Inorganic matter coated composite nanomaterial and preparation method thereof

Abstract

The invention relates to the technical field of preparation of perovskite nanocrystals, and particularly provides a composite nanomaterial wrapped by an inorganic matter and a preparation method. The invention aims to solve the problems of complex preparation process, poor stability of the prepared composite material and low up-down conversion efficiency in the prior art. The invention provides a preparation method of an inorganic matter coated composite nano material. The preparation method comprises the following steps: providing a mixed solution A formed by lanthanide series rare earth chloride ReCl3, an organic solvent A, a sodium source and a fluorine source; providing a mixed solution B formed by perovskite quantum dots, a zinc source, a sulfur source and an organic solvent B; adding the mixed solution B into the mixed solution A, reacting for a preset time at a preset temperature, cooling to room temperature, filtering, and drying to obtain a finished product. The inorganic matter coated composite nano material is synthesized through a one-pot method, coating of ZnS on the perovskite quantum dot and rare earth up-conversion nano particle composite material is achieved, the preparation method is simple, and the prepared composite material is good in stability and high in up-down conversion efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite nanocrystal preparation, and specifically provides an inorganic-coated composite nanomaterial and a preparation method thereof. Background Art

[0002] All-inorganic perovskite nanocrystals are being applied in the optoelectronics field due to their advantages, such as high photoluminescence quantum yield, large absorption cross-section, narrow emission peak, and tunable band gap. They have wide applications in lighting, display, photovoltaics, anti-counterfeiting, and other fields. However, perovskite materials suffer from poor stability and difficulty in emitting light at multiple wavelengths, limiting their application in medicine, biology, and other fields. Rare earth ions, with their abundant 4f-5d energy levels, have been used in perovskite doping. Rare earth-doped perovskites can effectively improve their stability and broaden their emission range. Ytterbium ions, in particular, have become a hot topic of research due to their unique "quantum tailoring" phenomenon, which allows them to absorb higher-energy light and convert it into two lower-energy light beams. However, rare earth ions suffer from low practical doping levels and low energy transfer efficiency from excitons to rare earth ions, hindering further improvement in their luminescence efficiency. Rare earth-doped upconversion nanoparticles are characterized by their high stability, near-infrared excitation, and the ability to precisely control the ratio of rare earth ion doping, thereby further increasing the concentration of rare earth-doped perovskites and improving the luminescence properties of rare earth ions in the perovskite and upconversion nanoparticles. However, upconversion nanoparticles suffer from lattice mismatch when combined with perovskite quantum dots, preventing them from forming a close connection with the perovskite, resulting in low energy transfer efficiency. Therefore, there is an urgent need to improve energy transfer efficiency through the use of composite materials.

[0003] CN118027972A discloses a quantum dot composite material and its preparation method. The method first prepares NaYF4:Yb upconversion nanoparticles, then uses inorganic perovskite quantum dots CsPbCl3:Yb as the structural material, and adds surface-aminated NaYF4:Yb upconversion nanoparticles to prepare the composite material. In order to ensure a close connection between the upconversion nanoparticles and the perovskite, the NaYF4:Yb upconversion nanoparticles must first be surface-aminated. This not only complicates the preparation process, but also results in poor stability and low up-down conversion efficiency of the resulting composite material.

[0004] Accordingly, this field requires a new technical solution to solve the above technical problems. Summary of the Invention

[0005] The present invention aims to solve the above technical problems, that is, to solve the problem in the prior art that in order to make the upconversion nanoparticles and titanochalcogenide closely connected, the surface of the NaYF4:Yb upconversion nanoparticles needs to be firstly aminated, which not only complicates the preparation process, but also leads to poor stability of the composite material and low up-down conversion efficiency.

[0006] In a first aspect, the present invention provides a method for preparing an inorganic-coated composite nanomaterial, wherein the preparation method comprises:

[0007] Providing a mixed solution A consisting of lanthanide rare earth chloride ReCl3, an organic solvent A, a sodium source, and a fluorine source;

[0008] Providing a mixed solution B formed by perovskite quantum dots, a zinc source, a sulfur source and an organic solvent B;

[0009] Add mixed solution B to mixed solution A, react at a preset temperature for a preset time, then cool to room temperature, filter, and dry to obtain the product.

