Perovskite precursor solution preparation method suitable for high humidity air environment and perovskite solar cell preparation method

Abstract

The application provides a perovskite precursor solution preparation method suitable for a high-humidity air environment and a perovskite solar cell preparation method, the nucleation and crystallization process of perovskite is balanced by controlling the proportion of triethyl phosphate (TEP), N-methyl pyrrolidone (NMP) and 2-methoxy ethanol (2-Me), and a smooth and dense film is obtained. Meanwhile, the perovskite film is formed by removing the solvent in a low-pressure condition in a flash evaporation mode. The ester solvent is used as a main solvent, which can not only reduce the influence of air humidity on the film quality, but also simultaneously meet the three conditions of air preparation, low toxicity of the solution and no anti-solvent process, so that high-quality perovskite films can be obtained in a room temperature (25±5 DEG C) and a relative humidity of 30%-80% air environment, which is conducive to the low-cost and large-scale preparation of perovskite solar cells.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, specifically relating to a method for preparing perovskite precursor solutions suitable for medium-high humidity air environments and a method for preparing perovskite solar cells. Background Technology

[0002] Global climate change caused by the excessive consumption of fossil fuels has become a problem that humanity worldwide must overcome. Achieving an energy transition as soon as possible and reversing the fossil fuel-dominated energy structure is crucial; and the efficient use of renewable solar energy is one of the reliable ways to solve this problem.

[0003] In recent years, perovskite materials have attracted widespread attention in the photovoltaic and light-emitting fields due to their advantages such as tunable bandgap, wide application, long carrier diffusion lifetime, and low-cost solution preparation. The photoelectric conversion efficiency of perovskite solar cells has increased from an initial 3.8% to 26.1%, demonstrating a very broad prospect for industrial application.

[0004] External environmental factors such as light, humidity, and oxygen can affect the crystallization and growth of perovskite, with humidity being the most significant factor affecting film quality. Fabricating perovskite films in open air environments easily results in discontinuous, porous films. This problem is exacerbated by increasing humidity. When defective films are used to fabricate perovskite solar cells, these defects become charge recombination centers, causing a severe decline in cell performance and even short circuits. Furthermore, the presence of these defects can accelerate material decomposition; perovskite films may not even survive until the device fabrication process is complete. Therefore, fabricating perovskite films in inert atmospheres such as nitrogen has become a primary approach in laboratory research. However, inert atmosphere fabrication processes inevitably increase the production cost of perovskite solar cells, making their industrial application more difficult.

[0005] In summary, developing a technology for preparing perovskite thin films in air is necessary. Currently, there are also technologies for preparing perovskite thin films in high humidity environments. For example, application number 201910336754.7, entitled "A Method for Preparing Perovskite Thin Films Suitable for High Humidity Environments," utilizes dynamic spin-coating technology to rapidly remove solvents, thus reducing the impact of humidity. Application number 202310056028.6, entitled "A Method for Preparing High-Performance Perovskite Solar Cells in High Humidity Air Environments," uses chemical bath deposition combined with a two-step spin-coating method to prepare perovskite solar cells under 60% humidity conditions. However, these methods share a common problem: the main solvent for preparing perovskite precursor solutions is mostly DMF, which has severe hepatotoxicity, causing harm to both the natural environment and the health of workers. The limitation of existing technologies lies in their inability to simultaneously meet the requirements of open-air environment preparation and low toxicity while ensuring high-quality perovskite thin films and high device efficiency, thus restricting their application in large-scale production. Summary of the Invention

[0006] The purpose of this invention is to solve the problems of perovskite materials being easily affected by humidity during the preparation process, as well as environmental and personnel safety issues, in the existing technology. It provides a method for preparing perovskite precursor solutions and a method for preparing perovskite solar cells that are suitable for medium-to-high humidity air environments.

[0007] The technical content of this invention is: a method for preparing a perovskite precursor solution, wherein the precursor solution is solution A or solution B, or a mixture of solution A and solution B;

[0008] The preparation method of solution A is as follows: organic iodide and lead iodide are mixed in a 1:1 ratio, and the mixed components are added to a low-toxicity ester solvent system to obtain a solution with a concentration of 1.3 mmol / 1000 μL-1.7 mmol / 1000 μL. An additive is added to the solution, and solution A is obtained by stirring at low temperature. The molar ratio of the additive to the mixed components is 20%-30%.

