Thin film, method for manufacturing the same, optoelectronic device, display device

Abstract

This application discloses a thin film and its preparation method, an optoelectronic device, and a display device, relating to the field of display technology. The thin film material includes quantum dots and first bromide ions, with the first bromide ions doped between the quantum dots. The thin film provided in this application exhibits a high fluorescence quantum yield.

Description

Technical Field

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

[0002] Quantum dots are nanoscale semiconductor materials, typically ranging in size from 1 to 20 nanometers, falling within the quantum size range. Because quantum dots are close to or smaller than the wavelength of an electron in three-dimensional space, they exhibit quantum size effects. The unique quantum size effects, macroscopic quantum tunneling effects, and surface effects of quantum dots endow them with outstanding physical properties, especially their optical properties.

[0003] However, among related technologies, the fluorescence quantum yield of thin films prepared by quantum dots is relatively poor and needs further improvement. Summary of the Invention

[0004] In view of this, this application provides a thin film and its preparation method, an optoelectronic device, and a display device.

[0005] The embodiments of this application are implemented as follows: a thin film, the material of which includes quantum dots and a first bromide ion, wherein the first bromide ion is doped between the quantum dots.

[0006] Accordingly, embodiments of this application also provide a method for preparing a thin film, comprising the following steps:

[0007] A preform is provided, wherein the material of the preform includes quantum dots;

[0008] A bromide is provided and disposed on the preformed membrane to obtain a thin film.

[0009] Accordingly, this application also provides an optoelectronic device, including an anode, an active layer and a cathode stacked together, wherein the active layer includes the thin film described above, or a thin film prepared by the preparation method described above.

[0010] Accordingly, this application also provides a display device, which includes the above-mentioned optoelectronic device.

[0011] The thin film provided in this application has a high fluorescence quantum yield. Attached Figure Description

[0012] 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.

[0013] Figure 1 This is a schematic diagram of the structure of the thin film provided in the embodiments of this application;

[0014] Figure 2 This is a flowchart of the thin film preparation method provided in the embodiments of this application;

[0015] Figure 3 This is a schematic diagram of the structure of the optoelectronic device provided in the embodiments of this application.

[0016] Figure label:

[0017] Optoelectronic devices 100;

[0018] Anode 20; Thin film 10; Cathode 30; Hole functional layer 40; Electron functional layer 50. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application.

[0020] In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operating state, specifically the orientation shown in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc., are used merely as illustrative purposes and do not impose numerical requirements or establish a numerical order.

[0021] 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.

[0022] In this application, "at least one" means one or more, and "more than one" means two or more. "One or more", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0023] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0024] Quantum dot light-emitting diodes (QLEDs) use stable quantum dots as the light-emitting material. Furthermore, QLEDs have a long lifespan and simple or no packaging process, making them a promising next-generation flat panel display with broad development prospects. QLEDs are electroluminescent based on inorganic semiconductor quantum dots, which are more stable than organic small molecules and polymers. Due to the quantum confinement effect, quantum dot materials have smaller emission linewidths, resulting in better color purity. However, existing quantum dot films suffer from high defect density, poor thermal stability, and limited luminous efficiency, restricting the further development and application of QLED technology.

[0025] The technical solution of this application is as follows:

[0026] Firstly, please refer to Figure 1 This application provides a thin film 10, the material of which includes quantum dots and a first bromide ion, wherein the first bromide ion is doped between the quantum dots.

[0027] The thin film 10 provided in this application includes quantum dots and a first bromide ion. The first bromide ion can diffuse and migrate between quantum dots through lattice defects, promoting the rearrangement and crystallization of quantum dots. This can effectively reduce the defect density in the thin film 10, reduce non-radiative recombination centers, thereby improving the fluorescence quantum yield of quantum dots, and can also improve the crystal quality, uniformity and thermal stability of the thin film 10, and reduce the surface roughness of the thin film 10.

[0028] In some embodiments, the film material further includes a second bromide ion, which is coordinated with the quantum dot. In other words, the second bromide ion acts as a ligand for the quantum dot, improving the surface state and charge density distribution of the quantum dot, thereby increasing the fluorescence quantum yield of the quantum dot.

[0029] In some embodiments, the mass fraction of the first bromide ion in the thin film 10 is 4 wt% to 8 wt%, for example, it can be 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, or any range between two values. Within the range of said mass fraction, the first bromide ion can sufficiently reduce defects and non-radiative recombination centers in the thin film 10.

[0030] In some embodiments, the mass fraction of the second bromide ion in the thin film 10 is 2 wt% to 5 wt%, for example, it can be 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, or any range between two values. Within the range of said mass fraction, the second bromide ion can sufficiently improve the surface state and charge density distribution of the quantum dots.

[0031] In some embodiments, the thin film 10 includes metal cations. Further, the metal cations include one or more of cadmium ions, zinc ions, mercury ions, tin ions, lead ions, indium ions, gallium ions, aluminum ions, copper ions, silver ions, nickel ions, cesium ions, chromium ions, manganese ions, cobalt ions, iron ions, germanium ions, europium ions, and ytterbium ions. The metal cations can be cations derived from quantum dots, or cations from bromides that were not completely removed during the preparation process when bromide ions were introduced. The first bromide ion maintains the electroneutrality of the thin film 10 by interacting with the metal cations.

[0032] In some embodiments, the quantum dot is bound with a first organic ligand.

[0033] Further, the first organic ligand includes one or more of the following: aliphatic amine ligands having 1 to 24 carbon atoms, fatty acid ligands having 1 to 24 carbon atoms, carboxyl ligands, phosphate ligands, thiol ligands having 1 to 24 carbon atoms, trialiphatic phosphine having 9 to 30 carbon atoms, triarylphosphine having 18 to 30 carbon atoms, trialiphatic phosphine oxide having 9 to 30 carbon atoms, and triarylphosphine oxide having 18 to 30 carbon atoms.

[0034] The aliphatic amine ligands having 1 to 24 carbon atoms include one or more of oleylamine, n-decylamine, octylamine, dioctylamine, trioctylamine, dodecylamine, myristicamine, palmitamine, and stearylamine.

[0035] The fatty acid ligands having 1 to 24 carbon atoms include one or more of oleic acid, decanoic acid, caprylic acid, dicaprylic acid, tricaprylic acid, dodecanoic acid, myristic acid, palmitic acid, stearic acid, thioglycolic acid, and thiopropionic acid.

[0036] The carboxylate ligand is selected from one or more of magnesium carboxylate ligands, calcium carboxylate ligands, aluminum carboxylate ligands, zirconium carboxylate ligands, lithium carboxylate ligands, sodium carboxylate ligands, and barium carboxylate ligands. The carboxyl group in the carboxylate ligand is a fatty acid ion with 1 to 20 carbon atoms.

[0037] The phosphate ligand is selected from one or more of magnesium phosphate ligand, calcium phosphate ligand, aluminum phosphate ligand, zirconium phosphate ligand, lithium phosphate ligand, sodium phosphate ligand, and barium phosphate ligand.

