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

Abstract

This application provides a method for preparing a perovskite thin film and related perovskite thin films, solar cells, and solar cell devices. The preparation method includes the following steps: (1) providing a target material containing the following elements: lead, halogens, and one or more alkali metals; (2) sputtering the target material obtained in step (1) using a rare gas, optionally argon, to obtain a thin film; (3) subjecting the thin film obtained in step (2) to a chemical bath treatment, wherein the chemical bath is a solution of AX, wherein A is selected from one or more of formamidinium and methylamine, and X is a halogen; and (4) sputtering the thin film obtained in step (3) using metallic tin, wherein the process gas is a rare gas, optionally a mixture of argon and halogen gases, to obtain a perovskite thin film. The method produces a high-quality film with good process controllability.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and in particular to a method for preparing a perovskite thin film and related perovskite thin films, solar cells, and solar cell devices. Background Technology

[0002] Perovskite thin-film solar cells have gradually become a hot topic in next-generation solar cell research due to their advantages such as low electron-hole recombination rate and strong light absorption over a wide range. Current methods for preparing perovskite thin films mainly include solution chemistry, spin coating, and vapor deposition. Among these, solution chemistry is the mainstream method for preparing high-quality films in laboratories due to its low cost and relatively simple process; however, it suffers from poor process stability and repeatability, hindering large-scale production. Coating is the mainstream method for fabricating large-area perovskite thin films, but its film formation is singular, heavily influenced by solution materials, and lacks flexible control, making it difficult to guarantee film uniformity. Existing vapor deposition methods require sophisticated equipment and struggle to control the relative proportions of precursors, significantly increasing the difficulty of preparing high-quality films and resulting in substantial raw material waste. Therefore, providing a new method for preparing perovskite thin films with excellent film quality and good process controllability is highly significant. Summary of the Invention

[0003] This application is made in view of the above-mentioned problems, and its purpose is to provide a method for preparing perovskite thin films, wherein the perovskite thin films obtained by the method are uniformly formed, and the various process parameters of the method are flexible and controllable, and the perovskite thin films can be adapted to different solar cell systems by adjusting the preparation parameters.

[0004] To achieve the above objectives, this application provides a method for preparing a perovskite thin film and related perovskite thin films, solar cells, and solar cell devices.

[0005] The first aspect of this application provides a method for preparing a perovskite thin film, which includes the following steps:

[0006] (1) Provide a target material containing the following elements: lead, halogens and one or more alkali metals;

[0007] (2) Sputtering is performed using the target material described in step (1), and the process gas is a rare gas, which can be argon, to obtain a thin film;

[0008] (3) The film obtained in step (2) is subjected to a chemical bath treatment, wherein the chemical bath is a solution of AX, wherein A is selected from one or more of formamidinium and methylamine, and X is a halogen; and

[0009] (4) Sputter the thin film obtained in step (3) using metallic tin. The process gas is a rare gas, which can be a mixture of argon and halogen gas, to obtain a perovskite thin film.

[0010] The method described in this application allows for adjustment of various parameters within a wider range, and the process stability and controllability are significantly improved compared to existing technologies.

[0011] In any embodiment, optionally, the target material in step (1) contains 10-40% alkali metal, 10-40% lead, and 50-90% halogens, totaling 100%, based on the total molar number of each element in the target material. When the molar content of each element is within the above range, the conversion efficiency of the corresponding solar cell is relatively high.

[0012] In any embodiment, optionally, the halogen in step (1) is one or more of chlorine, bromine or iodine, and the alkali metal is one or more of potassium, rubidium or cesium.

[0013] In any embodiment, optionally, the concentration of the AX solution in step (3) is 10-100 mg / ml, or optionally 20-70 mg / ml. This can further improve the uniformity of the perovskite film formation, thereby increasing the conversion efficiency of the corresponding battery.

[0014] In any embodiment, optionally, the temperature of the chemical bath treatment in step (3) is 40-120°C, or optionally 50-80°C. This can further improve the properties of the obtained perovskite film, thereby increasing the conversion efficiency of the corresponding battery.

