Composite film, preparation method thereof, optoelectronic device and display device

Abstract

This application discloses a composite thin film and its preparation method, optoelectronic device, and display device, relating to the field of display technology. The composite thin film includes a first film layer and a second film layer stacked together; wherein the material of the second film layer includes a first inorganic nanomaterial containing hydroxyl groups or a hydroxyl-containing compound, and the hydroxyl-containing compound includes one or more of hydroxyl-containing bioceramics, hydroxyl-containing resins, and hydroxyl-containing steroids. This application provides a novel composite thin film.

Description

Technical Field

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

[0002] Semiconductor thin films are thin films formed from semiconductor materials. Among related technologies, the performance of semiconductor thin films is relatively poor and needs further improvement. Summary of the Invention

[0003] In view of this, this application provides a composite thin film and its preparation method, an optoelectronic device and a display device.

[0004] The embodiments of this application are implemented as follows: a composite film includes a first film layer and a second film layer stacked together; wherein, the material of the second film layer includes a first inorganic nanomaterial containing hydroxyl groups or a compound containing hydroxyl groups, and the compound containing hydroxyl groups includes one or more of hydroxyl-containing bioceramics, hydroxyl-containing resins, and hydroxyl-containing steroids.

[0005] Accordingly, this application also provides a method for preparing a composite thin film, comprising the following steps:

[0006] Provide the first membrane layer;

[0007] A first inorganic nanomaterial or a hydroxyl-containing compound is provided and deposited on the first film layer to form a second film layer, thereby obtaining a composite film. The hydroxyl-containing compound includes one or more of hydroxyl-containing bioceramics, hydroxyl-containing resins, and hydroxyl-containing steroids.

[0008] or,

[0009] A first inorganic nanomaterial containing hydroxyl groups or a compound containing hydroxyl groups is provided, and the first inorganic nanomaterial containing hydroxyl groups or the compound containing hydroxyl groups is deposited to form a second film layer, wherein the compound containing hydroxyl groups includes one or more of hydroxyl-containing bioceramics, hydroxyl-containing resins, and hydroxyl-containing steroids.

[0010] A first film layer is formed on the second film layer to obtain a composite film.

[0011] Accordingly, this application also provides an optoelectronic device, including an anode, an active layer, an electronic functional layer, and a cathode stacked together; wherein the electronic functional layer includes the composite thin film described above, or the composite thin film prepared by the above preparation method;

[0012] The composite film includes a first film layer and a second film layer stacked together, wherein the first film layer is located between the active layer and the second film layer, or the second film layer is located between the active layer and the first film layer;

[0013] When the composite film further includes a third film layer, the second film layer is located between the first film layer and the third film layer.

[0014] Accordingly, this application also provides a display device, which includes the above-mentioned optoelectronic device.

[0015] This application provides a novel composite film. Attached Figure Description

[0016] 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.

[0017] Figure 1 This is a diagram showing the brightness changes of optoelectronic devices during operation in existing technologies;

[0018] Figure 2 This is a schematic diagram of the structure of the composite film provided in the embodiments of this application;

[0019] Figure 3 This is a schematic diagram of the structure of another composite film provided in the embodiments of this application;

[0020] Figure 4 This is a flowchart of the method for preparing the composite thin film provided in the embodiments of this application;

[0021] Figure 5 This is a flowchart of another composite film preparation method provided in the embodiments of this application;

[0022] Figure 6 This is a schematic diagram of the structure of the optoelectronic device provided in the embodiments of this application;

[0023] Figure 7 This is a schematic diagram of the structure of another optoelectronic device provided in the embodiments of this application;

[0024] Figure 8 This is a schematic diagram of the structure of another optoelectronic device provided in the embodiments of this application.

[0025] Figure label:

[0026] Composite film 10;

[0027] First membrane layer 11; Second membrane layer 12; Third membrane layer 13;

[0028] Optoelectronic devices 100;

[0029] Anode 20; Active layer 30; Cathode 40; Hole functional layer 50. Detailed Implementation

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] It should be noted that in this embodiment, the amount of hydroxyl groups on the film surface is determined using X-ray photoelectron spectroscopy (XPS). Specifically, in the X-ray photoelectron spectroscopy (XPS) results, the O1s spectrum can be divided into three sub-peaks: the OM peak (located between 529 eV and 531 eV), representing the molar concentration of oxygen atoms in the film; the OV peak (located between 531 eV and 532 eV), representing the molar concentration of oxygen vacancies in the film; and the OH peak (located between 532 eV and 534 eV), representing the molar concentration of hydroxyl groups on the film surface. The area ratio between each sub-peak represents the ratio of the molar concentrations of different types of oxygen atoms in the film. Therefore, the amount of hydroxyl groups on the film surface is defined as: the area of ​​the OH peak / the area of ​​the OM peak, that is, the amount of hydroxyl groups on the film surface is the ratio of the molar concentration of hydroxyl groups on the film surface to the molar concentration of oxygen atoms in the film.

[0036] Optoelectronic devices include high-boiling-point devices and low-boiling-point devices. High-boiling-point devices refer to devices whose film layers are prepared using inkjet printing. The solvent in the inkjet printer is a solvent with a high boiling point, and the semiconductor material in the ink contains hydroxyl groups. Low-boiling-point devices, on the other hand, are prepared by dissolving the semiconductor material in a low-boiling-point solvent. The semiconductor material contains a small amount of hydroxyl groups or no hydroxyl groups at all. Because the viscosity and droplet contact angle of low-boiling-point solvents are difficult to achieve the standards for inkjet printing, it is impossible to prepare the film layers of optoelectronic devices using inkjet printing, or the prepared film layers have poor film-forming properties. Furthermore, the introduction of low-boiling-point solvents, such as alcohols, which are highly polar, can have a quenching effect on non-polar film layers, such as light-emitting layers. Additionally, water in alcohols may come into contact with metal electrodes, leading to short circuits.

[0037] Inkjet printing is a mass-producible method for fabricating films; however, the presence or absence of hydroxyl groups in the ink leads to lower lifespan and limited scaling of optoelectronic devices. For example... Figure 1As shown, water or ethanol molecules are usually introduced by exposing the prepared membrane to air. However, this process is extremely unstable and is greatly affected by air humidity and the amount of ethanol added. It is difficult to adjust the amount introduced according to actual needs, and mass production is still limited.

[0038] The technical solution of this application is as follows:

[0039] Firstly, please refer to Figure 2 This application provides a composite film 10, which includes a first film layer 11 and a second film layer 12 stacked together; wherein, the material of the second film layer includes a first inorganic nanomaterial containing hydroxyl groups or a compound containing hydroxyl groups, and the compound containing hydroxyl groups includes one or more of hydroxyl-containing bioceramics, hydroxyl-containing resins, and hydroxyl-containing steroids.

