Preparation method for perovskite thin film, and perovskite cell

Abstract

Disclosed in the present application are a method for preparing a perovskite thin film, and a perovskite cell. The perovskite cell sequentially includes a cell substrate (11), a first electrode layer (12), a first carrier transport layer (13), a carrier transport passivation layer (14), a perovskite thin film (2), a second carrier transport layer (3) and a second electrode layer (4) from bottom to top.

Description

A method for preparing a perovskite thin film and a perovskite solar cell

[0001] This application claims priority to Chinese Patent Application No. 202411509609.1, filed on October 28, 2024, with the Chinese Patent Office, entitled "A Method for Preparing a Perovskite Thin Film and a Perovskite Battery", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, specifically to a method for preparing a perovskite thin film, and a perovskite battery prepared using the method for preparing the perovskite thin film. Background Technology

[0003] The statements herein are provided only as background information in connection with this application and do not necessarily constitute prior art.

[0004] In the field of perovskite solar cells, the wet preparation processes for perovskite thin films mainly include one-step and two-step methods. The one-step method involves mixing perovskite precursor materials in a solvent to prepare a perovskite precursor solution, which is then coated onto a substrate. Subsequently, the solvent is rapidly removed using processes such as anti-solvent extraction or vacuum extraction to achieve rapid supersaturation of the wet film, thus pre-crystallizing. Finally, the pre-crystallized film is annealed to obtain the perovskite thin film. Due to the higher number of crystal defects, the photoelectric conversion efficiency of perovskite solar cells prepared using the one-step method is relatively low. The two-step method involves first preparing a perovskite inorganic salt solution, coating it onto a substrate, and annealing it to form an inorganic substrate layer. Then, an organic halogen salt solution is infiltrated into the inorganic substrate layer and annealed to form the perovskite thin film. Perovskite thin films prepared using the two-step method have higher crystallinity and density, and the photoelectric conversion efficiency of perovskite solar cells prepared using this method is generally higher.

[0005] In the current two-step method, the inorganic substrate layer is typically formed by coating a perovskite inorganic salt solution onto a substrate using slot coating or blade coating, followed by annealing. However, the inorganic substrate layer prepared in this way suffers from defects such as poor uniformity and numerous pores, leading to serious defects in the perovskite thin film formed by the combination of organic halide salt solution and inorganic substrate layer, which affects the photoelectric conversion efficiency and long-term stability of perovskite solar cells. Summary of the Invention

[0006] The purpose of this application is to provide a method for preparing a perovskite thin film and a perovskite solar cell, including but not limited to solving the problem that defects such as poor uniformity and numerous pores in the inorganic substrate layer lead to serious defects in the perovskite thin film formed by the combination of organic halogen salt solution and the inorganic substrate layer, affecting the photoelectric conversion efficiency and long-term stability of the perovskite solar cell.

[0007] The technical solution adopted in the embodiments of this application is:

[0008] In a first aspect, a method for preparing a perovskite thin film is provided, comprising the following steps:

[0009] A perovskite inorganic salt solution containing a thickener is coated onto a battery substrate to form a first inorganic substrate layer, and the battery substrate and the first inorganic substrate layer are combined to form a wet film substrate.

[0010] The wet film substrate is cooled and allowed to stand, and the organic solvent in the first inorganic substrate layer is removed by vacuum flash evaporation to form a pre-dried film layer, which is composed of perovskite inorganic salt material and the thickener.

[0011] The pre-dried film layer is subjected to a first annealing treatment to remove the cationic substances in the thickener;

[0012] The pre-dried film layer is subjected to a second annealing treatment to remove anions from the thickener and obtain a second inorganic substrate layer;

[0013] An organic halogen salt solution was coated onto the second inorganic substrate, and after drying and annealing, a perovskite thin film was obtained.

[0014] In one embodiment, the perovskite inorganic salt solution is formed by mixing the perovskite inorganic salt material and a solvent; the perovskite inorganic salt material is AX and BX2, where A is a monovalent metal cation, including one or more of cesium and rubidium; B is a divalent metal cation, including one or more of lead and tin; X is a monovalent anion, including one or more of iodine, bromine, and chlorine; and the solvent includes one or more of dimethyl sulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone.