[0015] In any embodiment, optionally, the volume ratio of the rare gas, optionally argon, to the halogen gas in step (4) is 10:1 to 5:1. Using a mixture of rare gas and halogen gas as the process gas can further improve the properties of the resulting perovskite film, thereby increasing the conversion efficiency of the corresponding battery.

[0016] In any embodiment, optionally, the halogen gas in step (4) includes one or more of iodine vapor, bromine vapor, and chlorine vapor.

[0017] In any embodiment, step (4) may optionally be performed at a temperature of 50-250°C, or optionally 100-200°C.

[0018] The second aspect of this application provides a perovskite thin film that can be prepared by the method described in the first aspect of this application.

[0019] In any embodiment, the thickness of the perovskite film may optionally be 200-500 nm, optionally 400-500 nm, or more preferably 450-470 nm.

[0020] In any embodiment, optionally, the perovskite layer band gap of the perovskite thin film is 1.2-1.6 eV, optionally 1.4-1.5 eV.

[0021] A third aspect of this application provides a solar cell comprising the following components arranged sequentially from bottom to top:

[0022] Transparent conductive electrode;

[0023] Hole transport layer;

[0024] Perovskite layer;

[0025] Electron transport layer; and

[0026] Back electrode;

[0027] The positions of the hole transport layer and the electron transport layer are interchangeable, and the perovskite layer is a perovskite thin film prepared by the method described in the first aspect of this application or a perovskite thin film described in the second aspect of this application.

[0028] In any embodiment, the transparent conductive electrode may optionally be selected from one or more of indium tin oxide and fluorine-doped tin dioxide.

[0029] In any embodiment, optionally, the hole transport layer is selected from poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), polytriarylamine (PTAA), CuSCN, NiO x CuI, MoO x One or more of them.

[0030] In any embodiment, the electron transport layer is optionally selected from one or more of 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spiro-OMeTAD, WO3, polyethoxyethyleneimine (PEIE), polyethyleneimine (PEI), ZnO, TiO2, isomethyl [6,6]-phenyl-C61-butyrate (PCBM), SnO2, or fluorine-doped SnO2.

[0031] In any embodiment, the back electrode may optionally be selected from one or more of indium tin oxide, tungsten-doped indium oxide, aluminum-doped zinc oxide (AZO), Au, Ag, Cu, Al, Ni, Cr, Bi, Pt, and Mg.

[0032] A fourth aspect of this application provides a solar cell device comprising the solar cell described in the third aspect of this application.

[0033] The solar cells and solar cell devices of this application include perovskite thin films obtained by the preparation method of this application, and therefore have the same advantages as the preparation method of this application. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of a solar cell according to one embodiment of this application.

[0035] Explanation of reference numerals in the attached figures:

[0036] 1. Back electrode; 2. Hole transport layer; 3. Perovskite layer; 4. Electron transport layer; 5. Transparent conductive layer; 6. Glass Detailed Implementation

[0037] The following detailed description, with appropriate reference to the accompanying drawings, details the preparation method of the perovskite thin film of this application and related embodiments of the perovskite thin film, solar cell, and solar cell device. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0038] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0039] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0040] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0041] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0042] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0043] The terms “above” and “below” used in this application include the number itself. For example, “above one” means one or more, and “above one of A and B” means “A”, “B” or “A and B”.

[0044] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0045] The inventors of this application discovered in practical work that, in perovskite thin-film solar cells, different solar cells require different parameters such as band gap width in the perovskite thin film to improve conversion efficiency. However, the process conditions for preparing perovskite thin films in existing technologies are poorly controllable, making it difficult to adapt to the needs of different operating conditions. In actual production, this deficiency leads to increased preparation costs of perovskite thin films and potentially poor product quality, resulting in lower conversion efficiency of the solar cells. For example, solution chemical methods for preparing perovskite thin films not only use toxic solvents but also make it difficult to control the uniformity of large-area film formation, greatly limiting the practical application of perovskite solar cells in industry.

