Preparation method of perovskite thin film and perovskite battery

Abstract

The invention discloses a preparation method of a perovskite thin film and a perovskite cell, and relates to the technical field of solar cells. The preparation method of the perovskite thin film comprises the following steps: forming a mixed layer containing PbI2 on a substrate as a metal halide framework layer; coating the metal halide framework layer with an organic ammonium salt solution containing a crystallization regulating agent to obtain a first device; wherein the crystallization regulating agent contains a guanidine group; and carrying out annealing treatment on the first device to obtain the perovskite thin film. According to the perovskite thin film, the problems that perovskite prepared in the prior art is small in grain size and uneven in interface can be solved, and the performance of the perovskite thin film is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a method for preparing a perovskite thin film and a perovskite cell. Background Art

[0002] Perovskite solar cells utilize perovskite-type organic metal halide semiconductors as light-absorbing materials. They belong to the third generation of solar cells and are also known as new-concept solar cells. Due to their excellent light absorption and charge transfer rates, as well as their enormous development potential, perovskite solar cells have been hailed as "a new hope in the photovoltaic field."

[0003] Existing perovskite cells typically use a one-step or two-step method to prepare perovskite films. However, in the existing one-step process for preparing perovskite films, additives are added to the perovskite solution and directly interact with PbI2. Although this can reduce defects and improve battery performance, it is limited to preparing the perovskite layer from a full solution, and its grain morphology does not change significantly, resulting in poor flatness of the surface morphology of the perovskite film. The existing two-step process for preparing perovskite films typically involves reacting an organic ammonium halide with PbI2 to form a perovskite film. However, due to the rapid reaction between the organic ammonium salt and PbI2, a large number of crystal nuclei are easily generated, resulting in poor grains of the formed perovskite film (including small grains and an uneven surface). This can lead to many grain boundary defects and poor contact with the charge transfer layer. Therefore, how to provide a new method for preparing perovskite films to increase the grain size and make the surface morphology smoother is a technical problem that needs to be solved urgently. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing a perovskite film and a perovskite battery, which can improve the problems of small perovskite grains and uneven interface prepared by the prior art and improve the performance of the perovskite film.

[0005] The embodiment of the present invention is achieved as follows:

[0006] One aspect of the present invention provides a method for preparing a perovskite film, comprising: forming a mixed layer containing PbI2 on a substrate as a metal halide skeleton layer; applying an organic ammonium salt solution containing a crystallization modifier to the metal halide skeleton layer to obtain a first device; wherein the crystallization modifier contains a guanidine group; and annealing the first device to obtain a perovskite film. This perovskite film can improve the performance of perovskite films, which are produced using conventional techniques, such as small grains and uneven interfaces.

[0007] Optionally, forming a mixed layer containing PbI2 on the substrate as the metal halide skeleton layer includes: adopting an evaporation rate ratio of PbI2:CsBr of 10:1 to evaporate the mixed layer containing PbI2 as the metal halide skeleton layer.

[0008] Optionally, a mixed layer containing PbI2 is formed on a substrate as a metal halide skeleton layer, comprising: dissolving PbI2 powder and CsI powder in a mixed solvent and stirring to dissolve to obtain a mixed solution, wherein the mixed solvent comprises DMF and DMSO; dropping the mixed solution onto the surface of the substrate and coating it evenly; and annealing the substrate coated with the mixed solution to obtain a metal halide skeleton layer.

[0009] Optionally, performing an annealing treatment on the first device to obtain a perovskite film includes: performing an annealing treatment on the first device on a hot stage between 120° C. and 170° C. for 10 min to 40 min to obtain the perovskite film.

[0010] Optionally, the solute of the organic ammonium salt solution includes formamidine hydrobromide and formamidine hydroiodide; and the solvent of the organic ammonium salt solution is isopropyl alcohol.

[0011] Optionally, the molar ratio of formamidine hydrobromide to formamidine hydroiodide is between 1:1 and 2:1.

[0012] Optionally, the concentration of the crystallization modifier is between 0.2 mg / ml and 2.0 mg / ml.

[0013] Optionally, the crystallization modifier is any one of guanidine chloride, aminoguanidine chloride, 1,3-diaminoguanidine, phenformin, metformin and buformin, or a mixture of more thereof.

[0014] Another aspect of the present invention provides a perovskite cell, which includes a substrate and a perovskite film disposed on the substrate, and the perovskite film is prepared by the above-mentioned perovskite film preparation method.

[0015] Optionally, the base includes a substrate and a hole transport layer coated on the substrate.

