A method for preparing perovskite film by combining solvent mist and hot air

Abstract

This application relates to the field of perovskite film formation technology, and more particularly to a method for preparing a perovskite film combining solvent mist and hot air. The method includes the following steps: providing a perovskite precursor liquid; coating the perovskite precursor liquid onto a substrate to obtain a liquid film; spraying the surface of the liquid film; and then hot air treatment to obtain a wet perovskite film; wherein, in the spraying treatment, a first solvent is used to form a mist, the boiling point of which is lower than the boiling point of a second solvent in the perovskite precursor liquid; and annealing the wet perovskite film to obtain the perovskite film. This preparation method is not only simple, but also allows for the preparation of large-size, dense, and uniform perovskite films under atmospheric conditions.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of perovskite film forming process, and particularly relates to a perovskite film preparation method combining solvent mist and hot air. BACKGROUND

[0002] Perovskite is a material with the same crystal structure as mineral calcium titanium oxide (the earliest discovered perovskite crystal). Generally, the chemical formula of halogenated perovskite compound is ABX3; wherein A is a monovalent cation, which can be an inorganic cation such as cesium ion (Cs + ), or an organic cation such as methylamine cation (MA) and formamidinium cation (FA), B is a divalent metal cation, and X is a halogen anion. Due to the excellent photoelectric properties of organic-inorganic hybrid perovskite, it has attracted the attention of many researchers and technical personnel in the rapid development in the past decade.

[0003] At present, the certified photoelectric conversion efficiency of perovskite solar cells has reached as high as 25.5%, which is the most competitive and potential thin film battery. The perovskite thin film in it can be prepared by a solution method, and spin coating and doctor blading are two commonly used methods. In laboratory research, spin coating is a commonly used method for preparing high-efficiency perovskite solar cells, but it is difficult to realize the scale-up and industrialization of perovskite film. Although the doctor blading method can be used to prepare large-size perovskite films, the quality of the perovskite films obtained by general doctor blading is not high, and the perovskite films are prone to problems such as wrinkles, cracks and pores, which seriously affect the efficiency of perovskite solar cells. In particular, in order to promote the industrialization of perovskite films, the doctor blading method is used to prepare perovskite films in air, which makes the defects of the doctor blading method more prominent, thereby bringing great challenges to the preparation of high-quality perovskite films. SUMMARY

[0004] The purpose of the present application is to provide a perovskite film preparation method combining solvent mist and hot air, and a perovskite film obtained by the preparation method, aiming to solve the technical problem of how to improve the denseness and uniformity of the perovskite film.

[0005] To achieve the above-mentioned application purposes, the technical solutions adopted by the present application are as follows:

[0006] In a first aspect, the present application provides a perovskite film preparation method, comprising the following steps:

[0007] providing a perovskite precursor solution;

[0008] coating the perovskite precursor solution on a substrate to obtain a liquid film, performing mist treatment on the surface of the liquid film, and then performing hot air treatment to obtain a perovskite wet film; wherein a first solvent is used to form mist in the mist treatment, and the boiling point of the first solvent is lower than the boiling point of a second solvent in the perovskite precursor solution.

[0009] annealing the perovskite wet film to obtain a perovskite film.

[0010] In one embodiment, the direction of the mist in the spraying treatment is at an angle of 45-135° to the horizontal plane of the liquid film, and the direction of the hot air in the hot air treatment is at an angle of 45-135° to the liquid film.

[0011] In one embodiment, the step of coating the perovskite precursor liquid on a substrate to obtain a liquid film is to coat the perovskite precursor liquid on the substrate by using a doctor blade to obtain the liquid film, the step of the spraying treatment is to form a mist curtain on the liquid film by using a mist curtain knife, and the step of the hot air treatment is to form a hot air curtain on the liquid film by using a hot air curtain knife; along the direction of coating by the doctor blade, the doctor blade, the mist curtain knife and the hot air curtain knife are arranged in sequence and move at a uniform speed.

[0012] In one embodiment, the moving speed of the doctor blade is 0.1-200 mm / s, the moving speed of the mist curtain knife is 0.1-200 mm / s, and the moving speed of the hot air curtain knife is 0.1-200 mm / s.

[0013] In one embodiment, the distance between the doctor blade and the substrate is 0.001-10 mm, the distance between the mist curtain knife and the substrate is 1-10 cm, and the distance between the hot air curtain knife and the substrate is 1-10 cm.

[0014] In one embodiment, the temperature of the hot air in the hot air treatment is 40-120°C; and / or,

[0015] the flow rate of the hot air in the hot air treatment is 0.5-20 L / min; and / or,

[0016] the hot air in the hot air treatment is formed by at least one of dry air, nitrogen, argon, and oxygen.