[0015] In one embodiment, the perovskite inorganic salt material is prepared by mixing PbI2, PbBr2, CsI, and FAI in a certain proportion.

[0016] In one embodiment, the thickener includes one of ionic surfactants such as methyl acetate, methyl methacrylate, and methyl propionate.

[0017] In one embodiment, the coating method of the perovskite inorganic salt solution includes one of the deposition processes such as slot coating, blade coating, screen printing, and spray coating.

[0018] In one embodiment, in the step of cooling and allowing the wet film substrate to stand, and removing the organic solvent in the first inorganic substrate layer by vacuum flash evaporation to form a pre-dried film layer, wherein the pre-dried film layer is composed of perovskite inorganic salt material and the thickener, the cooling rate ranges from 1 to 30°C / min, the cooling and standing temperature ranges from -5 to 20°C, and the standing time ranges from 0 to 400 min.

[0019] In one embodiment, the cooling rate is 5°C / min, the cooling settling temperature is 5°C, and the settling time is 5min.

[0020] In one embodiment, the vacuum pressure drops to 1.0 × 10⁻⁶ within 1–1.5 seconds. -2 -1.0×10 -5 kPa.

[0021] In one embodiment, in the first annealing treatment of the pre-dried film layer to remove cationic substances from the thickener: the annealing temperature range is 40-90°C, and the annealing time ranges from 1-800 min.

[0022] In one embodiment, the annealing temperature is 60°C and the annealing time is 200 min.

[0023] In one embodiment, in the step of performing a second annealing treatment on the pre-dried film layer to remove anions from the thickener and obtain a second inorganic substrate layer: the annealing temperature range is 120-200°C, and the annealing time ranges from 1-500 min.

[0024] In one embodiment, the organic halide salt solution is formed by mixing a solute and a solvent; the solvent of the organic halide salt solution includes one of isopropanol, ethanol, n-butanol, etc.; the solute of the organic halide salt solution is CX, where C is a monovalent organic cation, including one or more of methylamino, formamidinyl, and phenylethylamine halides; and X is a monovalent anion, including one or more of iodine, bromine, and chlorine.

[0025] In one embodiment, the organic halide salt solution is formed by mixing a solute and a solvent; the solvent of the organic halide salt solution includes one of isopropanol, ethanol, n-butanol, etc.; the solute of the organic halide salt solution is CX, where C is a monovalent organic cation, including one or more of methylamino, formamidinyl, and phenylethylamine halides; and X is a monovalent anion, including one or more of iodine, bromine, and chlorine.

[0026] In one embodiment, the annealing temperature range is 70-300°C, and the annealing time ranges from 1-600 min.

[0027] Secondly, a perovskite solar cell is provided, comprising:

[0028] Battery substrate;

[0029] A first electrode layer disposed on the battery substrate;

[0030] A first carrier transport layer disposed on the first electrode layer;

[0031] A carrier transport passivation layer disposed on the first carrier transport layer;

[0032] A perovskite thin film disposed on the carrier transport passivation layer;

[0033] A second carrier transport layer is disposed on the perovskite thin film;

[0034] The second electrode layer is disposed on the second carrier transport layer;

[0035] The perovskite thin film is prepared by the perovskite thin film preparation method according to any one of claims 1-14.

[0036] In one embodiment, the battery substrate is a transparent glass substrate.

[0037] In one embodiment, the first carrier transport layer comprises one or more of NiO, SnO2, TiO2, and 2PACz.

[0038] In one embodiment, the second carrier transport layer is composed of C 60 Made of SnO2 material; C is deposited sequentially on the perovskite film by vapor deposition. 60 and SnO2 film.

[0039] In one embodiment, the second electrode layer is made of copper; the copper material is deposited on the second carrier transport layer by vapor deposition.

[0040] The perovskite thin film preparation method and the beneficial effects of the perovskite battery provided in this application are as follows: By adding a thickener to the perovskite inorganic salt solution, the fluid characteristics of the perovskite inorganic salt solution can be effectively improved, resulting in a high-viscosity first inorganic substrate layer. The fluidity of the first inorganic substrate layer decreases as the temperature decreases, thereby enabling the first inorganic substrate layer to be stably deposited and adhered on the battery substrate. By cooling and allowing the wet film substrate to stand, a vacuum flash evaporation process can be used to uniformly and initially solidify the wet film, reducing its fluidity. The perovskite thin film prepared by the wet film through two annealing treatments and in combination with an organic halide salt solution has good quality, which helps to improve the photoelectric conversion efficiency and long-term stability of the perovskite battery. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or exemplary technologies will be briefly introduced below. Obviously, the 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.

