A method for preparing a perovskite film and a perovskite module

Abstract

The present application relates to a kind of preparation methods of perovskite film, comprising the following steps: mixing imidazolium ionic liquid and lead halide in container according to the proportion of 1:1, adding DMF or DMSO solvent, heating and stirring, then adding first solvent and precipitating white precipitate, drying white precipitate to obtain white powder. White powder is mixed with at least one of MAI, FAI, CsI cation salt and second solvent, to configure perovskite precursor solution, after heating and stirring, filtering, placing filtrate in oven, to obtain perovskite crystal material. Perovskite crystal material is placed in tank, then methanamine vapor is introduced, to obtain perovskite intermediate, then the perovskite intermediate is dissolved in acetonitrile, to obtain acetonitrile mixed solution. Acetonitrile mixed solution is spin-coated or blade-coated on substrate, to obtain perovskite film layer. The present application also discloses perovskite assembly prepared by the method. The present application can prepare perovskite film in air environment without annealing treatment.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cell fabrication technology, and specifically relates to a method for preparing perovskite thin films in an air environment without annealing, as well as perovskite modules. Background Technology

[0002] Currently, the fabrication process of perovskite thin films is still carried out under nitrogen protection, mainly because perovskite materials are highly sensitive to water and oxygen, and are easily decomposed by either. Furthermore, the fabrication of perovskite layers often requires high-temperature annealing (>100℃) to obtain a dense and smooth perovskite film, which inevitably leads to high energy consumption in the industrial production of perovskite solar cells. Therefore, simplifying the fabrication conditions of perovskite thin films while reducing the energy consumption of the fabrication process is an inevitable trend for the future development of perovskite solar cells. Based on this background, developing a perovskite thin film fabrication process that can be carried out in an air environment without annealing is a necessary condition for accelerating its industrialization. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for preparing perovskite thin films and perovskite components, which solves the problems of high energy consumption and the need for nitrogen atmosphere protection in the existing perovskite thin film preparation process, and prepares perovskite thin films in an air environment without annealing.

[0004] This invention is achieved by providing a method for preparing perovskite thin films, comprising the following steps:

[0005] Step 1: Mix the imidazole ionic liquid and lead halide in a 1:1 molar ratio in a container, add N,N-dimethylformamide (DMF) or dimethyl sulfoxide (DMSO) solvent, heat and stir until the solution is clear, then add the first solvent. After a white precipitate precipitates in the clear solution, pour the solution and white precipitate from the container onto a vacuum filter to obtain a white precipitate. Wash the white precipitate 2-5 times with the first solvent, and then dry the washed white precipitate to obtain a white powder. The first solvent is any one of isopropanol, ethyl acetate, diethyl ether, toluene, and chlorobenzene, and the lead halide is at least one of PbI2, PbBr2, and PbCl2.

[0006] Step 2: Mix the white powder with at least one of the following: methyl iodoamine (MAI), formamidinium iodoamine (FAI), cesium iodide (CsI) cation salt, and a second solvent to prepare a perovskite precursor solution with a concentration of 0.8M~2M. Heat and stir the prepared perovskite precursor solution, then filter it. Place the filtrate in an oven and bake until the solvent evaporates completely to obtain perovskite crystal material. The second solvent is at least one of the following: dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), and γ-butyrolactone (GBL).

[0007] Step 3: Place the perovskite crystal material in a tank, then introduce methylamine vapor into the tank. The perovskite crystal material in the tank reacts with the methylamine vapor to form a perovskite intermediate. Then, dissolve the perovskite intermediate in acetonitrile to obtain an acetonitrile mixed solution containing the perovskite intermediate.

[0008] Step 4: Under air and room temperature conditions, the acetonitrile mixture is spread on the substrate by spin coating or blade coating. As the acetonitrile solvent evaporates rapidly, a dense and uniform perovskite film layer is obtained. The perovskite film layer does not require further annealing treatment.

[0009] Furthermore, the imidazole-based ionic liquid comprises a cation and anion, wherein the cation is any one of 1-alkylimidazolium, 1-alkyl-3-methylimidazolium, and 1-alkyl-2,3-dimethylimidazolium, and the anion is any one of chlorine, bromine, iodine, tetrafluoroboric acid, hexafluorophosphate, acetic acid, perchloric acid, dihydrogen phosphate hydrogen sulfate, trifluoroacetic acid, and p-toluenesulfonic acid.

