the anode, the content of electron-withdrawing groups in the composite film gradually increases.

5. The optoelectronic device according to claim 1, characterized in that, The electron-withdrawing group includes one or more of the following: sulfonic acid group, halogen group, cyano group, nitro group, carbonyl group, alkynyl group, and alkenyl group; and / or, The first metal oxide includes an undoped or boron-doped metal oxide, which includes one or more of indium oxide, tin oxide, copper oxide, titanium oxide, zirconium oxide, tungsten oxide, manganese oxide, and chromium oxide; optionally, the boron-doped metal oxide has a boron content of 0-3% by mass.

6. The optoelectronic device according to claim 1, characterized in that, The organic ligands include one or more of the following: sulfonic acid group, trifluoromethanesulfonate group, -F, -Cl, -Br, -I, cyano, acetocyano, isopentylcyano, nitro, carbonyl, pentanedionyl, ethynyl, propynyl, vinyl, allyl, acetyl, acetylacetone, trifluoroacetylacetone, hexafluoroacetylacetone, trifluoroacetate, fluoroborate, trifluoromethanethio, and trifluoropentanedione.

7. The optoelectronic device according to claim 1, characterized in that, The material of the light-emitting layer includes organic light-emitting materials or quantum dots. The organic light-emitting materials include at least one of the following: diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives or fluorene derivatives, blue-emitting TBPe fluorescent materials, green-emitting TTPA fluorescent materials, orange-emitting TBRb fluorescent materials, and red-emitting DBP fluorescent materials. The quantum dots include at least one of the following: single-structure quantum dots, core-shell structure quantum dots, and perovskite semiconductor materials. The shell of the core-shell structure quantum dots comprises one or more layers. The material of the single-structure quantum dots, the core material of the core-shell structure quantum dots, and the shell material of the core-shell structure quantum dots respectively include group II-VI compounds and group IV-VI compounds. At least one of group II-V compounds and group I-III-VI compounds; said group II-VI compounds include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeS, CdHgSeSe At least one of Te, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe; the IV-VI compounds include at least one of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe; the III-V compounds include at least one of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, and Ga At least one of NAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb; the group I-III-VI compounds include at least one of CuInS2, CuInSe2, and AgInS2;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 Cs; + Ion, M is a divalent metal cation selected from Pb 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Eu 2+ At least one of them, where X is a halide anion selected from Cl. - ,Br - I - At least one of the following; the general structural formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, wherein B is an organic amine cation selected from CH3(CH2). n-2 NH3 + Or [NH3(CH2)] n NH3] 2+ Where n≥2, M is a divalent metal cation selected from Pb 2+ Sn 2+ Cu 2+ Ni 2+ Cd 2+ Cr 2+ Mn 2+ Co 2+ Fe 2+ 、Ge 2+ Yb 2+ Eu 2+ At least one of them, where X is a halide anion selected from Cl. - ,Br - I - At least one of them; and / or, The anode and cathode each independently include a doped metal oxide particle electrode, a metal-metal oxide composite electrode, a graphene electrode, a carbon nanotube electrode, a metal electrode, or an alloy electrode. The material of the doped metal oxide particle electrode is selected from one or more of indium-doped tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, magnesium-doped zinc oxide, and aluminum-doped magnesium oxide. The metal-metal oxide composite electrode is selected from AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS, and ZnS / Al / ZnS. The material of the metal electrode is selected from one or more of Ag, Al, Cu, Mo, Au, Pt, Si, Ca, Mg, and Ba; and / or, The optoelectronic device further includes an electron transport layer disposed between the light-emitting layer and the cathode. The material of the electron transport layer includes at least one of N-type metal oxide and doped N-type metal oxide. The N-type metal oxide includes one or more of ZnO, TiO2, and SnO2. The N-type metal oxide in the doped N-type metal oxide includes one or more of ZnO, TiO2, and SnO2. The doping element includes one or more of Al, Mg, Li, In, and Ga.

8. A method for fabricating an optoelectronic device, characterized in that, Includes the following steps: Provide anode; A composite film layer is prepared on one side of the anode; A light-emitting layer is disposed on the side of the composite film layer opposite to the anode; A cathode is disposed on the side of the light-emitting layer opposite to the composite film layer; The step of preparing a composite film layer on one side of the anode includes: providing a mixed solution comprising a metal salt, a fuel, and a solvent, wherein the metal salt contains electron-withdrawing groups; The mixed solution is deposited on one side of the anode to form a liquid film; the liquid film is then heat-treated to obtain the composite film layer.