[0042] Figure 1 is a schematic flowchart of the method for preparing perovskite thin films provided in the embodiments of this application;

[0043] Figure 2 is a schematic diagram of the structure of the perovskite solar cell provided in the embodiment of this application.

[0044] The main markings in the attached figures are as follows:

[0045] 1. Battery substrate; 11. Battery substrate; 12. First electrode layer; 13. First carrier transport layer; 14. Carrier transport passivation layer; 2. Perovskite thin film; 3. Second carrier transport layer; 4. Second electrode layer. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the scope of this application.

[0047] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly or indirectly attached to that other component. When a component is referred to as "connected to" another component, it can be directly or indirectly connected to that other component. The terms "upper," "lower," "left," "right," etc., indicate orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, and are for ease of description only, not to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. "A plurality" means two or more, unless otherwise explicitly defined.

[0048] To illustrate the technical solutions provided in this application, the following detailed description is provided in conjunction with specific drawings and embodiments.

[0049] To address the aforementioned problems, this application provides a method for preparing a perovskite thin film and a perovskite solar cell. For ease of description, the specific structure of the perovskite solar cell is now described in detail.

[0050] Referring to Figure 2, the specific structure of this perovskite solar cell, from bottom to top, includes a solar cell substrate 11, a first electrode layer 12 disposed on the solar cell substrate, a first carrier transport layer 13 disposed on the first electrode layer 12, a carrier transport passivation layer 14 disposed on the first carrier transport layer 13, a perovskite thin film 2 disposed on the carrier transport passivation layer 14, a second carrier transport layer 3 disposed on the perovskite thin film 2, and a second electrode layer 4 disposed on the second carrier transport layer 3. The fabrication direction of this perovskite solar cell will now be described in detail, taking into account its specific structure. The fabrication method of this perovskite solar cell specifically includes the following steps:

[0051] Step 1: Provide a battery substrate 11. The battery substrate 11 may be a transparent glass substrate.

[0052] Step 2: Prepare the first electrode layer 12 on the battery substrate 11.

[0053] Step 3: Fabricate a first carrier transport layer 13 on the first electrode layer 12. Optionally, the first carrier transport layer 13 may include, but is not limited to, one or more of NiO, SnO2, TiO2, and 2PACz, and may be deposited using processes such as magnetron sputtering, evaporation, spraying, or slot coating. Specifically, in this embodiment, NiO may be selected as the material for the first carrier transport layer 13, and magnetron sputtering may be used as the deposition method to obtain a first carrier transport layer 13 with a film thickness of 50 nm.

[0054] Step 4: Prepare a carrier transport passivation layer 14 on the first carrier transport layer 13.

[0055] Step 5: Prepare a perovskite thin film 2 on the carrier transport passivation layer 14. Here, the perovskite thin film 2 is prepared by the method for preparing a perovskite thin film provided in this application embodiment. Referring to Figure 1, the method for preparing a perovskite thin film provided in this application embodiment specifically includes the following steps:

[0056] S1. A perovskite inorganic salt solution containing a thickener is coated onto the battery substrate 1 to form a first inorganic substrate layer. The battery substrate 1 and the first inorganic substrate layer are combined to form a wet film substrate. The battery substrate 1 can be a sheet material prepared by steps one to four above, and its specific structure includes a battery substrate 11, a first electrode layer 12, a first carrier transport layer 13, and a carrier transport passivation layer 14.

[0057] Perovskite inorganic salt solutions can be formed by mixing perovskite inorganic salt materials and solvents. The perovskite inorganic salt materials can be AX and BX2, where A is a monovalent metal cation, including but not limited to one or more of cesium and rubidium. B is a divalent metal cation, including but not limited to one or more of lead and tin. X is a monovalent anion, including but not limited to one or more of iodine, bromine, chlorine, or halogen-like substances. The solvent includes but is not limited to one or more of dimethyl sulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone.

[0058] Thickeners include, but are not limited to, one or more of ionic surfactants such as methyl acetate (MAAC), methyl methacrylate (MAFA), and methyl propionate (MAPA).