[0010] In the preferred technical solution of the above preparation method, the molar ratio of the lanthanide rare earth chloride ReCl3, the sodium source and the fluorine source is 1: (1-3): (2-7);

[0011] And / or, the molar ratio of the lanthanide rare earth chloride ReCl3 to the perovskite quantum dots, the zinc source and the sulfur source is 1:(0.1-0.5):(0.3-0.8):(0.3-0.8).

[0012] In the preferred technical solution of the above preparation method, the preset temperature is 30 to 250°C, preferably 40 to 230°C;

[0013] And / or, the preset time is 0.5 to 5 hours, preferably 1 to 3 hours.

[0014] In the preferred technical solution of the above preparation method, the mixed solution A is provided by the following method:

[0015] Add lanthanide rare earth chloride ReCl3 to organic solvent A, stir under inert gas protection and heat to temperature T1 until completely dissolved, then add sodium source and fluorine source, heat to temperature T2, react for time t1, and then cool to temperature T3 to obtain mixed solution A.

[0016] In the preferred technical solution of the above preparation method, the temperature T1 is 25 to 200°C, preferably 80 to 180°C;

[0017] And / or, the temperature T2 is 100-350°C, preferably 180-320°C; the reaction time t1 is 10-200 min, preferably 20-180 min;

[0018] And / or, the temperature T3 is 30-100°C, preferably 40-80°C.

[0019] In the preferred technical solution of the above preparation method, the ReCl3 is two or three of NdCl3, EuCl3, GdCl3, TbCl3, HoCl3, ErCl3, TmCl3, YbCl3 or LuCl3;

[0020] And / or, the sodium source is one or more of sodium hydroxide, sodium sulfide or sodium fluoride;

[0021] and / or, the fluorine source is one or more of sodium fluoride, ammonium fluoride, ammonium bifluoride or sodium bifluoride;

[0022] And / or, the organic solvent A is a mixed solvent of octadecene and oleic acid.

[0023] In the preferred technical solution of the above preparation method, the mixed solution B is provided by the following method:

[0024] The perovskite quantum dots, zinc source and sulfur source are dissolved in organic solvent B to obtain the product.

[0025] In the preferred technical solution of the above preparation method, the perovskite quantum dots are one of CsPbCl3, CsPbBr3 or CsPbI3;

[0026] And / or, the zinc source is one or more of zinc stearate, zinc sulfate or zinc oxide;

[0027] And / or, the sulfur source is one or more of sodium sulfide, sublimed sulfur or tributylphosphine sulfide;

[0028] And / or, the organic solvent B is one of methanol, ethanol, toluene, xylene, dichloromethane, cyclohexane, n-hexane or n-octane.

[0029] In a second aspect, the present invention provides an inorganic-coated composite nanomaterial, wherein the inorganic-coated composite nanomaterial is prepared by the above-mentioned preparation method.

[0030] In the preferred technical solution of the above-mentioned inorganic-coated composite nanomaterial, the inorganic-coated composite nanomaterial includes a core and a coating layer coating the core, the core is a composite material of perovskite quantum dots and rare earth upconversion nanoparticles, and the coating layer is ZnS.

[0031] The inorganic-coated composite nanomaterial and preparation method of the present invention have the following technical effects:

[0032] 1. The preparation method of the inorganic-coated composite nanomaterial provided by the present invention is simple and can be completed by a one-pot process. The prepared inorganic-coated composite nanomaterial can not only effectively passivate the surface defects of perovskite, improve the down-conversion efficiency, and enhance the stability of perovskite quantum dots; but also optimize the interface energy level structure, improve the energy level matching of up-conversion nanoparticles, reduce the energy loss between energy levels, and improve the up-conversion efficiency.

[0033] 2. The present invention adopts a one-pot method to synthesize ZnS-coated perovskite composite rare earth upconversion composite nanomaterials, which can simultaneously absorb ultraviolet light and infrared light for upconversion and downconversion luminescence. It is applied to silicon-based solar cells to expand the spectral response range, improve the photoelectric conversion efficiency, and realize the upgrade of third-generation solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0035] Figure 1 The present invention is a schematic diagram of a composite material of ZnS-coated perovskite quantum dots and rare earth up-conversion nanoparticles, wherein: 1 is a ZnS coating layer, 2 is a rare earth up-conversion quantum dot, and 3 is a perovskite down-conversion quantum dot. DETAILED DESCRIPTION

[0036] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0037] In this application, the term "and / or" describes the relationship between associated objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0038] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0039] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0040] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0041] The weights of the relevant components mentioned in the examples of this application may not only refer to the specific content of each component, but also represent the weight ratio between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the examples of this application, it is within the scope disclosed in the examples of this application. Specifically, the mass described in the examples of this application may be a mass unit known in the chemical industry, such as μg, mg, g, kg, etc.

