Compositions, films and methods of making the same, optoelectronic devices, display devices

Abstract

The application discloses a composition, a thin film and a preparation method thereof, an optoelectronic device and a display device, and relates to the technical field of display. The composition comprises a first quantum dot material, a first N-type semiconductor material and a mixed ionic liquid.

Description

Technical Field

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

[0002] Semiconductor materials are a class of materials whose conductivity lies between that of conductors and insulators. They possess characteristics such as doping capability, thermosensitivity, photosensitivity, negative resistivity temperature, and rectification capability, and are widely used in the manufacture of large-scale integrated circuits, power devices, optoelectronic devices, pressure sensors, microelectromechanical systems, and other fields. Summary of the Invention

[0003] In view of the above, this application provides a composition, a thin film and a method for preparing the same, an optoelectronic device, and a display device.

[0004] The embodiments of this application are implemented as follows: a composition comprising a first quantum dot material, a first N-type semiconductor material, and a mixed ionic liquid.

[0005] Accordingly, embodiments of this application also provide a thin film, the material of which includes a second quantum dot material, a second N-type semiconductor material, and a modified ionic liquid.

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

[0007] A composition is provided comprising a first quantum dot material, a first N-type semiconductor material, and a mixed ionic liquid;

[0008] The composition is deposited to obtain a thin film.

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

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

[0011] This application provides a novel composition. 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 1This 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] Thin film 10; First sublayer 11; Second sublayer 12; First ionic liquid 131; Second ionic liquid 132; Third ionic liquid 133;

[0018] Optoelectronic device 100; anode 20; cathode 30; hole functional layer 40. 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] The technical solution of this application is as follows:

[0025] In a first aspect, embodiments of this application provide a composition comprising a first quantum dot material, a first N-type semiconductor material, and a mixed ionic liquid.

[0026] In the composition provided in this application, the mixed ionic liquid serves as a solvent for both quantum dot materials and N-type semiconductor materials. The anions in the mixed ionic liquid enable good solubility of the quantum dot materials, while the ionic atmosphere in the mixed ionic liquid facilitates the dissolution and dispersion of the N-type semiconductor materials.

[0027] In some embodiments, the mixed ionic liquid includes a first acetate-based ionic liquid. The acetate ions in the first acetate-based ionic liquid are Lewis acids with short chain lengths, which can effectively passivate defects in quantum dot materials and N-type semiconductor materials after the film is prepared.

[0028] Furthermore, the first acetate-based ionic liquid includes one or more of amine acetate ionic liquids and ammonium acetate ionic liquids.

[0029] Furthermore, the amine acetate ionic liquid includes one or more of aniline acetate and methylamine acetate.

[0030] The ammonium acetate ionic liquid includes triethylammonium acetate.

[0031] In some embodiments, the polarity of the first quantum dot material is less than that of the N-type semiconductor material.

[0032] In some embodiments, the polarity difference between the first quantum dot material and the mixed ionic liquid is greater than the polarity difference between the N-type semiconductor material and the mixed ionic liquid. Since the polarities of the N-type semiconductor material and the mixed ionic liquid are closer, according to the principle of "like dissolves like," the N-type semiconductor material and the mixed ionic liquid are more tightly bonded and more difficult to separate than the quantum dot material and the mixed ionic liquid.

[0033] In some embodiments, the first quantum dot material includes a first quantum dot and a first ligand coordinated to the first quantum dot, the first ligand including a first linker group and a first end group, the first linker group connecting the first quantum dot and the first end group.

[0034] In some embodiments, the first N-type semiconductor material includes a first N-type inorganic nanoparticle and a second ligand coordinated with the first N-type inorganic nanoparticle. The second ligand includes a second end group, or includes a second linking group and a second end group. The second linking group connects the first N-type inorganic nanoparticle and the second end group.

[0035] In some embodiments, the polarity of the first end group is less than the polarity of the second end group.

[0036] Furthermore, the polarity difference between the first end group and the mixed ionic liquid is greater than the polarity difference between the second end group and the mixed ionic liquid. In other words, the polarity of the second ligand and the mixed ionic liquid is closer. According to the principle of "like dissolves like," the N-type semiconductor material and the mixed ionic liquid are more tightly connected and more difficult to separate than the quantum dot material and the mixed ionic liquid.

[0037] In some embodiments, the first linking group includes one or more of -COO-, -S-, -NH-, and -P-.

[0038] In some embodiments, the first terminal group comprises one or more of an aryl group having 6 to 20 ring atoms and a hydrocarbon group having 4 to 18 carbon atoms in the main chain. Further, the aryl group having 6 to 20 ring atoms comprises one or more of phenyl, anthracene, and biphenyl. The hydrocarbon group having 4 to 18 carbon atoms in the main chain comprises one or more of 9-octadecenyl, octyl, butyl, pentyl, hexyl, heptyl, dodecyl, and octadecyl.

[0039] In some embodiments, the first ligand includes one or more of acid ligands, phosphine ligands, amine ligands, and thiol ligands.

[0040] Furthermore, the acid ligands include oleic acid.

[0041] The phosphine ligands include one or more of trioctylphosphine, trioctyloxyphosphine, and tributylphosphine.

[0042] The amine ligands include oleylamine.

[0043] The thiol ligands include one or more of butanethiol, octetrazol, dodecathiol, octadecylthiol, benzylthiol, 1,2-benzenethiol, 1,3-benzenethiol, and 1,4-benzenethiol.

[0044] In some embodiments, the second linking group includes -O-.

[0045] In some embodiments, the second terminal group includes one or more of a hydroxyl group and a hydrocarbon group having 1 to 3 carbon atoms in the main chain. Within the range of the number of carbon atoms in the main chain, the second ligand has suitable polarity, maintaining a large polarity difference with the first ligand, which facilitates separation and precipitation.

[0046] Furthermore, the hydrocarbon group having 1 to 3 carbon atoms in the main chain includes one or more of methyl, ethyl, propyl, vinyl, and propenyl groups.