[0010] Furthermore, the alkyl group in the cation is any one of methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decanyl, dodecyl, tetradecyl, hexadecyl, and octadecyl.

[0011] Furthermore, in step one, the heating and stirring conditions are a heating temperature of 55℃~65℃ and a stirring time of 1~3 hours.

[0012] Furthermore, in step one, the conditions for drying the white precipitate are: vacuum drying at a temperature of 75℃~85℃ for 20~30 hours.

[0013] Furthermore, in step two, the heating and stirring conditions for the perovskite precursor solution are a heating temperature of 55°C to 65°C and a stirring time of 1 to 3 hours.

[0014] The present invention is implemented as follows, and also provides a perovskite component, wherein the perovskite component includes a perovskite thin film layer, the perovskite thin film layer being prepared using the perovskite thin film preparation method described above.

[0015] Compared with existing technologies, the perovskite thin film preparation method and perovskite module of this invention improve the quality of the prepared perovskite thin film by introducing functional groups from imidazole ionic liquids onto the surface of the perovskite molecules. This allows for the preparation of stable perovskite thin films in an air environment without the need for annealing, simplifying the preparation conditions and facilitating the large-scale production of perovskite solar cells. Since the perovskite film formation of this invention does not require high-temperature annealing, high-quality perovskite thin films can be directly obtained at room temperature through simple spin coating or blade coating, reducing the energy consumption required in the preparation process and contributing to the reduction of industrialization costs for perovskite solar cells. Detailed Implementation

[0016] To make the technical problems, solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0017] A preferred embodiment of the method for preparing perovskite thin films of the present invention includes the following steps:

[0018] Step 1: Mix the imidazole ionic liquid and lead halide in a 1:1 molar ratio in a container, add DMF or DMSO solvent, heat and stir until the solution is clear, then gradually add the first solvent. After a white precipitate precipitates in the clear solution, pour the solution and white precipitate from the container onto a vacuum filter to obtain a white precipitate. Wash the white precipitate 2-5 times with the first solvent, and then dry the washed white precipitate to obtain a white powder. The first solvent is any one of isopropanol, ethyl acetate, diethyl ether, toluene, and chlorobenzene, and the lead halide is at least one of PbI2, PbBr2, and PbCl2.

[0019] Step 2: Mix the white powder with at least one of MAI, FAI, and CsI cation salts and a second solvent to prepare a 0.8M~2M perovskite precursor solution. Heat and stir the prepared perovskite precursor solution and filter it. Place the filtrate in an oven at 100°C and bake until the solvent evaporates completely to obtain black perovskite crystal material. The second solvent is at least one of dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), and γ-butyrolactone (GBL).

[0020] Step 3: Place the black perovskite crystal material in a tank, and then introduce methylamine vapor into the tank. The perovskite crystal material in the tank reacts with the methylamine vapor to form a yellow liquid perovskite intermediate. Then, dissolve the perovskite intermediate in acetonitrile to obtain an acetonitrile mixed solution containing a certain concentration of perovskite intermediate.

[0021] Step 4: Under air and room temperature conditions, the acetonitrile mixture is spread on the substrate by spin coating or blade coating. As the solvent acetonitrile evaporates rapidly, a dense and uniform perovskite film layer is obtained. The perovskite film layer does not require further annealing treatment.

[0022] Specifically, the imidazole-based ionic liquid comprises a cation and an anion, wherein the cation is any one of 1-alkylimidazolium, 1-alkyl-3-methylimidazolium, and 1-alkyl-2,3-dimethylimidazolium, and the anion is any one of chlorine, bromine, iodine, tetrafluoroboric acid, hexafluorophosphate, acetic acid, perchloric acid, dihydrogen phosphate hydrogen sulfate, trifluoroacetic acid, and p-toluenesulfonic acid.

[0023] Specifically, the alkyl group in the cation is any one of methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decanyl, dodecyl, tetradecyl, hexadecyl, and octadecyl.

[0024] Specifically, in step one, the heating and stirring conditions are: heating temperature 55℃~65℃, stirring time 1~3 hours. The white precipitate is dried under vacuum at a temperature of 75℃~85℃ for 20~30 hours.