[0017] the first solvent is at least one selected from toluene, chlorobenzene, diethyl ether, chloroform, ethanol, acetonitrile, isopropanol, tert-butanol, n-butanol, 2,2,2-trifluoroethanol, acetone, methyl formate, diethyl carbonate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, and amyl acetate; and / or,

[0018] the second solvent is at least one selected from dimethyl sulfoxide, N,N-dimethylformamide, gamma butyrolactone, azomethyline pyrrolidone, and ethylene glycol monomethyl ether.

[0019] In one embodiment, the perovskite precursor solution is obtained by dissolving raw materials AX and PbY2 in the second solvent at a molar ratio of (1-1.5):(1-1.5); wherein A is at least one selected from methylamine, formamidine, cesium, rubidium, dimethylamine, guanidine, butylamine, ethylamine, propylenediamine, octylamine, oleylamine, aniline and benzylamine, and X and Y are independently at least one selected from fluorine, chlorine, bromine and iodine.

[0020] In one embodiment, the annealing treatment is performed at a temperature of 60-250℃.

[0021] In a second aspect, the present application provides a perovskite film prepared by the method described in the present application.

[0022] The method for preparing a perovskite film provided in the first aspect of the present application comprises the following steps: coating a perovskite precursor solution on a substrate to obtain a liquid film, and then performing spray treatment and hot air treatment on the surface of the liquid film. The first solvent in the spray treatment has a lower boiling point than the second solvent in the perovskite precursor solution. Therefore, when the mist enters the surface of the liquid film, the boiling point of the mixed solvent in the liquid film is reduced due to the mixing of the first solvent, and the perovskite is more likely to precipitate and crystallize. After the hot air treatment, the mixed solvent in the liquid film is quickly volatilized, a large number of crystal nuclei are formed instantaneously, and a perovskite wet film containing a dense intermediate phase and perovskite is deposited. After subsequent annealing, a dense and uniform perovskite film is obtained. The method provided in the present application is simple, and can be used to prepare a large-size, dense and uniform perovskite film in an atmospheric environment.

[0023] The perovskite film provided in the second aspect of the present application is prepared by the method for preparing a perovskite film provided in the present application. After the perovskite precursor solution is coated, the combined action of the spray treatment of the specific first solvent and the hot air treatment can improve the perovskite film forming quality and reduce the influence of water vapor in the air on the perovskite film. Therefore, the perovskite film provided in the present application has good uniformity and density, and has a good application prospect in perovskite devices such as perovskite solar cells. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0025] Figure 1 is a flowchart of the method for preparing a perovskite film provided in the embodiments of the present application;

[0026] Figure 2is a coating process schematic diagram of a preparation method of a perovskite film provided by an embodiment of the present application;

[0027] Figure 3 is a SEM diagram of a perovskite film provided by an embodiment of the present application;

[0028] Figure 4 is an ultraviolet-visible absorption spectrum diagram of a perovskite film provided by an embodiment of the present application;

[0029] Figure 5 is an XRD spectrum diagram of a perovskite film provided by an embodiment of the present application;

[0030] Figure 6 is a SEM diagram of a perovskite film provided by a comparative example of the present application. DETAILED DESCRIPTION

[0031] In order to make the technical problems to be solved by the present application, the technical solutions and beneficial effects clearer, the present application will be further described in detail below with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0032] In the present application, the term "and / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can represent the following three cases: A exists alone, A and B exist together, and B exists alone. Wherein A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after it.

[0033] In the present application, "at least one" means one or more, and "more" means two or more. "At least one of the following" or similar expressions means any combination of these items, including any combination of single item or multiple items.

[0034] It should be understood that in various embodiments of the present application, the size of the sequence number of the above-mentioned processes does not mean the order of execution, and part or all of the steps can be executed in parallel or in sequence, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0035] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0036] The terms "first", "second", "third", etc., are used only for the purpose of description, to distinguish between objects, such as substances, from each other, and cannot be understood as indicating or implying relative importance or implying the number of the indicated technical features. For example, without departing from the scope of the embodiments of the present application, the first XX can also be referred to as the second XX, and similarly, the second XX can also be referred to as the first XX. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features.

[0037] The first aspect of the embodiments of the present application provides a method for preparing a perovskite film by combining a solvent mist and hot air, as shown in the following formula: Figure 1 The method comprises the following steps:

[0038] S01: providing a perovskite precursor liquid;

[0039] S02: coating the perovskite precursor liquid on a substrate to obtain a liquid film, performing mist treatment on the surface of the liquid film, and then performing hot air treatment to obtain a perovskite wet film; wherein the mist in the mist treatment is formed by a first solvent, and the boiling point of the first solvent is lower than the boiling point of a second solvent in the perovskite precursor liquid;

[0040] S03: annealing the perovskite wet film to obtain a perovskite film.