[0009] The preparation method of solution B is as follows: inorganic iodide and lead iodide are dissolved in N-methylpyrrolidone organic solvent in a 1:1 ratio to obtain a solution with a concentration of 1.3 mmol / 1000 μL-1.7 mmol / 1000 μL, and solution B is obtained by stirring at low temperature.

[0010] Furthermore, in the method for preparing solution A, the low-toxicity ester solvent system is a mixture of triethyl phosphate and 2-methoxyethanol.

[0011] Furthermore, in the method for preparing solution B, the inorganic iodide is CsI.

[0012] Furthermore, the chemical formula of the solute is FA. x MA y Cs 1-x-y PbI3, 0≤X,Y≤1.

[0013] Furthermore, in the methods for preparing solution A and solution B, low-temperature stirring refers to stirring with a rotor for 1 to 3 hours within the range of room temperature to 40°C.

[0014] The method for preparing perovskite solar cells using the perovskite precursor solution prepared by the above method includes the following steps:

[0015] Step 1: Spin-coat a perovskite precursor solution onto a transparent conductive glass coated with an electron transport layer, and immediately flash-evaporate for 10-30 seconds after spin-coating; then anneal to form a perovskite film; the annealing temperature is 120℃-150℃; the spin-coating process is to spin-coat for 5-15 seconds at a speed between 4000rpm and 5500rpm.

[0016] Step 2: Spin-coat a hole transport layer onto the perovskite thin film. After spin-coating, oxidize the film in a drying cabinet. After oxidation for one to two days, thermally evaporate a metal electrode onto the top layer to prepare a perovskite solar cell.

[0017] Furthermore, in step 2, the metal electrode is one of gold, silver, or aluminum, with a thickness of 60nm-120nm.

[0018] Furthermore, in step 1, spin coating can be replaced by blade coating and slot coating in the spin coating + flash evaporation process; the flash evaporation process can also be replaced by an air knife; that is, perovskite films can be prepared by spin coating + flash evaporation, slot coating + flash evaporation, blade coating + flash evaporation, blade coating + air knife or slot coating + air knife process.

[0019] Beneficial effects

[0020] This invention balances the nucleation and crystallization processes of perovskite by controlling the ratio of solvents TEP, NMP, and 2-Me with additive MACl, thereby obtaining a smooth and dense perovskite film. The boiling point of the solvent decreases with decreasing gas pressure, and the solvent can be removed at room temperature by flash evaporation. Perovskite crystallization occurs during the wet film flash evaporation process. Accelerating solvent removal under low pressure rapidly increases the supersaturation of perovskite in the precursor, providing a driving force for nucleation and growth. When the nucleation rate is too high, the number of grain boundaries inside the film increases, leading to more defects and hindering carrier transport. When the nucleation rate is too low, the perovskite grains cannot completely cover the substrate, resulting in defects such as pores. This invention adjusts the properties of the entire solvent system by controlling the amount of solvents with different viscosities, boiling points, and binding forces with perovskite, thereby controlling the nucleation and crystallization processes of perovskite and preparing high-quality perovskite films.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] The perovskite thin film of this invention can be prepared in an air environment with a relative humidity of 30%-80%, which can greatly reduce the preparation cost compared to inert atmosphere protection.

[0023] This invention enables the fabrication of high-performance perovskite solar cells while taking into account three conditions: air preparation, low toxicity of the precursor solution, and no anti-solvent process. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the perovskite solar cell structure fabricated in an open air environment according to the present invention.

[0025] Figure 2 This is a surface morphology image of the perovskite thin film prepared in Example 1 under a relative humidity of 30%.

[0026] Figure 3 The image shows the surface morphology of the perovskite film prepared in Example 1 at a relative humidity of 50%.

[0027] Figure 4 The image shows the surface morphology of the perovskite film prepared in Example 1 at a relative humidity of 70%.

[0028] Figure 5 The current-voltage curve of the perovskite solar cell prepared in Example 1 under a relative humidity of 50% is shown.

[0029] Figure 6 The current-voltage curve of the perovskite solar cell prepared in Example 1 under a relative humidity of 70% is shown.

[0030] Figure 7 This is a surface morphology image of the perovskite thin film prepared in Example 2 under a relative humidity of 50%.

[0031] Figure 8 This is a surface morphology image of the perovskite thin film prepared in Example 2 under a relative humidity of 70%.

