CN115915881A

CN115915881A - Perovskite thin film and preparation method and application thereof

Info

Publication number: CN115915881A
Application number: CN202211695811.9A
Authority: CN
Inventors: 王良乐; 邵君; 于振瑞
Original assignee: Wuxi Utmolight Technology Co Ltd
Current assignee: Wuxi Utmolight Technology Co Ltd
Priority date: 2022-12-28
Filing date: 2022-12-28
Publication date: 2023-04-04

Abstract

The invention discloses a perovskite thin film and a preparation method and application thereof. The preparation method comprises the following steps: forming a metal halide film on a substrate; (2) Applying an organic halide solution on the metal halide thin film to form an organic halide thin film on the metal halide thin film; (3) Annealing the substrate material prepared in the step (2) to obtain a perovskite thin film; wherein in the step (2), the temperature of the organic halide solution is controlled to be 40-100 ℃. The method is simple in process, can be applied in a large scale, is suitable for preparing the perovskite thin film in a large area, and the prepared perovskite thin film is good in uniformity, high in crystallization and excellent in battery efficiency, and has large-size perovskite crystals.

Description

Perovskite thin film and preparation method and application thereof

Technical Field

The invention belongs to the technical field of solar cells, and particularly relates to a perovskite thin film and a preparation method and application thereof.

Background

Since the invention of the perovskite solar cell in 2009, the rapid increase of the photoelectric conversion efficiency thereof has been widely noticed and studied by academia and industry. The existing method for preparing the perovskite solar cell mainly focuses on a one-step method and a two-step method, compared with the one-step method, the perovskite thin film prepared by the two-step method can obtain larger crystal size, and the perovskite layer in the world recording efficiency of the perovskite/crystalline silicon lamination is prepared by the two-step method. The current two-step method mainly comprises a solution-solution two-step method and a vacuum-solution two-step method, wherein the vacuum-solution two-step method can easily prepare uniform perovskite thin films on the surface of an uneven substrate, and the large-area preparation is simple, so that the method becomes the key point of research. However, the vacuum-solution two-step method has not made a great breakthrough in cell efficiency at present, and particularly, related reports on a large area are very rare at present. Therefore, how to further improve the device efficiency of the two-step method becomes the key point of research, and how to solve the problem of large-area preparation is also the necessary way to realize industrialization.

At the present stage, when the perovskite thin film is prepared by the two-step solution method, the wettability requirements of the precursor solution in the first step on the substrate are high whether spin coating or blade coating, and the prepared film layer is easy to form pinholes, so that the film preparation in the second step is influenced, and the efficiency of a device is finally influenced. The vacuum-solution two-step method is not so high in the wettability and surface smoothness requirements of the substrate when the vacuum evaporation method is adopted in the first step, but the organic ink coating in the second step has disadvantages. Mainly, when the perovskite thin film is prepared in a large area, the viscosity of organic ink is not high, the volatility of the used solvent is strong, and in the coating process, the uneven volatilization of the solvent can cause the drift of solid solute therein, so that the metal halide in the first step and the organic material in the second step can not react uniformly, thereby influencing the uniformity of large-area film formation. In addition, because the organic solvent is volatile, the solute is easy to crystallize and difficult to clean in the coating knife head and the liquid outlet knife opening due to the volatilization of the reagent, so that the solute is brought into a coating area during coating to influence the coating effect, and the large-area film forming quality is also influenced.

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, the invention aims to provide a perovskite thin film and a preparation method and application thereof. The method has simple process, can be applied in large scale, is suitable for preparing the perovskite thin film in large area, has good uniformity and high crystallization of the prepared perovskite thin film, has large-size perovskite crystals, and has excellent battery efficiency of the battery prepared by the perovskite thin film.

In one aspect of the invention, a method of making a perovskite thin film is provided. According to an embodiment of the invention, the method comprises:

(1) Forming a metal halide film on a substrate;

(2) Applying an organic halide solution on the metal halide thin film to form an organic halide thin film on the metal halide thin film;

(3) Annealing the substrate material prepared in the step (2) to obtain a perovskite thin film;

wherein in the step (2), the temperature of the organic halide solution is controlled to be 40-100 ℃.