[0047] In some embodiments, the second ligand comprises a hydroxyl ligand.

[0048] Furthermore, the hydroxyl ligand includes one or more of hydroxyl groups, methanol, ethanol, propanol, ethylene glycol, glycerol, propylene glycol, allyl alcohol, and vinyl alcohol.

[0049] In some embodiments, the mass fraction of the first ligand in the first quantum dot material is 5% to 20%, for example, it can be 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, etc. Within the range of said mass fraction, the first ligand is beneficial for improving the solubility and dispersibility of the first quantum dots. It should be noted that in this application, the mass fraction of the ligand is determined by thermogravimetric analysis, and the same applies below.

[0050] In some embodiments, the mass fraction of the second ligand in the first N-type semiconductor material is 5% to 20%, for example, it can be 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, etc. Within the range of said mass fraction, it is beneficial for the second ligand to improve the solubility, dispersibility, and other properties of the first N-type inorganic nanoparticles.

[0051] In some embodiments, the average particle size of the first quantum dot is 5 nm to 20 nm; for example, it can be 8 nm, 10 nm, 12 nm, 15 nm, 18 nm, etc. It should be noted that in this application, the particle size of nanoparticles such as quantum dots and N-type inorganic nanoparticles is measured by transmission electron microscopy (TEM), and the same applies below.

[0052] In some embodiments, the average particle size of the first N-type inorganic nanoparticles is 2nm to 15nm; for example, it can be 5nm, 6nm, 8nm, 10nm, 12nm, etc.

[0053] In some embodiments, the first quantum dot may be selected from, but is not limited to, one or more of single-structure quantum dots, core-shell structure quantum dots, and perovskite quantum dots.

[0054] 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.

[0055] 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).

[0056] The materials used for the perovskite quantum dots can be selected from, but are 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.

[0057] In some embodiments, the first N-type inorganic nanoparticles are selected from one or more of a first doped metal oxide particle, a first undoped metal oxide particle, a group IIB-VIA semiconductor material, a group IIIA-VA semiconductor material, and a group IB-IIIA-VIA semiconductor material. The material of the first undoped metal oxide particle includes one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The metal oxide in the first doped metal oxide particle includes ZnO, TiO2, SnO2, and ZrO2. 2. One or more of 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.

[0058] In some embodiments, the mass concentration of the first quantum dot material in the composition is 10 mg / mL to 40 mg / mL, for example, it can be 12 mg / mL, 15 mg / mL, 18 mg / mL, 20 mg / mL, 22 mg / mL, 25 mg / mL, 28 mg / mL, 30 mg / mL, 32 mg / mL, 35 mg / mL, 38 mg / mL, etc. Within the mass concentration range, it is beneficial to dissolve and disperse the first quantum dot material.

[0059] In some embodiments, the mass concentration of the first N-type semiconductor material in the composition is 30 mg / mL to 90 mg / mL, for example, it can be 40 mg / mL, 50 mg / mL, 60 mg / mL, 70 mg / mL, 80 mg / mL, etc. Within the mass concentration range, it is beneficial to dissolve and disperse the first N-type semiconductor material.

[0060] It is understood that the composition can be obtained by mixing a first quantum dot material, a first N-type semiconductor material, and a mixed ionic liquid.

[0061] Secondly, please refer to Figure 1 This application also provides a thin film 10, the material of which includes a second quantum dot material, a second N-type semiconductor material, and a modified ionic liquid.

[0062] In some embodiments, the thin film 10 includes a first sublayer 11 and a second sublayer 12 stacked together, the material of the first sublayer 11 including the second quantum dot material, and the material of the second sublayer 12 including the second N-type semiconductor material; the modified ionic liquid includes one or more of the first ionic liquid 131, the second ionic liquid 132, and the third ionic liquid 133.

[0063] The material of the first sublayer 11 also includes the first ionic liquid 131.

[0064] The material of the second sublayer 12 also includes the second ionic liquid 132.

[0065] The third ionic liquid 133 is located between the first sublayer 11 and the second sublayer 12.

[0066] The thin film 10 provided in this application has a first ionic liquid 131 that can passivate defects in the second quantum dot material, a second ionic liquid 132 that can passivate defects in the second N-type semiconductor material, and a third ionic liquid 133 located between the interface of the first sublayer 11 and the second sublayer 12. It can passivate defects in both the second quantum dot material and the second N-type semiconductor material, and can make the first sublayer 11 and the second sublayer 12 more tightly connected. It can also effectively reduce the resistance of the thin film 10, promote electron transport, reduce charge accumulation, and improve the performance of the thin film 10.

[0067] The materials of the first ionic liquid 131, the second ionic liquid 132, and the third ionic liquid 133 can refer to the materials of the ionic liquids described above. Specifically, the first ionic liquid 131, the second ionic liquid 132, and the third ionic liquid 133 each independently include a second acetate-based ionic liquid. The second acetate-based ionic liquid includes one or more of acetate amine ionic liquids and ammonium acetate ionic liquids. The acetate amine ionic liquid includes one or more of acetate aniline and acetate methylamine. The ammonium acetate ionic liquid includes triethylammonium acetate.

[0068] In some embodiments, the materials of the first ionic liquid 131, the second ionic liquid 132, and the third ionic liquid 133 may be the same or different. It is understood that when multiple ionic liquids are present in the first aspect, it is possible that the first ionic liquid 131, the second ionic liquid 132, and the third ionic liquid 133 may be different during the preparation of the thin film 10.

[0069] In some embodiments, the second quantum dot material includes a second quantum dot and a third ligand coordinated to the second quantum dot.

[0070] In some embodiments, the second quantum dot material further includes a first acetic acid ligand connected to the second quantum dot.

[0071] In some embodiments, the second N-type semiconductor material includes a second N-type inorganic nanoparticle and a fourth ligand coordinated with the second N-type inorganic nanoparticle.