[0040] The composite thin film 10 provided in this application has a first film layer 11 and a second film layer 12 made of different materials. The second film layer 12 can be selected from a first inorganic nanomaterial containing hydroxyl groups, a bioceramic containing hydroxyl groups, a resin containing hydroxyl groups, and / or a steroid containing hydroxyl groups. The material of the second film layer 12 contains hydroxyl groups, which can affect the composite thin film 10, thereby improving the service life of the optoelectronic device 100 when the composite thin film 10 is applied to the optoelectronic device 100.

[0041] In some embodiments, the amount of surface hydroxyl groups in the first film layer 11 is less than the amount of surface hydroxyl groups in the second film layer 12. Since the amount of surface hydroxyl groups in the first film layer 11 is less than the amount of surface hydroxyl groups in the second film layer 12, this method can be used to fabricate the film using inkjet printing, making it suitable for large-scale mass production.

[0042] It should be noted that the amount of surface hydroxyl groups in the film of inorganic nanomaterials containing hydroxyl groups represents the content of hydroxyl ligands on the surface of the inorganic nanomaterials; while the amount of surface hydroxyl groups in the film of compounds containing hydroxyl groups represents the content of hydroxyl groups in the compounds containing hydroxyl groups.

[0043] In some embodiments, the amount of surface hydroxyl groups in the first film layer 11 is 0.001 to 0.005, for example, 0.002, 0.003, 0.004, etc. Within the range of surface hydroxyl group amount, it is advantageous for the first film layer 11 to be prepared by inkjet printing, which is suitable for large-scale mass production.

[0044] In some embodiments, the amount of surface hydroxyl groups in the first film layer 11 is 0.5 to 1, for example, 0.5, 0.6, 0.7, 0.8, 0.9, etc. Within the range of the amount of surface hydroxyl groups, it is beneficial for the second film layer 12 to affect the performance of the composite thin film 10, thereby improving the service life of the optoelectronic device 100.

[0045] Furthermore, the first inorganic nanomaterial containing hydroxyl groups includes a first inorganic nanomaterial and hydroxyl groups coordinated and linked to the first inorganic nanomaterial.

[0046] In some embodiments, the first inorganic nanomaterial includes a first N-type inorganic nanomaterial.

[0047] In some embodiments, the average particle size of the first N-type inorganic nanomaterial is 5 nm to 10 nm, for example, it can be 6 nm, 7 nm, 8 nm, 9 nm, etc.

[0048] In some embodiments, the first inorganic nanomaterial includes one or more of a first doped metal oxide, a first undoped metal oxide, a group IIB-VIA semiconductor material, a group IIIA-VA semiconductor material, and a group IB-IIIA-VIA semiconductor material. The first undoped metal oxide includes one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The metal oxide in the first doped metal oxide includes one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3. The doping element in the first doped metal oxide includes one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga. The group IIB-VIA semiconductor material includes one or more of ZnS, ZnSe, and CdS. The group IIIA-VA semiconductor material includes one or more of InP and GaP. The group IB-IIIA-VIA semiconductor material includes one or more of CuInS and CuGaS. The doping amount of the doping element in the first doped metal oxide is 0.1wt% to 15wt%, for example, it can be 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, or any range between two values.

[0049] In some embodiments, the first inorganic nanomaterial comprises a first N-type inorganic nanomaterial and a first ligand coordinated to the first N-type inorganic nanomaterial. Further, the first ligand comprises a halogen ligand. The halogen ligand comprises one or more of -Cl, -Br, and -I.

[0050] In some embodiments, when the material of the second membrane layer comprises the first inorganic nanomaterial containing hydroxyl groups, the material of the second membrane layer also contains water of crystallization. In other words, the first inorganic nanomaterial in this embodiment is bound to water molecules. Further, the water of crystallization is connected to the first inorganic nanomaterial through coordination bonds and / or hydrogen bonds.

[0051] In some embodiments, the hydroxyl-containing bioceramic includes hydroxyl-containing bioactive ceramics, the hydroxyl-containing bioactive ceramics include hydroxyl-containing surface bioactive ceramics, and the hydroxyl-containing surface bioactive ceramics include one or more of hydroxyapatite and bioactive glass.

[0052] In some embodiments, the hydroxyl-containing resin includes hydroxyl acrylic resin.

[0053] In some embodiments, the hydroxyl-containing steroid includes steroids, and the steroids include sterols.

[0054] In some embodiments, when the material of the second film layer 12 includes the first inorganic nanomaterial containing hydroxyl groups, the thickness of the second film layer 12 is 5 nm to 10 nm, for example, 6 nm, 7 nm, 8 nm, 9 nm, etc. Within this thickness range, the device lifetime can be effectively improved, and the first inorganic nanomaterial containing hydroxyl groups can also improve the conductivity and carrier migration performance of the composite film 10, thereby improving the stability of the device. It should be noted that in this application, the thickness of the film layer is measured using a step tester.

[0055] In some embodiments, when the material of the second film layer 12 includes the hydroxyl-containing compound, the thickness of the second film layer 12 is 1 nm to 5 nm, for example, it can be 2 nm, 3 nm, 4 nm, etc.

[0056] In some embodiments, the material of the first film layer 11 includes a second inorganic nanomaterial. The second inorganic nanomaterial in the material of the first film layer 11 can ensure the conductivity and carrier migration performance of the composite film 10.

[0057] In some embodiments, the average particle size of the second inorganic nanomaterial is 5 nm to 10 nm, for example, it can be 6 nm, 7 nm, 8 nm, 9 nm, etc. It should be noted that in this application, the particle size of the nanomaterial is obtained by transmission electron microscopy (TEM).

[0058] In some embodiments, the second inorganic nanomaterial includes one or more of a second doped metal oxide, a second undoped metal oxide, a group IIB-VIA semiconductor material, a group IIIA-VA semiconductor material, and a group IB-IIIA-VIA semiconductor material. The second undoped metal oxide includes one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The metal oxide in the second doped metal oxide includes one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3. The doping element in the second doped metal oxide includes one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga. The group IIB-VIA semiconductor material includes one or more of ZnS, ZnSe, and CdS. The group IIIA-VA semiconductor material includes one or more of InP and GaP. The group IB-IIIA-VIA semiconductor material includes one or more of CuInS and CuGaS. The doping amount of the doping element in the second doped metal oxide is 0.1wt% to 15wt%, for example, it can be 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, or any range between two values.

[0059] In some embodiments, the second inorganic nanomaterial comprises a second N-type inorganic nanomaterial and a second ligand coordinated to the second N-type inorganic nanomaterial. Further, the second ligand comprises one or more of oleic acid and oleylamine.

[0060] In some embodiments, the thickness of the first film layer 11 is 20nm to 40nm, for example, it can be 25nm, 30nm, 35nm, etc.

[0061] In some embodiments, please refer to Figure 3 The composite film 10 further includes a third film layer 13, which is located on the side of the second film layer 12 away from the first film layer 11, and the material of the third film layer 13 includes a third inorganic nanomaterial.

[0062] In some embodiments, the amount of surface hydroxyl groups in the third film layer 13 is less than the amount of surface hydroxyl groups in the second film layer 12.