According to the method for preparing the perovskite thin film of the embodiment of the invention, firstly, the metal halide thin film is formed on the substrate, then the organic halide solution is applied on the metal halide thin film, so that the organic halide thin film is formed on the metal halide thin film, and finally, the substrate material is annealed, so that the perovskite thin film is prepared. The inventor finds that controlling the temperature of the organic halide solution to be 40-100 ℃ is beneficial to preparing a high-quality perovskite thin film, and particularly, firstly, controlling the temperature of the organic halide solution is beneficial to uniformly volatilizing the solvent of the organic halide solution, simultaneously improving the solubility of the organic halide in the solvent, enabling the organic halide not to be easily separated out, avoiding the drift of the organic halide in the solution, enabling the metal halide and the organic halide to be uniformly reacted, thereby obtaining the perovskite thin film with good uniformity, simultaneously preventing the organic halide from being separated out at a liquid outlet knife edge, improving the crystallinity of the perovskite thin film, prolonging the service life of a current carrier and prolonging the diffusion length; secondly, controlling the temperature of the organic halide solution applied to the metal halide film is beneficial to the organic halide solution to perform one-time interface correction on the metal halide film, so that a better interface is formed between different film layers and a better crystal boundary is formed between different crystal grains in the same film layer, and the perovskite film with better performance is beneficial to being prepared; thirdly, controlling the temperature of the organic halide solution can enable the organic halide to form small particles more easily, according to the Ostwald ripening growth mechanism, the small particles have higher chemical potential, solubility and surface energy and have the tendency of dissolving and redepositing on the surface of the large particles of the organic halide, so that large-size perovskite crystal nuclei are more easily formed, and meanwhile, the ionic state of the organic halide in the solution is increased, the reaction with metal ions in the metal halide layer is promoted, the rapid nucleation of the perovskite is facilitated, and large-size perovskite crystals are formed; and finally, when the organic halide solution is applied to the metal halide film at room temperature, the solution can be rapidly cooled to assist rapid nucleation of the perovskite, and the highly-crystallized perovskite film is formed. Therefore, the method is simple in process, can be applied in large scale, is suitable for preparing the perovskite thin film in large area, and the prepared perovskite thin film is good in uniformity, high in crystallization and provided with large-size perovskite crystals.

In addition, the method for preparing the perovskite thin film according to the above embodiment of the invention may further have the following technical features:

in some embodiments of the invention, in step (1), the metal halide comprises at least one of lead iodide, lead chloride and lead bromide.

In some embodiments of the present invention, in step (1), the metal halide further comprises at least one of rubidium chloride, cesium iodide, cesium chloride and cesium bromide.

In some embodiments of the present invention, the metal halide thin film has a dry film thickness of 100 to 800nm. Thus, a high-quality perovskite thin film can be prepared.

In some embodiments of the invention, in step (2), the temperature of the organic halide solution is controlled to be 50 to 80 ℃, preferably 60 ℃. Therefore, the perovskite thin film with good uniformity, high crystallization and large size perovskite crystals can be prepared.

In some embodiments of the invention, in step (2), the concentration of the organic halide solution is 0.1 to 1.5mol/L. Thus, a high-quality perovskite thin film can be prepared.

In some embodiments of the present invention, in step (2), the organic halide comprises at least one, preferably 3, of iodomethylamine, iodoformamidine, bromomethylamine, bromoformamidine, chloromethylamine, and chloroformamidine.

In some embodiments of the present invention, in step (2), the solvent of the organic halide solution comprises at least one, preferably at least 2, of N, N-dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, 1, 3-dimethyl-2-imidazolidinone, ethylene glycol methyl ether, diethyl ether, lutidine N-oxide, ethyl acetate, N-propanol, isopropanol, 1, 2-propanediol, N-butanol, 2-butanol, N-hexane, chlorobenzene, 2-pentanol, methanol, t-butanol, acetonitrile and ethanol.

In some embodiments of the present invention, in the step (2), the dry film thickness of the organic halide thin film is 50 to 700nm. Thus, a high-quality perovskite thin film can be prepared.

In some embodiments of the present invention, in the step (3), the annealing temperature is 100 to 180 ℃. Thus, a high-quality perovskite thin film can be prepared.

In a second aspect of the invention, a perovskite thin film is provided. According to the embodiment of the invention, the perovskite thin film is prepared by the method. Therefore, the perovskite thin film has good uniformity, high crystallization and large-size perovskite crystals.