[0072] And the second acetic acid ligand on the second N-type inorganic nanoparticle.

[0073] The material and particle size of the second quantum dot can be found in the description of the first quantum dot above, and the material and particle size of the second N-type inorganic nanoparticle can be found in the description of the second N-type inorganic nanoparticle above. The material of the third ligand can be found in the description of the first ligand above, and the material of the fourth ligand can be found in the description of the second ligand above.

[0074] It should be noted that the first acetic acid ligand on the second quantum dot can be derived from the first ionic liquid 131 and / or the third ionic liquid 133. The first ionic liquid 131 and / or the third ionic liquid 133 replace some of the first ligands on the first quantum dot and connect to the first quantum dot to form the second quantum dot and the first acetic acid ligand located on the second quantum dot. The part of the first ligand that is not replaced is the third ligand. The first acetic acid ligand can effectively passivate the defects of the second quantum dot, and the carbon chain of the first acetic acid ligand is relatively short, which is beneficial to improving the fluorescence quantum yield of the first sublayer 11.

[0075] Similarly, the second acetic acid ligand on the second N-type inorganic nanoparticle can be derived from the second ionic liquid 132 and / or the third ionic liquid 133. The second ionic liquid 132 and / or the third ionic liquid 133 replace some of the second ligands on the first N-type inorganic nanoparticle, connecting to the first N-type inorganic nanoparticle to form the second N-type inorganic nanoparticle and the second acetic acid ligand located on the second N-type inorganic nanoparticle. The unreplaced second ligand is the fourth ligand. The second acetic acid ligand can effectively passivate the defects of the second N-type inorganic nanoparticle, and the carbon chain of the second acetic acid ligand is relatively short, which is beneficial to improving the electron transport efficiency of the second sublayer 12.

[0076] In some embodiments, the mass fraction of the third ligand in the second quantum dot material is less than the mass fraction of the first ligand in the first quantum dot material.

[0077] In some embodiments, the mass fraction of the fourth ligand in the second N-type semiconductor material is less than the mass fraction of the second ligand in the first N-type semiconductor material.

[0078] In some embodiments, the thickness of the first sublayer 11 is 5nm to 20nm, for example, it can be 6nm, 8nm, 10nm, 12nm, 14nm, 16nm, 18nm, etc. It should be noted that in this application, the thickness of the film layers such as the first sublayer 11 and the second sublayer 12 is measured by a profilometer, and the same applies below.

[0079] In some embodiments, the thickness of the second sublayer 12 is 10nm to 50nm, for example, it can be 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, etc.

[0080] Thirdly, please refer to Figure 2 This application also provides a method for preparing a thin film 10, comprising the following steps:

[0081] S11. A composition is provided, the composition comprising a first quantum dot material, a first N-type semiconductor material, and a mixed ionic liquid;

[0082] S12. Deposit the composition to obtain film 10.

[0083] The thin film provided in this application is prepared by a composition comprising a first quantum dot material, a first N-type semiconductor material, and a mixed ionic liquid. The polarity difference between the mixed ionic liquid and the quantum dot material and the N-type semiconductor material can be used to prepare a film layer containing quantum dot material and a film layer containing N-type semiconductor material in one step, which is simple and convenient. Moreover, the modified ionic liquid in the thin film 10 can effectively passivate the defects of the quantum dot material and the N-type semiconductor material, thereby improving the performance of the quantum dot material and the N-type semiconductor material.

[0084] In some embodiments, the mixed ionic liquid includes one or more of a first ionic liquid 131, a second ionic liquid 132, and a third ionic liquid 133.

[0085] In some embodiments, depositing the composition includes depositing the composition under a first heat treatment to form a first sublayer 11 and a second sublayer 12. The material of the first sublayer 11 includes a second quantum dot material and a first ionic liquid 131, and the material of the second sublayer 12 includes a second N-type semiconductor material and a second ionic liquid 132. A third ionic liquid 133 is located between the first sublayer 11 and the second sublayer 12. It should be noted that the first quantum dot material reacts with the first ionic liquid 131 to precipitate and form the first sublayer 11, and the first N-type semiconductor material reacts with the second ionic liquid 132 to precipitate and form the second sublayer 12.

[0086] Further, the temperature of the first heat treatment is 120℃~180℃, for example, 130℃, 140℃, 150℃, 160℃, 170℃, etc.; the time is 10s~60s, for example, 15s, 20s, 25s, 30s, 35s, 40s, 45s, 50s, 55s, etc. Thus, under the conditions of the first heat treatment, part of the ionic liquid evaporates and is removed during the deposition of the composition. The first quantum dot material and the mixed ionic liquid have a large difference in polarity, and first react with the first ionic liquid 131 and / or the third ionic liquid 133 to precipitate and form the first sublayer 11. Then, as the mixed ionic liquid further decreases, the first N-type semiconductor material reacts with the second ionic liquid 132 and / or the third ionic liquid 133 to precipitate and form the second sublayer 12.

[0087] In some embodiments, after depositing the composition, a second heat treatment is performed to form a first sublayer 11 and a second sublayer 12. The material of the first sublayer 12 includes a second quantum dot material and the first ionic liquid 131. The material of the second sublayer 12 includes a second N-type semiconductor material and the second ionic liquid 132. The third ionic liquid 133 is located between the first sublayer 11 and the second sublayer 12.

[0088] In some embodiments, the material of the first sublayer 11 includes a second quantum dot material and the first ionic liquid 131; and / or, the material of the second sublayer 12 further includes a second N-type semiconductor material and the second ionic liquid 132; and / or, the third ionic liquid 133 is located between the first sublayer 11 and the second sublayer 12.

[0089] The temperature of the second heat treatment is 80℃ to 160℃, for example, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, etc.; the time is 10min to 240min, for example, 20min, 50min, 60min, 80min, 100min, 120min, 150min, 160min, 180min, 200min, 220min, etc. Thus, under the conditions of the second heat treatment, a portion of the mixed ionic liquid in the deposited composition is evaporated and removed, which facilitates the formation of the first sublayer 11 and the second sublayer 12.