[0046] After extensive research, the inventors discovered a novel method for preparing perovskite thin films, which significantly improves process stability and controllability compared to existing technologies. Furthermore, by further optimizing the processing steps and corresponding process parameters, the inventors significantly improved the uniformity and properties of the resulting film, leading to higher conversion efficiency in solar cells containing the film.

[0047] [Preparation methods for perovskite thin films]

[0048] The first aspect of this application provides a method for preparing a perovskite thin film, which includes the following steps:

[0049] (1) Provide a target material containing the following elements: lead, halogens and one or more alkali metals;

[0050] (2) Sputtering is performed using the target material described in step (1), and the process gas is a rare gas, which can be argon, to obtain a thin film;

[0051] (3) The film obtained in step (2) is subjected to a chemical bath treatment, wherein the chemical bath is a solution of AX, wherein A is selected from one or more of formamidinium and methylamine, and X is a halogen; and

[0052] (4) Sputter the thin film obtained in step (3) using metallic tin. The process gas is a rare gas, which can be a mixture of argon and halogen gas, to obtain a perovskite thin film.

[0053] The above-mentioned method for preparing perovskite thin films, through the organic combination of various processing steps, allows for the adjustment of process parameters within a wider range, and the process stability and controllability are significantly improved compared with existing technologies.

[0054] Furthermore, the inventors discovered in further research that by adjusting the various process parameters of the preparation method, the uniformity of the obtained film can be further improved, the film quality can be improved, and thus the solar cell containing the obtained film layer can have a higher conversion efficiency.

[0055] In some embodiments, optionally, the target material in step (1) contains 10-40% alkali metal, 10-40% lead and 50-90% halogen, totaling 100%, based on the total molar number of each element in the target material.

[0056] Although the mechanism is not yet clear, the inventors have found in their research that when the content of the elements, especially alkali metals and lead, is within the above range, the perovskite thin film prepared by the method described in this application using the target material is more uniform, and the conversion efficiency of the resulting solar cell is also higher.

[0057] In some embodiments, optionally, the halogen in step (1) is one or more of chlorine, bromine or iodine, and the alkali metal is one or more of potassium, rubidium or cesium.

[0058] In this application, a preliminary sputtering process is performed in step (2) to obtain a film layer. It should be noted that this application does not have special requirements for the equipment used in the sputtering step; equipment commonly used in the art is sufficient. For example, step (2) can be performed in a magnetron sputtering apparatus. Furthermore, when sputtering the target material, a certain substrate can generally be used, and the thin film formed on the surface of the substrate is the thin film described in step (2) of this application. In this document, there are no particular limitations on the selection of the substrate. For example, the substrate can be ceramics, glass, tin dioxide, doped tin dioxide, or other substrates commonly used in the art.

[0059] The method described in this application does not have special requirements regarding the temperature for performing step (2), for example, it can be performed at room temperature. However, those skilled in the art will understand that the temperature should not be too low to avoid an excessively low sputtering rate.

[0060] In some embodiments, step (2) may optionally use a rare gas, optionally argon, as the process gas. The presence of the process gas is beneficial for improving the uniformity of the resulting perovskite film.

[0061] In some embodiments, the flow rate of the process gas in step (2) can optionally be 100-500 sccm, or optionally 150-300 sccm.

[0062] In some implementations, optionally, when step (2) is performed in a magnetron sputtering apparatus, the corresponding magnetron sputtering apparatus power is 100W-20kW, optionally 500W-5kW.

[0063] In some implementations, optionally, the chamber pressure in the device during step (2) is 0-200 Pa, excluding 0 Pa.

[0064] In some implementations, the sputtering thickness in step (2) can optionally be 10-300 nm.

[0065] In the method described in this application, organic ions, such as methylamine ions (CH3NH3), can be introduced into the membrane by subjecting the membrane obtained in step (2) to a chemical bath treatment. + MA + ) or formamidinium ion (FA + This improves the quality of the film layer and further enhances the conversion efficiency of the corresponding solar cell.