[0063] In some embodiments, the amount of surface hydroxyl groups in the third film layer 13 is 0.001 to 0.005, for example, 0.002, 0.003, 0.004, etc. Within the range of surface hydroxyl group amount, it is advantageous for the third film layer 13 to be prepared by inkjet printing, which is suitable for large-scale mass production.

[0064] In some embodiments, the average particle size of the third inorganic nanomaterial is 5 nm to 10 nm, for example, it can be 6 nm, 7 nm, 8 nm, 9 nm, etc.

[0065] In some embodiments, the third inorganic nanomaterial includes one or more of a third doped metal oxide, a third undoped metal oxide, a group IIB-VIA semiconductor material, a group IIIA-VA semiconductor material, and a group IB-IIIA-VIA semiconductor material. The third undoped metal oxide includes one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The metal oxide in the third doped metal oxide includes one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3. The doping element in the third doped metal oxide includes one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga. The group IIB-VIA semiconductor material includes one or more of ZnS, ZnSe, and CdS. The group IIIA-VA semiconductor material includes one or more of InP and GaP. The group IB-IIIA-VIA semiconductor material includes one or more of CuInS and CuGaS. The doping amount of the doping element in the third doped metal oxide is 0.1wt% to 15wt%, for example, it can be 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, or any range between two values.

[0066] In some embodiments, the third inorganic nanomaterial comprises a third N-type inorganic nanomaterial and a third ligand coordinated to the third N-type inorganic nanomaterial. Further, the third ligand comprises one or more of oleic acid and oleylamine.

[0067] In some embodiments, the thickness of the third film layer 13 is 20nm to 40nm, for example, it can be 25nm, 30nm, 35nm, etc.

[0068] The third film layer 13 may be the same as or different from the first film layer 11 in terms of material, thickness, etc. The third film layer 13 can improve the overall conductivity and electron mobility of the composite film 10. The third film layer 13 can prevent the second film layer 12 from directly contacting the active layer 30 or electrodes in the device, avoiding adverse effects such as quenching the active layer 30 or causing short circuits in the electrodes, thereby improving the performance of the device.

[0069] Secondly, please refer to Figure 4 This application also provides a method for preparing a composite thin film 10, comprising the following steps:

[0070] S11, Provide the first film layer 11;

[0071] S12. Provide a first inorganic nanomaterial or a hydroxyl-containing compound, deposit it on the first film layer 11 to form a second film layer 12, and obtain a composite film 10, wherein the hydroxyl-containing compound includes one or more of hydroxyl-containing bioceramics, hydroxyl-containing resins, and hydroxyl-containing steroids.

[0072] It is understood that the order of the first film layer 11 and the second film layer 12 is not limited.

[0073] In other embodiments, please refer to Figure 5 The method for preparing the composite thin film 10 includes the following steps:

[0074] S21. Provide a first inorganic nanomaterial or a hydroxyl-containing compound, and deposit the first inorganic nanomaterial or the hydroxyl-containing compound to form a second film layer 12; wherein the hydroxyl-containing compound includes one or more of hydroxyl-containing bioceramics, hydroxyl-containing resins, and hydroxyl-containing steroids.

[0075] S22. A first film layer 11 is formed on the second film layer to obtain a composite film 10.

[0076] In some embodiments, the method of forming the first film layer 11 includes inkjet printing.

[0077] Specifically, the method for forming the first film layer 11 includes: providing ink, the ink comprising a second inorganic nanomaterial and a first solvent; and depositing the ink to form the first film layer 11.

[0078] In some embodiments, the preparation method of the second inorganic nanomaterial includes: providing an anhydrous metal salt and a second solvent, mixing them to obtain the second inorganic nanomaterial.

[0079] In some embodiments, the anhydrous metal salt includes one or more of the following: anhydrous zinc salt, anhydrous titanium salt, anhydrous tin salt, anhydrous tantalum salt, anhydrous zirconium salt, anhydrous cadmium salt, anhydrous copper salt, anhydrous indium salt, anhydrous gallium salt, anhydrous aluminum salt, anhydrous magnesium salt, anhydrous lithium salt, anhydrous yttrium salt, anhydrous lanthanum salt, and anhydrous cerium salt.

[0080] In some embodiments, the anhydrous metal salt includes one or more of anhydrous oleate and anhydrous stearate. For example, the zinc salt includes one or more of anhydrous zinc oleate and anhydrous zinc stearate.

[0081] In some embodiments, the second solvent includes one or more of n-hexane, n-octane, isooctane, cyclohexane, ethyl acetate, benzene, toluene, chloroform, carbon tetrachloride, dichloromethane, and dimethyl ether.

[0082] In some embodiments, after the anhydrous metal salt is mixed with the second solvent, the concentration of the anhydrous metal salt is 20 mg / mL to 60 mg / mL, for example, 30 mg / mL, 35 mg / mL, 40 mg / mL, 45 mg / mL, 50 mg / mL, etc. Within this concentration range, it is beneficial for the complete dissolution and dispersion of the anhydrous metal salt.

[0083] In some embodiments, the mixing of the anhydrous metal salt with the second solvent further includes the addition of a second ligand. Further, the molar ratio of the anhydrous metal salt to the second ligand is 3:(0.5–1.8), for example, 3:0.6, 3:0.8, 3:1, 3:1.2, 3:1.5, etc. Within the range of the stated molar ratio, the second ligand can be effectively attached to the generated second N-type inorganic nanorods, improving the performance of the second inorganic nanomaterial.

[0084] In some embodiments, after the anhydrous metal salt and the second solvent are mixed, the mixture further includes sequentially undergoing a first heating and a second heating.

[0085] Furthermore, the temperature of the first heating is 120℃~140℃, for example, it can be 122℃, 125℃, 128℃, 130℃, 132℃, 135℃, 138℃, etc.; the time is 20min~30min, for example, it can be 22min, 25min, 28min, etc.

[0086] The second heating temperature is 200℃~250℃, for example, it can be 210℃, 220℃, 230℃, 240℃; the time is 1h~2h, for example, it can be 1.2h, 1.5h, 1.8h, etc.

[0087] It should be noted that the first heating is a degassing treatment, and the second heating is a ripening treatment. Under the conditions of the first heating, it is beneficial to fully remove the gas; under the conditions of the second heating, it is beneficial to fully react and generate the first inorganic nanomaterial.

[0088] In some embodiments, the concentration of the second inorganic nanomaterial in the ink is 40 mg / mL to 60 mg / mL, for example, 40 mg / mL, 45 mg / mL, 50 mg / mL, 55 mg / mL, etc. Within this concentration range, it is beneficial for the second inorganic nanomaterial to be sufficiently and uniformly dispersed.

[0089] In some embodiments, the boiling point of the first solvent is 150°C to 220°C, for example, it can be 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, etc.

[0090] In some embodiments, the viscosity of the ink is 2 Pa·s to 10 Pa·s, for example, it can be 4 Pa·s, 5 Pa·s, 6 Pa·s, 7 Pa·s, 8 Pa·s, 9 Pa·s, etc.

[0091] In some embodiments, the contact angle of the ink is less than or equal to 30°, for example, it can be 25°, 20°, 15°, 10°, etc. It should be noted that in this application, the contact angle is measured by a contact angle measuring instrument.