[0042] The terms "first" and "second" are used solely for descriptive purposes to distinguish objects, such as substances, from one another and should not be understood to indicate or imply relative importance or to implicitly specify the quantity of the technical features being referred to. For example, without departing from the scope of the embodiments of this application, a first XX may also be referred to as a second XX, and similarly, a second XX may also be referred to as a first XX. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of such features.

[0043] The experimental methods in the following examples are conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples are commercially available unless otherwise specified.

[0044] Based on the prior art pointed out in the background art, in order to make the upconversion nanoparticles closely connected to the perovskite, it is necessary to first perform surface amination on the NaYF4:Yb upconversion nanoparticles, which not only complicates the preparation process but also has poor stability and low up-down conversion efficiency of the resulting composite material. The present invention provides an inorganic-coated composite nanomaterial and a preparation method thereof. The inorganic-coated composite nanomaterial is synthesized by a one-pot process to achieve ZnS coating of a composite material of perovskite quantum dots and rare earth upconversion nanoparticles. Not only is the preparation method simple, but the resulting composite material has good stability and high up-down conversion efficiency.

[0045] Specifically, in a first aspect, the present invention provides a method for preparing an inorganic-coated composite nanomaterial, wherein the preparation method comprises:

[0046] Providing a mixed solution A consisting of lanthanide rare earth chloride ReCl3, an organic solvent A, a sodium source, and a fluorine source;

[0047] Providing a mixed solution B formed by perovskite quantum dots, a zinc source, a sulfur source and an organic solvent B;

[0048] Add mixed solution B to mixed solution A, react at a preset temperature for a preset time, then cool to room temperature, filter, and dry to obtain the product.

[0049] The present invention synthesizes inorganic-coated composite nanomaterials through a one-pot method to achieve ZnS coating of a composite material of perovskite quantum dots and rare earth upconversion nanoparticles. Not only is the preparation method simple, but the obtained composite material has good stability and high up-down conversion efficiency. It can simultaneously absorb ultraviolet light and infrared light for up-conversion and down-conversion luminescence. It is applied to silicon-based solar cells, expands the spectral response range, improves the photoelectric conversion efficiency, and realizes the upgrade of third-generation solar cells.

[0050] In some specific embodiments, the molar ratio of the lanthanide rare earth chloride ReCl3, the sodium source, and the fluorine source is 1:(1-3):(2-7), for example, 1:1:2, 1:3:7, 1:2:5, or any value within the molar ratio range.

[0051] In some specific embodiments, the molar ratio of the lanthanide rare earth chloride ReCl3 to the perovskite quantum dots, the zinc source, and the sulfur source is 1:(0.1-0.5):(0.3-0.8):(0.3-0.8). For example, the molar ratio can be 1:0.1:0.3:0.3, 1:0.5:0.5:0.8, 1:0.3:0.5:0.7, or any value within the molar ratio range.

[0052] In some specific embodiments, the preset temperature is 30-250° C. For example, it can be 30° C., 50° C., 80° C., 100° C., 150° C., 180° C., 200° C., 220° C., 250° C., or any value within the temperature range.

[0053] In some preferred embodiments, the preset temperature is 40-230° C. For example, it can be 40° C., 50° C., 80° C., 100° C., 150° C., 180° C., 200° C., 220° C., 230° C. or any value within the temperature range.

[0054] In some specific embodiments, the preset time is 0.5 to 5 hours, for example, 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, or any value within the time range.

[0055] In some preferred embodiments, the preset time is 1 to 3 hours, for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, or any value within the time range.

[0056] In some embodiments, the mixed solution A is provided by the following method:

[0057] Add lanthanide rare earth chloride ReCl3 to organic solvent A, stir under inert gas protection and heat to temperature T1 until completely dissolved, then add sodium source and fluorine source, heat to temperature T2, react for time t1, and then cool to temperature T3 to obtain mixed solution A.