[0041] The method for preparing a perovskite film provided by the embodiments of the present application first coats a perovskite precursor liquid on a substrate to obtain a liquid film, and then performs mist treatment and hot air treatment on the surface of the liquid film. Since the boiling point of the first solvent forming the mist in the mist treatment is lower than the boiling point of the second solvent in the perovskite precursor liquid, the mixed solvent in the liquid film is reduced in boiling point due to the mixing of the first solvent after the mist enters the surface of the liquid film, and the perovskite is more likely to precipitate and crystallize. After the hot air blowing in the hot air treatment, the mixed solvent in the liquid film is quickly volatilized, a large number of crystal nuclei are formed instantaneously, and a perovskite wet film containing a dense intermediate phase and perovskite is deposited. After subsequent annealing, a dense and uniform perovskite film is obtained. The preparation method of the present application not only has a simple process, but also can prepare a dense and uniform perovskite film in a large size in an atmospheric environment.

[0042] In the above step S01, the perovskite precursor liquid is a precursor solution configured from perovskite raw materials. Specifically, a soluble monovalent cation salt and a divalent cation salt (the above-mentioned salt contains a halogen anion) are dissolved in a second solvent to obtain a perovskite precursor liquid.

[0043] In one embodiment, the perovskite precursor solution is obtained by dissolving raw materials AX and PbY2 in a second solvent in a molar ratio of (1-1.5):(1-1.5); wherein A is a monovalent cation selected from at least one of monovalent methylamine (MA), formamidine (FA), cesium (Cs), rubidium (Rb), dimethylamine, guanidine, butylamine, ethylamine, propylenediamine, octylamine, oleylamine, aniline, benzylamine, and the divalent cation is lead ion, and X and Y are halide anions independently selected from at least one of fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). The second solvent can be selected from at least one of dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), gamma-butyrolactone (GBL), N-methyl pyrrolidone (NMP), and ethylene glycol monomethyl ether (EM). In this way, an organic-inorganic hybrid perovskite with better photoelectric properties can be finally obtained. The above-mentioned second solvent can better dissolve monovalent cation salts and divalent cation salts, and the boiling point is higher than that of the first solvent which forms mist.

[0044] The above step S02 is the process of forming a perovskite wet film from the perovskite precursor solution.

[0045] The perovskite precursor solution is coated on the substrate to obtain a liquid film, which is a liquid film formed by the perovskite precursor solution. Spray treatment and hot air treatment are performed on the surface of the liquid film. The solvent mist used in the spray treatment is a mist formed by a first solvent with a low boiling point (lower than the boiling point of the second solvent in the perovskite precursor solution). In this way, the solvent mist enters the surface of the liquid film, and the first solvent and the second solvent in the liquid film form a mixed solvent. Because the boiling point of the first solvent is lower than that of the second solvent, the boiling point of the mixed solvent in the liquid film is reduced, making it easier to evaporate, and the perovskite is more likely to precipitate and crystallize, forming a liquid film that is easy to evaporate and nucleate. Subsequent hot air treatment causes the mixed solvent to evaporate quickly, and a large number of crystal nuclei form instantaneously, thereby forming a dense intermediate phase perovskite wet film.

[0046] In one embodiment, the first solvent is selected from at least one of toluene, chlorobenzene, diethyl ether, chloroform, acetonitrile, ethanol, isopropanol, tert-butanol, n-butanol, 2,2,2-trifluoroethanol, acetone, methyl formate, diethyl carbonate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, and pentyl acetate. The above-mentioned first solvent can form a solvent mist well, and the boiling point is lower than that of the second solvent. For example, in some embodiments of the present application, the first solvent is acetonitrile, ethyl acetate, acetone, or ethanol, and the second solvent is dimethyl sulfoxide and / or N,N-dimethylformamide.

[0047] In an embodiment, the mist in the spraying treatment forms an angle of 45-135° with the liquid film, and the hot air in the hot air treatment forms an angle of 45-135° with the liquid film. In the embodiment of the present application, the mist formed by the first solvent in the spraying treatment can be sprayed on the surface of the liquid film at a certain angle with the liquid film, and the hot air in the hot air treatment can also be blown to the surface of the liquid film at a certain angle with the liquid film. Further, the spraying direction in the spraying treatment is perpendicular to the surface of the liquid film, and the hot air in the hot air treatment is perpendicular to the surface of the liquid film, so that the mist can be mixed with the second solvent more uniformly, and the mixed solvent can be volatilized more uniformly by the hot air. It should be noted that the spraying treatment refers to spraying the first solvent on the surface of the liquid film formed by the perovskite precursor liquid in the form of solvent mist, and the falling speed, area and other manners of the mist are not particularly limited, as long as the first solvent falls on the surface of the liquid film in the form of mist (such as mist curtain), which is within the protection scope of the present application. Similarly, the hot air treatment is also within the protection scope of the present application, as long as the gas falls on the surface of the liquid film in the form of hot air (such as hot air mist).