In a third aspect of the invention, a perovskite solar cell is presented. According to an embodiment of the present invention, the battery has the perovskite thin film prepared by the above method or the above perovskite thin film. Thus, the battery has excellent battery efficiency.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a process diagram of slot coating of a metal halide film with an organic halide solution according to an embodiment of the present invention;

FIG. 2 is a diagram of a process for doctor-coating a metal halide film with an organic halide solution according to an embodiment of the invention;

FIG. 3 is a graph of current density versus voltage for solar cells of example 1, example 6 and comparative examples 1-2 of the present invention;

FIG. 4 is a graph showing the results of absorbance tests of the perovskite thin films of example 1 of the present invention and comparative examples 1 to 2;

FIG. 5 is an SEM image of perovskite thin films of example 1 of the present invention and comparative examples 1-2.

Detailed Description

The following detailed description of the embodiments of the invention is intended to be illustrative, and not to be construed as limiting the invention.

s100: forming a metal halide film on a substrate

In this step, a metal halide thin film is formed on a substrate, and further, the dry film thickness of the metal halide thin film is controlled to be 100 to 800nm. The method for forming the metal halide thin film on the substrate may be a solution method or a vacuum method, and a vacuum method including a vacuum evaporation method, a near space sublimation method, an ion sputtering method, a gas phase transport method, and the like is preferable. It will be understood by those skilled in the art that the metal halide is a conventional material in the art, and may be selected by those skilled in the art according to the actual application, for example, the metal halide includes at least one of lead iodide, lead chloride and lead bromide, and further, the metal halideThe compound further includes at least one of rubidium chloride, cesium iodide, cesium chloride, and cesium bromide. Meanwhile, the specific preparation method and the process conditions can be selected by the skilled person according to the actual conditions. For example, if a metal halide film, pbI, is to be formed on a substrate by vacuum evaporation, close-space sublimation, ion sputtering or vapor transport ₂ 、PbCl ₂ 、PbBr ₂ The optimal evaporation rate range of the RbCl material is 1-20A/s, the optimal evaporation rate range of the CsI, csCl and CsBr materials is 0.1-1A/s, and the deposition sequence of different metal halides is not limited; if prepared by a wet film-forming method such as slot coating and wire bar or doctor blade, the coating speed is 5-50mm/s, preferably 30mm/s, the coating annealing temperature is 50-100 deg.C, preferably 70 deg.C, and the metal halide includes PbI ₂ 、PbCl ₂ And PbBr ₂ Further, the metal halide further includes at least one of RbCl, csI, csCl, and CsBr, and the solvent includes at least one of N, N-Dimethylformamide (DMF), dimethylsulfoxide (DMSO), γ -butyrolactone, N-methylpyrrolidone (NMP), 1, 3-dimethyl-2-imidazolidinone (DMI), ethylene glycol methyl ether (2-ME), diethyl ether, lutidine N-oxide (DMPO), ethyl acetate, N-propanol, isopropanol (IPA), 1, 2-propanediol, N-butanol, 2-butanol, N-hexane, chlorobenzene, 2-pentanol, methanol, t-butanol, acetonitrile, or ethanol.

S200: application of organic halide solutions to metal halide films

In this step, an organic halide solution is applied to the metal halide thin film to form an organic halide thin film on the metal halide thin film, wherein the temperature of the organic halide solution is controlled to be 40 to 100 ℃, preferably 50 to 80 ℃, and more preferably 60 ℃. The inventor finds that controlling the temperature of the organic halide solution to be 40-100 ℃ is beneficial to preparing a high-quality perovskite thin film, and particularly, firstly, controlling the temperature of the organic halide solution is beneficial to uniformly volatilizing the solvent of the organic halide solution, simultaneously improving the solubility of the organic halide in the solvent, enabling the organic halide not to be easily separated out, avoiding the drift of the organic halide in the solution, enabling the metal halide and the organic halide to be uniformly reacted, thereby obtaining the perovskite thin film with good uniformity, simultaneously preventing the organic halide from being separated out at a liquid outlet knife edge, improving the crystallinity of the perovskite thin film, prolonging the service life of a current carrier and prolonging the diffusion length; secondly, controlling the temperature of the organic halide solution applied to the metal halide film is beneficial to the organic halide solution to perform one-time interface correction on the metal halide film, so that a better interface is formed between different film layers and a better crystal boundary is formed between different crystal grains in the same film layer, and the perovskite film with better performance is beneficial to being prepared; thirdly, controlling the temperature of the organic halide solution can enable the organic halide to form small particles more easily, according to the Ostwald ripening growth mechanism, the small particles have higher chemical potential, solubility and surface energy and have the tendency of dissolving and redepositing on the surface of the large particles of the organic halide, so that large-size perovskite crystal nuclei are more easily formed, and meanwhile, the ionic state of the organic halide in the solution is increased, the reaction with metal ions in the metal halide layer is promoted, the rapid nucleation of the perovskite is facilitated, and large-size perovskite crystals are formed; and finally, when the organic halide solution is applied to the metal halide film at room temperature, the solution can be rapidly cooled to assist rapid nucleation of the perovskite, and the highly-crystallized perovskite film is formed.