[0092] Thus, under the constraints of the boiling point of the first solvent, the viscosity of the ink, and the contact angle, the ink is conducive to inkjet printing, and the prepared first film layer 11 has good film-forming performance.

[0093] In some embodiments, the first solvent comprises a mixed solvent of 3-methoxy-1-propanol and diethylene glycol diethyl ether. Further, in the mixed solvent, the molar ratio of 3-methoxy-1-propanol to diethylene glycol diethyl ether is 1:1.

[0094] In some embodiments, after depositing the ink, a vacuum pumping process is further included. The vacuum pumping can remove a first solvent from the ink.

[0095] For example, vacuum evacuation can be performed in steps: first evacuate at 0.01 mbar for 40 seconds, then at 0.001 mbar for 30 seconds, and finally at 0.0001 mbar for 300 seconds.

[0096] In some embodiments, when the material of the second film layer 12 includes the first inorganic nanomaterial containing hydroxyl groups, the preparation method of the second film layer 12 includes spin coating.

[0097] Specifically, when the material of the second film layer 12 includes the first inorganic nanomaterial containing hydroxyl groups, the preparation method of the second film layer 12 includes: providing a first dispersion liquid containing the first inorganic nanomaterial containing hydroxyl groups and a third solvent, and spin-coating the first dispersion liquid to form the second film layer 12.

[0098] In some embodiments, the preparation method of the first inorganic nanomaterial containing hydroxyl groups includes: providing a metal salt, an alkali and a fourth solvent, mixing them to obtain the first inorganic nanomaterial containing hydroxyl groups.

[0099] In some embodiments, the metal cations in the metal salt include one or more of zinc ions, titanium ions, tin ions, tantalum ions, zirconium ions, cadmium ions, copper ions, indium ions, gallium ions, aluminum ions, magnesium ions, lithium ions, yttrium ions, lanthanum ions, and cerium ions; the anions in the metal salt include one or more of acetate ions, sulfate ions, halide ions, and nitrate ions. It should be noted that the metal salt can be a hydrous metal salt, such as zinc acetate dihydrate.

[0100] In some embodiments, the alkali includes one or more of potassium hydroxide, lithium hydroxide, sodium hydroxide, ammonium hydroxide, ethylenediamine, ethanolamine, diethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide.

[0101] In some embodiments, the molar ratio of the metal salt to the alkali is (3-6):6, for example, 3:6, 3.5:6, 4:6, 4.5:6, 5:6, 5.5:6, etc. Within this range of molar ratios, it is beneficial for the metal salt and the alkali to react fully to generate a first inorganic nanomaterial containing hydroxyl groups.

[0102] In some embodiments, the concentration of the metal salt in the mixture of the metal salt, the alkali, and the fourth solvent is 20 mg / mL to 40 mg / mL, for example, 22 mg / mL, 25 mg / mL, 28 mg / mL, 30 mg / mL, 32 mg / mL, 35 mg / mL, 38 mg / mL, etc. Within this concentration range, the fourth solvent provides a favorable reaction atmosphere, promoting the formation of the first hydroxyl-containing inorganic nanomaterial from the metal salt.

[0103] In some embodiments, the fourth solvent includes one or more of methanol, ethanol, butanol, 4-methylcyclohexanol, isopropanol, ethylene glycol monomethyl ether, benzyl alcohol, and cyclopentanol.

[0104] In some embodiments, after mixing the metal salt, the alkali, and the fourth solvent, a third heating process is further included. Further, the temperature of the third heating is 60℃ to 90℃, for example, 62℃, 65℃, 68℃, 70℃, 72℃, 75℃, 78℃, 80℃, 82℃, 85℃, 88℃, etc.; the time is 0.5h to 2h, for example, 0.8h, 1h, 1.2h, 1.5h, 1.8h, etc. The third heating is a aging treatment, and under the conditions of the third heating, it is beneficial to efficiently synthesize the first inorganic nanomaterial containing hydroxyl groups.

[0105] In some embodiments, the concentration of the hydroxyl-containing first inorganic nanomaterial in the first dispersion is 20 mg / mL to 50 mg / mL, for example, it can be 30 mg / mL, 35 mg / mL, 40 mg / mL, 45 mg / mL, etc. Within this concentration range, it is beneficial for the hydroxyl-containing first inorganic nanomaterial to be fully and uniformly dispersed.

[0106] In some embodiments, the boiling point of the third solvent is 40°C to 120°C, for example, it can be 45°C, 50°C, 60°C, 70°C, 85°C, 90°C, 95°C, 100°C, 115°C, etc.

[0107] In some embodiments, the viscosity of the first dispersion is 0.1 Pa·s to 1.5 Pa·s, for example, it can be 0.2 Pa·s, 0.5 Pa·s, 0.8 Pa·s, 1 Pa·s, 1.2 Pa·s, 1.5 Pa·s, 1.8 Pa·s, etc.

[0108] In some embodiments, the contact angle of the first dispersion is greater than or equal to 60°, for example, it can be 65°, 70°, 75°, 80°, etc.

[0109] Thus, given the boiling point of the third solvent, the viscosity of the first dispersion, and the contact angle, the first material dispersion can be prepared into a film by spin coating, which is not conducive to film formation by inkjet printing.

[0110] In some embodiments, the third solvent includes one or more of methanol, ethanol, butanol, 4-methylcyclohexanol, isopropanol, ethylene glycol monomethyl ether, benzyl alcohol, and cyclopentanol.

[0111] In some embodiments, after spin-coating the first dispersion, thermal annealing is further included. Further, the thermal annealing temperature is 80℃~140℃, for example, 90℃, 100℃, 110℃, 120℃, 130℃, etc.; the thermal annealing time is 8min~20min, for example, 10min, 12min, 15min, 18min, etc. Thus, under the conditions of thermal annealing, it is beneficial to remove the third solvent and improve the film-forming properties of the first sublayer 121. It should be noted that the third solvent is difficult to completely remove; some hydroxyl groups in the third solvent will be attached to the first inorganic nanomaterial, increasing the active sites of the first inorganic nanomaterial and improving the lifespan of the device when it is applied.

[0112] In some embodiments, the preparation method of the second sublayer 122 includes vapor deposition.

[0113] Specifically, when the material of the second film layer 12 includes the hydroxyl-containing compound, the method for preparing the second film layer 12 includes: providing the hydroxyl-containing compound, evaporating the hydroxyl-containing compound, and forming the second film layer 12.

[0114] Furthermore, the vacuum degree of the vapor deposition is ≤10. -3 Pa, for example, can be 10. -3 Pa, 10 -4 Pa, 10 -5 Pa, etc.; evaporation temperature is 1000℃~2000℃, for example, 1100℃, 1200℃, 1300℃, 1400℃, 1500℃, 1600℃, 1700℃, 1800℃, 1900℃, etc.; evaporation rate is... For example, it can be... wait.

[0115] Thus, under the aforementioned vapor deposition conditions, it is beneficial to improve the film-forming properties of the second film layer 12.