[0059] The coating methods for perovskite inorganic salt solutions include, but are not limited to, deposition processes such as slot coating, blade coating, screen printing, and spraying.

[0060] Specifically, in this embodiment, the perovskite inorganic salt material can be prepared by mixing PbI2, PbBr2, CsI, and FAI in a certain proportion. The solvent in the perovskite inorganic salt solution can be dimethyl sulfoxide (DMSO). The thickener can be methylamine acetate (MAAC). A 1 mol / L perovskite inorganic salt solution is prepared according to a DMSO:MAAC volume ratio of 1:50. The above perovskite inorganic salt solution is printed onto the battery substrate 1 using screen printing to form the first inorganic substrate layer. The printing screen can be a 240-420 mesh polyester screen or a stainless steel screen, with a tension range of 10-24 N. In this embodiment, a 300 mesh polyester screen is used for coating the perovskite inorganic salt solution.

[0061] S2. The wet film substrate is cooled and allowed to stand. The organic solvent in the first inorganic substrate layer is removed by vacuum flash evaporation to form a pre-dried film layer. The pre-dried film layer is composed of perovskite inorganic salt material and a thickener. The organic solvent in the first inorganic substrate layer can be the solvent in the aforementioned perovskite inorganic salt solution. Optionally, the cooling rate ranges from 1 to 30°C / min, the cooling and standing temperature ranges from -5 to 20°C, and the standing time ranges from 0 to 400 min. The pressure in the vacuum chamber needs to be reduced to 1.0 × 10⁻⁶ within 1 to 1.5 seconds. -2 -1.0×10 -5 kPa. Specifically, in this embodiment, the cooling rate can be 5°C / min, the cooling settling temperature can be 5°C, and the settling time can be 5min. The pressure in the vacuum box drops to 3.5 × 10 kPa within 5 seconds. -2 kPa. In this structure, due to the presence of the thickener, the fluidity of the first inorganic substrate layer decreases as the temperature decreases, thereby enabling the first inorganic substrate layer to be stably deposited and attached on the battery substrate 1.

[0062] S3. Perform a first annealing treatment on the pre-dried film layer to remove cationic ions from the thickener. This means that performing a first annealing treatment on the first inorganic substrate layer after vacuuming can remove anionic ions from the thickener, such as Ac... - PA - FA - The remaining thickener contains cationic and perovskite inorganic salt materials. Optionally, the annealing temperature ranges from 40 to 90°C, and the annealing time ranges from 1 to 800 minutes. Specifically, in the embodiments of this application, the annealing temperature can be 60°C, and the annealing time can be 200 minutes.

[0063] S4. The pre-dried film layer undergoes a second annealing treatment to remove anions from the thickener and obtain a second inorganic substrate layer. The second annealing treatment completely decomposes the thickener through heating, removing the anions and leaving only the perovskite inorganic salt material, thus forming a uniform, high-purity perovskite inorganic substrate layer. Optionally, the annealing temperature range is 120-200℃, and the annealing time ranges from 1-500 min. Specifically, in the embodiments of this application, the annealing temperature can be 140℃, and the annealing time can be 60 min.

[0064] S5. The organic halide salt solution is coated onto the second inorganic substrate layer, and after drying and annealing, a perovskite thin film 2 is obtained. First, the organic halide salt solution is prepared. Optionally, the organic halide salt solution is formed by mixing a solute and a solvent. The solvent of the organic halide salt solution includes, but is not limited to, volatile solvents such as isopropanol, ethanol, and n-butanol, which will not dissolve the second inorganic substrate layer. The solute of the organic halide salt solution can be CX, where C is a monovalent organic cation, including but not limited to one or more cations such as methylamino or formamidinyl, or phenylethylamine halides; X is a monovalent anion, including but not limited to one or more anions such as iodine, bromine, chlorine, or halogen-like ions. Specifically, in the embodiments of this application, the solvent of the organic halide salt solution can be n-butanol, and the solute of the organic halide salt solution can be prepared by mixing FAI, MAI, and FABr in a certain proportion to prepare an organic halide salt solution of 15 mg / mL.