[0038] The thiol ligand having 1 to 24 carbon atoms is selected from one or more of 1,2-ethanedithiol, propanethiol, butanethiol, octylthiol, dodecanethiol, octadecylthiol, benzylthiol, 1,2-benzenethiol, 1,3-benzenethiol, and 1,4-benzenethiol.

[0039] The trialiphatic phosphine having 9 to 30 carbon atoms is selected from one or more of tripropylphosphine, tributylphosphine, tripentylphosphine, trihexylphosphine, triheptylphosphine, trioctylphosphine, trinonylphosphine, and tridecylphosphine.

[0040] The triarylphosphine having 18 to 30 carbon atoms is selected from one or more of triphenylphosphine, tri(m-toluene)phosphine, tri(2-toluene)phosphine, and tri(p-methylphenyl)phosphine.

[0041] The trialiphatic phosphine oxide with 9 to 30 carbon atoms is selected from one or more of tripropylphosphine oxide, tributylphosphine oxide, tripentylphosphine oxide, trihexylphosphine oxide, triheptylphosphine oxide, trioctylphosphine oxide, trinonylphosphine oxide, and tridecylphosphine oxide.

[0042] The triarylphosphine oxide having 18 to 30 carbon atoms is selected from one or more of triphenylphosphine oxide, tri(m-toluene)phosphine oxide, tri(2-toluene)phosphine oxide, and tri(p-methylphenyl)phosphine oxide.

[0043] In some embodiments, the mass ratio of the second bromide ion to the first organic ligand is (2-5):(1-2), for example, it can be 2.5:1.5, 3:1.5, 3.5:1.5, 4:1.5, 4.5:1.5, 4:1.2, 4:1.8, or any range between two ratios. It should be noted that in the actual preparation process, the quantum dots contain organic ligands, and the second bromide ion cannot completely replace the organic ligands; therefore, the quantum dots still contain a portion of the first organic ligand.

[0044] In some embodiments, the average particle size of the quantum dots is 5 nm to 12 nm, for example, it can be 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, or any range between two values. It should be noted that in this application, the particle size of particles such as quantum dots is measured by transmission electron microscopy (TEM), and the same applies below.

[0045] In some embodiments, the quantum dot includes one or more of the following: single-structure quantum dot, core-shell structure quantum dot, and perovskite semiconductor material.

[0046] The materials for the single-structure quantum dots, the core material of the core-shell quantum dots, and the shell material of the core-shell quantum dots can be selected from, but are not limited to, one or more of group II-VI compounds, group IV-VI compounds, group III-V compounds, and group I-III-VI compounds. The shell of the core-shell quantum dots may include one or more layers. The group II-VI compounds may be selected from, but are not limited to, one or more of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe. The IV-VI group compounds may be selected from, but are not limited to, one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe. The group III-V compounds may be selected from, but are not limited to, one or more of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb. The group I-III-VI compounds may be selected from, but are not limited to, one or more of CuInS2, CuInSe2, and AgInS2.

[0047] As an example, the core-shell structured quantum dots can be selected from, but are not limited to, one or more of 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. In the above descriptions of CdSe / ZnS, etc., the " / " indicates that the material after the " / " (as the shell) covers the material before the " / " (as the core).

[0048] The perovskite semiconductor material can be selected from, but is not limited to, 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+ One or more of them, where X is a halide anion selected from Cl. - ,Br - I - One or more of the following. The general structural formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, where 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+ One or more of them, where X is a halide anion selected from Cl. - ,Br - I -One or more of them.

[0049] In some embodiments, the thickness of the thin film 10 is 25 nm to 60 nm, for example, it can be 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, or any range between two values. It should be noted that in this application, the thickness of the film layer is measured by a profilometer, and the same applies below.

[0050] In some embodiments, the surface roughness of the thin film 10 is 1 nm to 1.5 nm, for example, it can be 1.1 nm, 1.2 nm, 1.3 nm, 1.4 nm, or any range between two values. It should be noted that, in this application, the surface roughness of the thin film 10 is measured by AFM atomic force microscopy.

[0051] Secondly, please refer to Figure 2 This application also provides a method for preparing a thin film 10, comprising the following steps:

[0052] S11. A preform is provided, wherein the material of the preform includes quantum dots;

[0053] S12. Provide bromide and place the bromide on the preformed film to obtain film 10.

[0054] In S11:

[0055] The quantum dots in the preform are described above and will not be repeated here.

[0056] The pre-formed film can be prepared using conventional techniques in the art, such as chemical or physical methods. Chemical methods include chemical vapor deposition, continuous ion layer adsorption and reaction, anodic oxidation, electrolytic deposition, and co-precipitation. Physical methods include physical deposition and solution methods. Physical deposition methods include thermal evaporation deposition, electron beam evaporation deposition, magnetron sputtering, multi-arc ion deposition, physical vapor deposition, atomic layer deposition, and pulsed laser deposition, etc. Solution methods can include spin coating, printing, inkjet printing, blade coating, dip coating, immersion coating, spraying, roller coating, casting, slot coating, and strip coating, etc.

[0057] It should be noted that the quantum dot is bound with a second organic ligand, and in the pre-formed film, the mass fraction of the second organic ligand is greater than the mass fraction of the first organic ligand in the thin film 10.

[0058] Specifically, in the preformed membrane, the mass fraction of the second organic ligand is 6wt% to 10wt%, for example, it can be 7wt%, 8wt%, 9wt%, or any range between two values.

[0059] The second organic ligand is introduced during the preparation of quantum dots.

[0060] Specifically, the second organic ligand includes one or more of the following: aliphatic amine ligands having 1 to 24 carbon atoms, fatty acid ligands having 1 to 24 carbon atoms, carboxyl ligands, phosphate ligands, thiol ligands having 1 to 24 carbon atoms, trialiphatic phosphine having 9 to 30 carbon atoms, triarylphosphine having 18 to 30 carbon atoms, trialiphatic phosphine oxide having 9 to 30 carbon atoms, and triarylphosphine oxide having 18 to 30 carbon atoms.

[0061] The aliphatic amine ligands having 1 to 24 carbon atoms include one or more of oleylamine, n-decylamine, octylamine, dioctylamine, trioctylamine, dodecylamine, myristicamine, palmitamine, and stearylamine.

[0062] The fatty acid ligands having 1 to 24 carbon atoms include one or more of oleic acid, decanoic acid, caprylic acid, dicaprylic acid, tricaprylic acid, dodecanoic acid, myristic acid, palmitic acid, stearic acid, thioglycolic acid, and thiopropionic acid.

[0063] The carboxylate ligand is selected from one or more of magnesium carboxylate ligands, calcium carboxylate ligands, aluminum carboxylate ligands, zirconium carboxylate ligands, lithium carboxylate ligands, sodium carboxylate ligands, and barium carboxylate ligands. The carboxyl group in the carboxylate ligand is a fatty acid ion with 1 to 20 carbon atoms.