[0016] The beneficial effects of the present invention include:

[0017] The preparation method of the perovskite film provided by the present application comprises: forming a mixed layer containing PbI2 as a metal halide skeleton layer on a substrate; applying an organic ammonium salt solution containing a crystallization regulator to the metal halide skeleton layer to obtain a first device; wherein the crystallization regulator contains a guanidine group; and annealing the first device to obtain a perovskite film. The present application regulates the growth of perovskite crystals through a two-step procedure, introducing a crystallization regulator containing a guanidine group into an organic ammonium salt solution for coating, so that the guanidine group of the crystallization regulator can interact strongly with PbI2, thereby delaying the reaction between the ammonium salt and PbI2, and thus reducing the formation of crystal nuclei. In this way, the size of the perovskite grains can be significantly increased, and the surface morphology can be made smoother, which is conducive to the interface contact between the perovskite film and the charge transfer layer. In addition, due to the reduction in trap density, the carrier lifetime can also be extended, the PL intensity can also be significantly enhanced, and the open circuit voltage of the perovskite cell can also be increased. In addition, this preparation method can be applied to both wet and dry two-step preparation of perovskite films. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 One of the flow charts of the method for preparing a perovskite thin film provided in an embodiment of the present invention;

[0020] Figure 2 A second flow chart of a method for preparing a perovskite film according to an embodiment of the present invention;

[0021] Figure 3 Surface SEM image of the perovskite film prepared in Comparative Example 1;

[0022] Figure 4 This is a surface SEM image of the perovskite film produced in Example 1 provided by the present invention;

[0023] Figure 5 IV curves of the perovskite cells prepared in Example 1, Example 2, Comparative Example 1 and Comparative Example 2 provided in the present invention under irradiation with AM1.5G sunlight intensity. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0025] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0026] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0027] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" and the like indicate positions or locations based on the positions shown in the accompanying drawings, or the positions or locations in which the inventive product is typically placed when in use. These terms are intended solely to facilitate the description of the present invention and to simplify the description, and are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third," etc., are used solely to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0028] Furthermore, terms such as "horizontal" and "vertical" do not necessarily mean that a component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but rather that it can be slightly tilted.

[0029] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0030] Please refer to Figure 1This embodiment provides a method for preparing a perovskite film, and the method for preparing the perovskite film includes:

[0031] S100, forming a mixed layer containing PbI2 on a substrate as a metal halide skeleton layer.

[0032] It should be noted that the above-mentioned substrate can be any substrate that can form a perovskite thin film, and this application does not impose any specific restrictions on this. For example, optionally, the substrate can include a substrate and a hole transport layer coated on the substrate.

[0033] The substrate may be glass with ITO, and the material of the hole transport layer may be PTAA.

[0034] It should be noted that the mixed layer containing PbI2 can be formed by evaporation or the like, or by a solution method, and this application does not impose any specific limitation.

[0035] For example, in a first feasible embodiment, optionally, the above step S100, forming a mixed layer containing PbI2 on the substrate as a metal halide skeleton layer, can be achieved by:

[0036] A mixed layer containing PbI2 was evaporated as the metal halide skeleton layer using an evaporation rate ratio of PbI2:CsBr of 10:1.

[0037] The thickness of the mixed layer containing PbI 2 may be between 200 nm and 400 nm, for example, 300 nm.

[0038] The evaporation rate ratio of PbI 2 :CsBr in forming the mixed layer of PbI 2 may be between 5:1 and 20:1, for example, 10:1.

[0039] In the second possible embodiment, please refer to Figure 2 Optionally, the above step S100, forming a mixed layer containing PbI2 on the substrate as a metal halide skeleton layer, can be achieved by:

[0040] S110, dissolving PbI2 powder and CsI powder in a mixed solvent and stirring to dissolve to obtain a mixed solution, wherein the mixed solvent includes DMF and DMSO.

[0041] The amount of PbI2 powder may be between 650 mg and 700 mg, and the amount of CsI powder may be between 15 mg and 20 mg. For example, the amount of PbI2 powder may be 691.5 mg, and the amount of CsI powder may be 18 mg.

[0042] The mixed solution may be between 0.8 mL and 1.2 mL. For example, the mixed solution may be 1 mL. The volume ratio of DMF and DMSO included in the mixed solution may be 9:1.

[0043] When the PbI2 powder and the CsI powder are dissolved in the mixed solvent and stirred to dissolve, the stirring and dissolving can be carried out at a temperature of 70°C.

[0044] S120, dropping the mixed solution onto the surface of the substrate and coating it evenly.

[0045] It should be noted that the volume of the mixed solution can be 50 μL. When the mixed solution is dropped onto the surface of the substrate and coated evenly (specifically, by spin coating, slit coating, or doctor blade coating), the coating can be performed at a speed of 2500 r / s for 30 seconds.

[0046] S130 , annealing the substrate coated with the mixed solution to obtain a metal halide skeleton layer.

[0047] It should be noted that the annealing temperature and annealing time can be determined as needed. For example, after the mixed solution coating in step S120 is completed, the obtained device can be annealed on a hot plate at 70° C. for 1 minute to complete the preparation of the metal halide skeleton layer.