[0065] Next, an organic halogen salt solution is coated onto a second inorganic substrate to form an organic halogen salt solution liquid film. After sufficient reaction with the second inorganic substrate, the organic halogen salt solution liquid film is pre-crystallized and dried using a drying process to form a perovskite pre-crystallized thin film nucleation. Optionally, the organic halogen salt solution is coated onto the second inorganic substrate using methods including, but not limited to, slot coating, blade coating, screen printing, and spraying. After the organic halogen salt solution is coated onto the second inorganic substrate, a reaction time of 1-5000 seconds is required. The drying process includes, but is not limited to, natural drying, air drying, and infrared drying; the drying time ranges from 1-5000 seconds. Specifically, in this embodiment, a slot coating process is used to coat the organic halogen salt solution onto the second inorganic substrate, and after waiting for 20 seconds, it is dried using a 5 mm / s fan.

[0066] Finally, the perovskite pre-crystallized film is annealed to obtain perovskite film 2. Optionally, the annealing temperature range is 70-300℃, and the annealing time ranges from 1-600 min. Specifically, in the embodiments of this application, the annealing temperature can be 140℃, and the annealing time can be 300 min.

[0067] Step Six: Fabricate a second carrier transport layer 3 on the perovskite thin film 2. Optionally, the second carrier transport layer 3 can be made of C 60 It is made of SnO2 material. Specifically, C is deposited sequentially on the perovskite thin film 2 by vapor deposition. 60 and SnO2 film. Among them, C 60 The thickness of the film can be 34 nm, and the thickness of the SnO2 film can be 20 nm.

[0068] Step 7: Fabricate a second electrode layer 4 on the second carrier transport layer 3. Optionally, the second electrode layer 4 can be made of copper. Specifically, copper is deposited on the second carrier transport layer 3 by vapor deposition, and the thickness of the second electrode layer 4 can be 150 nm.

[0069] To verify the performance of the perovskite solar cell prepared by the perovskite thin film preparation method provided in this application, four sets of experiments are provided for comparison and demonstration, namely Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3.

[0070] The perovskite solar cell prepared in Example 1 is obtained by the above steps one to seven.

[0071] The difference between the perovskite solar cell preparation method provided in Comparative Example 1 and the perovskite solar cell preparation method provided in Example 1 lies in the preparation method of the perovskite thin film in step five. Comparative Example 1 uses a one-step method to prepare the perovskite thin film 2, and the specific steps are as follows:

[0072] The first step involves using DMF / DMSO as a solvent and CsI, PbI2, PbBr2, and FAI as perovskite precursor materials to prepare a perovskite precursor solution by blending the perovskite precursor materials in the solvent.

[0073] The second step involves preparing a perovskite wet film on the battery substrate 1 by a scraping method, and then rapidly removing the solvent from the perovskite wet film by vacuum flash evaporation to form a pre-crystallized dry film.

[0074] The third step is to anneal the pre-crystallized dry film to form a perovskite thin film 2.

[0075] The other steps of the perovskite solar cell preparation method provided in Comparative Example 1 are the same as the corresponding steps of the perovskite solar cell preparation method provided in Example 1, and will not be repeated here.

[0076] The difference between the perovskite solar cell preparation method provided in Comparative Example 2 and the perovskite solar cell preparation method provided in Example 1 lies in the preparation method of the perovskite thin film in step five. The specific steps for preparing the perovskite thin film 2 in Comparative Example 2 are as follows:

[0077] The first step involves using DMF / NMP as a solvent and CsI, PbI2, PbBr2, and FAI as perovskite precursor materials to prepare a perovskite inorganic salt solution by blending the perovskite precursor materials in the solvent.

[0078] The second step involves coating the perovskite inorganic salt solution onto the battery substrate 1 using a scraping method, followed by annealing to form an inorganic substrate layer.

[0079] The other steps of the perovskite solar cell preparation method provided in Comparative Example 2 are the same as the corresponding steps of the perovskite solar cell preparation method provided in Example 1, and will not be repeated here.

[0080] The difference between the perovskite solar cell preparation method provided in Comparative Example 3 and the perovskite solar cell preparation method provided in Example 1 lies in the preparation method of the perovskite thin film in step five. The specific steps for preparing the perovskite thin film 2 in Comparative Example 3 are as follows:

[0081] The first step involves using CsI, PbI2, PbBr2, and FAI as perovskite inorganic salt materials, DMSO as the solvent for the perovskite inorganic salt solution, and MAAC as a thickener to prepare a 1 mol / L perovskite inorganic salt solution at a DMSO:MAAC volume ratio of 1:50.