[0064] The phosphate ligand is selected from one or more of magnesium phosphate ligand, calcium phosphate ligand, aluminum phosphate ligand, zirconium phosphate ligand, lithium phosphate ligand, sodium phosphate ligand, and barium phosphate ligand.

[0065] The thiol ligand having 1 to 24 carbon atoms is selected from one or more of 1,2-ethanedithiol, propanethiol, butanethiol, octylthiol, dodecanethiol, octadecylthiol, benzylthiol, 1,2-benzenethiol, 1,3-benzenethiol, and 1,4-benzenethiol.

[0066] The trialiphatic phosphine having 9 to 30 carbon atoms is selected from one or more of tripropylphosphine, tributylphosphine, tripentylphosphine, trihexylphosphine, triheptylphosphine, trioctylphosphine, trinonylphosphine, and tridecylphosphine.

[0067] The triarylphosphine having 18 to 30 carbon atoms is selected from one or more of triphenylphosphine, tri(m-toluene)phosphine, tri(2-toluene)phosphine, and tri(p-methylphenyl)phosphine.

[0068] The trialiphatic phosphine oxide with 9 to 30 carbon atoms is selected from one or more of tripropylphosphine oxide, tributylphosphine oxide, tripentylphosphine oxide, trihexylphosphine oxide, triheptylphosphine oxide, trioctylphosphine oxide, trinonylphosphine oxide, and tridecylphosphine oxide.

[0069] The triarylphosphine oxide having 18 to 30 carbon atoms is selected from one or more of triphenylphosphine oxide, tri(m-toluene)phosphine oxide, tri(2-toluene)phosphine oxide, and tri(p-methylphenyl)phosphine oxide.

[0070] In S12:

[0071] In some embodiments, the cations in the quantum dots are the same as those in the bromide. This improves the compatibility between the bromide and the quantum dots, and further facilitates the diffusion of bromide ions.

[0072] In some embodiments, the bromide includes one or more of CdBr2, ZnBr2, HgBr2, SnBr2, PbBr2, CuBr2, NiBr2, CrBr2, MnBr2, CoBr2, FeBr2, GeBr2, YbBr2, and EuBr.

[0073] In some embodiments, the average particle size of the bromide is 5 nm to 12 nm, for example, it can be 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm or any range between two values.

[0074] In some embodiments, the step of setting the bromide on the preform includes:

[0075] S121. A bromide solution is provided, the bromide solution comprising bromide and solvent;

[0076] S122. The bromide solution is placed on the pre-formed membrane, and pressure is applied to obtain a thin film 10.

[0077] In S121:

[0078] In some embodiments, the solvent includes one or more of chlorobenzene, diethylene glycol monobutyl ether, trimethoxybutanol, triethylene glycol monobutyl ether, diethylene glycol dimethyl ether, methanol, ethanol, propanol, butanol, ethylene glycol, isopropanol, glycerol, dimethyl sulfoxide, acetone, acetophenone, tetrahydrofuran, N,N-dimethylformamide, ethyl acetate, pyrrole, butyric acid, and cresol.

[0079] In some embodiments, the bromide concentration in the bromide solution is 10 mg / mL to 20 mg / mL, for example, it can be 11 mg / mL, 12 mg / mL, 13 mg / mL, 14 mg / mL, 15 mg / mL, 16 mg / mL, 17 mg / mL, 18 mg / mL, 19 mg / mL, or any range between two values. Within this concentration range, it is beneficial for the bromide to be uniformly dispersed in the solvent.

[0080] In S122:

[0081] In some embodiments, the applied pressure is 40 kPa to 60 kPa, for example, it can be 42 kPa, 45 kPa, 48 kPa, 50 kPa, 52 kPa, 55 kPa, 58 kPa, or any range between two values. The applied pressure time is 0.3 h to 24 h, for example, it can be 2 h, 5 h, 8 h, 10 h, 12 h, 15 h, 18 h, 20 h, 22 h, or any range between two values. Thus, under the applied pressure conditions, it is beneficial to improve the film-forming uniformity of the thin film 10 and promote the penetration of bromide into the pre-formed film, so that the bromide ions improve the performance of the quantum dots and the thin film 10.

[0082] In some embodiments, the applied pressure further includes heat treatment, wherein the applied pressure is performed during a first time period and the heat treatment is performed during a second time period, the first time period and the second time period at least partially overlapping.

[0083] Furthermore, the heat treatment temperature is 80℃ to 100℃, for example, it can be 82℃, 85℃, 88℃, 90℃, 92℃, 95℃, 98℃, or any range between two values; the heat treatment time is 20min to 60min, for example, it can be 25min, 30min, 35min, 40min, 45min, 50min, 55min, or any range between two values. Thus, under the heat treatment conditions, the diffusion of bromide ions from the bromide into the preformed film can be accelerated, making the diffusion degree controllable and improving the film-forming properties of the film 10.

[0084] It should be noted that, in this application, heat treatment refers to heat treatment methods other than electron beam heat treatment, such as infrared heating, resistance heating, gas convection heating, etc.

[0085] In some embodiments, under the applied pressure, electron beam heat treatment is further performed, the applied pressure is performed during a first time period, and the heat treatment is performed during a third time period, the first time period and the third time period at least partially overlap.

[0086] Furthermore, the accelerating voltage of the electron beam heat treatment is 1×10⁻⁶. 3 K~5×10 3 K, for example, can be 2 × 10 3 K, 3×10 3 K, 4×10 3 K or the range between any two values, etc.; the energy density of the electron beam heat treatment is 0.6 J / cm². 2 ~1J / cm 2 For example, it can be 0.7 J / cm2 0.8J / cm 2 0.9J / cm 2 The electron beam heat treatment time is 30 min to 90 min, for example, it can be 40 min, 50 min, 60 min, 70 min, 80 min, or any range between two values. Thus, under the electron beam heat treatment conditions, the diffusion of bromide ions from the bromide into the pre-formed film can be accelerated, making the diffusion degree controllable and improving the film-forming properties of the thin film 10.

[0087] In some embodiments, the electron beam heat treatment includes performing electron beam heat treatment multiple times at intervals.

[0088] Furthermore, the time between two consecutive electron beam thermal treatments can be 5s to 15s, for example, 6s, 7s, 8s, 9s, 10s, 11s, 12s, 13s, 14s, or any range between two values. The time for a single electron beam thermal treatment can be 0.1s to 1s, for example, 0.2s, 0.3s, 0.4s, 0.5s, 0.6s, 0.7s, 0.8s, 0.9s, or any range between two values. Performing electron beam thermal treatments at intervals can reduce heat transfer and further reduce the impact of temperature on the properties of the thin film 10.

[0089] It should be noted that both the heat treatment and the electron beam heat treatment are performed on bromides to avoid affecting the performance of the preform by heating or electron beam heat treatment of the preform.