It should be noted that the organic halide and the solvent are conventional materials in the art, and may be selected by those skilled in the art according to the actual application. For example, the organic halide includes at least one of iodomethylamine (MAI), iodoformamidine (FAI), bromomethylamine (MABr), bromoformamidine (FABr), chloromethylamine (MACl), and chloromethylamidine (FACl), preferably 3. The solvent includes at least one of N, N-Dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), 1, 3-dimethyl-2-imidazolidinone (DMI), ethylene glycol methyl ether (2-ME), diethyl ether, lutidine N-oxide (DMPO), ethyl acetate, N-propanol, isopropyl alcohol (IPA), 1, 2-propanediol, N-butanol, 2-butanol, N-hexane, chlorobenzene, 2-pentanol, methanol, t-butanol, acetonitrile and ethanol, preferably at least 2.

It will be appreciated by those skilled in the art that the method of applying the organic halide solution to the metal halide film is conventional and can be selected by those skilled in the art according to the application, for example, by slot coating, knife coating, spraying, or dipping. Specifically, for example, referring to fig. 1, the prepared organic halide solution is injected into a heatable container bottle 100 to be heated and maintained, sucked by a syringe 200 and injected into a coating blade 300 by a slit coating process, the coating blade 300 may be a blade having a micro-heating function, the organic halide solution discharged is guaranteed to have a certain temperature, the organic halide solution at a certain temperature is coated on a metal halide thin film 400 at room temperature by the blade, and then a dense and uniform perovskite thin film is formed by annealing. For another example, referring to fig. 2, the prepared organic halide solution is poured into a heatable bottle to be heated and kept warm by using a doctor blade process, and then the pipetting gun 500 sucks the organic halide solution with a certain temperature to the doctor blade bar 600, and the organic halide solution with a certain temperature is doctor-coated on the metal halide film 700 at room temperature as the doctor blade bar 600 moves horizontally, and then a dense and uniform perovskite film is formed by annealing.

According to an embodiment of the invention, the concentration of the organic halide solution is 0.1 to 1.5mol/L. The inventor finds that the content of solid solution in the organic halide solution needs to be kept in a proper proportion with the metal halide to react to form a better perovskite film, and if the concentration of the organic halide solution is too high, the amount of the organic halide solution needed is reduced, so that the organic halide solution is difficult to be laid on the metal halide well to form a uniform wet film; if the concentration of the organic halide solution is too low, the required amount of the organic halide solution is large, and if the amount of the organic halide solution is too large, a thick wet film is formed on the surface of the metal halide, which is not favorable for uniform volatilization of the solvent, and the solution may shake on the surface of the metal halide, so that the solid solution is not uniform, and the large-area uniformity is affected. Therefore, the organic halide solution with the concentration of 0.1-1.5 mol/L is adopted, and the high-quality perovskite thin film can be prepared. Further, in order to prepare a high-quality perovskite thin film, the dry film thickness of the organic halide thin film is controlled to be 50-700 nm.

S300: annealing the substrate material

In the step, the substrate material prepared in the step S200 is annealed, and the annealing temperature is controlled to be 100-180 ℃, so that the perovskite thin film is prepared. It should be noted that the selection of annealing equipment and annealing-related processes is conventional in the art, and those skilled in the art can select specific annealing equipment and related process parameters according to actual practice.

Therefore, the method is simple in process, can be applied in large scale, is suitable for preparing the perovskite thin film in large area, and the prepared perovskite thin film is good in uniformity, high in crystallization and provided with large-size perovskite crystals.