[0082] The second step involves screen printing the perovskite inorganic salt solution onto the battery substrate 1 to form an inorganic substrate layer. The printing screen can be a 240-420 mesh polyester screen or a stainless steel screen, with a tension range of 10-24 N. Specifically, Comparative Example 3 uses a 300 mesh polyester screen for coating the perovskite inorganic salt solution.

[0083] The other steps of the perovskite solar cell preparation method provided in Comparative Example 3 are the same as the corresponding steps of the perovskite solar cell preparation method provided in Example 1, and will not be repeated here.

[0084] The viscosity characteristics of the perovskite inorganic salt solution in Example 1, the perovskite precursor solution in Comparative Example 1, and the perovskite inorganic salt solution in Comparative Example 2 were tested using a rheometer at 20-40℃. The test results are shown in Table 1 below.

[0085] Table 1. Viscosities of perovskite inorganic salt solutions in Example 1, Comparative Example 1, and Comparative Example 2

[0086]

[0087] The data comparison above shows that the viscosity of the perovskite inorganic salt solution provided in Example 1 is significantly higher than that of the perovskite precursor solution provided in Comparative Example 1, and also higher than that of the perovskite inorganic salt solution provided in Comparative Example 2. This indicates that the viscosity of the perovskite inorganic salt solution provided in Example 1 is significantly increased due to the addition of a thickener. At a DMSO:MAAC volume ratio of 1:50, the fluid requirements for screen printing can be met.

[0088] A standard solar intensity calibration was performed using a solar simulator, and the calibration was applied to an area of ​​1.0 cm². 2 The perovskite solar cell underwent a long-term IV test with a starting voltage of 0V, a cutoff voltage of 1.3V, and a range of 100mA. The test results are shown in Table 2 below.

[0089] Table 2 Test results of perovskite solar cells provided in Example 1 and Comparative Examples 1-3

[0090]

[0091] The data comparison above shows that:

[0092] 1. As can be seen from the comparison between Example 1 and Comparative Example 1, the performance of the perovskite battery obtained by preparing the perovskite thin film 2 in one step is significantly lower than that of the perovskite battery obtained by preparing the perovskite thin film 2 in two steps.

[0093] 2. By comparing Example 1 and Comparative Example 2, it can be seen that the performance of the perovskite battery prepared by adding a thickener to the perovskite film 2 is significantly higher than that of the perovskite battery prepared by not using a thickener.

[0094] 3. By comparing Example 1 with Comparative Example 3, it can be seen that the step of preparing perovskite thin film 2 by adding thickener in Comparative Example 3 did not undergo cooling curing, vacuum flash evaporation and other treatments, resulting in poor quality of the inorganic substrate layer and low photoelectric conversion efficiency of the prepared perovskite solar cell.

[0095] The above are merely optional embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for preparing a perovskite thin film, characterized in that, Includes the following steps: A perovskite inorganic salt solution containing a thickener is coated onto a battery substrate to form a first inorganic substrate layer, and the battery substrate and the first inorganic substrate layer are combined to form a wet film substrate. The wet film substrate is cooled and allowed to stand, and the organic solvent in the first inorganic substrate layer is removed by vacuum flash evaporation to form a pre-dried film layer, which is composed of perovskite inorganic salt material and the thickener. The pre-dried film layer is subjected to a first annealing treatment to remove the cationic substances in the thickener; The pre-dried film layer is subjected to a second annealing treatment to remove anions from the thickener and obtain a second inorganic substrate layer; An organic halogen salt solution was coated onto the second inorganic substrate, and after drying and annealing, a perovskite thin film was obtained.

2. The method for preparing the perovskite thin film as described in claim 1, characterized in that: The perovskite inorganic salt solution is formed by mixing the perovskite inorganic salt material and a solvent; the perovskite inorganic salt material is AX and BX2, where A is a monovalent metal cation, including one or more of cesium and rubidium; B is a divalent metal cation, including one or more of lead and tin; X is a monovalent anion, including one or more of iodine, bromine, and chlorine; and the solvent includes one or more of dimethyl sulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone.