[0090] The overlap between the first and second time periods is 0–60 minutes, for example, it can be 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, or any range between two values. Within the aforementioned overlapping time range, the synergistic effect of applied pressure and heat treatment promotes the diffusion of bromide ions.

[0091] It should be noted that when the overlap between the first time period and the second time period is 0, it means that the application of pressure and the heat treatment are performed alternately. Pressure can be applied first and then heat treatment can be performed, or heat treatment can be performed first and then pressure can be applied.

[0092] The overlap between the first and third time periods is 0–90 minutes, for example, it can be 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, or any range between two values. Within the overlapped time range, the synergistic effect of applied pressure and electron beam heat treatment is conducive to the diffusion of bromide ions.

[0093] It should be noted that when the overlap between the first time period and the third time period is 0, it means that the application of pressure and the electron beam heat treatment are performed alternately. The application of pressure can be performed first and then the electron beam heat treatment can be performed first and then the pressure can be applied.

[0094] The method for preparing the thin film 10 provided in this application involves placing a bromide on a pre-formed film and then subjecting it to pressure treatment, allowing bromide ions from the bromide to permeate into the pre-formed film. A portion of the bromide ions (i.e., the aforementioned first bromide ions) migrate between quantum dots, promoting rearrangement and crystallization of the quantum dots and reducing surface defects and non-radiative recombination centers. Another portion of the bromide ions (i.e., the aforementioned second bromide ions) undergoes a displacement reaction with organic ligands on the quantum dots, altering the surface state and charge density distribution of the quantum dots and improving the fluorescence quantum yield. Furthermore, the method of placing bromide on the pre-formed film to allow bromide diffusion can reduce the surface roughness of the thin film 10 and improve its film-forming properties.

[0095] In some embodiments, after the bromide is applied to the preform, the process further includes cleaning with a cleaning agent. The cleaning agent removes bromide that has not penetrated into the preform, as well as some of the second organic ligands displaced by bromide ions.

[0096] Furthermore, the cleaning agent includes one or more of the following: chlorobenzene, diethylene glycol monobutyl ether, trimethoxybutanol, triethylene glycol monobutyl ether, diethylene glycol dimethyl ether, methanol, ethanol, propanol, butanol, ethylene glycol, isopropanol, glycerol, dimethyl sulfoxide, acetone, acetophenone, tetrahydrofuran, N,N-dimethylformamide, ethyl acetate, pyrrole, butyric acid, and cresol.

[0097] Thirdly, please refer to Figure 3 This application also provides an optoelectronic device 100, which includes an anode 20, an active layer and a cathode 30 stacked together. The active layer includes the thin film 10 described above, or the thin film 10 prepared by the above preparation method.

[0098] This application uses the aforementioned thin film 10 as the active layer of the optoelectronic device 100, which can effectively improve the luminous efficiency, stability and lifespan of the optoelectronic device 100.

[0099] In some embodiments, the active layer includes a light-emitting layer.

[0100] In some embodiments, the optoelectronic device 100 includes a light-emitting diode.

[0101] In some embodiments, the optoelectronic device 100 further includes one or more of a hole functional layer 40 and an electronic functional layer 50, wherein the hole functional layer 40 is disposed between the anode 20 and the active layer, and the electronic functional layer 50 is disposed between the active layer and the cathode 30.

[0102] Furthermore, the hole functional layer 40 includes one or more of a hole injection layer and a hole transport layer.

[0103] The electronic functional layer 50 includes one or more of an electron injection layer and an electron transport layer.

[0104] In some embodiments, the anode 20 and the cathode 30 each independently comprise one or more of a metal, a carbon material, and a metal oxide; the metal comprises one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon material comprises one or more of graphite, carbon nanotubes, graphene, and carbon fibers; the metal oxide comprises a metal oxide electrode or a composite electrode consisting of a metal sandwiched between doped or undoped transparent metal oxides, wherein the material of the metal oxide electrode comprises one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, MoO3, and AMO; and the composite electrode comprises one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2. In this context, " / " indicates a stacked structure. For example, AZO / Ag / AZO represents a composite electrode consisting of sequentially stacked AZO, Ag, and AZO layers.

[0105] Furthermore, in the anode 20 and / or the cathode 30, the metal thickness is less than or equal to 35 nm, and the transmittance of visible light is greater than or equal to 90%. This is beneficial for light emission.

[0106] In some embodiments, the material of the electronic functional layer 50 includes an organic N-type semiconductor material or an inorganic N-type semiconductor material, wherein the organic N-type semiconductor material includes 8-hydroxyquinoline aluminum, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi), 4,7-diphenyl-1,10-o-diazaphenanthroline, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole, bis(2-methyl-8-hydroxyquinoline-N1,O8)-( 1,1'-Biphenyl-4-hydroxy)aluminum, bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum, 2,2'-(1,3-phenyl)bis[5-(4-tert-butylphenyl)-1,3,4-oxadiazole], tris[2,4,6-trimethyl-3-(3-pyridyl)phenyl]borane, tetra[(m-pyridyl)-phenyl-3-yl]biphenyl, 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1”-terphenyl]-3,3”-diyl]dipyridine, 1,3-bis(3,5-dipyridyl-3-ylphenyl) The inorganic N-type semiconductor material comprises one or more of the following: n-(naphthyl-1-yl)-n,n′-bis(phenyl)benzidine; n,n′-bis(naphthyl-1-yl)-n,n′-bis(phenyl)benzidine; the inorganic N-type semiconductor material comprises one or more of the following: first doped metal oxide particles, first undoped metal oxide particles, group IIB-VIA semiconductor materials, group IIIA-VA semiconductor materials, and group IB-IIIA-VIA semiconductor materials; the first undoped metal oxide particles comprise one or more of the following: ZnO, TiO2, SnO2, ZrO2, and Ta2O5; the metal oxide in the first doped metal oxide particles comprises ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The first doped metal oxide particle contains one or more of the following: iO2, SnO2, ZrO2, Ta2O5, and Al2O3; the doping element in the first doped metal oxide particle includes one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga; the IIB-VIA group semiconductor material includes one or more of ZnS, ZnSe, and CdS; the IIIA-VA group semiconductor material includes one or more of InP and GaP; and the IB-IIIA-VIA group semiconductor material includes one or more of CuInS and CuGaS.