In a second aspect of the invention, a perovskite thin film is provided. According to the embodiment of the invention, the perovskite thin film is prepared by the method. Therefore, the perovskite thin film has good uniformity, high crystallization and large-size perovskite crystals. It should be noted that the features and advantages described for the above method for preparing a perovskite thin film are also applicable to the perovskite thin film, and are not described herein again.

In a third aspect of the invention, a perovskite solar cell is presented. According to an embodiment of the present invention, the battery has the perovskite thin film prepared by the above method or the above perovskite thin film. Thus, the battery has excellent battery efficiency. It should be noted that the features and advantages described above for the perovskite thin film and the preparation method thereof are also applicable to the perovskite solar cell, and are not described herein again.

The invention will now be described with reference to specific examples, which are intended to be illustrative only and not to be limiting in any way.

Example 1

Preparing a layer of tin oxide film (SnO) on FTO conductive glass by using a chemical bath deposition method ₂ ) Then coated with SnO ₂ FTO glass of the film is transferred to a substrate carrier of a close space sublimation system (CSS) and the substrate enters a preparation chamberAnd then, closing the valve, vacuumizing the preparation chamber, opening the valves of the preparation chamber and the CSS chamber or the vapor deposition chamber after the preparation chamber and the CSS chamber or the vapor deposition chamber are vacuumized to a certain vacuum degree, and beginning to deposit the metal halide preset layer film after the substrate enters the CSS chamber or the vapor deposition chamber. The component is PbI ₂ 350nm thick, pbI ₂ The sublimation source temperature was 350 ℃ and the substrate stage temperature was set at room temperature (25 ℃). Then, the organic halide solution with the temperature of 60 ℃ is scraped to the PbI with the room temperature by a scraping device ₂ On the film, the organic halide solution solute is FAI/MAI/MACl, the solvent is IPA solution, the concentration is 0.5mol/L, the coating speed is 30mm/s, the glue dropping amount per second is 40 mu L/s, the gap is 100 mu m, and the dry film thickness of the organic halide film is controlled to be 200nm. And immediately transferring the substrate into an annealing furnace after the organic halide solution is coated, and carrying out chemical reaction on the metal halide and the organic halide to form the perovskite film under the heating action of a temperature control box at the temperature of 150 ℃. Then 22'77' -tetrakis [ NN-bis (4-methoxyphenyl) amino ] with the thickness of 250nm is coated on the perovskite film]And (3) preparing the Perovskite Solar Cells (PSCs) by-99' -spirobifluorene (Spiro-OMeTAD) and finally evaporating 60nm of Au as an electrode.

Example 2

Example 2 differs from example 1 in that: then the organic halide solution with the temperature of 40 ℃ is coated on the PbI with the room temperature by a blade coating device ₂ On the film.

Example 3

Example 3 differs from example 1 in that: then the organic halide solution with the temperature of 50 ℃ is coated on the PbI with the room temperature by a blade coating device ₂ On the film.

Example 4

Example 4 differs from example 1 in that: then the organic halide solution with the temperature of 80 ℃ is scraped to PbI with the room temperature by a scraping device ₂ On the film.

Example 5

Example 5 differs from example 1 in that: then, the organic halide solution with the temperature of 100 ℃ is scraped to the PbI with the room temperature by a scraping device ₂ On the film.

Example 6

Preparing a layer of nickel oxide film (NiOx) on FTO conductive glass by a magnetron sputtering method, then transferring the FTO glass coated with the NiOx film to a substrate carrying table of near space sublimation equipment (CSS), closing a valve after a substrate enters a preparation chamber, vacuumizing the preparation chamber, opening the valve of the preparation chamber and a CSS chamber or a vapor deposition chamber after vacuumizing to a certain vacuum degree, and beginning to deposit a metal halide film layer after the substrate enters the CSS chamber or the vapor deposition chamber. The component is PbI ₂ Thickness of 350nm, pbI ₂ The sublimation source temperature was 350 ℃ and the substrate stage temperature was set at room temperature (25 ℃). Then coating the organic ink with the temperature of 60 ℃ on PbI at room temperature by using slot die equipment ₂ On the film, the solute of the organic halide solution is FAI/MAI/MACl; the solvents were IPA and DMSO solutions, and the ratio per ml was 975:25ul of organic halide solution, the concentration of the organic halide solution is 0.5mol/L, the coating speed is 30mm/s, the glue dropping amount per second is 40 mu L/s, the gap is 100 mu m, and the dry film thickness of the organic halide film is controlled to be 200nm. And immediately transferring the substrate into an annealing furnace after the organic halide solution is coated, and carrying out chemical reaction on the organic precursor and the inorganic precursor to form the perovskite film under the heating action of a temperature control box at the temperature of 150 ℃. Then evaporating and plating a layer of C with the thickness of 25nm on the perovskite film ₆₀ And 5.3nm BCP is used as an electron transport layer, and finally a layer of 80nm Cu is evaporated and used as an electrode, so that the Perovskite Solar Cells (PSCs) are prepared.