[0116] In some embodiments, after the first film layer 11 and the second film layer 12 are formed sequentially, a third film layer 13 is formed on the side of the second film layer 12 away from the first film layer 11.

[0117] In some other embodiments, a third film layer 13 is formed before the second film layer 12 and the first film layer 11 are formed in sequence, on which the second film layer 12 and the first film layer 11 are formed in sequence.

[0118] In some embodiments, the preparation method for forming the third film layer 13 may refer to the preparation method for the first film layer 11, and will not be repeated here.

[0119] The method for preparing the composite film 10 provided in this application is simple and conducive to its application in large-scale mass production.

[0120] Thirdly, please refer to Figure 6 and Figure 7 This application also provides an optoelectronic device 100, which includes an anode 20, an active layer 30, an electronic functional layer and a cathode 40 stacked together; wherein the electronic functional layer includes the above-mentioned composite thin film 10, or the composite thin film 10 prepared by the above-mentioned preparation method.

[0121] It should be noted that the composite film 10 includes a first film layer 11 and a second film layer 12 stacked together. In some embodiments, the first film layer 11 is located between the active layer 30 and the second film layer 12. In other embodiments, the second film layer 12 is located between the active layer 30 and the first film layer 11.

[0122] Further, please refer to Figure 8 When the composite film 10 includes a third film layer 13, the second film layer 12 is located between the first film layer 11 and the third film layer 13; the first film layer 11 is located between the active layer 30 and the second film layer 12, and the third film layer 13 is located between the second film layer 12 and the cathode 40, or the third film layer 13 is located between the second film layer 12 and the active layer 30, and the first film layer 11 is located between the second film layer 12 and the cathode 40.

[0123] The optoelectronic device 100 provided in this application has hydroxyl groups in the second film layer 12 that can increase active sites and extend the service life of the optoelectronic device 100.

[0124] In some embodiments, the optoelectronic device 100 further includes a hole functional layer 50, which is located between the anode 20 and the active layer 30.

[0125] The hole functional layer 50 includes one or more of a hole injection layer and a hole transport layer.

[0126] In some embodiments, the hole functional layer 50 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... 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-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-Phenylacetene], 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, fourth-doped metal oxide The metal oxide particles are selected from one or more of the following: metal oxide particles, fourth undoped metal oxide particles, metal sulfides, metal selenides, and metal nitrides. The metal oxides in the fourth doped metal oxide particles and the metal oxides in the fourth 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 fourth 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.The doping amount of the doping element in the fourth doped metal oxide is 0.1wt% to 15wt%, for example, it can be 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, or any range between two values.

[0127] In some embodiments, the materials of the anode 20 and the cathode 40 independently include one or more of metals, carbon materials, and metal oxides; the metals include one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon materials include one or more of graphite, carbon nanotubes, graphene, and carbon fibers; 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.

[0128] In some embodiments, the optoelectronic device 100 is a light-emitting diode.

[0129] In some embodiments, the active layer 30 includes a light-emitting layer.

[0130] In some embodiments, the material of the light-emitting layer includes one or more of organic light-emitting materials and quantum dots.

[0131] The organic light-emitting materials include one or more of the following: 4,4'-bis(N-carbazole)-1,1'-biphenyl: tris[2-(p-tolyl)pyridinium(III)], 4,4',4”-tris(carbazole-9-yl)triphenylamine: tris[2-(p-tolyl)pyridinium(III)], diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials, DBP fluorescent materials, delayed fluorescence materials, TTA materials, TADF materials, polymers containing BN covalent bonds, HLCT materials, and Exciplex light-emitting materials.

[0132] In some embodiments, the quantum dots may be selected from, but are not limited to, one or more of single-structure quantum dots, core-shell structure quantum dots, and perovskite quantum dots.

[0133] 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 compounds from group II-VI, group IV-VI, group III-V, and group I-III-VI. The shell of the core-shell quantum dots may consist of 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.

[0134] 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).

[0135] The perovskite quantum dots can be selected from, but are not limited to, doped or undoped inorganic perovskite quantum dots, or organic-inorganic hybrid perovskite quantum dots. The general structural formula of the inorganic perovskite quantum dots 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 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 quantum dots 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 them.

[0136] Fourthly, embodiments of this application also provide a display device, which includes the aforementioned optoelectronic device 100.

[0137] 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.

[0138] 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.

[0139] Example 1

[0140] This embodiment provides a composite thin film, the preparation method of which is as follows:

[0141] Preparation of the second / third inorganic nanomaterial: Weigh 3 mmol zinc oleate and 1.8 mmol oleic acid and n-hexane, mix them, degas at 140℃ for 20 min, then ripen at 250℃ for 2 h, dilute with toluene and then precipitate with ethanol, collect the precipitate to obtain the second / third inorganic nanomaterial.

[0142] Preparation of the first inorganic nanomaterial: Weigh 3 mmol of zinc acetate dihydrate, 6 mmol of sodium hydroxide and ethanol, mix them, and ripen at 80°C for 1 h. Add ethanolamine and ripen for another 1 h. Centrifuge 3 times and collect the precipitate to obtain the first inorganic nanomaterial.

[0143] The second inorganic nanomaterial was dissolved in a mixed solvent of 3-methoxy-1-propanol and diethylene glycol diethyl ether, with a molar ratio of 1:1, to obtain an ink with a concentration of 50 mg / mL. After inkjet printing this ink, vacuum evacuation was performed, specifically by first evacuating at 0.01 mbar for 40 s, then at 0.001 mbar for 30 s, and finally at 0.0001 mbar for 300 s, to form the first film layer.

[0144] The first inorganic nanomaterial was dissolved in ethanol to obtain a first dispersion with a concentration of 40 mg / mL. The dispersion was then spin-coated onto the first film layer and heated at 100°C for 10 min to form a second film layer with a thickness of 8 nm.

[0145] The method for forming the first film layer involves using a third inorganic nanomaterial to form a third film layer on the second film layer, thereby obtaining a composite film.

[0146] Example 2

[0147] This embodiment is basically the same as Embodiment 1, except that zinc oleate is replaced with titanium oleate when preparing the second and third inorganic nanomaterials in this embodiment.

[0148] Example 3

[0149] This embodiment is basically the same as Embodiment 1, except that the thickness of the second film layer in this embodiment is 10nm.

[0150] Example 4

[0151] This embodiment is basically the same as Embodiment 1, except that the thickness of the second film layer in this embodiment is 5nm.

[0152] Example 5

[0153] This embodiment is basically the same as Embodiment 1, except that the preparation method of the second film layer in this embodiment includes: taking hydroxyapatite, in 10 -3 Evaporation was carried out in a vacuum environment at a pressure of Pa, with an evaporation temperature of 1500℃ and an evaporation rate of [missing information]. A second film with a thickness of 3 nm is formed.

[0154] Example 6

[0155] This embodiment is basically the same as embodiment 5, except that hydroxyapatite is replaced with bioactive glass in this embodiment.