[0048] In an embodiment, the perovskite precursor liquid can be coated on the substrate by using a coating tool, the spraying treatment can be performed on the surface of the liquid film by using a spraying tool, and the hot air treatment can be performed on the surface of the liquid film by using a hot air tool. Further, in the step of coating the perovskite precursor liquid on the substrate to obtain the liquid film, the liquid film is obtained by doctor blade coating the perovskite precursor liquid, in the step of the spraying treatment, the mist curtain is formed on the liquid film by using a mist curtain knife, and in the step of the hot air treatment, the hot air curtain is formed on the liquid film by using a hot air curtain knife; the doctor blade, the mist curtain knife and the hot air curtain knife are arranged in sequence along the doctor blade coating direction and move at a constant speed. The mist curtain is like a curtain when the mist formed by the first solvent is blown to the wet film, and the hot air curtain is like a curtain when the hot air is blown to the wet film, and the mist curtain and the hot air curtain can be perpendicular to the wet film. In the embodiment, the doctor blade, the mist curtain knife and the hot air curtain knife can move at a constant speed in sequence, or the doctor blade and the mist curtain knife can move at a constant speed first, and then the hot air curtain knife moves after the mist curtain ends.

[0049] As Figure 2As shown, the doctor blade, the mist curtain knife and the hot air curtain knife are sequentially assembled on the blade coating equipment, and the three components are sequentially scraped over the substrate at the same speed. First, the perovskite precursor solution is spread on the substrate by the doctor blade to obtain a stable state liquid film with adjustable thickness, then the liquid film surface is sprayed by a first solvent formed mist curtain, and after mixing, an easily volatile and easily nucleated liquid film is formed. Further, after the liquid film passes through the mist curtain, when it passes through the hot air curtain knife formed by the hot air curtain knife, the mixed solvent removal speed is greatly improved, and the number of nucleation is also greatly improved, forming a more dense intermediate phase perovskite wet film. In this process, by combining the mist curtain of the first solvent and the hot air curtain, the mist curtain of the first solvent lowers the boiling point of the liquid film, and then part of the solvent in the liquid film is removed by the hot air curtain, and subsequent annealing can be further obtained., a dense perovskite film can be obtained. In this way, the boiling point of the liquid film is lowered by the mist curtain of the first solvent, and the volatilization speed of the liquid film is improved by the hot air curtain, so that the number of nucleation of the liquid film can be greatly improved, and a dense and uniform perovskite film can be formed in the air.

[0050] Specifically, the substrate to be coated is fixed on the water platform of the blade coating machine, and the distance between the doctor blade and the substrate is adjustable in the range of 0.001-10mm, for example, the distance between the doctor blade and the substrate can be 0.001-1mm, 0.001-0.1mm, further 0.001-0.01mm, 0.001-0.015mm, 0.001-0.02mm, or 0.001-0.05mm, and the thickness of the liquid film can be adjusted according to the required thickness, and the adjustment accuracy is 0.001mm.

[0051] Specifically, the mist curtain knife and the hot air curtain knife are modified from the air knife, the first solvent ultrasonic mist liquid is used, nitrogen gas is introduced into the mist curtain knife at a flow rate of 0.5-10L / min to form a mist curtain, and a gas with a temperature of 40-120℃ is introduced into the hot air curtain knife at a flow rate of 0.5-20L / min to form a hot air curtain. The perovskite precursor solution is added at the position of the doctor blade, and the stepping motor of the blade coating machine drives the doctor blade and the mist curtain knife to move at a certain speed. After the doctor blade passes, a liquid film with a set thickness is formed on the substrate, and the liquid film contains a large amount of second solvent, has a high boiling point, is stable, and is not easy to precipitate and crystallize. After the mist curtain knife passes, the liquid film is mixed with the first solvent with a low boiling point, thereby adjusting the properties of the liquid film, so that the liquid film has a lower boiling point and is more volatile and more likely to precipitate and crystallize. After the doctor blade and the mist curtain knife move, the hot air curtain knife sweeps over the liquid film at a certain speed, and under the blowing of the high-temperature gas, the mixed solvent in the liquid film volatilizes rapidly when the hot air curtain knife passes, a large number of crystal nuclei are formed instantaneously in the liquid film, and therefore a dense intermediate phase and a brown mixed wet film of perovskite are deposited.