Comparative example 1

Comparative example 1 differs from example 1 in that: the organic halide solution at room temperature (25 ℃) was knife coated to room temperature PbI using a knife coating apparatus ₂ On the film.

Comparative example 2

Comparative example 2 differs from example 1 in that: the organic halide solution with the temperature of 120 ℃ is coated on the PbI with the room temperature by a blade coating device ₂ On the film.

The solar cells prepared in examples 1-2 and comparative examples 1-2 were measured for their performance, and the results are shown in table 1.

TABLE 1

As can be seen from table 1 and fig. 2, the efficiency of the battery obtained by the method of the present application, i.e. by heating the solution at a reasonable temperature range (40-100 ℃), is increased compared to the room temperature, which is mainly reflected in the current, because the perovskite thin film obtained by the method has better quality and stronger light absorption capability, and once the temperature exceeds the adaptive temperature (120 ℃), the efficiency of the battery is also severely reduced, mainly because the film forming property of the perovskite thin film is not good, the current is greatly reduced, and the reduction of the Fill Factor (FF) is also caused by the poor contact at the interface and the increase of defects due to the poor film surface of the perovskite thin film.

From fig. 4 it can be seen that the absorption capacity of the perovskite thin film obtained by the method of the present application is increased, but too high temperature in turn destroys the perovskite crystals, resulting in poorer perovskite thin films, leading to a reduction of the absorption capacity, which is also in line with the data in table 1, further confirming our conclusion. Fig. 5 shows several typical perovskite thin films, from which it can be seen that the perovskite thin film obtained by the scheme of the present application exhibits larger crystal grains than the thin film of comparative example 1 at room temperature, while the defects at the grain boundaries are significantly reduced, which is benefited by the better reaction of the metal halide thin film in hot solution, and above the reasonable temperature range (100 ℃), as seen in comparative example 2, the quality of the perovskite thin film starts to deteriorate, the inter-grain gaps increase, which greatly increases the recombination of carriers, which in turn affects the battery efficiency.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. A method of making a perovskite thin film, comprising:

(1) Forming a metal halide film on a substrate;

2. The method of claim 1, wherein in step (1), the metal halide comprises at least one of lead iodide, lead chloride, and lead bromide;

optionally, the metal halide further comprises at least one of rubidium chloride, cesium iodide, cesium chloride, and cesium bromide;

optionally, the dry film thickness of the metal halide thin film is 100 to 800nm.

3. The method according to claim 1, wherein in step (2), the temperature of the organic halide solution is controlled to be 50 to 80 ℃, preferably 60 ℃.

4. The method according to claim 1 or 3, wherein in the step (2), the concentration of the organic halide solution is 0.1 to 1.5mol/L.

5. The method of claim 1, wherein in step (2), the organic halide comprises at least one, preferably 3, of iodomethylamine, iodoformamidine, bromomethylamine, bromoformamidine, chloromethane, and chloroformamidine.

6. The method according to claim 1 or 5, wherein in the step (2), the solvent of the organic halide solution comprises at least one, preferably at least 2, of N, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 1, 3-dimethyl-2-imidazolidinone, ethylene glycol methyl ether, diethyl ether, lutidine N-oxide, ethyl acetate, N-propanol, isopropanol, 1, 2-propanediol, N-butanol, 2-butanol, N-hexane, chlorobenzene, 2-pentanol, methanol, t-butanol, acetonitrile and ethanol.

7. The method according to claim 1 or 5, wherein in the step (2), the dry film thickness of the organic halide thin film is 50 to 700nm.

8. The method of claim 1, wherein in step (3), the annealing temperature is 100 to 180 ℃.

9. A perovskite thin film produced by the method according to any one of claims 1 to 8.

10. A perovskite solar cell, characterized by having a perovskite thin film produced by the method of any one of claims 1 to 8 or the perovskite thin film of claim 9.