[0156] Example 7

[0157] This embodiment is basically the same as embodiment 5, except that hydroxyapatite is replaced with sterol in this embodiment.

[0158] Example 8

[0159] This embodiment is basically the same as embodiment 5, except that the thickness of the second film layer in this embodiment is 5nm.

[0160] Example 9

[0161] This embodiment is basically the same as embodiment 5, except that the thickness of the second film layer in this embodiment is 1 nm.

[0162] Example 10

[0163] This embodiment is basically the same as Embodiment 1, except that this embodiment does not contain a third film layer.

[0164] Example 11

[0165] This embodiment is basically the same as Embodiment 2, except that this embodiment does not contain a third film layer.

[0166] Example 12

[0167] This embodiment is basically the same as embodiment 5, except that this embodiment does not contain a third film layer.

[0168] Example 13

[0169] This embodiment is basically the same as embodiment 6, except that this embodiment does not contain a third film layer.

[0170] Example 14

[0171] This embodiment is basically the same as embodiment 7, except that this embodiment does not contain a third film layer.

[0172] Comparative Example 1

[0173] This comparative example is basically the same as Example 1, except that this comparative example contains only the first film layer.

[0174] Comparative Example 2

[0175] This comparative example is basically the same as Example 1, except that this comparative example contains only the second film layer.

[0176] Comparative Example 3

[0177] This comparative example is basically the same as Example 2, except that this comparative example contains only the first film layer.

[0178] Comparative Example 4

[0179] This comparative example is basically the same as Example 2, except that this comparative example contains only the second film layer.

[0180] Device Example 1

[0181] This embodiment provides an optoelectronic device, the fabrication method of which is as follows:

[0182] Clean the substrate with patterned electrodes; treat the surface of the ITO substrate with ultraviolet-ozone for 5 minutes to further remove organic matter attached to the surface of the ITO substrate and improve the work function of the ITO substrate to form an anode;

[0183] TFB solution was spin-coated onto the anode and annealed at 150°C for 20 min to form a hole-functional layer.

[0184] A CdZnS quantum dot dispersion is provided and spin-coated onto a hole transport layer to form a light-emitting layer;

[0185] A composite thin film (electronic functional layer) is prepared on the quantum dot emitting layer using the method described in Example 1, wherein the first film layer is located between the emitting layer and the second film layer;

[0186] A layer of silver is thermally vaporized through a mask in a vapor deposition chamber to form a cathode;

[0187] Packaging yields optoelectronic devices.

[0188] Device Examples 2-9

[0189] Device Examples 2-9 are basically the same as Device Example 1, except that the composite films in Device Examples 2-9 are prepared by the methods of Examples 2-9 respectively.

[0190] Device Examples 10-14

[0191] Device Examples 10-14 are basically the same as Device Example 1, except that the composite thin film is prepared by the method of Examples 10-14 respectively in Device Examples 10-14, wherein the second film layer is located between the first film layer and the cathode.

[0192] Device Examples 15-19

[0193] Device Examples 15-19 are basically the same as Device Example 1, except that the composite film is prepared in Device Examples 15-19 by referring to the methods of Examples 10-14, wherein the second film layer is located between the first film layer and the light-emitting layer.

[0194] Device Comparison Examples 1-4

[0195] 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 by the methods of Comparative Examples 1 to 4 respectively.

[0196] The external quantum efficiency (EQE), burn-out rate, lifetime (T95), and lifetime (T95@1000nit) of the optoelectronic devices of Device Examples 1-19 and Device Comparative Examples 1-4 were tested respectively, and the results are shown in Table 1.

[0197] External quantum efficiency (EQE) is measured as the ratio of electron-hole pairs injected into a quantum dot to emitted photons, expressed as a percentage (%). It is a crucial parameter for evaluating the quality of electroluminescent devices and can be obtained using an EQE optical testing instrument. The specific calculation formula is as follows:

[0198]

[0199] Where, η e For optical output coupling efficiency, η rχ is the ratio of recombination carriers to injected carriers, and K is the ratio of excitons producing photons to the total number of excitons. R K is the radiation process rate. NR This represents the rate of a non-radiative process.

[0200] Test conditions: Conducted at room temperature with an air humidity of 30-60%.

[0201] The burn-out rate test method is to test the voltage-current density (JV) of 100 optoelectronic devices, record the number of optoelectronic devices that burn out due to short circuit, and the burn-out rate = number of burn-out optoelectronic devices / 100 × 100%.

[0202] The test method for lifetime T95@1000nit 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 formula. For example, the lifetime at 1000nit is measured as T95@1000nit. The specific calculation formula is as follows:

[0203]

[0204] 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.

[0205] Table 1

[0206]

[0207]

[0208] As shown in Table 1:

[0209] As can be seen from Device Examples 1-9 and Device Comparative Examples 1-4, compared with the optoelectronic device containing only the first film layer in Device Comparative Example 1, Device Examples 1-9 have a second film layer added between the first and third film layers, which significantly improves the external quantum efficiency of the optoelectronic device, reduces the burn-out rate of the optoelectronic device, and especially significantly improves the service life of the optoelectronic device. Device Comparative Example 2 contains only the second film layer, and the hydroxyl groups and water of crystallization it contains make it prone to short circuits and easy to quench the light-emitting layer. Therefore, its external quantum efficiency is low, its burn-out rate is high, and its mass production is more difficult.

[0210] As can be seen from Device Examples 10-14 and Device Comparative Examples 1-2, the arrangement of a first film layer and a second film layer between the light-emitting layer and the cathode, with the second film layer located between the first film layer and the cathode, is also beneficial for improving the external quantum efficiency and lifespan of the optoelectronic device compared to Device Example 1, thus extending its lifespan. In Device Examples 10-11, the presence of water of crystallization, which comes into contact with the cathode, affects the normal operation of the optoelectronic device, resulting in a slightly higher burn-out rate than other device examples. However, compared to Device Comparative Example 1, which only contains the first film layer, Device Examples 10-11 show a significantly extended lifespan for the optoelectronic device. Compared to Device Comparative Example 2, which only contains the second film layer, Device Examples 10-11 show a significantly improved external quantum efficiency and a reduced burn-out rate, resulting in improved overall performance.

[0211] As can be seen from Device Examples 15-19 and Device Comparative Example 1, by setting a first film layer and a second film layer between the light-emitting layer and the cathode, and with the second film layer located between the first film layer and the light-emitting layer, the lifespan of the optoelectronic device can still be effectively extended and the burn-out rate of the optoelectronic device can be reduced. It should be noted that the second film layer is set close to the side of the light-emitting layer, and the hydroxyl groups in it will cause quenching of the light-emitting layer, so the external quantum efficiency is lower than that of Device Comparative Example 1.

[0212] 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 composite film, characterized in that, It includes a first membrane layer and a second membrane layer stacked together; wherein the material of the second membrane layer includes a first inorganic nanomaterial containing hydroxyl groups or a compound containing hydroxyl groups, and the compound containing hydroxyl groups includes one or more of hydroxyl-containing bioceramics, hydroxyl-containing resins, and hydroxyl-containing steroids.