[0090] In some embodiments, the second heat treatment is performed in a vacuum environment.

[0091] Furthermore, the vacuum level of the vacuum environment is 10. -4 Pa~3×10 -4 Pa, for example, can be 1.5 × 10⁻⁶. -4 Pa, 2×10-4 Pa, 2.5 × 10 -4 Pa, etc. Within the aforementioned vacuum level, it is beneficial to improve the efficiency of mixed ionic liquid evaporation and shorten the film formation time of the thin film 10.

[0092] It should be noted that both the first heat treatment and the second heat treatment can be performed to improve the film-forming properties of the first sublayer 11 and the second sublayer 12.

[0093] It should be noted that the first quantum dot material in the composition includes a first quantum dot and a first ligand located on the first quantum dot, and the first N-type semiconductor material includes a first N-type inorganic nanoparticle and a second ligand coordinated with the first N-type inorganic nanoparticle. During the volatilization and removal process under heat treatment, the mixed ionic liquid is difficult to completely remove, and some of the mixed ionic liquid will remain between the first sublayer 11, the second sublayer 12, and the interface between the first sublayer 11 and the second sublayer 12 (i.e., modified ionic liquid), which improves the performance of the thin film 10. Among them, some of the mixed ionic liquid will undergo ligand exchange with the first ligand on the first quantum dot, so that the quantum dot also contains the first acetate ligand of the acetate ionic liquid, which is more conducive to passivating the defects of the quantum dot. Similarly, some of the ionic liquid will undergo ligand exchange with the second ligand on the first N-type inorganic nanoparticle, so that the N-type inorganic nanoparticle also contains the second acetate ligand of the acetate ionic liquid, thereby more effectively passivating the defects of the N-type inorganic nanoparticle.

[0094] The method for preparing the thin film 10 provided in this application involves a one-step deposition of a composition containing a first quantum dot material, a first N-type semiconductor material, and a mixed ionic liquid. Then, a portion of the mixed ionic liquid is removed by heating. Based on the polarity difference between the quantum dot material, the N-type semiconductor material, and the mixed ionic liquid, the quantum dot material first precipitates to form a first sublayer 11, and the N-type semiconductor material then precipitates to form a second sublayer 12. This method is simple and convenient, improves preparation efficiency, and is conducive to large-scale application. Furthermore, the presence of some mixed ionic liquid residue between the first sublayer 11, the second sublayer 12, or the interface between the first and second sublayers 11 and 12 helps to improve the tightness of the interface between the first and second sublayers 11 and 12. The residual mixed ionic liquid can also effectively passivate defects in the quantum dot material and the N-type semiconductor material, thereby improving the performance of the thin film 10.

[0095] Fourthly, please refer to Figure 3 This application also provides an optoelectronic device 100, which includes an anode 20, a functional layer and a cathode 30 stacked together. The functional layer includes the thin film 10 described above, or the thin film 10 prepared by the above preparation method.

[0096] In some embodiments, when the thin film 10 includes a first sublayer 11 and a second sublayer 12, the first sublayer 11 is located between the anode 20 and the second sublayer 12.

[0097] In some embodiments, the anode 20 and the cathode 30 are each independently selected from one or more metals and metal oxides; the metals include one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the metal oxides include metal oxide electrodes or composite electrodes in which metals are disposed between doped or undoped transparent metal oxides, the materials of the metal oxide electrodes include one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, MoO3, and AMO, and the composite electrodes include 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.

[0098] In some embodiments, the optoelectronic device 100 further includes a hole functional layer 40 located between the anode 20 and the thin film 10.

[0099] In some embodiments, the hole functional layer 40 is made of materials including 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(carbazolyl-9-yl)triphenylamine, trichloroisocyanuric acid, and terbium-doped phosphate-based green... Quantum dot 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-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-Phenylacetide], 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, spiroNPB, nanocrystalline diamond, microcrystalline cellulose and tetracyanoquinone dimethane, doped graphene, undoped graphene, second-doped metals The metal oxide particles are selected from one or more of the following: oxide particles, second undoped metal oxide particles, metal sulfides, metal selenides, and metal nitrides. The metal oxides in the second doped metal oxide particles and the metal oxides in the second undoped metal oxide particles each independently include one or more of the following: MoO3, WO3, NiO, CrO3, CuO, and V2O5. The doping element in the second doped metal oxide particles includes one or more of the following: Mo, W, Ni, Cr, Cu, and V. The metal sulfides include one or more of the following: CuS, MoS3, and WS3. The metal selenides include one or more of the following: MoSe3 and WSe3. The metal nitrides include p-type gallium nitride.

[0100] The optoelectronic device 100 provided in this application has fewer defects in the thin film 10, and the first sublayer 11 and the second sublayer 12 are closely connected, which is conducive to electron transport, reduces charge accumulation, lowers resistance and power consumption of the optoelectronic device 100, improves the luminous efficiency, brightness and stability of the optoelectronic device 100, and extends the service life of the optoelectronic device 100.

[0101] Fifthly, embodiments of this application also provide a display device, the display device including the above-described optoelectronic device 100.

[0102] 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.

[0103] 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.

[0104] Example 1

[0105] This embodiment provides a composition and a thin film prepared using the composition. The method for preparing the thin film includes:

[0106] An N-type semiconductor material and a quantum dot material are provided. The N-type semiconductor material includes N-type inorganic nanoparticles ZnO and -OH ligands on its surface, and the quantum dot material includes CdSe quantum dots and oleic acid ligands on their surface. The N-type semiconductor material, the quantum dot material and the ionic liquid aniline acetate are mixed, wherein the mass concentration of the N-type semiconductor material is 60 mg / mL and the mass concentration of the quantum dot material is 25 mg / mL, to obtain a composition.