[0058] In some specific embodiments, the temperature T1 is 25-200° C. For example, it can be 25° C., 50° C., 100° C., 150° C., 200° C., or any value within the temperature range.

[0059] In some specific embodiments, the temperature T1 is 80-180° C. For example, it can be 80° C., 90° C., 100° C., 150° C., 180° C., or any value within the temperature range.

[0060] In some specific embodiments, the temperature T2 is 100-350° C. For example, it can be 100° C., 150° C., 200° C., 250° C., 300° C., 350° C., or any value within the temperature range.

[0061] In some specific embodiments, the temperature T2 is 180-320° C. For example, it can be 180° C., 200° C., 250° C., 300° C., 320° C., or any value within the temperature range.

[0062] In some specific embodiments, the reaction time t1 is 10 to 200 min, for example, 10 min, 50 min, 100 min, 150 min, 200 min, or any value within the time range.

[0063] In some preferred embodiments, the reaction time t1 is 20 to 180 min, for example, 20 min, 50 min, 80 min, 100 min, 150 min, 180 min, or any value within the time range.

[0064] In some specific embodiments, the temperature T3 is 30-100° C. For example, it can be 30° C., 50° C., 80° C., 100° C., or any value within the temperature range.

[0065] In some specific embodiments, the temperature T3 is 40-80° C. For example, it can be 40° C., 50° C., 60° C., 70° C., 80° C., or any value within the temperature range.

[0066] In some specific embodiments, the ReCl3 is two or three of NdCl3, EuCl3, GdCl3, TbCl3, HoCl3, ErCl3, TmCl3, YbCl3 or LuCl3.

[0067] In some specific embodiments, the sodium source is one or more of sodium hydroxide, sodium sulfide or sodium fluoride.

[0068] In some specific embodiments, the fluorine source is one or more of sodium fluoride, ammonium fluoride, ammonium bifluoride or sodium bifluoride.

[0069] In some specific embodiments, the organic solvent A is a mixed solvent of octadecene and oleic acid.

[0070] In some embodiments, the mixed solution B is provided by the following method:

[0071] The perovskite quantum dots, zinc source and sulfur source are dissolved in organic solvent B to obtain the product.

[0072] In some specific embodiments, the perovskite quantum dots are one of CsPbCl3, CsPbBr3 or CsPbI3;

[0073] In some specific embodiments, the zinc source is one or more of zinc stearate, zinc sulfate or zinc oxide.

[0074] In some specific embodiments, the sulfur source is one or more of sodium sulfide, sublimed sulfur, or tributylphosphine sulfide.

[0075] In some specific embodiments, the organic solvent B is one of methanol, ethanol, toluene, xylene, dichloromethane, cyclohexane, n-hexane or n-octane.

[0076] Furthermore, the present invention provides an inorganic-coated composite nanomaterial in a second aspect, wherein the inorganic-coated composite nanomaterial is prepared by the above-mentioned preparation method.

[0077] Specifically, the inorganic-coated composite nanomaterial includes a core and a coating layer coating the core, wherein the core is a composite material of perovskite quantum dots and rare earth upconversion nanoparticles, and the coating layer is ZnS. A schematic diagram of the composite material of ZnS-coated perovskite quantum dots and rare earth upconversion nanoparticles is shown in FIG. Figure 1 shown.

[0078] The present invention uses ZnS to coat the composite material of perovskite quantum dots and rare earth upconversion nanoparticles, which can effectively passivate the surface defects of perovskite, improve the down-conversion efficiency, and enhance the stability of perovskite quantum dots; it can also optimize the interface energy level structure, improve the energy level matching of upconversion nanoparticles, reduce energy loss between energy levels, and improve upconversion efficiency.

[0079] The inorganic-coated composite nanomaterial and its preparation method of the present invention are described in detail below through several specific embodiments.

[0080] Example 1

[0081] This embodiment provides an inorganic-coated composite nanomaterial and a preparation method, wherein the inorganic-coated composite nanomaterial comprises a core and a coating layer coating the core, wherein the core is a composite material of perovskite quantum dots and rare earth upconversion nanoparticles, and the coating layer is ZnS. A schematic diagram of the composite material of ZnS-coated perovskite quantum dots and rare earth upconversion nanoparticles is shown in FIG. Figure 1 shown.