[0066] In some embodiments, optionally, the concentration of the AX solution in step (3) is 10-100 mg / ml, or optionally 20-70 mg / ml.

[0067] When the concentration of AX solution is below the above range, chemical bath treatment has little effect on improving film performance, resulting in lower conversion efficiency of the solar cell. When the concentration of AX solution is too high, it may introduce excessive methylamine or formamidinium ions, which could damage the film quality. Optionally, a solution concentration of AX of 10-100 mg / ml, preferably 20-70 mg / ml, has a better effect on improving film quality.

[0068] In some embodiments, optionally, the solvent in the solution of AX is a solvent commonly used in the art, such as aromatic compounds like xylene, toluene, or alkylnaphthalene; chlorinated aromatic hydrocarbons or chlorinated aliphatic hydrocarbons like chlorobenzene, vinyl chloride, or dichloromethane; alcohols like butanol, isopropanol, or ethylene glycol and their ethers and esters; ketones like acetone, methyl ethyl ketone, methyl isobutyl ketone, or cyclohexanone; highly polar solvents like dimethylformamide and dimethyl sulfoxide; and one or more of water. Optionally, the solvent is one or more of isopropanol or chlorobenzene.

[0069] In some embodiments, the temperature of the chemical bath treatment in step (3) is optionally 40-120°C, or optionally 50-80°C.

[0070] An appropriate chemical bath treatment temperature promotes the penetration and migration of dopant ions into the film layer, improving film quality. When the chemical bath treatment temperature is too low, such as below room temperature, the process is very slow. When the chemical bath treatment temperature exceeds 150°C, it may cause film deterioration, worsening film properties and leading to a significant reduction in the conversion efficiency of the solar cell.

[0071] The method described in this application also includes a post-treatment step (4) of the thin film obtained by chemical bath treatment. Unlike step (2), the sputtering treatment in step (4) can improve the film quality defects caused by possible improper operation in the aforementioned treatment steps. On the other hand, it can also further improve the film quality by introducing metal tin and halogens, so that the prepared perovskite thin film has uniform film thickness and excellent film quality, thereby improving the conversion efficiency of the corresponding solar cell.

[0072] In some embodiments, optionally, the volume ratio of the rare gas, optionally argon, to the halogen gas in step (4) is 10:1 to 5:1.

[0073] In this application, the rare gas, optionally argon, serves two purposes: firstly, it provides protection, preventing damage to the equipment or safety accidents caused by high temperatures; secondly, it can be used to bombard and generate ions, such as bombarding a target material or halogen gas, thereby doping the resulting film and improving its quality. Optionally, in this application, adjusting the volume ratio of the rare gas, optionally argon, and halogen gas while keeping the total amount constant, is beneficial for improving film quality. In particular, the improvement in film quality is more significant when the volume ratio of the rare gas, optionally argon, to the halogen gas is between 10:1 and 5:1.

[0074] In some embodiments, the halogen gas in step (4) may optionally include one or more of iodine vapor, bromine vapor, and chlorine vapor.

[0075] In some embodiments, optionally, the halogen gas in step (4) is a mixture of bromine vapor and iodine vapor, wherein the volume ratio of bromine vapor to iodine vapor is 1:3 to 3:1.

[0076] In some embodiments, the flow rate of the process gas in step (4) is optionally 100-500 sccm, or optionally 150-300 sccm.

[0077] In some implementations, step (4) may optionally be performed at a temperature of 50-250°C, or optionally 100-200°C.

[0078] When step (4) is performed within the aforementioned temperature range, the corresponding sputtering reaction rate is faster, which is beneficial for improving equipment efficiency. Furthermore, the high temperature helps accelerate ion migration, thereby speeding up the annealing process of the overall film layer. In addition, an appropriate operating temperature helps prevent condensation and deterioration of the film layer performance, thus avoiding a decline in the conversion efficiency of the solar cell.

[0079] In some implementations, optionally, when step (4) is performed in a magnetron sputtering apparatus, the corresponding magnetron sputtering apparatus power is 600W-5kW.

[0080] In some implementations, optionally, the chamber pressure in the device during step (4) is 0-200 Pa, excluding 0 Pa.