[0107] The spin-coating composition was spin-coated at a speed of 4000 rpm for 30 s, followed by a second heat treatment at 120°C for 100 min. Part of the ionic liquid evaporated, and quantum dot material precipitated to form a first sublayer. N-type semiconductor material precipitated on the first sublayer to form a second sublayer. The unevaporated ionic liquid was doped into the first sublayer, the second sublayer, and between the first and second sublayers to obtain a thin film.

[0108] Example 2

[0109] This embodiment is basically the same as Embodiment 1, except that the ionic liquid aniline acetate is replaced with methylamine acetate in this embodiment.

[0110] Example 3

[0111] This embodiment is basically the same as Embodiment 1, except that the ionic liquid aniline acetate is replaced with triethylammonium acetate in this embodiment.

[0112] Example 4

[0113] This embodiment is basically the same as Embodiment 1, except that the oleic acid ligand on the surface of the CdSe quantum dots is replaced with benzenethiol.

[0114] Example 5

[0115] This embodiment is basically the same as Embodiment 1, except that the -OH ligand on the ZnO surface is replaced with the -CH2OH ligand in this embodiment.

[0116] Example 6

[0117] This embodiment is basically the same as Example 1, except that the mass concentration of quantum dot material in the composition in this embodiment is 40 mg / mL.

[0118] Example 7

[0119] This embodiment is basically the same as Example 1, except that the mass concentration of quantum dot material in the composition in this embodiment is 10 mg / mL.

[0120] Example 8

[0121] This embodiment is basically the same as Embodiment 1, except that the mass concentration of the N-type semiconductor material in the composition in this embodiment is 90 mg / mL.

[0122] Example 9

[0123] This embodiment is basically the same as Embodiment 1, except that the mass concentration of the N-type semiconductor material in the composition in this embodiment is 30 mg / mL.

[0124] Example 10

[0125] This embodiment is basically the same as Embodiment 1, except that the temperature of the second heat treatment in this embodiment is 160°C.

[0126] Example 11

[0127] This embodiment is basically the same as Embodiment 1, except that the temperature of the second heat treatment in this embodiment is 80°C.

[0128] Example 12

[0129] This embodiment is basically the same as Embodiment 1, except that the second heat treatment time in this embodiment is 240 minutes.

[0130] Example 13

[0131] This embodiment is basically the same as Embodiment 1, except that the second heat treatment time in this embodiment is 10 minutes.

[0132] Example 14

[0133] This embodiment is basically the same as Embodiment 1, except that the second heat treatment in this embodiment is performed at a vacuum degree of 3×10⁻⁶. -4 The procedure is carried out in a vacuum environment of Pa.

[0134] Example 15

[0135] This embodiment is basically the same as Embodiment 1, except that the second heat treatment is not performed in this embodiment. The spin coating composition is carried out under the conditions of the first heat treatment, the temperature of the first heat treatment is 150°C and the time is 30s.

[0136] Example 16

[0137] This embodiment is basically the same as embodiment 15, except that the temperature of the first heat treatment in this embodiment is 180°C.

[0138] Example 17

[0139] This embodiment is basically the same as embodiment 15, except that the temperature of the first heat treatment in this embodiment is 120°C.

[0140] Example 18

[0141] This embodiment is basically the same as embodiment 15, except that the first heat treatment time in this embodiment is 60s.

[0142] Example 19

[0143] This embodiment is basically the same as embodiment 15, except that the first heat treatment time in this embodiment is 10 seconds.

[0144] Example 20

[0145] This embodiment is basically the same as Embodiment 1, except that the spin coating composition is carried out under the first heat treatment conditions, the temperature of the first heat treatment is 150°C and the time is 30s.

[0146] Example 21

[0147] This embodiment is basically the same as embodiment 14, except that the spin coating composition is carried out under the first heat treatment conditions, the temperature of the first heat treatment is 150°C and the time is 30s.

[0148] Comparative Example 1

[0149] This comparative example is basically the same as Example 1, except that the ionic liquid in the composition is replaced with ethanol.

[0150] Comparative Example 2

[0151] This comparative example provides a thin film prepared by means of: spin-coating a 25 mg / mL CdSe quantum dot n-octane dispersion to form a first sublayer; and then spin-coating a 60 mg / mL ZnO ethanol dispersion onto the first sublayer to form a second sublayer, thereby obtaining a thin film.

[0152] Comparative Example 3

[0153] This comparative example is basically the same as Example 1, except that the first composition is prepared according to the method of the composition, but the first composition does not contain ZnO, and the first composition is spin-coated to form a first sublayer; the second composition is prepared according to the method of the composition, but the first composition does not contain CdSe quantum dots, and the second composition is spin-coated to form a second sublayer, thus obtaining a thin film.

[0154] Comparative Example 4

[0155] This comparative example is basically the same as comparative example 2, except that the third composition is prepared according to the method of the composition, but the third composition does not contain ZnO and CdSe quantum dots, but only ionic liquid. The third composition is spin-coated between the first sublayer and the second sublayer to form the third sublayer.

[0156] The fluorescence quantum yield (PLQY) and resistance at 1 mA of the thin films of Examples 1-21 and Comparative Examples 1-4 were tested respectively, and the results are shown in Table 1.

[0157] Fluorescence quantum yield (PLQY) was measured using a steady-state fluorescence spectrometer from Edinburgh Instruments, model FS5, with the corresponding accessory SC-30 for measuring fluorescence quantum yield.

[0158] The resistance at 1 mA is obtained by differentiating the current-voltage curve and then fitting the resistance at 1 mA. Resistance reflects the electron migration rate; the smaller the resistance, the higher the surface electron migration efficiency.