[0082] The preparation method of the above-mentioned inorganic-coated composite nanomaterial is as follows:

[0083] S1. Add lanthanide rare earth chloride YbCl3 (8 mmol) and NdCl3 (2 mmol) to organic solvent A (a mixed solvent of octadecene and oleic acid, 120 mL, with a volume ratio of octadecene to oleic acid of 5:3), stir under argon protection and heat to temperature T1 (120°C) until complete dissolution, then add sodium source (NaOH, 25 mmol) and fluorine source (NaF, 40 mmol), heat to temperature T2 (200°C), react for t1 (100 min), and then cool to temperature T3 (75°C) to obtain mixed solution A;

[0084] S2, dissolving perovskite quantum dots (CsPbCl3, 3 mmol), zinc source (zinc stearate, 5 mmol), and sulfur source (sodium sulfide, 5 mmol) in organic solvent B (methanol, 30 ml) to obtain a mixed solution B;

[0085] S3. Adding mixed solution B to mixed solution A, reacting at a preset temperature (180° C.) for a preset time (2 h) under argon protection, then cooling to room temperature, centrifuging, and drying to obtain the inorganic-coated composite nanomaterial.

[0086] Example 2

[0087] This embodiment provides an inorganic-coated composite nanomaterial and a preparation method, wherein the inorganic-coated composite nanomaterial includes a core and a coating layer coating the core, the core is a composite material of perovskite quantum dots and rare earth upconversion nanoparticles, and the coating layer is ZnS.

[0088] The preparation method of the above-mentioned inorganic-coated composite nanomaterial is as follows:

[0089] S1. Add lanthanide rare earth chloride YbCl3 (5 mmol) and ErCl3 (5 mmol) to organic solvent A (a mixed solvent of octadecene and oleic acid, 120 mL, with a volume ratio of octadecene to oleic acid of 5:3), stir under argon protection and heat to temperature T1 (180°C) until complete dissolution, then add sodium source (sodium sulfide, 10 mmol) and fluorine source (ammonium fluoride, 20 mmol), heat to temperature T2 (320°C), react for t1 (20 min), and then cool to temperature T3 (80°C) to obtain mixed solution A;

[0090] S2, dissolving perovskite quantum dots (CsPbBr3, 2 mmol), zinc source (zinc sulfate, 3 mmol), and sulfur source (sodium sulfide, 3 mmol) in organic solvent B (methanol, 30 ml) to obtain a mixed solution B;

[0091] S3. Add the mixed solution B to the mixed solution A, react at a preset temperature (40° C.) for a preset time (1 h) under argon protection, then cool to room temperature, centrifuge, and dry to obtain the inorganic-coated composite nanomaterial.

[0092] Example 3

[0093] This embodiment provides an inorganic-coated composite nanomaterial and a preparation method, wherein the inorganic-coated composite nanomaterial includes a core and a coating layer coating the core, the core is a composite material of perovskite quantum dots and rare earth upconversion nanoparticles, and the coating layer is ZnS.

[0094] The preparation method of the above-mentioned inorganic-coated composite nanomaterial is as follows:

[0095] S1. Add lanthanide rare earth chloride YbCl3 (4 mmol) and ErCl3 (6 mmol) to organic solvent A (a mixed solvent of octadecene and oleic acid, 120 mL, with a volume ratio of octadecene to oleic acid of 5:3), stir under argon protection and heat to temperature T1 (80°C), until completely dissolved, then add sodium source (sodium fluoride, 30 mmol) and fluorine source (ammonium bifluoride, 70 mmol), heat to temperature T2 (180°C), react for t1 (180 min), and then cool to temperature T3 (40°C) to obtain mixed solution A;

[0096] S2, dissolving perovskite quantum dots (CsPbI3, 5 mmol), zinc source (zinc oxide, 8 mmol), and sulfur source (sodium sulfide, 8 mmol) in organic solvent B (methanol, 30 ml) to obtain a mixed solution B;

[0097] S3. Add the mixed solution B to the mixed solution A, react at a preset temperature (230° C.) for a preset time (3 h) under argon protection, then cool to room temperature, centrifuge, and dry to obtain the inorganic-coated composite nanomaterial.

[0098] Example 4

[0099] This embodiment provides an inorganic-coated composite nanomaterial and a preparation method, wherein the inorganic-coated composite nanomaterial includes a core and a coating layer coating the core, the core is a composite material of perovskite quantum dots and rare earth upconversion nanoparticles, and the coating layer is ZnS.