[0052] Further, the moving speed of the scraper is 0.1-200 mm / s, which can further be 10 mm / s, 20 mm / s, 40 mm / s, 50 mm / s, 80 mm / s, 100 mm / s, 150 mm / s, 200 mm / s, etc.; the moving speed of the fog curtain knife is 0.1-200 mm / s, which can further be 10 mm / s, 20 mm / s, 40 mm / s, 50 mm / s, 80 mm / s, 100 mm / s, 150 mm / s, 200 mm / s, etc.; and the moving speed of the hot air curtain knife is 0.1-200 mm / s, which can further be 10 mm / s, 20 mm / s, 40 mm / s, 50 mm / s, 80 mm / s, 100 mm / s, 150 mm / s, 200 mm / s, etc. The scraper and the fog curtain knife can move at the same speed at first, and then the hot air curtain knife moves at a uniform speed after the fog curtain ends. The slit width of the knife edge of the fog curtain knife and the hot air curtain knife can be 0.1-5 mm.

[0053] Further, the distance between the fog curtain knife and the substrate is 1-10 cm, such as 1 cm, 2 cm, 5 cm, 8 cm, 10 cm, etc., and the distance between the hot air curtain knife and the substrate can also be 1-10 cm, such as 1 cm, 2 cm, 5 cm, 8 cm, 10 cm, etc.

[0054] In an embodiment, the hot air temperature in the hot air treatment is 40-120℃, such as 40℃, 50℃, 80℃, 100℃, 110℃, 120℃, etc.; the hot air flow rate in the hot air treatment is 0.5-20 L / min, such as 0.5 L / min, 1 L / min, 5 L / min, 10 L / min, 15 L / min, etc.; and the hot air in the hot air treatment is formed by at least one of dry air, nitrogen, argon, and oxygen.

[0055] Finally, step S03 is an annealing process. The dense perovskite wet film is annealed on a hot stage, and a dense, uniform, high-quality perovskite film can be obtained. In an embodiment, the annealing temperature is 60-250℃, such as 60℃, 120℃, 150℃, 200℃, 220℃, 250℃, etc.

[0056] The application also provides a perovskite film prepared by the above method for preparing a perovskite film.

[0057] The perovskite film of the embodiment of the present application is prepared by the preparation method of the perovskite film specific to the embodiment of the present application. After the perovskite precursor solution is coated, the perovskite film quality is improved and the influence of water vapor in the air on the perovskite film is reduced through the combined action of the spray treatment of the first solvent with a low boiling point and the hot air treatment. Therefore, the perovskite film of the present application has good uniformity and compactness, and has a good application prospect in perovskite devices such as perovskite solar cells.

[0058] The embodiment of the present application provides a preparation method of a perovskite film through the spray treatment of a first solvent with a low boiling point and the hot air treatment when the perovskite precursor solution is coated, which can adapt to the air environment to prepare high-quality organic-inorganic hybrid perovskite films, which is of great significance for the large-scale preparation and commercialization of perovskite solar cells.

[0059] The specific embodiments will be described below.

[0060] Embodiment 1

[0061] Reference Figure 2 A preparation method of a perovskite film, comprising the following steps:

[0062] Step S11: preparing perovskite precursor solution;

[0063] A FAI, 0.21 mmol MAI, 0.06 mmol Csl, 1.1 mmol Pbl2, and 0.2 mmol PbBr2 are dissolved in 300 μL of DMSO and 300 μL of DMF to form a perovskite precursor solution. 0.83 MA 0.17 CsPbI 0.9 Br 0.1 A perovskite precursor solution, 1.03 mmol of FAI, 0.21 mmol of MAI, 0.06 mmol of Csl, 1.1 mmol of Pbl2, and 0.2 mmol of PbBr2 are dissolved in 300 μL of DMSO and 300 μL of DMF, stirred and heated to form a perovskite precursor solution.

[0064] Step S12: coating perovskite wet film;

[0065] The substrate to be scraped is fixed on the water platform of the scraping machine, and the scraper is 5 μm away from the substrate. The acetonitrile ultrasonic mist liquid is passed into the mist curtain knife at a flow rate of 2 L / min by nitrogen, and dry air at a temperature of 60 ℃ is passed into the hot air curtain knife at a flow rate of 10 L / min. The perovskite precursor solution is added at the position of the scraper, and the stepping motor of the scraping machine pushes the scraper and the mist curtain knife at a speed of 50 mm / s. After the scraper passes, a 5 μm thick liquid film is formed on the substrate, and the mist curtain knife mixes the liquid film with lower boiling point acetonitrile. Then, the 60 ℃ dry air at a flow rate of 10 L / min is blown on the liquid film by the hot air curtain knife at a moving speed of 100 mm / s, so that a brown perovskite wet film is obtained.