3. The method for preparing the perovskite thin film as described in claim 2, characterized in that: The perovskite inorganic salt material is made by mixing PbI2, PbBr2, CsI, and FAI in a certain proportion.

4. The method for preparing the perovskite thin film as described in claim 1, characterized in that: The thickener includes one of the following ionic surfactants: methyl acetate, methyl methacrylate, and methyl propionate.

5. The method for preparing the perovskite thin film as described in claim 1, characterized in that: The coating method of the perovskite inorganic salt solution includes one of the deposition processes such as slot coating, blade coating, screen printing, and spray coating.

6. The method for preparing perovskite thin films according to any one of claims 1-5, characterized in that: In the step of cooling and allowing the wet film substrate to stand, removing the organic solvent in the first inorganic substrate layer by vacuum flash evaporation to form a pre-dried film layer, the pre-dried film layer being composed of perovskite inorganic salt material and the thickener, the cooling rate ranges from 1 to 30°C / min, the cooling and standing temperature ranges from -5 to 20°C, and the standing time ranges from 0 to 400 min.

7. The method for preparing the perovskite thin film as described in claim 6, characterized in that: The cooling rate is 5℃ / min, the cooling settling temperature is 5℃, and the settling time is 5min.

8. The method for preparing the perovskite thin film as described in claim 6, characterized in that: The vacuum pressure drops to 1.0 × 10⁻⁶ within 1–1.5 seconds. -2 -1.0×10 -5 kPa.

9. The method for preparing a perovskite thin film according to any one of claims 1-5, characterized in that: In the first annealing treatment of the pre-dried film layer to remove the cationic substances in the thickener: the annealing temperature range is 40-90℃, and the annealing time ranges from 1-800 min.

10. The method for preparing the perovskite thin film as described in claim 9, characterized in that: The annealing temperature is 60°C and the annealing time is 200 min.

11. The method for preparing a perovskite thin film according to any one of claims 1-5, characterized in that: In the step of performing a second annealing treatment on the pre-dried film layer to remove anions from the thickener and obtain a second inorganic substrate layer: the annealing temperature range is 120-200℃, and the annealing time ranges from 1-500min.

12. The method for preparing a perovskite thin film according to any one of claims 1-5, characterized in that: The organic halide salt solution is formed by mixing a solute and a solvent; the solvent of the organic halide salt solution includes one of isopropanol, ethanol, n-butanol, etc.; the solute of the organic halide salt solution is CX, where C is a monovalent organic cation, including one or more of methylamino, formamidinyl, and phenylethylamine halides; and X is a monovalent anion, including one or more of iodine, bromine, and chlorine.

13. The method for preparing perovskite thin films according to any one of claims 1-5, characterized in that: In the step of coating the organic halogen salt solution onto the second inorganic substrate and obtaining a perovskite thin film after drying and annealing: after coating the organic halogen salt solution onto the second inorganic substrate, the substrate is left to stand for 1-5000 seconds, and then dried and annealed.

14. The method for preparing perovskite thin films according to claim 13, characterized in that: The annealing temperature range is 70-300℃, and the annealing time range is 1-600min.

15. A perovskite solar cell, characterized in that, include: Battery substrate; A first electrode layer disposed on the battery substrate; A first carrier transport layer disposed on the first electrode layer; A carrier transport passivation layer disposed on the first carrier transport layer; A perovskite thin film disposed on the carrier transport passivation layer; A second carrier transport layer is disposed on the perovskite thin film; The second electrode layer is disposed on the second carrier transport layer; The perovskite thin film is prepared by the perovskite thin film preparation method according to any one of claims 1-14.

16. The perovskite solar cell as described in claim 15, characterized in that: The battery substrate is a transparent glass base plate.

17. The perovskite solar cell as described in claim 15, characterized in that: The first carrier transport layer includes one or more of NiO, SnO2, TiO2, and 2PACz.

18. The perovskite solar cell as described in claim 15, characterized in that: The second carrier transport layer consists of C 60 Made of SnO2 material; C is deposited sequentially on the perovskite film by vapor deposition. 60 and SnO2 film.

19. The perovskite solar cell as described in claim 15, characterized in that: The second electrode layer is made of copper; copper is deposited on the second carrier transport layer by vapor deposition.

Images