[0081] In some implementations, the sputtering thickness in step (4) may be 120-200 nm, or 150-170 nm.

[0082] [Perovskite Thin Film]

[0083] The second aspect of this application provides a perovskite thin film that can be prepared by the method described in the first aspect of this application.

[0084] In some embodiments, the thickness of the perovskite film may optionally be 200-500 nm, optionally 400-500 nm, or more preferably 450-470 nm.

[0085] It should be noted that in this application, the term "thickness of perovskite film" refers to the thickness of the film obtained after all steps (1)-(4) have been performed.

[0086] In some embodiments, the perovskite layer band gap of the perovskite thin film is optionally 1.2-1.6 eV, or optionally 1.4-1.5 eV.

[0087] [Solar Cell]

[0088] A third aspect of this application provides a solar cell comprising the following components arranged sequentially from bottom to top:

[0089] Transparent conductive electrode;

[0090] Hole transport layer;

[0091] Perovskite layer;

[0092] Electron transport layer; and

[0093] Back electrode;

[0094] The positions of the hole transport layer and the electron transport layer are interchangeable, and the perovskite layer is a perovskite thin film prepared by the method described in the first aspect of this application or a perovskite thin film described in the second aspect of this application.

[0095] In some embodiments, the transparent conductive electrode is optionally selected from one or more of indium tin oxide and fluorine-doped tin dioxide.

[0096] In some embodiments, the hole transport layer may optionally be selected from poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), polytriarylamine (PTAA), CuSCN, NiO x CuI, MoO x One or more of them.

[0097] In some embodiments, the electron transport layer is optionally selected from one or more of 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spiro-OMeTAD, WO3, polyethoxyethyleneimine (PEIE), polyethyleneimine (PEI), ZnO, TiO2, isomethyl [6,6]-phenyl-C61-butyrate (PCBM), SnO2, or fluorine-doped SnO2.

[0098] In some embodiments, the back electrode may optionally be selected from one or more of indium tin oxide, tungsten-doped indium oxide, aluminum-doped zinc oxide (AZO), Au, Ag, Cu, Al, Ni, Cr, Bi, Pt, and Mg.

[0099] In some embodiments, the solar cell described in this application may optionally be fabricated using methods commonly used in the art. For example, a transparent conductive electrode, a hole transport layer, a perovskite layer, an electron transport layer, and a back electrode layer may be stacked together in sequence, followed by winding and pressing, wherein the positions of the hole transport layer and the electron transport layer may be interchanged.

[0100] [Solar Cell Devices]

[0101] Perovskite thin films have a wide range of applications in functional materials, especially in the optoelectronic field. As an example, this application investigates the application of perovskite thin films prepared by the method described herein in the field of solar cells. It should be understood that the examples provided in this application are only for illustrating the uses of perovskite thin films prepared by the method of this application, and those skilled in the art will understand that the uses of the perovskite thin films are not limited to those provided in the examples.

[0102] The fourth aspect of this application provides a solar cell device comprising one or more of the perovskite thin film prepared by the method described in the first aspect of this application, the perovskite thin film of the second aspect of this application, or the solar cell described in the third aspect of this application.

[0103] Example

[0104] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0105] The sources of the raw materials used in the examples are shown in the table below:

[0106]

[0107] Example 1-1

[0108] Preparation of perovskite thin films

[0109] ① Take a set of fluorine-doped tin dioxide (FTO, fluorine doping amount of 10%, based on the weight of tin dioxide) conductive glass with a specification of 1.5cm*1.5cm*2.2mm, and use a laser marking machine to etch away a portion of the FTO (the unetched area is a square area extending 0.5cm from the center of the 1.5cm*1.5cm surface of the FTO to each of the four sides); clean the etched FTO conductive glass sheet several times with acetone and isopropanol in sequence, and finally immerse it in deionized water and sonicate for 10 minutes until there are no foreign objects or dirt on the glass surface. After drying the obtained material, use it as a substrate.