[0066] Step S3: annealing to obtain perovskite film;

[0067] The brownish perovskite wet film is placed on a hot stage at 100°C to remove residual solvent, and finally a dense and uniform perovskite film is obtained.

[0068] Example 2

[0069] Reference Figure 2 A method for preparing a perovskite film, comprising the following steps:

[0070] Step S21: preparing perovskite precursor solution;

[0071] A MAPbI3perovskite precursor solution with a molar ratio of AX:PbY2=1:1 is configured, 1.2 mmol of MAI and 1.2 mmol of PbI2are dissolved in 700 μL of DMSO and 300 μL of DMF, and stirring and heating are performed to form a perovskite precursor solution.

[0072] Step S22: coating perovskite wet film;

[0073] A substrate to be blade-coated is fixed on the water platform of a blade coater, and the distance between the blade and the substrate is 5 μm. Ethanol is ultrasonically atomized, nitrogen gas is passed into the atomized curtain at a flow rate of 2 L / min, and dry nitrogen gas at a temperature of 60°C is passed into the hot air curtain at a flow rate of 5 L / min. The perovskite precursor solution is added at the position of the blade, and the stepping motor of the blade coater pushes the blade and the atomized curtain at a speed of 50 mm / s. After the blade passes, a liquid film with a thickness of 5 μm is formed on the substrate, and after the atomized curtain passes, the liquid film is mixed with ethanol with a lower boiling point. Dry nitrogen gas at a temperature of 60°C at a flow rate of 10 L / min is blown onto the liquid film by the hot air curtain at a moving speed of 100 mm / s, and a brownish perovskite wet film is obtained.

[0074] Step S23: annealing to obtain perovskite film;

[0075] The brownish perovskite wet film is placed on a hot stage at 110°C to remove residual solvent, and finally a dense and uniform perovskite film is obtained.

[0076] Example 3

[0077] Reference Figure 2 A method for preparing a perovskite film, comprising the following steps:

[0078] Step S31: preparing perovskite precursor solution;

[0079] A FA 0.85 Cs 0.15 PbI 0.9 Br 0.1Perovskite precursor solution, 1.01 mmol of FAI, 0.20 mmol of Csl, 0.14 mmol of FABr, 1.21 mmol of Pbl2, 0.14 mmol of PbBr2 were dissolved in 300 μL of DMSO and 300 μL of DMF, stirred and heated to form a perovskite precursor solution.

[0080] Step S32: coating perovskite wet film;

[0081] The substrate to be blade-coated was fixed on the water platform of the blade coater, and the distance between the blade and the platform was 30 μm. The ethyl acetate ultrasonic mist liquid was passed through the mist curtain knife with nitrogen at a flow rate of 2 L / min, and dry air at a temperature of 60 ℃ was passed through the hot air curtain knife at a flow rate of 5 L / min. The perovskite precursor solution was added at the position of the blade, and the stepping motor of the blade coater pushed the blade and the mist curtain knife at a speed of 20 mm / s. After the blade passed, a liquid film with a thickness of 30 μm was formed on the substrate, and after the mist curtain knife passed, the liquid film mixed with the lower boiling point ethyl acetate. The liquid film was then blown by the hot air curtain knife at a moving speed of 100 mm / s with dry air at a temperature of 60 ℃ and a flow rate of 5 L / min to obtain a perovskite wet film.

[0082] Step S33: annealing to obtain perovskite film;

[0083] The above perovskite wet film was placed on a hot stage at a temperature of 150 ℃ to remove residual solvents, and finally a dense and uniform perovskite film was obtained.

[0084] Example 4

[0085] Reference Figure 2 A method for preparing a perovskite film, comprising the following steps:

[0086] Step S41: preparing perovskite precursor solution;

[0087] FA was configured in a molar ratio of AX:PbY2 = 1:1 0.83 Cs 0.17 RbPbI 0.85 Br 0.15 Perovskite precursor solution, 1.0 mmol of FAI, 0.2 mmol of MABr, 0.1 mmol of Rbl, 1.1 mmol of Pbl2, 0.2 mmol of PbBr2 were dissolved in 200 μL of DMSO and 400 μL of DMF, stirred and heated to form a perovskite precursor solution.