[0107] In some embodiments, the material of the hole functional layer 40 includes an organic p-type semiconductor material or an inorganic p-type semiconductor material, wherein the organic p-type semiconductor material includes 4,4'-N,N'-dicarbazolyl-biphenyl, N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro, N,N'- bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 4,4',4'-tris(N-carbazolyl)-triphenylamine, 4,4',4'-tris(carbazol-9-yl)triphenylamine, trichloroisocyanuric acid, terbium-doped phosphate-based green luminescent materials, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4, 4'-(N-(4-sec-butylphenyl)diphenylamine)], poly(4-butylphenyl-diphenylamine), poly[bis(4-phenyl)(4-butylphenyl)amine], polyaniline, polypyrrole, poly(p-)phenylenevinylene, poly(phenylenevinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene], copper phthalocyanine, aromatic tertiary amines, polynuclear aromatic tertiary amines, 4,4'-bis(p-carbazolyl)-1, 1'-Biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT, PEDOT:PSS and its derivatives, PEDOT:PSS derivatives doped with s-MoO3, poly(N-vinylcarbazole) and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, N,N'-di(naphthyl-1-yl)-N,N'-diphenylbenzidine, spiron NPB, nanocrystalline diamond, microcrystalline cellulose and tetracyanoquinone dimethane, doped graphene, undoped graphene;The inorganic P-type semiconductor material comprises one or more of the following: second-doped metal oxide particles, second-undoped metal oxide particles, metal sulfides, metal selenides, and metal nitrides. The metal oxides in the second-doped and second-undoped metal oxide particles each independently comprise one or more of MoO3, WO3, NiO, CrO3, CuO, and V2O5. The doping element in the second-doped metal oxide particles comprises one or more of Mo, W, Ni, Cr, Cu, and V. The metal sulfide comprises one or more of CuS, MoS3, and WS3. The metal selenide comprises one or more of MoSe3 and WSe3. The metal nitride comprises P-type gallium nitride.

[0108] Fourthly, embodiments of this application also provide a display device, which includes the aforementioned optoelectronic device 100.

[0109] The display device can be any electronic product with display function, 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. Among them, smart wearable devices can be, for example, smart bracelets, smartwatches, virtual reality (VR) headsets, etc.

[0110] The present application will be specifically described below through specific embodiments. The following embodiments are only some embodiments of the present application and are not intended to limit the present application.

[0111] Example 1

[0112] This embodiment provides a thin film, prepared by the following method:

[0113] A pre-coated film was formed by spin-coating a 20 mg / mL CdS quantum dot n-octane dispersion at a spin speed of 2000 rpm for 30 s.

[0114] A 15 mg / mL CdBr2 ethanol dispersion was spin-coated onto the pre-formed membrane at a spin speed of 2000 rpm for 30 s. Then, a pressure of 50 kPa was applied and the membrane was allowed to stand for 12 h to allow CdBr2 to diffuse into the pre-formed membrane. The membrane was then placed in an ambient pressure environment and rinsed with ethanol. The rinsing was repeated three times to obtain a film with a thickness of 5 nm.

[0115] Example 2

[0116] This embodiment is basically the same as Embodiment 1, except that CdS quantum dots are replaced with ZnS quantum dots and CdBr2 is replaced with ZnBr2.

[0117] Example 3

[0118] This embodiment is basically the same as Embodiment 1, except that the pressure applied in this embodiment is 60 kPa.

[0119] Example 4

[0120] This embodiment is basically the same as embodiment 1, except that the pressure applied in this embodiment is 40 kPa.

[0121] Example 5

[0122] This embodiment is basically the same as Embodiment 1, except that the pressure is applied for 24 hours in this embodiment.

[0123] Example 6

[0124] This embodiment is basically the same as Embodiment 1, except that the pressure application time in this embodiment is 0.3h.

[0125] Example 7

[0126] This embodiment is basically the same as Embodiment 1, except that in this embodiment, heat treatment is performed during the application of 50 kPa pressure, the heat treatment temperature is 90°C, the heat treatment time is 30 min, and rinsing is performed after the heat treatment is completed.

[0127] Example 8

[0128] This embodiment is basically the same as embodiment 7, except that the heat treatment temperature in this embodiment is 100°C.

[0129] Example 9

[0130] This embodiment is basically the same as embodiment 7, except that the heat treatment temperature in this embodiment is 80°C.

[0131] Example 10

[0132] This embodiment is basically the same as embodiment 7, except that the heat treatment time in this embodiment is 40 minutes.

[0133] Example 11

[0134] This embodiment is basically the same as embodiment 7, except that the heat treatment time in this embodiment is 20 minutes.

[0135] Example 12

[0136] This embodiment is basically the same as Embodiment 1, except that electron beam heat treatment is performed during the application of pressure of 50 kPa, and the accelerating voltage of the electron beam is 3 × 10⁻⁶ kPa. 3K, energy density 0.825 J / cm³ 2 The single electron beam heat treatment time is 10 -2 The process is repeated 360 times at 10-second intervals, and rinsing is performed immediately after the electron beam heat treatment is completed.

[0137] Example 13

[0138] This embodiment is basically the same as Embodiment 12, except that the accelerating voltage of the electron beam is 5 × 10⁻⁶. 3 K.

[0139] Example 14

[0140] This embodiment is basically the same as Embodiment 12, except that the accelerating voltage of the electron beam is 10. 3 K.

[0141] Example 15

[0142] This embodiment is basically the same as Embodiment 12, except that the energy density of the electron beam is 1 J / cm². 2 .

[0143] Example 16

[0144] This embodiment is basically the same as Embodiment 12, except that the energy density of the electron beam is 0.6 J / cm². 2 .

[0145] Comparative Example 1

[0146] This comparative example is basically the same as Example 1, except that the film in this comparative example is the pre-made film in Example 1.

[0147] Comparative Example 2

[0148] This comparative example is basically the same as Example 7, except that CdBr2 was not spin-coated in this comparative example, and the pre-made film was directly heat-treated.

[0149] Comparative Example 3

[0150] This comparative example is basically the same as Example 12, except that CdBr2 was not spin-coated in this comparative example, and the pre-formed film was directly subjected to electron beam heat treatment.

[0151] Comparative Example 4

[0152] This comparative example is basically the same as Example 1, except that in this comparative example, the octane dispersion of CdS quantum dots and the ethanol dispersion of CdBr2 are mixed and then spin-coated to prepare a thin film.

[0153] Comparative Example 5

[0154] This comparative example is basically the same as Example 1, except that in this comparative example, after spin-coating the ethanol dispersion of CdBr2, no pressure treatment was applied, and the CdBr2 film layer was directly formed on the pre-made film.

[0155] The fluorescence quantum yield PLQY and surface roughness Rq of the films of Examples 1-16 and Comparative Examples 1-5 were tested respectively, and the results are shown in Table 1.

[0156] The photoluminescence quantum yield (PLQY) was measured using a steady-state fluorescence spectrometer (FS5) from Edinburgh Instruments, with the SC-30 accessory used for measuring the fluorescence quantum yield. Surface roughness (Ra) was measured using atomic force microscopy (AFM).

[0157] Table 1

[0158]

[0159]

[0160] As shown in Table 1:

[0161] As can be seen from Examples 1-6 and Comparative Examples 1 and 4-5, this application sets bromide ions on the preform and then allows the bromide ions to permeate into the preform by applying pressure to obtain a thin film. The bromide ions exist in the thin film in a manner that connects to the surface of the quantum dots and is free between the quantum dots, which effectively improves the fluorescence quantum yield of the thin film, reduces the surface roughness of the thin film, and improves the density and uniformity of the thin film.