[0159] Table 1

[0160]

[0161]

[0162] As shown in Table 1:

[0163] As can be seen from Examples 1-5 and Comparative Examples 1-4, the thin film prepared by spin coating using the composition provided in this application effectively improves the fluorescence quantum yield and reduces the resistance, indicating that the ionic liquid has a beneficial effect on both the first and second sublayers, promoting the luminescence of the first sublayer and improving the electron transport efficiency. Comparative Examples 3 and 4 prepared a first sublayer containing ionic liquid and quantum dot material and a second sublayer containing ionic liquid and N-type semiconductor material, or prepared a third sublayer formed by ionic liquid alone. The performance of the thin film containing ionic liquid is better than that of the thin film without ionic liquid in Comparative Examples 1-2. However, the preparation method of Comparative Examples 3-4 is more complicated than that of the examples, and the interface connection between the first and second sublayers is not as tight as that of the examples. Therefore, its fluorescence quantum yield is also lower than that of the examples, and the resistance is higher, which is not conducive to electron transport.

[0164] As can be seen from Examples 1, 6-13 and Comparative Examples 1-4, the ratio of quantum dot material, N-type semiconductor material and ionic liquid in the composition and the conditions for the second heat treatment after setting the composition have a certain influence on the thin film. Compared with the comparative examples, within the scope provided in this application, the thin film has a higher fluorescence quantum yield and a lower resistance, which is beneficial to electron transport and recombination with holes in the light-emitting layer to emit light.

[0165] As can be seen from Examples 14-21 and Comparative Examples 1-4, spin-coating the composition under the first heat treatment condition can also promote the volatilization of ionic liquids, sequentially precipitating the first and second sublayers, thereby improving the fluorescence quantum yield of the film and reducing the resistance. Performing both the first and second heat treatments has a better effect on improving the performance of the film. In particular, in Example 21, after the first heat treatment, the second heat treatment was performed in a vacuum environment, which significantly improved the fluorescence quantum yield of the film, reduced the resistance, and promoted electron transport.

[0166] Device Example 1

[0167] This embodiment provides an optoelectronic device, the fabrication method of which is as follows:

[0168] The ITO conductive glass was cleaned with a cleaning agent to initially remove the stains on the surface. Then, it was ultrasonically cleaned for 20 minutes each in deionized water, acetone, anhydrous ethanol, and deionized water to remove impurities on the surface. It was then dried with high-purity nitrogen and irradiated with ultraviolet light for 15 minutes to form the ITO anode.

[0169] PEDOT:PSS was spin-coated onto the ITO anode at a speed of 5000 rpm to form a hole injection layer.

[0170] TFB solution was spin-coated onto the hole injection layer at a speed of 3000 rpm for 30 seconds, and then baked at 150°C for 20 minutes to form a hole transport layer.

[0171] A thin film was prepared on the hole transport layer as described in Example 1, wherein the first sublayer of the thin film is located between the hole transport layer and the second sublayer.

[0172] On the electronic functional layer, Al is deposited by thermal evaporation with a vacuum level not exceeding 3 x 10⁻⁶. -4 Pa, velocity 1 angstrom / second, time 100 s, thickness 10 nm; Ag is deposited by thermal evaporation, vacuum degree not exceeding 3 x 10⁻⁶. -4 Pa, velocity of 1 angstrom / second, time of 200 s, thickness of 20 nm; forming a cathode;

[0173] Packaging yields optoelectronic devices.

[0174] Device Examples 2-21

[0175] Device Examples 2 to 21 are basically the same as Device Example 1, except that the thin films of Device Examples 2 to 21 are prepared in accordance with Examples 2 to 21 respectively.

[0176] Comparative Examples 1-4

[0177] The devices in Comparative Examples 1 to 4 are basically the same as those in Device Example 1, except that the thin films in Comparative Examples 1 to 4 are prepared with reference to Comparative Examples 1 to 4 respectively.

[0178] The current efficiency CE (Cd / A) and current efficiency stability CE of the optoelectronic devices in Device Examples 1-21 and Device Comparative Examples 1-4 were tested respectively. d (%) and T95@1k nit, the results are shown in Table 2.

[0179] Current efficiency stability C.Ed represents the CE degradation of an optoelectronic device after being placed at 80°C for 7 days. It includes both current efficiency CE and current efficiency stability CE. d The testing method is as follows:

[0180] After placing the optoelectronic device in an environment with a temperature of 80℃ and a relative humidity of 80% for 7 days, the brightness value of the optoelectronic device was intermittently collected within the voltage range of 0V to 8V, with a collection every 0.2V. The current efficiency of the optoelectronic device under the collection conditions was obtained by dividing the brightness value collected each time by the corresponding current density. The initial current efficiency was C.E1, and the obtained current density was 32mA / cm. 2 The current efficiency (C.E2, cd / A) is calculated to obtain CE. d (%) = C.E2 / C.E1 × 100%. The larger A% is, the higher the stability of the current efficiency of the optoelectronic device. Conversely, the smaller A% is, the lower the stability of the current efficiency of the optoelectronic device.

[0181] The measurement method for lifetime T95@1k nit is as follows: Under constant current or voltage drive, the time required for the brightness of the device 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 fitting formula. For example, the lifetime at 1000 nits is measured as T95@1k nit. The specific calculation formula is as follows:

[0182]

[0183] 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 1 knit, 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.

[0184] Table 2

[0185]

[0186]

[0187] As shown in Table 2:

[0188] As can be seen from Device Examples 1-5 and Device Comparative Examples 1-4, the composition provided in this application is used to prepare the first sublayer and the second sublayer on the hole transport layer, which serve as the light-emitting layer and the electronic functional layer. This can effectively improve the current efficiency and stability of the optoelectronic device and extend its service life. In Device Comparative Examples 3-4, ionic liquids were introduced into the optoelectronic device, and the performance of the optoelectronic device was slightly better than that of Device Comparative Examples 1-2. However, the preparation process was more complicated than that of Device Examples 1-5 and Device Comparative Examples 1-2, and the performance of the optoelectronic device was also worse than that of Device Examples 1-5. This may be because the one-step method provided in this application makes the connection between the first sublayer and the second sublayer more compact.