[0100] The preparation method of the above-mentioned inorganic-coated composite nanomaterial is as follows:

[0101] S1. Add lanthanide rare earth chloride GdCl3 (7 mmol) and TmCl3 (3 mmol) to organic solvent A (a mixed solvent of octadecene and oleic acid, 120 mL, with a volume ratio of octadecene to oleic acid of 5:3), stir under argon protection and heat to temperature T1 (25°C), until completely dissolved, then add sodium source (NaOH, 20 mmol) and fluorine source (sodium bifluoride, 50 mmol), heat to temperature T2 (100°C), react for t1 (10 min), and then cool to temperature T3 (30°C) to obtain mixed solution A;

[0102] S2, dissolving perovskite quantum dots (CsPbCl3, 3.5 mmol), zinc source (zinc stearate, 4 mmol), and sulfur source (sublimed sulfur, 4 mmol) in organic solvent B (methanol, 30 ml) to obtain a mixed solution B;

[0103] S3. Add the mixed solution B to the mixed solution A, react at a preset temperature (30° C.) for a preset time (0.5 h) under argon protection, then cool to room temperature, centrifuge, and dry to obtain the inorganic-coated composite nanomaterial.

[0104] Example 5

[0105] This embodiment provides an inorganic-coated composite nanomaterial and a preparation method, wherein the inorganic-coated composite nanomaterial includes a core and a coating layer coating the core, the core is a composite material of perovskite quantum dots and rare earth upconversion nanoparticles, and the coating layer is ZnS.

[0106] The preparation method of the above-mentioned inorganic-coated composite nanomaterial is as follows:

[0107] S1. Add lanthanide rare earth chloride GdCl3 (5 mmol) and YbCl3 (5 mmol) to organic solvent A (a mixed solvent of octadecene and oleic acid, 120 mL, with a volume ratio of octadecene to oleic acid of 5:3), stir under argon protection and heat to temperature T1 (200°C), until completely dissolved, then add sodium source (NaOH, 22 mmol) and fluorine source (NaF, 35 mmol), heat to temperature T2 (350°C), react for t1 (200 min), and then cool to temperature T3 (100°C) to obtain mixed solution A;

[0108] S2. Dissolve perovskite quantum dots (CsPbI3, 2.5 mmol), zinc source (zinc stearate, 5.5 mmol), and sulfur source (tributylphosphine sulfide, 5.5 mmol) in organic solvent B (methanol, 30 ml) to obtain a mixed solution B;

[0109] S3. Add the mixed solution B to the mixed solution A, react at a preset temperature (250° C.) for a preset time (5 h) under argon protection, then cool to room temperature, centrifuge, and dry to obtain the inorganic-coated composite nanomaterial.

[0110] Comparative Example 1

[0111] This comparative example provides a method for preparing an uncoated composite nanomaterial.

[0112] Lanthanide rare earth chloride YbCl3 (8 mmol) and NdCl3 (2 mmol) were added to organic solvent A (a mixed solvent of octadecene and oleic acid, 120 mL, with a volume ratio of octadecene to oleic acid of 5:3), stirred under argon protection and heated to temperature T1 (120°C) until completely dissolved, then added with sodium source (NaOH, 25 mmol) and fluorine source (NaF, 40 mmol), heated to temperature T2 (200°C), reacted for time t1 (100 min), and then cooled to temperature T3 (75°C) to obtain mixed solution A; perovskite quantum dots (CsPbCl3, 3 mmol) were added to mixed solution A, reacted at a preset temperature (180°C) for a preset time (2 h) under argon protection, then cooled to room temperature, centrifuged, and dried to obtain uncoated composite nanomaterials.

[0113] Test Example 1

[0114] This test example investigates the stability of the composite materials prepared in the examples and comparative examples of the present invention.

[0115] Test method: Stability test was performed on each embodiment and comparative example. The specific method is as follows:

[0116] Under a high temperature and high humidity test environment (85°C temperature and 85% humidity), the luminescence intensity (PL Intensity) of the inorganic-coated composite nanomaterials prepared in each embodiment and comparative example after being placed for different times was measured, and the PL ratio after placement to before placement was calculated.

[0117] The test results are shown in Table 1:

[0118] Table 1

[0119] It can be seen from the results in Table 1 that, compared with Comparative Example 1, the stability of the composite material prepared in the present invention is significantly improved.