[0032] Figure 9 This is the current-voltage curve of the perovskite solar cell prepared in Example 2 under a relative humidity of 50%.

[0033] Figure 10 This is a surface morphology image of the perovskite thin film prepared in Example 3 under a relative humidity of 50%.

[0034] Figure 11This is the current-voltage curve of the perovskite solar cell prepared in Example 3 under a relative humidity of 50%.

[0035] Figure 12 This is a surface morphology image of the perovskite thin film prepared in Example 4 under a relative humidity of 50%.

[0036] Figure 13 The current-voltage curve of the perovskite solar cell prepared in Example 4 under a relative humidity of 50% is shown.

[0037] Figure 14 This diagram illustrates the perovskite thin film preparation process in this embodiment, including spin coating, flash evaporation, and annealing.

[0038] Explanation of reference numerals in the attached figures: 1. Conductive substrate; 2. Electron transport layer; 3. Perovskite layer; 4. Hole transport layer; 5. Metal electrode. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0040] The first objective of this invention is to provide a perovskite solar cell that can be fabricated at room temperature (25±5°C) in an air environment with a relative humidity of 30%-80%, see [link to previous document]. Figure 1 The structure of a perovskite solar cell, from bottom to top, consists of a conductive substrate layer, an electron transport layer, a perovskite layer, a hole transport layer, and a metal electrode.

[0041] This embodiment employs a film-forming method combining spin coating and flash evaporation, optimizing the formulation and process to further facilitate its industrial-scale production. Specifically, the perovskite layer preparation process includes spin coating, flash evaporation, and annealing.

[0042] First, a brief explanation of the preparation process:

[0043] The precursor mixed solvents include triethyl phosphate (TEP), N-methyl-2-pyrrolidone (NMP), and 2-methoxyethanol (2-Me).

[0044] The perovskite preparation process is carried out in an open air environment. The environmental conditions for perovskite preparation are relative humidity of 30%-80%, with the optimal relative humidity range being 45%-55%.

[0045] A perovskite precursor solution is spin-coated onto a conductive glass coated with an electron transport layer. The wet film is then flash-evaporated and heat-treated for annealing to obtain a perovskite thin film.

[0046] A hole transport layer is formed on a perovskite thin film, and then a metal electrode is thermally deposited on the hole transport layer to prepare a perovskite solar cell.

[0047] The perovskite precursors are AX and BX2 type compounds, where A is CH3NH3. + HC(=NH)NH 2+ or Cs + B is Pb 2+ X represents a halide ion.

[0048] When spin-coating the perovskite precursor solution onto transparent conductive glass coated with an electron transport layer, a spin-coating flash evaporation method is used. The specific process is as follows: After spin-coating at a high speed of 4000-6000 rpm for 15-30 seconds, the solution is transferred to a flash evaporation chamber where the solvent is removed by vacuum. Then, the solution is heat-treated at 150°C for 10-90 minutes to obtain a perovskite thin film with a thickness of 280-350 nm. The optimal process in this invention is to spin-coat at a high speed of 5000 rpm for 20 seconds, then transfer the solution to a flash evaporation chamber where the solvent is removed by vacuum, followed by heat treatment at 150°C for 10 minutes.

[0049] A second objective of this invention is to provide a method for preparing the above-mentioned perovskite solar cell, specifically comprising the following steps:

[0050] S1. Preparation of perovskite precursor solution:

[0051] Organic iodide and lead iodide are mixed in a 1:1 ratio. The mixture is then added to a low-toxicity ester solvent system to obtain a solution with a concentration of 1.3 mmol / 1000 μL–1.7 mmol / 1000 μL. An additive is added to this solution, and solution A is prepared by stirring at low temperature (25℃–45℃). The molar ratio of the additive to the mixed component is 20%–30%. Inorganic iodide (CsI) and lead iodide are dissolved in NMP organic solvent in a 1:1 ratio to obtain a solution with a concentration of 1.3 mmol / 1000 μL–1.7 mmol / 1000 μL. Solution B is prepared by stirring at low temperature. Organic perovskite solar cells can be prepared using a single solution A; organic-inorganic hybrid perovskite solar cells require a mixture of solutions A and B. The iodide used can be MAPbI3, FAPbI3, CsPbI3, a binary system (such as FAMAPbI3), or a ternary system (such as FAMACsPbI3).