[0162] As can be seen from Examples 1, 7-11 and Comparative Examples 1-2, after bromide ions are placed on the preform, heating can promote the penetration of bromide ions into the preform, shorten the time, and facilitate the uniform distribution of bromide ions in the film, thereby improving the film performance, increasing the fluorescence quantum yield and reducing the surface roughness.

[0163] As can be seen from Examples 1, 12-16 and Comparative Examples 1 and 3, electron beam heat treatment can promote the movement and diffusion of bromide ions. Its effect is better than static pressure and heating. It significantly improves the fluorescence quantum yield and surface roughness of the film, thus improving the performance of the film.

[0164] Device Example 1

[0165] This embodiment provides an optoelectronic device, the fabrication method of which is as follows:

[0166] Provide ITO glass, use a cotton swab dipped in a small amount of soapy water to wipe the ITO surface to remove visible impurities, then use deionized water, acetone, ethanol, and isopropanol for ultrasonic cleaning for 15 minutes, then blow dry with nitrogen gas and irradiate with UV for 15 minutes to form an ITO anode.

[0167] PEDOT:PSS was spin-coated onto the ITO anode at a speed of 5000 rpm for 30 seconds, followed by heating at 150°C for 15 minutes to form a hole injection layer.

[0168] TFB was dissolved in chlorobenzene at a concentration of 8 mg / mL and spin-coated onto the hole injection layer at a speed of 3000 rpm for 30 s. Then, it was treated with UV irradiation for 10 min and heated at 200℃ for 10 min to form a hole transport layer.

[0169] A thin film (light-emitting layer) is formed on the hole transport layer using the method described in Example 1;

[0170] An ethanol dispersion of ZnO was spin-coated onto a thin film at a speed of 3000 rpm for 30 seconds, followed by heating at 80°C for 30 minutes to form an electron transport layer.

[0171] Ag was thermally evaporated onto the electron transport layer at a rate of 1 Å / s for 200 s to form a cathode with a thickness of 20 nm.

[0172] Optoelectronic devices are obtained by encapsulating with epoxy resin.

[0173] Device Examples 2-16

[0174] Device Examples 2-16 are basically the same as Device Example 1, except that thin films are prepared according to Examples 2-16 respectively.

[0175] Device Comparison Examples 1-5

[0176] The devices in Comparative Examples 1 to 5 are basically the same as those in Device Example 1, except that thin films were prepared according to Comparative Examples 1 to 5 respectively.

[0177] The current efficiency CE and maximum luminance L of the optoelectronic devices in Examples 1-16 and Comparative Examples 1-5 were tested respectively. max The service life of T95 and T95@1000nit was also determined, and the results are shown in Table 2.

[0178] The current efficiency and maximum brightness were obtained through testing and calculation using a Keithley 2400 high-precision digital source meter, an Ocean OpticUSB2000+ spectrometer, and an LS-160 luminance meter.

[0179] The test methods for lifetimes T95 and T95@1000nit are as follows: Under constant current or voltage drive, the time required for the device's brightness to decrease to a certain percentage of its maximum brightness is defined as T95. 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 the extended exponential decay brightness decay formula. For example, the lifetime at 1000nit is measured as T95@1000nit. The specific calculation formula is as follows:

[0180]

[0181] 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.

[0182] Table 2

[0183]

[0184]

[0185] As shown in Table 2:

[0186] As can be seen from Device Examples 1-6 and Device Comparative Examples 1 and 4-5, applying the thin film provided in this application to the light-emitting layer of an optoelectronic device can effectively improve the current efficiency and maximum brightness of the optoelectronic device, extend the service life of the optoelectronic device, and enhance the performance of the optoelectronic device.

[0187] As can be seen from Device Examples 1, 7-11 and Device Comparative Examples 1-2, the application of a thin film that promotes the diffusion and permeation of bromide ions by heating to the light-emitting layer of an optoelectronic device is more conducive to the migration and diffusion of bromide ions than the static method. Device Examples 1, 7-11 significantly improve the current efficiency and maximum brightness of the optoelectronic device compared to Device Comparative Examples 1-2, and extend the service life of the optoelectronic device.

[0188] As can be seen from Device Examples 1, 12-16 and Device Comparative Examples 1 and 3, electron beam thermal treatment of bromide ions on the pre-film is beneficial to the diffusion of bromide ions in the pre-film. Bromide ions can reduce the defect density in the light-emitting layer and reduce non-radiative recombination centers by changing the surface state and charge density distribution of quantum dots, thereby promoting the effective recombination of electrons and holes, thus improving the current efficiency and maximum brightness of optoelectronic devices. Furthermore, the crystal quality and uniformity of the light-emitting layer are effectively improved, thereby improving the stability of optoelectronic devices and extending their service life.

[0189] 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. A thin film, characterized in that, The material of the thin film includes quantum dots and a first bromide ion, wherein the first bromide ion is doped between the quantum dots.

2. The thin film as described in claim 1, characterized in that, The material of the thin film further includes a second bromide ion, which is coordinated with the quantum dot; and / or The quantum dot is bound with a first organic ligand; and / or The thin film contains metal cations.

3. The thin film as described in claim 2, characterized in that, In the thin film, the mass fraction of the first bromide ion is 4 wt% to 8 wt%; and / or In the film, the mass fraction of the second bromide ion is 2wt% to 5wt%; and / or The mass ratio of the second bromide ion to the first organic ligand is (2-5):(1-2); and / or The metal cations include one or more of the following: cadmium ion, zinc ion, mercury ion, tin ion, lead ion, indium ion, gallium ion, aluminum ion, copper ion, silver ion, nickel ion, cesium ion, chromium ion, manganese ion, cobalt ion, iron ion, germanium ion, europium ion, and ytterbium ion.