[0120] Test Example 2

[0121] This test example investigates the up-down conversion efficiency of the composite materials prepared in the examples of the present invention and the comparative examples.

[0122] Test Method: Both up-conversion and down-conversion quantum yields were measured using a spectrometer equipped with an integrating sphere. The excitation wavelength used for up-conversion quantum yield measurements was 1523 nm, and the excitation wavelength used for down-conversion quantum yield measurements was 365 nm.

[0123] The test results are shown in Table 2:

[0124] Table 2 Upconversion efficiency Down-conversion efficiency Example 1 18.59％ 75.38％ Example 2 16.52％ 79.21％ Example 3 15.71％ 82.12％ Example 4 17.23％ 77.69％ Example 5 18.06％ 80.35％ Comparative Example 1 9.57％ 66.31％

[0125] It can be seen from the results in Table 2 that, compared with Comparative Example 1, the up-down conversion efficiency of the composite material prepared in the present invention is significantly improved.

[0126] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A method for preparing an inorganic-coated composite nanomaterial, characterized in that: The preparation method comprises: Providing a mixed solution A consisting of lanthanide rare earth chloride ReCl3, an organic solvent A, a sodium source, and a fluorine source; Providing a mixed solution B formed by perovskite quantum dots, a zinc source, a sulfur source and an organic solvent B; Add mixed solution B to mixed solution A, react at a preset temperature for a preset time, then cool to room temperature, filter, and dry to obtain the product.

2. The preparation method according to claim 1, characterized in that The molar ratio of the lanthanide rare earth chloride ReCl3, the sodium source and the fluorine source is 1: (1-3): (2-7); And / or, the molar ratio of the lanthanide rare earth chloride ReCl3 to the perovskite quantum dots, the zinc source and the sulfur source is 1:(0.1-0.5):(0.3-0.8):(0.3-0.8).

3. The preparation method according to claim 2, characterized in that The preset temperature is 30-250°C, preferably 40-230°C; And / or, the preset time is 0.5 to 5 hours, preferably 1 to 3 hours.

4. The preparation method according to claim 1, characterized in that The mixed solution A is provided by the following method: Add lanthanide rare earth chloride ReCl3 to organic solvent A, stir under inert gas protection and heat to temperature T1 until completely dissolved, then add sodium source and fluorine source, heat to temperature T2, react for time t1, and then cool to temperature T3 to obtain mixed solution A.

5. The preparation method according to claim 4, characterized in that The temperature T1 is 25-200°C, preferably 80-180°C; And / or, the temperature T2 is 100-350°C, preferably 180-320°C; the reaction time t1 is 10-200 min, preferably 20-180 min; And / or, the temperature T3 is 30-100°C, preferably 40-80°C.

6. The preparation method according to claim 5, characterized in that The ReCl3 is two or three of NdCl3, EuCl3, GdCl3, TbCl3, HoCl3, ErCl3, TmCl3, YbCl3 or LuCl3; And / or, the sodium source is one or more of sodium hydroxide, sodium sulfide or sodium fluoride; And / or, the fluorine source is one or more of sodium fluoride, ammonium fluoride, ammonium bifluoride or sodium bifluoride; And / or, the organic solvent A is a mixed solvent of octadecene and oleic acid.

7. The preparation method according to claim 1, characterized in that The mixed solution B is provided by the following method: The perovskite quantum dots, zinc source and sulfur source are dissolved in organic solvent B to obtain the product.

8. The preparation method according to claim 7, characterized in that The perovskite quantum dots are one of CsPbCl3, CsPbBr3 or CsPbI3; And / or, the zinc source is one or more of zinc stearate, zinc sulfate or zinc oxide; And / or, the sulfur source is one or more of sodium sulfide, sublimed sulfur or tributylphosphine sulfide; And / or, the organic solvent B is one of methanol, ethanol, toluene, xylene, dichloromethane, cyclohexane, n-hexane or n-octane.

9. An inorganic-coated composite nanomaterial, characterized in that: The inorganic-coated composite nanomaterial is prepared by the preparation method according to any one of claims 1 to 8.

10. The inorganic-coated composite nanomaterial according to claim 9, characterized in that: The inorganic-coated composite nanomaterial comprises a core and a coating layer coating the core, the core is a composite material of perovskite quantum dots and rare earth upconversion nanoparticles, and the coating layer is ZnS.

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