[0025] Specifically, in step two, the heating and stirring conditions for the perovskite precursor solution are a heating temperature of 55°C to 65°C and a stirring time of 1 to 3 hours.

[0026] The preparation method of the perovskite thin film of the present invention is further illustrated below through specific embodiments.

[0027] Example 1

[0028] An embodiment of the first method for preparing perovskite thin films of the present invention includes the following steps:

[0029] Step 11: Mix 280 μL of 1-propyl-3-methylimidazolium hexafluorophosphate ionic liquid and 461 mg of PbI2 in a 10 mL round-bottom flask, add 5 mL of DMF, and stir at 60 °C for 2 hours. The solution gradually changes from yellow to clear. Then, add an appropriate amount of diethyl ether to the flask to obtain a white precipitate. Pour the solution in the flask onto the filter paper inside the funnel of the vacuum filtration apparatus. A white precipitate is obtained on the filter paper. Wash the filter paper three times with diethyl ether. Then, place the white precipitate on the filter paper in a vacuum dryer and dry it at 80 °C for 24 hours.

[0030] Step 12: Take a certain amount of white powder and MAI, use DMSO as solvent to prepare a 1.2M perovskite precursor solution, stir at 60°C for 2 hours and filter. Place the filtrate in a vacuum drying oven at 100°C. After 72 hours, take out the black perovskite crystal material from which the solvent has completely evaporated.

[0031] Step 13: Next, place the black perovskite crystal material in a beaker and treat it with methylamine vapor for 30 minutes to obtain a yellow liquid perovskite intermediate. Take out the liquid perovskite intermediate and use acetonitrile as a solvent to prepare a perovskite intermediate mixed solution of a certain concentration.

[0032] Step 14: Subsequently, the perovskite film is coated onto the substrate in an air environment at room temperature. As the solvent evaporates, a dense and uniform perovskite film layer can be obtained on the substrate surface.

[0033] Example 2

[0034] An embodiment of the second method for preparing perovskite thin films of the present invention includes the following steps:

[0035] Step 21: Mix 280 μL of 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid, 415 mg of PbI2, and 36.7 mg of PbBr2 in a 10 mL round-bottom flask. Add 5 mL of DMSO and stir at 55 °C for 3 hours. The solution gradually changes from yellow to clear. Then, add an appropriate amount of isopropanol to the flask to obtain a white precipitate. Pour the solution from the flask onto the filter paper inside the funnel of the vacuum filtration apparatus. A white precipitate is obtained on the filter paper. Wash the filter paper twice with isopropanol. Then, place the white precipitate on the filter paper in a vacuum dryer and dry it at 85 °C for 20 hours.

[0036] Step 22: Take a certain amount of white powder and FAI, use NMP as solvent to prepare a 1.2M perovskite precursor solution, stir at 65°C for 1 hour and filter. Place the filtrate in a vacuum drying oven at 100°C. After 72 hours, take out the black perovskite crystal material from which the solvent has completely evaporated.

[0037] Step 23: Next, place the black perovskite crystal material in a beaker and treat it with methylamine vapor for 30 minutes to obtain a yellow liquid perovskite intermediate. Take out the liquid perovskite intermediate and use acetonitrile as a solvent to prepare a perovskite intermediate mixed solution of a certain concentration.

[0038] Step 24: Subsequently, spin-coat the substrate in an air environment at room temperature. As the solvent evaporates, a dense and uniform perovskite thin film layer can be obtained on the substrate surface.

[0039] Example 3

[0040] An embodiment of the third method for preparing perovskite thin films of the present invention includes the following steps:

[0041] Step 31: Mix 280 μL of 1-pentyl-3-methylimidazolium hexafluorophosphate ionic liquid and 461 mg of PbI2 in a 10 mL round-bottom flask, add 5 mL of DMF, and stir at 65 °C for 1 hour. The solution gradually changes from yellow to clear. Then, add an appropriate amount of diethyl ether to the flask to obtain a white precipitate. Pour the solution in the flask onto the filter paper inside the funnel of the vacuum filtration apparatus. A white precipitate is obtained on the filter paper. Wash the filter paper 5 times with diethyl ether. Then, place the white precipitate on the filter paper in a vacuum dryer and dry it at 75 °C for 30 hours.