9. The preparation method according to claim 8, characterized in that, The metal salt includes one or more of indium, tin, copper, titanium, zirconium, tungsten, manganese, and chromium salts; and / or, The electron-withdrawing group includes one or more of the following: sulfonic acid group, halogen group, cyano group, nitro group, carbonyl group, alkynyl group, and alkenyl group; and / or, The fuel includes an oxygen-containing reducing agent, which includes one or more of hydrogen peroxide, urea, glycine, citric acid, and tris(hydroxymethyl)aminomethane; and / or, The solvent includes one or more of methanol, ethanol, n-propanol, isopropanol, butanol, tert-butanol, pentanol, glycerol, methoxyethanol, N,N-dimethylformamide, and dimethyl sulfoxide; and / or, The mixed solution further includes additives, optionally including acetylacetone or 2,3-butanedione; and / or, The mixed solution further includes a boron compound containing an electron-withdrawing group, said boron compound including one or more of 2-cyanophenylboronic acid, 4-cyano-2-nitrophenylboronic acid, 2-cyano-4-fluorophenylboronic acid, 2-chloro-4-cyanophenylboronic acid, and 4-boronbenzenesulfonic acid; and / or, Add 10–60 mg of the metal salt per mL of the solvent; and / or, The mass ratio of the metal salt to the fuel is 100:(2-8); and / or, The heat treatment temperature is 150–230°C; and / or, The heat treatment time is 20 to 40 minutes.

10. The preparation method according to claim 9, characterized in that, The indium salt comprises one or more of indium trifluoromethanesulfonate, indium acetylacetone (III), indium trifluoroacetate (III), and indium trifluoroacetylacetone (III); and / or, The tin salt comprises one or more of the following: tributyl(1-propynyl)tin, tetraallyltin, tin(II) hexafluoroacetylacetonate, trifluorophenyltin, dibutyltin (bis(trifluoromethanesulfonate)), butyltin trichloride, stannous fluoroborate, tin trifluoromethanesulfonate, and tin methanesulfonate; and / or, The copper salt comprises one or more of copper fluoroborate, copper acetylacetone, copper trifluoroacetate, copper dichloro(1,10-phenanthroline) (II), copper trifluoromethanethiol (I), copper tetraacetonitrile hexafluorophosphate (I), and copper bis(triphenylphosphine) nitrate; and / or, The titanium salt comprises one or more of titanium triisopropyltrichlorochloride, tetra(2,4-pentanedione)titanium(IV), cyclopentadienyltitanium trichloride(IV), and bis(trifluoromethanesulfonic acid)titanium bis(trifluoromethanesulfonic acid)titanium; and / or The zirconium salt comprises one or more of ammonium fluorozirconate, zirconium dichlorocerocene, zirconium tetratetra(trifluoro-2,4-pentanedione)(IV), zirconium acetylacetonate, and zirconium trichloride cyclopentadienyl(IV); and / or, The tungsten salt comprises one or more of oxotungsten chloride (VI), mesitylenetricarbonyltungsten, pentacarbonyltungsten-N-pentylisocyanate, and bis(cyclopentadienyl)tungsten dichloride; and / or The manganese salt comprises one or more of decacarbonyldimanganese, manganese(II) trifluoromethanesulfonate, manganese acetylacetone, and 2-methylcyclopentadiene tricarbonylmanganese; and / or The chromium salt includes one or more of chromium acetylacetone and chromium tricarbonyl acetylacetone; and / or, When the mixed solution further includes the additive, the mass ratio of the metal salt to the additive in the mixed solution is 100:(1-4); and / or, When the mixed solution further includes the boron compound containing electron-withdrawing groups, the mass percentage of the boron compound containing electron-withdrawing groups in the mixed solution is 1-3% of the total mass of the boron compound containing electron-withdrawing groups and the metal salt.

11. A display device, characterized in that, It includes the optoelectronic device according to any one of claims 1 to 7, or the optoelectronic device prepared by the preparation method according to any one of claims 8 to 10.

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