[0088] Step S42: coating perovskite wet film;

[0089] The substrate to be blade-coated is fixed on the water platform of the blade coater, and the distance between the blade and the platform is 5 μm. The ethyl acetate ultrasonic mist liquid is passed into the mist curtain knife with nitrogen at a flow rate of 5 L / min, and dry air at a temperature of 60 ℃ is passed into the hot air curtain knife at a flow rate of 5 L / min. The perovskite precursor liquid is added at the position of the blade, and the stepping motor of the blade coater pushes the blade and the mist curtain knife at a speed of 100 mm / s. After the blade passes, a liquid film with a thickness of 5 μm is formed on the substrate, and the liquid film is mixed with lower boiling point ethyl acetate after the mist curtain knife passes. The liquid film is then swept by the hot air curtain knife of dry air at a temperature of 60 ℃ at a moving speed of 100 mm / s, and a perovskite wet film is obtained.

[0090] Step S43: annealing to obtain perovskite film;

[0091] The perovskite wet film is placed on a hot stage at a temperature of 130 ℃ to remove residual solvent, and a dense and uniform perovskite film is finally obtained.

[0092] Example 5

[0093] Reference Figure 2 A method for preparing a perovskite film, comprising the following steps:

[0094] Step S51: preparing perovskite precursor solution;

[0095] FAI, MABr, MACl, PbI2, and PbBr2 are dissolved in 100 μL of DMSO and 800 μL of DMF to form a perovskite precursor liquid. 0.88 MA 0.12 PbI 0.92 Br 0.06 Cl 0.01 A perovskite precursor liquid is prepared by dissolving 1.4 mmol of FAI, 0.1 mmol of MABr, 0.1 mmol of MACl, 1.5 mmol of PbI2, and 0.1 mmol of PbBr2 in 100 μL of DMSO and 800 μL of DMF, stirring, and heating.

[0096] Step S52: coating perovskite wet film;

[0097] The substrate to be blade-coated is fixed on the water platform of the blade coater, and the distance between the blade and the platform is 10 μm. The acetone ultrasonic mist liquid is passed into the mist curtain knife with nitrogen at a flow rate of 3 L / min, and dry air at a temperature of 80 ℃ is passed into the hot air curtain knife at a flow rate of 3 L / min. The perovskite precursor liquid is added at the position of the blade, and the stepping motor of the blade coater pushes the blade and the mist curtain knife at a speed of 80 mm / s. After the blade passes, a liquid film with a thickness of 10 μm is formed on the substrate, and the liquid film is mixed with lower boiling point acetone after the mist curtain knife passes. The liquid film is then swept by the hot air curtain knife of dry air at a temperature of 80 ℃ at a moving speed of 100 mm / s, and a perovskite wet film is obtained.

[0098] Step S53: annealing to obtain high-quality perovskite film;

[0099] The perovskite wet film is removed of residual solvent on a hot stage at a temperature of 105°C, and a dense, uniform perovskite film is finally obtained.

[0100] Example 6

[0101] Referring to Figure 2 A method for preparing a perovskite film includes the following steps:

[0102] Step S61: preparing perovskite precursor solution;

[0103] A CsPbI2Br perovskite precursor solution with a molar ratio of AX:PbY2=1.5:1 of CsI excess is configured, 1 mmol of PbI2 and 1 mmol of CsBr are dissolved in 1 mL of DMSO, stirred and heated to form a solution, and then 0.5 mmol of CsI is added to the solution, stirred and heated to form a perovskite precursor solution.

[0104] Step S62: coating perovskite wet film;

[0105] A substrate to be blade coated is fixed on a water platform of a blade coater, and the distance between the blade and the platform is 15 μm. Ethanol is ultrasonically atomized, nitrogen gas is passed into the atomized curtain at a flow rate of 2 L / min, and dry air at a temperature of 100°C is passed into the hot air curtain at a flow rate of 15 L / min. The perovskite precursor solution is added at the position of the blade, and the stepping motor of the blade coater pushes the blade at a speed of 20 mm / s, and the atomized curtain moves at a constant speed. After the blade passes, a liquid film with a thickness of 15 μm is formed on the substrate, and after the atomized curtain passes, the liquid film is mixed with ethanol with a lower boiling point. The liquid film is blown by the hot air curtain at a moving speed of 100 mm / s with dry air at a temperature of 100°C and a flow rate of 15 L / min, and a perovskite wet film is obtained.

[0106] Step S63: annealing to obtain perovskite film;

[0107] The perovskite wet film is removed of residual solvent on a hot stage at a temperature of 190°C, and a dense, uniform perovskite film is finally obtained.

[0108] Comparative Example 1

[0109] A method for preparing a perovskite film includes the following steps:

[0110] Preparation of perovskite precursor solution: A FA 0.83 MA 0.17 CsPbI 0.9 Br 0.1Perovskite precursor solution, 1.03 mmol of FAI, 0.21 mmol of MAI, 0.06 mmol of CsI, 1.1 mmol of PbI2, and 0.2 mmol of PbBr2 were dissolved in 300 μL of DMSO and 300 μL of DMF, stirred and heated to form a perovskite precursor solution.