[0110] ② The substrate obtained in step ① was sputtered using target 1 in a magnetron sputtering equipment. An RF power supply with a power of 3kW was used, the pressure in the magnetron sputtering equipment chamber was 0.3Pa, the process gas was argon with a flow rate of 500sccm, the coating time (i.e., sputtering treatment time) was 10min, and the resulting film thickness was 200nm.

[0111] ③ The membrane obtained in step ② is transferred to a 100ml isopropanol solution of formamidine for chemical bath treatment. The solution concentration is 60mg / ml, the bath temperature is 50℃, and the treatment time is 20min. After that, the solvent is removed by drying.

[0112] ④ The film obtained in step ③ is sputtered in a magnetron sputtering apparatus. A tin target is used, and the process gas is a mixture of argon, iodine vapor, and bromine vapor in a volume ratio of 20:1:1. The flow rate of argon is 200 sccm, and the flow rates of both iodine and bromine vapor are 10 sccm. An RF power supply with a power of 2 kW is used. The temperature inside the magnetron sputtering chamber is 100℃, the chamber pressure is 0.3 Pa, and the deposition time (i.e., sputtering treatment time) is 40 min. The film thickness increased by 150 nm after sputtering in this step.

[0113] The perovskite thin film of this application can be obtained by following the above steps.

[0114] Fabrication of perovskite solar cells

[0115] ① Take a set of fluorine-doped tin dioxide (FTO, fluorine doping amount of 10%, based on the weight of tin dioxide) conductive glass with a specification of 1.5cm*1.5cm*2.2mm, and use a laser marking machine to etch away a portion of the FTO (the unetched area is a square area extending 0.5cm from the center of the FTO to each of the four sides); clean the etched FTO conductive glass sheet several times with acetone and isopropanol in sequence, and finally immerse it in deionized water and sonicate for 10 minutes until there are no foreign objects or dirt on the glass surface. Use the obtained material as the substrate.

[0116] ② The FTO conductive glass sheet obtained in step ① was dried in a forced-air drying oven to remove moisture, and then transferred to a magnetron sputtering equipment to sputter nickel oxide. An RF power supply with a power of 1.5kW was used. The temperature in the magnetron sputtering equipment chamber was 50℃, the chamber pressure was 0.2Pa, the argon flow rate was 300sccm, the oxygen flow rate was 50sccm, the coating time was 5min, and the resulting film thickness was 30nm.

[0117] ③ Using the FTO conductive glass sputtered with nickel oxide obtained in step ② as a substrate, the perovskite thin film described in this application is prepared on the substrate. The preparation process is the same as the preparation process of the aforementioned perovskite thin film.

[0118] ④ Place the perovskite film sputtered in step ③ into a vacuum coating machine. Then, add 20g of C60 (fullerene C60) and 20g of BCP powder (2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline) to the magnetron sputtering equipment. First, deposit C60 by vapor deposition. Evaporation up to 5nm, then Evaporation was performed to a depth of 30 nm. Then, BCP was deposited using [a specific method / method Evaporation up to 2nm, then Evaporation up to 8nm.

[0119] ⑤ Place the wafer obtained in step ④ into a vapor deposition machine and vapor deposit an Ag electrode with a thickness of 50 nm.

[0120] The perovskite solar cell described in this application can be obtained by following the above steps.

[0121] Relevant parameter testing methods

[0122] Band gap testing of perovskite thin films

[0123] The transmittance and absorption spectrum of the thin film were measured using a Shimadzu UV-3600 spectrophotometer. A 5cm*5cm*2.2mm clear glass plate coated with a perovskite film was placed on the test window. The transmittance and absorption formulations for the 300-1100nm range were selected in the software, and the transmittance and absorption spectrum of the perovskite film were then measured. The band gap value of the perovskite thin film was obtained by finding the intersection of the tangent line and the energy axis using Tauc curve conversion.

[0124] Efficiency testing of perovskite solar cells

[0125] According to the standard IEC61215:2016 efficiency test method, the efficiency of the component was tested using the IVS-KA6000 from Guangyan Technology Co., Ltd.