2. The composite film as described in claim 1, characterized in that, The amount of surface hydroxyl groups in the first film layer is less than the amount of surface hydroxyl groups in the second film layer; and / or The amount of surface hydroxyl groups in the first film layer is 0.001–0.005; and / or The amount of surface hydroxyl groups in the second film layer is 0.5–1; and / or The first inorganic nanomaterial containing hydroxyl groups comprises a first inorganic nanomaterial and hydroxyl groups coordinated and linked to the first inorganic nanomaterial; and / or The hydroxyl-containing bioceramic includes hydroxyl-containing bioactive ceramics, which in turn include hydroxyl-containing surface bioactive ceramics, which include one or more of hydroxyapatite and bioactive glass; and / or The hydroxyl-containing resin includes hydroxyl acrylic resin; and / or The hydroxyl-containing steroid includes steroids, and the steroids include sterols; and / or When the material of the second film layer includes the first inorganic nanomaterial containing hydroxyl groups, the thickness of the second film layer is 5 nm to 10 nm; when the material of the second film layer includes the compound containing hydroxyl groups, the thickness of the second film layer is 1 nm to 5 nm; and / or The thickness of the first film layer is 20nm to 40nm.

3. The composite film as described in claim 1, characterized in that, The first inorganic nanomaterial includes a first N-type inorganic nanomaterial and a first ligand coordinated to the first N-type inorganic nanomaterial; and / or The material of the first film layer includes a second inorganic nanomaterial, the second inorganic nanomaterial including a second N-type inorganic nanomaterial and a second ligand coordinated to the second N-type inorganic nanomaterial; and / or When the material of the second film layer includes the first inorganic nanomaterial containing hydroxyl groups, the material of the second film layer also contains water of crystallization, which is connected to the first inorganic nanomaterial through coordination bonds and / or hydrogen bonds.

4. The composite film as described in claim 3, characterized in that, The average particle size of the first type N inorganic nanomaterial is 5 nm to 10 nm; and / or The average particle size of the second type N inorganic nanomaterial is 5 nm to 10 nm; and / or The first type N-type inorganic nanomaterial and the second type N-type inorganic nanomaterial each independently include one or more of the following: a first doped metal oxide, a first undoped metal oxide, a group IIB-VIA semiconductor material, a group IIIA-VA semiconductor material, and a group IB-IIIA-VIA semiconductor material. The first undoped metal oxide includes one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The metal oxide in the first doped metal oxide includes one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3. The first doped metal oxide contains one or more of the following doping elements: Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga; the IIB-VIA group semiconductor material contains one or more of ZnS, ZnSe, and CdS; the IIIA-VA group semiconductor material contains one or more of InP and GaP; and the IB-IIIA-VIA group semiconductor material contains one or more of CuInS and CuGaS. The doping amount of the first doped metal oxide is 0.1 wt% to 15 wt%. The first ligand includes a halogen ligand, wherein the halogen ligand includes one or more of -Cl, -Br, and -I; and / or The second ligand includes one or more of oleic acid and oleylamine.

5. The composite film as described in claim 1, characterized in that, The composite film further includes a third film layer, which is located on the side of the second film layer away from the first film layer, and the material of the third film layer includes a third inorganic nanomaterial; wherein... The amount of surface hydroxyl groups in the third film layer is less than the amount of surface hydroxyl groups in the second film layer; and / or The surface hydroxyl content of the third film layer is 0.001–0.005; and / or The average particle size of the third inorganic nanomaterial is 5 nm to 10 nm; and / or The third inorganic nanomaterial includes one or more of the following: a third doped metal oxide, a third undoped metal oxide, a group IIB-VIA semiconductor material, a group IIIA-VA semiconductor material, and a group IB-IIIA-VIA semiconductor material. The third undoped metal oxide includes one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The third doped metal oxide includes one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3. The doping elements in the oxide include one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga; the IIB-VIA group semiconductor materials include one or more of ZnS, ZnSe, and CdS; the IIIA-VA group semiconductor materials include one or more of InP and GaP; and the IB-IIIA-VIA group semiconductor materials include one or more of CuInS and CuGaS. The doping amount of the doping element in the third-doped metal oxide is 0.1 wt% to 15 wt%; and / or The third inorganic nanomaterial comprises a third N-type inorganic nanomaterial and a third ligand coordinated to the third N-type inorganic nanomaterial, wherein the third ligand comprises one or more of oleic acid and oleylamine; and / or The thickness of the third film layer is 20nm to 40nm.

6. A method for preparing a composite thin film, characterized in that, Includes the following steps: Provide the first membrane layer; A first inorganic nanomaterial or a compound containing hydroxyl groups is provided and deposited on the first film layer to form a second film layer, thereby obtaining a composite film. or, A first inorganic nanomaterial or a hydroxyl-containing compound is provided, and the first inorganic nanomaterial or the hydroxyl-containing compound is deposited to form a second film layer; A first film layer is formed on the second film layer to obtain a composite film; The hydroxyl-containing compounds include one or more of hydroxyl-containing bioceramics, hydroxyl-containing resins, and hydroxyl-containing steroids.

7. The preparation method according to claim 6, characterized in that, The method for forming the first film layer includes: providing an ink comprising a second inorganic nanomaterial and a first solvent; and depositing the ink to form the first film layer.

8. The preparation method according to claim 7, characterized in that, In the ink, the concentration of the second inorganic nanomaterial is 40 mg / mL to 60 mg / mL; and / or The boiling point of the first solvent is 150℃~220℃; and / or The viscosity of the ink is 2 Pa·s to 10 Pa·s; and / or The contact angle of the ink is less than or equal to 30°; and / or The first solvent comprises a mixed solvent of 3-methoxy-1-propanol and diethylene glycol diethyl ether.

9. The preparation method according to claim 7, characterized in that, The preparation method of the second inorganic nanomaterial includes: providing an anhydrous metal salt and a second solvent, mixing them, and obtaining the second inorganic nanomaterial; Optionally, the anhydrous metal salt includes one or more of the following: anhydrous zinc salt, anhydrous titanium salt, anhydrous tin salt, anhydrous tantalum salt, anhydrous zirconium salt, anhydrous cadmium salt, anhydrous copper salt, anhydrous indium salt, anhydrous gallium salt, anhydrous aluminum salt, anhydrous magnesium salt, anhydrous lithium salt, anhydrous yttrium salt, anhydrous lanthanum salt, and anhydrous cerium salt. Optionally, the anhydrous metal salt includes one or more of anhydrous oleate and anhydrous stearate; Optionally, the second solvent includes one or more of the following: n-hexane, n-octane, isooctane, cyclohexane, ethyl acetate, benzene, toluene, chloroform, carbon tetrachloride, dichloromethane, and dimethyl ether. Optionally, after the anhydrous metal salt is mixed with the second solvent, the concentration of the anhydrous metal salt is 20 mg / mL to 60 mg / mL; Optionally, after the anhydrous metal salt and the second solvent are mixed, the mixture further includes a first heating and a second heating in sequence; the temperature of the first heating is 120℃~140℃ and the time is 20min~30min; the temperature of the second heating is 200℃~250℃ and the time is 1h~2h.