[0189] As can be seen from device examples 1, 6-14 and device comparative examples 1-4, the mass ratio of quantum dot material, N-type semiconductor material and ionic liquid in the composition, as well as the conditions for the second heat treatment of the thin film preparation, all have a certain impact on the performance of optoelectronic devices. Among them, the effect of performing the second heat treatment under vacuum is better and can effectively improve the performance of optoelectronic devices.

[0190] As can be seen from Device Examples 15-21 and Device Comparative Examples 1-4, spin-coating the composition under the first heat treatment condition can also cause quantum dot material and N-type semiconductor material to precipitate and form the first sublayer and the second sublayer, respectively, thereby improving the performance of optoelectronic devices. In particular, in Device Example 21, a second heat treatment was performed under vacuum after the first heat treatment, which significantly improved the current efficiency and stability of the optoelectronic device, slowed down the decay rate of current efficiency, and extended the service life of the optoelectronic device.

[0191] The compositions, thin films and their preparation methods, optoelectronic devices and display devices provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A composition, characterized in that, The composition includes a first quantum dot material, a first N-type semiconductor material, and a mixed ionic liquid.

2. The composition according to claim 1, characterized in that, In the composition, the mass concentration of the first quantum dot material is 10 mg / mL to 40 mg / mL; and / or In the composition, the mass concentration of the first N-type semiconductor material is 30 mg / mL to 90 mg / mL; and / or The mixed ionic liquid includes a first acetic acid ionic liquid; the first acetic acid ionic liquid includes one or more of amine acetate ionic liquids and ammonium acetate ionic liquids; optionally, the amine acetate ionic liquid includes one or more of aniline acetate and methyl acetate; optionally, the ammonium acetate ionic liquid includes triethylammonium acetate.

3. The composition according to claim 1, characterized in that, The polarity of the first quantum dot material is less than that of the N-type semiconductor material; and / or The polarity difference between the first quantum dot material and the mixed ionic liquid is greater than the polarity difference between the N-type semiconductor material and the mixed ionic liquid.

4. The composition according to claim 1, characterized in that, The first quantum dot material includes a first quantum dot and a first ligand coordinated to the first quantum dot; the first ligand includes a first linker group and a first end group, the first linker group connecting the first quantum dot and the first end group; and / or The first N-type semiconductor material includes a first N-type inorganic nanoparticle and a second ligand coordinated with the first N-type inorganic nanoparticle; the second ligand includes a second end group, or includes a second linking group and a second end group, wherein the second linking group connects the first N-type inorganic nanoparticle and the second end group.

5. The composition according to claim 4, characterized in that, The polarity of the first end group is less than the polarity of the second end group; and / or The polarity difference between the first end group and the mixed ionic liquid is greater than the polarity difference between the second end group and the mixed ionic liquid; and / or The first linking group includes one or more of -COO-, -S-, -NH-, and -P-; and / or The first end group comprises one or more of an aryl group having 6 to 20 ring atoms and a hydrocarbon group having 4 to 18 carbon atoms in the main chain; optionally, the aryl group having 6 to 20 ring atoms comprises one or more of phenyl, anthracene, and biphenyl; optionally, the hydrocarbon group having 4 to 18 carbon atoms in the main chain comprises one or more of 9-octadecenyl, octyl, butyl, pentyl, hexyl, heptyl, dodecyl, and octadecyl; and / or The second linking group includes -O-; and / or The second end group includes one or more of hydroxyl groups and hydrocarbon groups with 1 to 3 carbon atoms in the main chain; optionally, the hydrocarbon groups with 1 to 3 carbon atoms in the main chain include one or more of methyl, ethyl, propyl, vinyl, and propenyl groups.

6. The composition according to claim 4, characterized in that, The first ligand comprises one or more of acid ligands, phosphine ligands, amine ligands, and thiol ligands; optionally, the acid ligand comprises oleic acid; optionally, the phosphine ligand comprises one or more of trioctylphosphine, trioctylphosphine oxide, and tributylphosphine; optionally, the amine ligand comprises oleylamine; optionally, the thiol ligand comprises one or more of butanethiol, octylthiol, dodecylthiol, octadecylthiol, benzylthiol, 1,2-benzenethiol, 1,3-benzenethiol, and 1,4-benzenethiol; and / or The second ligand includes a hydroxyl ligand; optionally, the hydroxyl ligand includes one or more of hydroxyl groups, methanol, ethanol, propanol, ethylene glycol, glycerol, propylene glycol, allyl alcohol, and vinyl alcohol; and / or In the first quantum dot material, the mass fraction of the first ligand is 5% to 20%; and / or In the first N-type semiconductor material, the mass fraction of the second ligand is 5% to 20%.

7. The composition according to claim 4, characterized in that, The average particle size of the first quantum dot is 5 nm to 20 nm; and / or The average particle size of the first type N inorganic nanoparticles is 2 nm to 15 nm; and / or The first quantum dot is selected from one or more of single-structure quantum dots, core-shell quantum dots, and perovskite quantum dots; 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 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 dot includes one or more layers; the group II-VI compounds are selected from CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, and CdSeS. One or more of the following compounds: 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 are selected from SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe; the III-V compound is selected from GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, 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 / 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 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; and / or The first N-type inorganic nanoparticles are selected from one or more of the following: first doped metal oxide particles, first undoped metal oxide particles, IIB-VIA group semiconductor materials, IIIA-VA group semiconductor materials, and IB-IIIA-VIA group semiconductor materials. The first undoped metal oxide particles are made of one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The metal oxides in the first doped metal oxide particles are made of one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3. The doping elements in the first doped metal oxide particles are made of one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga. The IIB-VIA group semiconductor materials are made of one or more of ZnS, ZnSe, and CdS. The IIIA-VA group semiconductor materials are made of one or more of InP and GaP. The IB-IIIA-VIA group semiconductor materials are made of one or more of CuInS and CuGaS.