[0042] Step 32: Take a certain amount of white powder and MAI, FAI, and CsI, use GBL as solvent to prepare a 1.5M perovskite precursor solution, stir at 55°C for 3 hours and filter. Place the filtrate in a vacuum drying oven at 100°C and after 72 hours, take out the black perovskite crystal material from which the solvent has completely evaporated.

[0043] Step 33: Next, place the black perovskite crystal material in a beaker and treat it with methylamine vapor for 30 minutes to obtain a yellow liquid perovskite intermediate. Take out the liquid perovskite intermediate and use acetonitrile as a solvent to prepare a perovskite intermediate mixed solution of a certain concentration.

[0044] Step 34: Subsequently, spin-coat the substrate in an air environment at room temperature. As the solvent evaporates, a dense and uniform perovskite thin film layer can be obtained on the substrate surface.

[0045] The present invention also discloses a perovskite component, wherein the perovskite component includes a perovskite thin film layer, the perovskite thin film layer being prepared using the perovskite thin film preparation method described above.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a perovskite thin film, characterized in that, Includes the following steps: Step 1: Mix the imidazole ionic liquid and lead halide in a 1:1 molar ratio in a container, add N,N-dimethylformamide or dimethyl sulfoxide solvent, heat and stir until the solution is clear, then add the first solvent. After a white precipitate precipitates in the clear solution, pour the solution and white precipitate in the container onto a vacuum filter to obtain a white precipitate. Wash the white precipitate 2-5 times with the first solvent, and then dry the washed white precipitate to obtain a white powder. The first solvent is any one of isopropanol, ethyl acetate, diethyl ether, toluene, and chlorobenzene, and the lead halide is at least one of PbI2, PbBr2, and PbCl2. Step 2: Mix the white powder with at least one of iodomethylamine, iodoformamidine, and cesium iodide cation salt, and a second solvent to prepare a perovskite precursor solution with a concentration of 0.8M~2M. Heat and stir the prepared perovskite precursor solution, then filter it. Place the filtrate in an oven and bake until the solvent evaporates completely to obtain perovskite crystal material. The second solvent is at least one of dimethyl sulfoxide, N,N-dimethylformamide, N-methylpyrrolidone, and γ-butyrolactone. Step 3: Place the perovskite crystal material in a tank, and then introduce methylamine vapor into the tank. The perovskite crystal material in the tank reacts with the methylamine vapor to form a perovskite intermediate. Then, dissolve the perovskite intermediate in acetonitrile to obtain an acetonitrile mixed solution containing the perovskite intermediate. Step 4: In an air environment, the acetonitrile mixture is spread evenly on the substrate by spin coating or blade coating. As the acetonitrile solvent evaporates rapidly, a dense and uniform perovskite film layer is obtained. The perovskite film layer does not require further annealing treatment.

2. The method for preparing perovskite thin films according to claim 1, characterized in that, The imidazole-based ionic liquid comprises a cation and an anion, wherein the cation is any one of 1-alkylimidazolium, 1-alkyl-3-methylimidazolium, and 1-alkyl-2,3-dimethylimidazolium, and the anion is any one of chlorine, bromine, iodine, tetrafluoroboric acid, hexafluorophosphate, acetic acid, perchloric acid, dihydrogen phosphate hydrogen sulfate, trifluoroacetic acid, and p-toluenesulfonic acid.

3. The method for preparing perovskite thin films according to claim 2, characterized in that, The alkyl group in the cation is any one of methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decanyl, dodecyl, tetradecyl, hexadecyl, and octadecyl.

4. The method for preparing perovskite thin films according to claim 1, characterized in that, In step one, the heating and stirring conditions are a heating temperature of 55℃~65℃ and a stirring time of 1~3 hours.

5. The method for preparing perovskite thin films according to claim 1, characterized in that, In step one, the conditions for drying the white precipitate are: vacuum drying at a temperature of 75℃~85℃ for 20~30 hours.

6. The method for preparing perovskite thin films according to claim 1, characterized in that, In step two, the conditions for heating and stirring the perovskite precursor solution are a heating temperature of 55℃~65℃ and a stirring time of 1~3 hours.

7. A perovskite module, wherein the perovskite module includes a perovskite thin film layer, characterized in that, The perovskite thin film layer is prepared using the perovskite thin film preparation method according to any one of claims 1 to 6.