[0052] Because perovskites offer advantages such as tunable composition and band gap, existing research systems in this field include MAPbI3, FAPbI3, CsPbI3, binary systems (FAMAPbI3, FACsPbI3, MACsPbI3), and ternary systems (FAMACsPbI3). Therefore, the ratio of MAI, FAI, and CsI in the preparation of perovskite precursor solutions is not limited and can be adjusted according to the specific research system being studied.

[0053] S2, Fabrication of perovskite solar cells:

[0054] A perovskite precursor solution is spin-coated onto a transparent conductive glass coated with an electron transport layer. Immediately after spin-coating, the solution is flash-evaporated for 10-30 seconds to remove excess solvent. The solution is then transferred to a hot plate for annealing to form a perovskite thin film.

[0055] A hole transport layer is spin-coated onto a perovskite thin film, oxidized in a drying cabinet for one to two days, and then a metal electrode is thermally vapor-deposited on top of it to prepare a perovskite solar cell.

[0056] Furthermore, the low-toxicity ester solvent system in S1 refers to the mixed solvent system of triethyl phosphate (TEP) and 2-methoxyethanol (2-Me).

[0057] Furthermore, in S1, low-temperature stirring refers to stirring with a rotor at a temperature below 40°C for one to three hours. In this patent, the preferred time is two hours; in S2, the spin coating process involves spin coating at a speed between 4000 rpm and 5500 rpm for 5-15 seconds.

[0058] Furthermore, the metal electrode in S2 is one of gold, silver, or aluminum, and the thickness of the metal electrode is 60-120 nm, preferably 80 nm.

[0059] The perovskite precursor formulations mentioned in this invention can be matched with other solvent-free processes, such as blade coating + flash evaporation, blade coating + air knife coating, slot coating + flash evaporation, and slot coating + air knife coating.

[0060] When using a blade coating + flash evaporation method: a perovskite precursor solution is blade coated onto a transparent conductive glass covered with an electron transport layer. Immediately after blade coating, flash evaporation is performed, followed by annealing to form a perovskite thin film. The blade coating process parameters are: blade height 200μm-500μm, blade speed 1mm / s-5mm / s, solution volume 20μL-50μL, and flash evaporation time (depending on the film color change time) 30s-60s.

[0061] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings, but the embodiments described are not intended to limit the present invention.

[0062] Example 1

[0063] A precursor solution formulation and process for preparing perovskite solar cells in medium-to-high humidity air environments, comprising the following steps:

[0064] S1. Weigh 0.97 mmol of FAI and 0.97 mmol of PbI2 powder in a nitrogen glove box. Mix the FAI and PbI2 powders in a specific ratio, and dissolve them in a mixed solvent of 630 μL TEP (triethyl phosphate) and 45 μL 2-Me (2-methoxyethanol). Add MACl to the resulting solution, wherein the molar ratio of MACl to the mixture of FAI and PbI2 powders is 25%, to prepare solution A.

[0065] Weigh 0.03 mmol of CsI and 0.03 mmol of PbI2 in a nitrogen glove box, mix the CsI and PbI2 in the specified ratio, and dissolve them in 55 μL of NMP (N-methylpyrrolidone) to prepare solution B.

[0066] A perovskite precursor solution is prepared by mixing solutions A and B.

[0067] S2. Take 25 μL of the perovskite precursor and drop it onto a glass substrate covered with an electron transport layer of TiO2 and FTO. Spin-coat at high speed (5000 rpm) for 20 s. After flash evaporation, heat-treat at 145℃ for 20 min to prepare a perovskite film with a uniform and smooth surface. See [link to documentation]. Figures 2-4 .

[0068] S3. Spin-coat a hole transport layer Spiro-OMeTAD with a thickness of 150 nm onto the perovskite film and oxidize it in a drying cabinet for 12 hours.

[0069] S4. Deposit a layer with an area of ​​0.1 cm² on the hole transport layer. 2 An 80nm thick Au electrode yields a perovskite solar cell; device performance is described in [reference needed]. Figure 5 and Figure 6 .

[0070] Example 2

[0071] A formulation and process for preparing perovskite solar cell precursor solutions in medium-to-high humidity air environments, comprising the following steps:

[0072] S1. Weigh 0.97 mmol of FAI and 0.97 mmol of PbI2 powder in a nitrogen glove box. Mix the FAI and PbI2 powders in the specified ratio, dissolve them in 620 μL of TEP (triethyl phosphate) solvent without adding 2-Me (2-methoxyethanol), and add MACl to the resulting solution. The molar ratio of MACl to the mixture of FAI and PbI2 powders is 30%, thus preparing solution A.