[0111] Coating of perovskite wet film: The substrate to be scraped was fixed on the water platform of the scraping machine, and the scraper was 5 μm away from the substrate. The perovskite precursor solution was added at the position of the scraper, and the stepping motor of the scraping machine pushed the scraper at a speed of 50 mm / s to obtain a perovskite wet film.

[0112] Annealing to obtain perovskite film: The perovskite wet film was placed on a hot stage at 100°C to remove the solvent, and finally a perovskite film was obtained.

[0113] Comparative analysis

[0114] Taking Example 1 as an example, the SEM image of the perovskite film obtained in Example 1 is shown in Figure 3 , the ultraviolet-visible absorption spectrum is shown in Figure 4 , and the XRD spectrum is shown in Figure 5 . The SEM image of the perovskite film obtained in Comparative Example 1 is shown in Figure 6 . By comparison, it can be seen that the perovskite film obtained in Example 1 is dense and uniform, while in Comparative Example 1, although a certain thickness of liquid film is scraped by the scraper, the solvent in the liquid film is difficult to volatilize, and the volatilization speed of the solvent in the annealing step is difficult to meet the requirement of forming a large number of crystal nuclei, so it is difficult to form a dense perovskite film.

[0115] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for producing a perovskite film, characterized by, The method comprises the following steps: providing a perovskite precursor solution; coating the perovskite precursor solution on a substrate to obtain a liquid film, performing a spray treatment on the surface of the liquid film, and then performing a hot air treatment to obtain a perovskite wet film; wherein the spray treatment uses a first solvent to form mist, the boiling point of the first solvent is lower than the boiling point of a second solvent in the perovskite precursor solution, and the first solvent is selected from at least one of diethyl ether, acetonitrile, tert-butyl alcohol, n-butyl alcohol, 2,2,2-trifluoroethanol, acetone, methyl formate, diethyl carbonate, methyl acetate, propyl acetate, butyl acetate, and amyl acetate; in the step of coating the perovskite precursor solution on a substrate to obtain a liquid film, the perovskite precursor solution is coated on the substrate to obtain the liquid film by using a doctor blade; in the step of the spray treatment, a mist curtain is formed on the liquid film by using a mist curtain knife; in the step of the hot air treatment, a hot air curtain is formed on the liquid film by using a hot air curtain knife; the doctor blade, the mist curtain knife, and the hot air curtain knife are arranged in sequence along the direction of the doctor blade coating, and move at a uniform speed; the moving speed of the doctor blade and the moving speed of the mist curtain knife are the same, and are 20-200 mm / s; the hot air curtain knife moves at a uniform speed after the mist curtain ends; performing an annealing treatment on the perovskite wet film to obtain a perovskite film.

2. The production method according to claim 1, wherein The direction of the mist in the spray treatment is at an angle of 45-135° with the horizontal plane of the liquid film, and the direction of the hot air in the hot air treatment is at an angle of 45-135° with the liquid film.

3. The production method according to claim 1, wherein The moving speed of the hot air curtain knife is 0.1-200 mm / s.

4. The production method according to claim 1, wherein The distance between the doctor blade and the substrate is 0.001-10 mm, the distance between the mist curtain knife and the substrate is 1-10 cm, and the distance between the hot air curtain knife and the substrate is 1-10 cm.

5. The production method according to claim 1, wherein The temperature of the hot air in the hot air treatment is 40-120℃; and / or, The flow rate of the hot air in the hot air treatment is 0.5-20 L / min; and / or, The hot air in the hot air treatment is formed by at least one of dry air, nitrogen, argon, and oxygen.

6. The production method according to any one of claims 1 to 5, wherein The second solvent is selected from at least one of dimethyl sulfoxide, N,N-dimethylformamide, gamma butyrolactone, azamethyline pyrrolidone, and ethylene glycol monomethyl ether.

7. The production method according to any one of claims 1 to 5, wherein The perovskite precursor solution is obtained by dissolving raw materials AX and PbY2 in the second solvent at a molar ratio of (1-1.5):(1-1.5); wherein A is selected from at least one of methylamine, formamidine, cesium, rubidium, dimethylamine, guanidine, butylamine, ethylamine, propylenediamine, octylamine, oleylamine, aniline, and benzylamine, and X and Y are independently selected from at least one of fluorine, chlorine, bromine, and iodine.

8. The production method according to any one of claims 1 to 5, wherein The method is characterized in that, The temperature of the annealing treatment is 60-250℃.

9. A perovskite film, characterized by, The perovskite film is prepared by the method of any one of claims 1-8.

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