[0126] Examples 1-2 to 1-5

[0127] Except that the concentrations of the isopropanol solution of methyl iodide were 10 mg / ml, 20 mg / ml, 70 mg / ml and 100 mg / ml during the preparation of the perovskite thin film, the other conditions in Examples 1-2 to 1-5 were the same as in Example 1-1.

[0128] Examples 1-6 to 1-9

[0129] Except for the chemical bath temperatures of 40°C, 80°C, 100°C and 120°C during the preparation of the perovskite thin film, the other conditions in Examples 1-6 to 1-9 were the same as those in Example 1-1.

[0130] Comparative Example 1

[0131] Except that the concentration of the isopropanol solution of methyl iodide was 5 mg / ml during the preparation of the perovskite thin film, the other conditions of Comparative Example 1 were the same as those of Examples 1-1.

[0132] Comparative Examples 2-3

[0133] Except for the chemical bath temperatures of 150°C and 170°C during the preparation of the perovskite thin film, the other conditions of Comparative Examples 2-3 were the same as those of Examples 1-1.

[0134] Comparative Example 4

[0135] Except for the absence of chemical bath treatment during the preparation of the perovskite thin film, the other conditions of Comparative Example 4 were the same as those of Examples 1-1.

[0136] Table 1. Experimental results of Examples 1-1 to 1-9 and Comparative Examples 1-4

[0137]

[0138]

[0139] As shown in Table 1, chemical bath treatment of the obtained perovskite film can effectively improve the conversion efficiency of solar cells. However, when the solubility of AX is too low or the chemical bath treatment temperature is too high, increasing the chemical bath treatment may actually worsen the performance of the perovskite film, leading to a decrease in the conversion efficiency of the solar cell.

[0140] Examples 2-1 to 2-5

[0141] Except for the volume ratios of argon:iodine vapor:bromine vapor in the post-treatment process of step (4) during the preparation of perovskite thin films, which are 20:1:1, 10:1:1, 20:0.5:0.5, 20:1.5:0.5, and 10:0:1 respectively, the other conditions in Examples 2-1 to 2-5 are the same as those in Example 1-1.

[0142] Comparative Examples 5-6

[0143] Except that the volume ratios of argon:iodine vapor:bromine vapor were 0:0:0 and 1:0:0 respectively during the post-treatment process of step (4) in the preparation of perovskite thin films, the other conditions of Comparative Examples 5-6 were the same as those of Examples 1-1.

[0144] Table 2 shows the experimental results of Examples 2-1 to 2-5 and Comparative Examples 5-6.

[0145]

[0146] As shown in Table 2, during the post-processing in step (4), the simultaneous presence of argon and halogen gases can effectively improve the performance of the perovskite thin film and increase the efficiency of the solar cell. In particular, when the volume ratio of argon to halogen gas is 10:1 to 5:1, the conversion efficiency of the solar cell can be further improved.

[0147] Examples 3-1 to 3-4

[0148] Except for the sputtering temperatures of 50°C, 150°C, 200°C and 250°C in the post-processing of step (4) during the preparation of perovskite thin films, the other conditions of Examples 3-1 to 3-4 are the same as those of Example 1-1.

[0149] Comparative Examples 7-8

[0150] Except for the sputtering temperatures of 30°C and 300°C in the post-processing of step (4) during the preparation of the perovskite thin film, the other conditions of Comparative Examples 7-8 are the same as those of Examples 1-1.

[0151] Table 3 shows the experimental results of Examples 3-1 to 3-4 and Comparative Examples 7-8.

[0152]

[0153] As shown in Table 3, when the sputtering temperature in the post-processing of step (4) is 50-250℃, it is beneficial to improve the performance of the perovskite thin film, thereby increasing the efficiency of the solar cell. In particular, when the sputtering temperature is 100-200℃, the improvement effect on the efficiency of the solar cell is more obvious.