[0073] Weigh 0.03 mmol of CsI and 0.03 mmol of PbI2 in a nitrogen glove box, mix the CsI and PbI2 in the specified ratio, and dissolve them in 60 μL of NMP (N-methylpyrrolidone) to prepare solution B.

[0074] A perovskite precursor solution is prepared by mixing solutions A and B.

[0075] S2. Take 25 μL of the perovskite precursor and drop it onto a glass substrate covered with an electron transport layer of TiO2 and FTO. Spin-coat at high speed (5000 rpm) for 20 s. After flash evaporation, heat-treat at 145℃ for 20 min to prepare a perovskite film with a uniform and smooth surface. See [link to documentation]. Figure 7 , 8 .

[0076] S3. Spin-coat a hole transport layer Spiro-OMeTAD with a thickness of 150 nm onto the perovskite film and oxidize it in a drying cabinet for 12 hours.

[0077] S4. Deposit a layer with an area of ​​0.1 cm² on the hole transport layer. 2 An 80nm thick Au electrode yields a perovskite solar cell; performance details can be found in [reference needed]. Figure 9 .

[0078] Example 3

[0079] A formulation and process for preparing perovskite solar cell precursor solutions in medium-to-high humidity air environments, comprising the following steps:

[0080] S1. Weigh 0.97 mmol of FAI and 0.97 mmol of PbI2 powder in a nitrogen glove box. Mix the FAI and PbI2 powders in a specific ratio, and dissolve them in a mixed solvent of 550 μL TEP (triethyl phosphate) and 50 μL 2-Me (2-methoxyethanol). Add MACl to the resulting solution, wherein the molar ratio of MACl to the mixture of FAI and PbI2 powders is 20%, to prepare solution A.

[0081] Weigh 0.03 mmol of CsI and 0.03 mmol of PbI2 in a nitrogen glove box, mix the CsI and PbI2 in the specified ratio, and dissolve them in 30 μL of NMP (N-methylpyrrolidone) to prepare solution B.

[0082] A perovskite precursor solution is prepared by mixing solutions A and B.

[0083] S2. Take 25 μL of the perovskite precursor and drop it onto a glass substrate covered with an electron transport layer of TiO2 and FTO. Spin-coat at high speed (5000 rpm) for 20 s. After flash evaporation, heat-treat at 120℃ for 20 min to prepare a perovskite film with a uniform and smooth surface. See [link to documentation]. Figure 10 .

[0084] S3. Spin-coat a hole transport layer Spiro-OMeTAD with a thickness of 150 nm onto the perovskite film and oxidize it in a drying cabinet for 12 hours.

[0085] S4. Deposit a layer with an area of ​​0.1 cm² on the hole transport layer. 2 An 80nm thick Au electrode yields a perovskite solar cell; performance details can be found in [reference needed]. Figure 11 .

[0086] Example 4

[0087] A method for fabricating perovskite solar cells with high humidity air tolerance includes the following steps:

[0088] S1. Weigh 0.97 mmol of FAI and 0.97 mmol of PbI2 powder in a nitrogen glove box. Mix the FAI and PbI2 powders in a specific ratio, and dissolve them in a mixed solvent of 620 μL TEP (triethyl phosphate) and 5 μL 2-Me (2-methoxyethanol). Add MACl to the resulting solution, wherein the molar ratio of MACl to the mixture of FAI and PbI2 powders is 25%, to prepare solution A.

[0089] Weigh 0.03 mmol of CsI and 0.03 mmol of PbI2 in a nitrogen glove box, mix the CsI and PbI2 in the specified ratio, and dissolve them in 80 μL of NMP (N-methylpyrrolidone) to prepare solution B.

[0090] A perovskite precursor solution is prepared by mixing solutions A and B.

[0091] S2. 25 μL of the perovskite precursor was dropped onto a glass substrate covered with an electron transport layer of TiO2 and FTO. The substrate was spin-coated at high speed (5000 rpm) for 20 seconds. After flash evaporation, it was heat-treated at 125℃ for 20 minutes to prepare a uniform and dense perovskite film. (See [link to documentation]). Figure 12 .

[0092] S3. Spin-coat a hole transport layer Spiro-OMeTAD with a thickness of 150 nm onto the perovskite film and oxidize it in a drying cabinet for 12 hours.