4. The thin film as described in claim 2, characterized in that, The quantum dots are selected from one or more of single-structure quantum dots, core-shell quantum dots, and perovskite quantum dots; the materials of the single-structure quantum dots, the core materials of the core-shell quantum dots, and the shell materials of the core-shell quantum dots are respectively selected from one or more of group II-VI compounds, group IV-VI compounds, group III-V compounds, and group I-III-VI compounds; the shell of the core-shell quantum dots includes one or more layers; the group II-VI compounds are selected from CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, C One or more of dSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe; the IV-VI group compounds are selected from SnS, SnSe, S The compounds are selected from one or more of the following: nTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe; the III-V compounds are selected from GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, and AlNAs. One or more of AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb; wherein the group I-III-VI compounds are selected from one or more of CuInS2, CuInSe2, and AgInS2;The core-shell quantum dots are selected from one or more of 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; the perovskite quantum dots are made of doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors; the inorganic perovskite semiconductor has the general structural formula 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+ One or more of the following, where X is a halide anion selected from Cl... - ,Br - I - One or more of the following; the general structural formula of the organic-inorganic hybrid perovskite semiconductor is BMX3, where 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+ One or more of the following, where X is a halide anion selected from Cl... - ,Br - I - One or more of the following; and / or The first organic ligand comprises one or more of the following: aliphatic amine ligands with 1 to 24 carbon atoms, fatty acid ligands with 1 to 24 carbon atoms, carboxylate ligands, phosphate ligands, thiols with 1 to 24 carbon atoms, trialiphatic phosphine with 9 to 30 carbon atoms, triarylphosphine with 18 to 30 carbon atoms, trialiphatic phosphine oxide with 9 to 30 carbon atoms, and triarylphosphine oxide with 18 to 30 carbon atoms; optionally, the aliphatic amine ligands with 1 to 24 carbon atoms include oleylamine, n-decylamine, octylamine, dioctylamine, trioctylamine, dodecylamine, myristylamine, palmitamine, and stearylamine. One or more; optionally, the fatty acid ligand having 1 to 24 carbon atoms includes one or more of oleic acid, n-decanoic acid, octanoic acid, dioctanoic acid, trioctanoic acid, dodecanoic acid, myristic acid, palmitic acid, stearic acid, mercaptoacetic acid, and mercaptopropionic acid; optionally, the carboxyl salt ligand is selected from one or more of magnesium carboxylate ligand, calcium carboxylate ligand, aluminum carboxylate ligand, zirconium carboxylate ligand, lithium carboxylate ligand, sodium carboxylate ligand, and barium carboxylate ligand; wherein the carboxyl group in the carboxyl salt ligand is a fatty acid ion having 1 to 20 carbon atoms; optionally, the phosphate ligand is selected from magnesium phosphate ligand, calcium phosphate ligand, ... One or more of aluminum phosphate ligands, zirconium phosphate ligands, lithium phosphate ligands, sodium phosphate ligands, and barium phosphate ligands; optionally, the thiol ligand having 1 to 24 carbon atoms is selected from one or more of 1,2-ethanedithiol, propanethiol, butanethiol, octylthiol, dodecanethiol, octadecylthiol, benzenethiol, 1,2-benzenethiol, 1,3-benzenethiol, and 1,4-benzenethiol; optionally, the trialiphatic phosphine having 9 to 30 carbon atoms is selected from one or more of tripropylphosphine, tributylphosphine, tripentylphosphine, trihexylphosphine, triheptylphosphine, trioctylphosphine, trinonylphosphine, and tridecylphosphine; optionally, the... The triarylphosphine having 18 to 30 carbon atoms is selected from one or more of triphenylphosphine, tri(m-toluene)phosphine, tri(2-toluene)phosphine, and tri(p-methylphenyl)phosphine; optionally, the trialilophosphine oxide having 9 to 30 carbon atoms is selected from one or more of tripropylphosphine oxide, tributylphosphine oxide, tripentylphosphine oxide, trihexylphosphine oxide, triheptylphosphine oxide, trioctylphosphine oxide, trinonylphosphine oxide, and tridecylphosphine oxide; optionally, the triarylphosphine oxide having 18 to 30 carbon atoms is selected from one or more of triphenylphosphine oxide, tri(m-toluene)phosphine oxide, tri(2-toluene)phosphine oxide, and tri(p-methylphenyl)phosphine oxide.

5. The thin film as claimed in claim 1, characterized in that, The average particle size of the quantum dots is 5 nm to 12 nm; and / or The thickness of the thin film is 25 nm to 60 nm; and / or The surface roughness of the film is 1 nm to 1.5 nm.

6. A method for preparing a thin film, characterized in that, Includes the following steps: A preform is provided, wherein the material of the preform includes quantum dots; A bromide is provided and disposed on the preformed membrane to obtain a thin film.

7. The preparation method according to claim 6, characterized in that, The cations in the quantum dots are the same as the cations in the bromide; and / or The bromide includes one or more of CdBr2, ZnBr2, HgBr2, SnBr2, PbBr2, CuBr2, NiBr2, CrBr2, MnBr2, CoBr2, FeBr2, GeBr2, YbBr2, and EuBr; and / or The bromide has an average particle size of 5 nm to 12 nm; and / or In the pre-formed film, a second organic ligand is bound to the quantum dots; optionally, the mass fraction of the second organic ligand is 6 wt% to 10 wt%; optionally, the second organic ligand includes one or more of the following: aliphatic amine ligands with 1 to 24 carbon atoms, fatty acid ligands with 1 to 24 carbon atoms, carboxyl ligands, phosphate ligands, thiols with 1 to 24 carbon atoms, trialiphatic phosphine with 9 to 30 carbon atoms, triarylphosphine with 18 to 30 carbon atoms, trialiphatic phosphine oxide with 9 to 30 carbon atoms, and triarylphosphine oxide with 18 to 30 carbon atoms; wherein the carbon atom number is 1 The fatty amine ligands with 1 to 24 carbon atoms include one or more of oleylamine, n-decylamine, octylamine, dioctylamine, trioctylamine, dodecylamine, myristicamine, palmitamine, and stearylamine; the fatty acid ligands with 1 to 24 carbon atoms include one or more of oleic acid, n-decanoic acid, octanoic acid, dioctanoic acid, trioctanoic acid, dodecanoic acid, myristic acid, palmitic acid, stearic acid, mercaptoacetic acid, and mercaptopropionic acid; the carboxyl salt ligand is selected from one or more of magnesium carboxylate ligand, calcium carboxylate ligand, aluminum carboxylate ligand, zirconium carboxylate ligand, lithium carboxylate ligand, sodium carboxylate ligand, and barium carboxylate ligand; wherein the carboxyl group in the carboxyl salt ligand has 1 to 2 carbon atoms. The fatty acid anion has a carbon number of 0; the phosphate ligand is selected from one or more of magnesium phosphate ligand, calcium phosphate ligand, aluminum phosphate ligand, zirconium phosphate ligand, lithium phosphate ligand, sodium phosphate ligand, and barium phosphate ligand; the thiol ligand with a carbon number of 1 to 24 is selected from one or more of 1,2-ethanedithiol, propanethiol, butanethiol, octylthiol, dodecanethiol, octadecylthiol, benzylthiol, 1,2-benzenethiol, 1,3-benzenethiol, and 1,4-benzenethiol; the trialiphatic phosphine with a carbon number of 9 to 30 is selected from tripropylphosphine, tributylphosphine, tripentylphosphine, trihexylphosphine, triheptylphosphine, trioctylphosphine, trinonylphosphine, and tri... One or more of decylphosphine; the triarylphosphine having 18 to 30 carbon atoms is selected from one or more of triphenylphosphine, tri(m-toluene)phosphine, tri(2-toluene)phosphine, and tri(p-methylphenyl)phosphine; the trialilophosphine having 9 to 30 carbon atoms is selected from one or more of tripropylphosphine, tributylphosphine, tripentylphosphine, trihexylphosphine, triheptylphosphine, trioctylphosphine, trinonylphosphine, and tridecylphosphine; the triarylphosphine having 18 to 30 carbon atoms is selected from one or more of triphenylphosphine, tri(m-toluene)phosphine, tri(2-toluene)phosphine, and tri(p-methylphenyl)phosphine.