10. The preparation method according to claim 6, characterized in that, The amount of surface hydroxyl groups in the first film layer is less than the amount of surface hydroxyl groups in the second film layer; and / or The first inorganic nanomaterial containing hydroxyl groups comprises a first inorganic nanomaterial and hydroxyl groups coordinated and linked to the first inorganic nanomaterial; and / or The hydroxyl-containing bioceramic includes hydroxyl-containing bioactive ceramics, which in turn include hydroxyl-containing surface bioactive ceramics, which include one or more of hydroxyapatite and bioactive glass; and / or The hydroxyl-containing resin includes hydroxyl acrylic resin; and / or The hydroxyl-containing steroid includes steroids, and the steroids include sterols.

11. The preparation method according to claim 10, characterized in that, When the material of the second film layer includes the first inorganic nanomaterial containing hydroxyl groups, the preparation method of the second film layer includes: providing a first dispersion containing the first inorganic nanomaterial containing hydroxyl groups and a third solvent; spin-coating the first dispersion to form a second film layer; or When the material of the second film layer includes the hydroxyl-containing compound, the method for preparing the second film layer includes: providing the hydroxyl-containing compound, evaporating the hydroxyl-containing compound, and forming the second film layer.

12. The preparation method according to claim 11, characterized in that, In the first dispersion, the concentration of the hydroxyl-containing first inorganic nanomaterial is 20 mg / mL to 50 mg / mL; and / or The boiling point of the third solvent is 40℃~120℃; and / or The viscosity of the first dispersion is 0.1 Pa·s to 1.5 Pa·s; and / or The contact angle of the first dispersion is greater than or equal to 60°; and / or The third solvent includes one or more of methanol, ethanol, butanol, 4-methylcyclohexanol, isopropanol, ethylene glycol monomethyl ether, benzyl alcohol, and cyclopentanol; and / or After spin-coating the first dispersion, the process further includes thermal annealing; the thermal annealing temperature is 80℃~140℃, and the time is 8min~20min; and / or The vacuum degree of the vapor deposition is ≤10. -3 Pa; the evaporation temperature of the vapor deposition is 1000℃~2000℃; the vapor deposition rate of the vapor deposition is 13. The preparation method according to claim 12, characterized in that, The preparation method of the first inorganic nanomaterial containing hydroxyl groups includes: providing a metal salt, an alkali and a fourth solvent, mixing them, and obtaining the first inorganic nanomaterial containing hydroxyl groups. Optionally, the metal cations in the metal salt include one or more of zinc ions, titanium ions, tin ions, tantalum ions, zirconium ions, cadmium ions, copper ions, indium ions, gallium ions, aluminum ions, magnesium ions, lithium ions, yttrium ions, lanthanum ions, and cerium ions; the anions in the metal salt include one or more of acetate ions, sulfate ions, halide ions, and nitrate ions. Optionally, the alkali includes one or more of potassium hydroxide, lithium hydroxide, sodium hydroxide, ammonium hydroxide, ethylenediamine, ethanolamine, diethanolamine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide; Optionally, the molar ratio of the metal salt to the alkali is (3-6):6; Optionally, in the mixture of the metal salt, the alkali, and the fourth solvent, the concentration of the metal salt is 20 mg / mL to 40 mg / mL. Optionally, the fourth solvent includes one or more of methanol, ethanol, butanol, 4-methylcyclohexanol, isopropanol, ethylene glycol monomethyl ether, benzyl alcohol, and cyclopentanol; Optionally, after mixing the metal salt, the alkali, and the fourth solvent, a third heating process is further included; the temperature of the third heating is 60℃~90℃, and the time is 0.5h~2h.

14. The preparation method according to claim 6, characterized in that, After the first film layer and the second film layer are formed sequentially, the method further includes forming a third film layer on the side of the second film layer away from the first film layer; or Before the second film layer and the first film layer are formed in sequence, a third film layer is formed, on which the second film layer and the first film layer are formed in sequence.

15. An optoelectronic device, characterized in that, It includes an anode, an active layer, an electronic functional layer, and a cathode stacked together; wherein the electronic functional layer includes a composite film as described in any one of claims 1 to 5, or a composite film prepared by the preparation method described in any one of claims 6 to 14; The composite film includes a first film layer and a second film layer stacked together, wherein the first film layer is located between the active layer and the second film layer, or the second film layer is located between the active layer and the first film layer.

16. The optoelectronic device as described in claim 15, characterized in that, The composite film further includes a third film layer, wherein the second film layer is located between the first film layer and the third film layer; and / or The anode and cathode are each made of one or more of the following materials: metal, carbon material, and metal oxide; the metal includes one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon material includes one or more of graphite, carbon nanotubes, graphene, and carbon fiber; the metal oxide includes a metal oxide electrode or a composite electrode in which a metal is disposed between doped or undoped transparent metal oxides; the metal oxide electrode is made of one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, MoO3, and AMO; the composite electrode includes 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 active layer includes a light-emitting layer, the material of which includes one or more organic light-emitting materials and quantum dot light-emitting materials; the organic light-emitting material is selected from 4,4'-bis(N-carbazole)-1,1'-biphenyl:tris[2-(p-tolyl)pyridinium(III)], 4,4',4”-tris(carbazole-9-yl)triphenylamine:tris[2-(p-tolyl)pyridinium], diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials, DBP fluorescent materials, delayed fluorescence materials, etc. The quantum dot luminescent material is selected from one or more of the following: fluorescent materials, TTA materials, TADF materials, polymers containing BN covalent bonds, HLCT materials, and Exciplex luminescent materials; the quantum dot luminescent material is selected from one or more of the following: single-structure quantum dots, core-shell structure quantum dots, and perovskite quantum dots; the material of the single-structure quantum dot, the core material of the core-shell structure quantum dot, and the shell material of the core-shell structure quantum dot are respectively selected from one or more of the following: group II-VI compounds, group IV-VI compounds, group III-V compounds, and group I-III-VI compounds; the core-shell structure quantum dot... The shell comprises one or more layers; the II-VI group compounds are selected from 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, CdZnS eTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe; wherein the IV-VI compound is selected from one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe;The III-V compounds are selected from 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. Multiple types; the I-III-VI group compounds are selected from one or more of CuInS2, CuInSe2, and AgInS2; the core-shell structured 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 optoelectronic device further includes a hole functional layer, which is located between the anode and the active layer;The hole functional layer 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, 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-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, spironolactone (NPB), nanocrystalline diamond, microcrystalline cellulose and tetracyanoquinone dimethane, doped graphene, undoped graphene, fourth-doped metal oxide particles The metal oxide comprises one or more of the following: a fourth undoped metal oxide particle, a metal sulfide, a metal selenide, and a metal nitride. The metal oxide in the fourth doped metal oxide particle and the metal oxide in the fourth undoped metal oxide particle each independently include one or more of MoO3, WO3, NiO, CrO3, CuO, and V2O5. The doping element in the fourth 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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