[0093] S4. Deposit a layer with an area of ​​0.1 cm² on the hole transport layer. 2 An 80nm thick Au electrode yields a perovskite solar cell; performance details can be found in [reference needed]. Figure 13 .

[0094] Example 5

[0095] A precursor solution formulation and process for preparing perovskite solar cells in medium-to-high humidity air environments, comprising the following steps:

[0096] S1. Weigh 0.97 mmol of FAI and 0.97 mmol of PbI2 powder in a nitrogen glove box. Mix the FAI and PbI2 powders according to the specified ratio, and dissolve them in a mixed solvent of 620 μL TEP (triethyl phosphate) and 5 μL 2-Me (2-methoxyethanol). Add MACl to the resulting solution, wherein the molar ratio of MACl to the mixture of FAI and PbI2 powders is 25%, to prepare a perovskite precursor solution.

[0097] S2. Take 25 μL of the perovskite precursor and drop it onto the FTO substrate covered with the electron transport layer TiO2. Spin coat at high speed (5000 rpm) for 20 s. After flash evaporation, heat treat at 145℃ for 20 min to prepare a perovskite film with a uniform and smooth surface.

[0098] S3. Spin-coat a hole transport layer Spiro-OMeTAD with a thickness of 150 nm onto the perovskite film and oxidize it in a drying cabinet for 12 hours.

[0099] S4. Deposit a layer with an area of ​​0.1 cm² on the hole transport layer. 2 An Au electrode with a thickness of 80 nm is used to obtain a perovskite solar cell.

[0100] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent modifications or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a perovskite precursor solution, characterized in that, The precursor solution is a mixture of solution A and solution B; The preparation method of solution A is as follows: Organic iodide and lead iodide are mixed in a 1:1 ratio to obtain a specific component. This specific component is added to a low-toxicity ester solvent system to obtain a solution with a concentration of 1.3 mmol / 1000 μL-1.7 mmol / 1000 μL. An additive is added to the solution, and solution A is obtained by low-temperature stirring. The molar ratio of the additive to the specific component is 20%-30%. The low-toxicity ester solvent system is a mixture of triethyl phosphate and 2-methoxyethanol. The preparation method of solution B is as follows: inorganic iodide and lead iodide are dissolved in N-methylpyrrolidone organic solvent in a 1:1 ratio to obtain a solution with a concentration of 1.3 mmol / 1000μL-1.7 mmol / 1000μL, and solution B is obtained by stirring at low temperature.

2. The method for preparing perovskite precursor solution as described in claim 1, characterized in that, In the method for preparing solution B, the inorganic iodide is CsI.

3. The method for preparing perovskite precursor solution as described in claim 1, characterized in that, The chemical formula of the solute is ,0≤X,Y≤1.

4. The method for preparing perovskite precursor solution as described in claim 1, characterized in that, In the methods for preparing solution A and solution B, low-temperature stirring refers to stirring with a rotor for 1 to 3 hours within the range of room temperature to 40 ℃.

5. A method for preparing perovskite solar cells using the perovskite precursor solution prepared by the method of claim 1, characterized in that, Includes the following steps: Step 1: Spin-coat the perovskite precursor solution onto a transparent conductive glass coated with an electron transport layer, and immediately flash-evaporate for 10 s-30 s after spin-coating; The film is then annealed to form a perovskite film; the annealing temperature is 120 ℃-150 ℃; the spin coating process is to spin coat at a speed between 4000 rpm and 5500 rpm for 5 s-15 s. Step 2: Spin-coat a hole transport layer onto the perovskite thin film. After spin-coating, oxidize the film in a drying cabinet. After oxidation for one to two days, thermally evaporate a metal electrode onto the top layer to prepare a perovskite solar cell.

6. The method for preparing a perovskite solar cell as described in claim 5, characterized in that, In step 2, the metal electrode is one of gold, silver, or aluminum, with a thickness of 60 nm to 120 nm.

7. The method for preparing a perovskite solar cell as described in claim 5, characterized in that, In step 1, spin coating and flash evaporation processes can be replaced by blade coating or slot coating; the flash evaporation process can also be replaced by air knife; that is, perovskite films can be prepared by spin coating and flash evaporation, slot coating and flash evaporation, blade coating and flash evaporation, blade coating and air knife or slot coating and air knife processes.

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