[0154] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for preparing a perovskite thin film, comprising the following steps: (1) Provide a target material containing the following elements: lead, halogens and one or more alkali metals; (2) Sputtering is performed using the target material described in step (1), with the process gas being a rare gas, to obtain a thin film; (3) The film obtained in step (2) is subjected to a chemical bath treatment, wherein the chemical bath is a solution of AX, wherein A is selected from one or more of formamidinium and methylamine, and X is a halogen; and (4) Sputter the thin film obtained in step (3) using metallic tin. The process gas is a mixture of rare gas and halogen gas to obtain a perovskite thin film. The halogen mentioned in step (1) is one or more of chlorine, bromine or iodine, and the alkali metal is one or more of potassium, rubidium or cesium.

2. The method according to claim 1, wherein the rare gas in step (2) is argon.

3. The method according to claim 1 or 2, wherein the rare gas in step (4) is argon.

4. The method according to claim 1 or 2, wherein The target material in step (1) contains 10-40% alkali metal, 10-40% lead and 50-90% halogen, totaling 100%, based on the total molar number of each element in the target material.

5. The method according to claim 1 or 2, wherein The concentration of the AX solution mentioned in step (3) is 10-100 mg / ml.

6. The method according to claim 1 or 2, wherein The concentration of the AX solution mentioned in step (3) is 20-70 mg / ml.

7. The method according to claim 1 or 2, wherein The temperature of the chemical bath treatment in step (3) is 40-120℃.

8. The method according to claim 1 or 2, wherein The temperature of the chemical bath treatment in step (3) is 50-80℃.

9. The method according to claim 1 or 2, wherein In step (4), the volume ratio of rare gas to halogen gas is 10:1 to 5:

1.

10. The method according to claim 1 or 2, wherein The halogen gas mentioned in step (4) includes one or more of iodine vapor, bromine vapor, and chlorine vapor.

11. The method according to claim 1 or 2, wherein Step (4) is carried out at a temperature of 50-250℃.

12. The method according to claim 1 or 2, wherein Step (4) is carried out at a temperature of 100-200℃.

13. A perovskite thin film prepared by any one of claims 1-12.

14. The perovskite thin film according to claim 13, wherein... The thickness of the perovskite film is 200-500 nm.

15. The perovskite thin film according to claim 13 or 14, wherein... The thickness of the perovskite film is 400-500 nm.

16. The perovskite thin film according to claim 13 or 14, wherein... The thickness of the perovskite film is 450-470 nm.

17. The perovskite thin film according to claim 13 or 14, wherein... The perovskite layer band gap of the perovskite thin film is 1.2-1.6 eV.

18. The perovskite thin film according to claim 13 or 14, wherein... The perovskite layer band gap of the perovskite thin film is 1.4-1.5 eV.

19. A solar cell comprising the following components arranged sequentially from bottom to top: Transparent conductive electrode; Hole transport layer; Perovskite layer; Electron transport layer; and Back electrode; The positions of the hole transport layer and the electron transport layer are interchangeable, and the perovskite layer is a perovskite film prepared by the method of any one of claims 1-12 or a perovskite film of any one of claims 13-18.

20. The solar cell according to claim 19, wherein The transparent conductive electrode is selected from one or more of indium tin oxide and fluorine-doped tin dioxide.

21. The solar cell according to claim 19 or 20, wherein The hole transport layer is selected from poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), polytriarylamine (PTAA), CuSCN, and NiO. x CuI, MoO x One or more of them.

22. The solar cell according to claim 19 or 20, wherein The electron transport layer is selected from one or more of 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spiro-OMeTAD, WO3, polyethoxyethyleneimine (PEIE), polyethyleneimine (PEI), ZnO, TiO2, isomethyl [6,6]-phenyl-C61-butyrate (PCBM), SnO2, or fluorine-doped SnO2.

23. The solar cell according to claim 19 or 20, wherein The back electrode is selected from one or more of indium tin oxide, tungsten-doped indium oxide, aluminum-doped zinc oxide (AZO), Au, Ag, Cu, Al, Ni, Cr, Bi, Pt, and Mg.

24. A solar cell device, characterized in that, The solar cell includes any one of claims 19-23.

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