8. A thin film, characterized in that, The materials of the thin film include a second quantum dot material, a second N-type semiconductor material, and a modified ionic liquid.

9. The thin film as claimed in claim 8, characterized in that, The thin film comprises a first sublayer and a second sublayer stacked together, wherein the material of the first sublayer comprises the second quantum dot material, and the material of the second sublayer comprises the second N-type semiconductor material; the modified ionic liquid comprises one or more of a first ionic liquid, a second ionic liquid, and a third ionic liquid; wherein... The material of the first sublayer also includes the first ionic liquid; and / or The material of the second sublayer also includes the second ionic liquid; and / or The third ionic liquid is located between the first sublayer and the second sublayer.

10. The thin film as claimed in claim 9, characterized in that, The second quantum dot material comprises a second quantum dot and a third ligand coordinated to the second quantum dot; optionally, the third ligand comprises one or more of acid ligands, phosphine ligands, amine ligands, and thiol ligands; the acid ligand comprises oleic acid; the phosphine ligand comprises one or more of trioctylphosphine, trioctylphosphine oxide, and tributylphosphine; the amine ligand comprises oleylamine; the thiol ligand comprises one or more of butanethiol, octylthiol, dodecanethiol, octadecylthiol, benzylthiol, 1,2-benzenethiol, 1,3-benzenethiol, and 1,4-benzenethiol; and / or The second N-type semiconductor material includes second N-type inorganic nanoparticles and a fourth ligand coordinated with the second N-type inorganic nanoparticles; optionally, the fourth ligand includes a hydroxyl ligand; the hydroxyl ligand includes one or more of hydroxyl, methanol, ethanol, propanol, ethylene glycol, glycerol, propylene glycol, allyl alcohol, and vinyl alcohol; The first ionic liquid, the second ionic liquid, and the third ionic liquid may be made of the same or different materials; and / or The thickness of the first sublayer is 5 nm to 20 nm; and / or The thickness of the second sublayer is 10nm to 50nm.

11. The thin film as claimed in claim 10, characterized in that, The second quantum dot material further includes a first acetic acid ligand connected to the second quantum dot; and / or The second N-type semiconductor material further includes a second acetate ligand connected to the second N-type inorganic nanoparticles; and / or The first ionic liquid, the second ionic liquid, and the third ionic liquid each independently include a second acetate-based ionic liquid; the second acetate-based ionic liquid includes one or more of amine acetate-based ionic liquids and ammonium acetate-based ionic liquids; optionally, the amine acetate-based ionic liquid includes one or more of aniline acetate and methyl acetate; optionally, the ammonium acetate-based ionic liquid includes triethylammonium acetate.

12. A method for preparing a thin film, characterized in that, Includes the following steps: A composition is provided comprising a first quantum dot material, a first N-type semiconductor material, and a mixed ionic liquid; The composition is deposited to obtain a thin film.

13. The preparation method according to claim 12, characterized in that, The mixed ionic liquid includes one or more of a first ionic liquid, a second ionic liquid, and a third ionic liquid; The deposition of the composition includes depositing the composition under a first heat treatment to form a first sublayer and a second sublayer, wherein the material of the first sublayer comprises a second quantum dot material and a first ionic liquid, the material of the second sublayer comprises a second N-type semiconductor material and a second ionic liquid, and a third ionic liquid is located between the first sublayer and the second sublayer; and / or After depositing the composition, the process further includes a second heat treatment to form a first sublayer and a second sublayer. The material of the first sublayer includes a second quantum dot material and the first ionic liquid, and the material of the second sublayer includes a second N-type semiconductor material and the second ionic liquid. The third ionic liquid is located between the first sublayer and the second sublayer.

14. The preparation method according to claim 13, characterized in that, The temperature of the first heat treatment is 120℃~180℃; and / or The first heat treatment time is 10s to 60s; and / or The temperature of the second heat treatment is 80℃~160℃; and / or The second heat treatment time is 10 min to 240 min; and / or The second heat treatment is performed in a vacuum environment; optionally, the vacuum level of the vacuum environment is 10. -4 Pa~3×10 - 4 Pa.

15. An optoelectronic device, characterized in that, It includes an anode, a functional layer, and a cathode stacked together, wherein the functional layer includes a thin film as described in any one of claims 8 to 11, or a thin film prepared by the preparation method as described in any one of claims 12 to 14.

16. The optoelectronic device as described in claim 15, characterized in that, When the thin film comprises a first sublayer and a second sublayer, the first sublayer is located between the anode and the second sublayer; and / or The anode and the cathode are each independently selected from one or more metals and metal oxides; the metals include one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the metal oxides include metal oxide electrodes or composite electrodes with metals disposed between doped or undoped transparent metal oxides, the materials of the metal oxide electrodes include one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, MoO3, and AMO; the composite electrodes include 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 a hole functional layer, which is located between the anode and the thin film;The hole functional layer materials include 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(carbazolyl-9-yl)triphenylamine, trichloroisocyanuric acid, terbium-doped phosphate-based green quantum dot 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-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- [Phenylidene vinylidene], 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, spiroNPB, nanocrystalline diamond, microcrystalline cellulose and tetracyanoquinone dimethane, doped graphene, undoped graphene, second-doped metal oxide particles The metal oxide comprises one or more of the following: a second undoped metal oxide particle, a metal sulfide, a metal selenide, and a metal nitride. The metal oxides in the second doped metal oxide particle and the second undoped metal oxide particle each independently include one or more of MoO3, WO3, NiO, CrO3, CuO, and V2O5. The doping element in the second doped metal oxide particle includes one or more of Mo, W, Ni, Cr, Cu, and V. The metal sulfide includes one or more of CuS, MoS3, and WS3. The metal selenide includes one or more of MoSe3 and WSe3. The metal nitride includes p-type gallium nitride.

17. A display device, characterized in that, Including the optoelectronic device as described in any one of claims 15 to 16.

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