8. The preparation method according to claim 6, characterized in that, The step of setting the bromide on the preform includes: A bromide solution is provided, the bromide solution comprising a bromide and a solvent; The bromide solution is placed on the pre-formed membrane, and pressure is applied to obtain a thin film.

9. The preparation method according to claim 8, characterized in that, The applied pressure is 40 kPa to 60 kPa, and the applied pressure is applied for 0.3 h to 24 h; and / or In the bromide solution, the mass concentration of the bromide is 10 mg / mL to 20 mg / mL; and / or The solvent includes one or more of the following: chlorobenzene, diethylene glycol monobutyl ether, trimethoxybutanol, triethylene glycol monobutyl ether, diethylene glycol dimethyl ether, methanol, ethanol, propanol, butanol, ethylene glycol, isopropanol, glycerol, dimethyl sulfoxide, acetone, acetophenone, tetrahydrofuran, N,N-dimethylformamide, ethyl acetate, pyrrole, butyric acid, and cresol.

10. The preparation method according to claim 8, characterized in that, The application of pressure also includes heat treatment, wherein the application of pressure is carried out during a first time period and the heat treatment is carried out during a second time period, wherein the first time period and the second time period at least partially overlap. or The applied pressure also includes electron beam heat treatment, wherein the applied pressure is performed during a first time period and the heat treatment is performed during a third time period, wherein the first time period and the third time period at least partially overlap.

11. The preparation method according to claim 10, characterized in that, The heat treatment temperature is 80℃~100℃, and the time is 20min~60min; or The accelerating voltage of the electron beam heat treatment is 1×10⁻⁶. 3 K~5×10 3 K, with an energy density of 0.6 J / cm³ 2 ~1J / cm 2 The time is 30 to 90 minutes; or The overlap between the first time period and the second time period is 0–60 min; or The overlap between the first time period and the third time period is 0 to 90 minutes.

12. An optoelectronic device, characterized in that, It includes an anode, an active layer, and a cathode stacked together, wherein the active layer includes a thin film as described in any one of claims 1 to 5, or a thin film prepared by the preparation method as described in any one of claims 6 to 11.

13. The optoelectronic device as described in claim 12, characterized in that, The anode and the cathode each independently comprise one or more of a metal, a carbon material, and a metal oxide; the metal comprises one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon material comprises one or more of graphite, carbon nanotubes, graphene, and carbon fibers; the metal oxide comprises a metal oxide electrode or a composite electrode consisting of a metal sandwiched between doped or undoped transparent metal oxides; the metal oxide electrode material comprises one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, MoO3, and AMO; the composite electrode comprises one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2; and / or The optoelectronic device further includes an electronic functional layer disposed between the active layer and the cathode; the material of the electronic functional layer includes organic N-type semiconductor materials or inorganic N-type semiconductor materials, wherein the organic N-type semiconductor material includes 8-hydroxyquinoline aluminum, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi), 4,7-diphenyl-1,10-o-diazaphenanthroline, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole, bis( 2-Methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum, bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum, 2,2'-(1,3-phenyl)bis[5-(4-tert-butylphenyl)-1,3,4-oxadiazole], tris[2,4,6-trimethyl-3-(3-pyridyl)phenyl]borane, tetra[(m-pyridyl)-phenyl-3-yl]biphenyl, 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1”-terphenyl]-3,3”-diyl]dipyridine, 1,3-bis( 3,5-Dipyridin-3-ylphenyl)benzene, n,n′-bis(naphthyl-1-yl)-n,n′-bis(phenyl)benzidine; the inorganic N-type semiconductor material includes one or more of the following: first doped metal oxide particles, first undoped metal oxide particles, group IIB-VIA semiconductor materials, group IIIA-VA semiconductor materials, and group IB-IIIA-VIA semiconductor materials; the first undoped metal oxide particles include one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5; the metal oxide in the first doped metal oxide particles includes ZnO, TiO2, SnO2, ZrO2, and Ta2O5. One or more of nO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3, wherein the doping element in the first doped metal oxide particle includes one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga; the IIB-VIA group semiconductor material includes one or more of ZnS, ZnSe, and CdS; the IIIA-VA group semiconductor material includes one or more of InP and GaP; and the IB-IIIA-VIA group semiconductor material includes one or more of CuInS and CuGaS; and / or The optoelectronic device further includes a hole functional layer disposed between the anode and the active layer; the material of the hole functional layer includes organic P-type semiconductor materials or inorganic P-type semiconductor materials, wherein the organic P-type semiconductor material includes 4,4'-N,N'-dicarbazolyl-biphenyl, N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4’-diamine, and N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4’-diamine. 4,4',4'-Bis(phenyl)-spiro, N,N'-Di(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 4,4',4'-Tris(N-carbazolyl)-triphenylamine, 4,4',4'-Tris(carbazol-9-yl)triphenylamine, trichloroisocyanuric acid, terbium-doped phosphate-based green luminescent materials, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzphenanthrene, 4,4',4'-Tris(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene- 2,7-dimethyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(4-butylphenyl-diphenylamine), poly[bis(4-phenyl)(4-butylphenyl)amine], polyaniline, polypyrrole, poly(p-)phenylenevinylene, poly(phenylenevinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene], copper phthalocyanine, aromatic tertiary amines, polynuclear aromatic tertiary amines, 4,4'-bis(p-)phenylenevinylene Carbazolyl)-1,1'-biphenyl compounds, N,N,N',N'-tetraaryl benzidine, PEDOT, PEDOT:PSS and its derivatives, PEDOT:PSS derivatives doped with s-MoO3, poly(N-vinylcarbazole) and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, N,N'-di(naphthyl-1-yl)-N,N'-diphenylbenzidine, spironolactone (NPB), nanocrystalline diamond, microcrystalline cellulose and tetracyanoquinone dimethane, doped graphene, undoped graphene;The inorganic P-type semiconductor material comprises one or more of the following: second-doped metal oxide particles, second-undoped metal oxide particles, metal sulfides, metal selenides, and metal nitrides. The metal oxides in the second-doped and second-undoped metal oxide particles each independently comprise one or more of MoO3, WO3, NiO, CrO3, CuO, and V2O5. The doping element in the second-doped metal oxide particles comprises one or more of Mo, W, Ni, Cr, Cu, and V. The metal sulfide comprises one or more of CuS, MoS3, and WS3. The metal selenide comprises one or more of MoSe3 and WSe3. The metal nitride comprises P-type gallium nitride.

14. A display device, characterized in that, Including the optoelectronic device as described in any one of claims 12 to 13.

Images