[0048] S200, applying an organic ammonium salt solution containing a crystallization modifier to the metal halide skeleton layer to obtain a first device; wherein the crystallization modifier contains a guanidine group.

[0049] Optionally, the solute of the organic ammonium salt solution includes formamidine hydrobromide and formamidine hydroiodide; and the solvent of the organic ammonium salt solution is isopropyl alcohol.

[0050] The volume of the organic ammonium salt solution may be between 80 μL and 120 μL, for example, 100 μL. The molar ratio of formamidine hydrobromide to formamidine hydroiodide in the organic ammonium salt solution may be between 1:1 and 2:1. For example, the molar ratio of formamidine hydrobromide to formamidine hydroiodide is 1.75:1.

[0051] Optionally, the concentration of the crystallization modifier is between 0.2 mg / ml and 2.0 mg / ml. That is, the concentration of the crystallization modifier added to the organic ammonium salt solution is between 0.2 mg / ml and 2.0 mg / ml. Exemplarily, the concentration of the crystallization modifier added to the organic ammonium salt solution can be 0.2 mg / ml, 0.5 mg / ml, 0.8 mg / ml, 1 mg / ml, 1.5 mg / ml or 2 mg / ml.

[0052] In addition, the organic ammonium salt solution containing the crystallization modifier can be applied to the surface of the metal halide skeleton layer to obtain the first device by spin coating at a speed of 3000 r / s for 30 seconds. It should be noted that the application of the organic ammonium salt solution by spin coating is merely an example and does not specifically limit the application of the organic ammonium salt solution to the metal halide skeleton layer.

[0053] In addition, the crystallization modifier may be any one of guanidine chloride, aminoguanidine chloride, 1,3-diaminoguanidine, phenformin, metformin and buformin, or a mixture of multiple thereof.

[0054] That is to say, the crystallization modifier is a type of substance containing a guanidine group. For example, it can be a monoguanidine or a biguanidine. Among them, the monoguanidine substance can be guanidine chloride, aminoguanidine chloride and 1,3-diaminoguanidine, etc.; the biguanidine substance can be phenformin, metformin and buformin, etc.

[0055] The application will be coated with an organic ammonium salt solution containing a crystallization control agent on the surface of the metal halide skeleton layer, so that the guanidine group can interact with PbI2 more strongly, thereby delaying the reaction between the organic ammonium salt and PbI2, thereby reducing the generation of crystal nuclei, so that the size of the perovskite grains can be significantly increased, and its surface morphology can also be made more flat, which is conducive to the interface contact between the perovskite film and the charge transfer layer. In addition, due to the reduction in trap density, the carrier lifetime can also be extended, and the PL intensity can be significantly enhanced. However, after introducing the crystallization control agent, the chemical composition of the perovskite itself and its band gap do not change significantly. At the same time, the perovskite film prepared by the preparation method of the perovskite film provided by the application is relatively improved compared to the prior art, and its open circuit voltage can also be significantly improved (hereinafter, the perovskite film prepared by the application and the perovskite film prepared by the prior art will be verified).

[0056] In addition, it is worth noting that biguanide small molecules containing two guanidine groups are more effective than monoguanidines. Since phenformin contains a benzene ring, its unique structure makes the electron cloud around the molecule have electron-rich and electron-poor domains, and its dipole moment is large. This enables phenformin to form a stronger interaction with PbI2 and has a better passivation effect. Therefore, in this embodiment, phenformin is preferably used as a crystallization regulator.

[0057] S300 , performing annealing treatment on the first device to obtain a perovskite thin film.

[0058] Optionally, the above step S300, annealing the first device to obtain a perovskite film, includes: annealing the first device on a hot plate at a temperature between 120° C. and 170° C. for 10 min to 40 min to obtain the perovskite film.

[0059] For example, the annealing treatment in step S300 can be performed on a hot plate at 150° C. for 30 minutes. Of course, the above annealing temperature and time are merely examples and are not limitations of the present application. Those skilled in the art may also appropriately adjust the above annealing temperature and time according to actual needs.

[0060] In summary, the preparation method of the perovskite film provided by the present application comprises: forming a mixed layer containing PbI2 on a substrate as a metal halide skeleton layer; applying an organic ammonium salt solution containing a crystallization regulator to the surface of the metal halide skeleton layer to obtain a first device; wherein the crystallization regulator contains a guanidine group; and annealing the first device to obtain a perovskite film. The present application regulates the growth of perovskite crystals through a two-step procedure, introducing a crystallization regulator containing a guanidine group into an organic ammonium salt solution for coating, so that the guanidine group of the crystallization regulator can interact strongly with PbI2, thereby delaying the reaction between the ammonium salt and PbI2, and thus reducing the generation of crystal nuclei. In this way, the size of the perovskite grains can be significantly increased, and its surface morphology can be made smoother, which is beneficial to the interface contact between the perovskite film and the charge transfer layer. In addition, due to the reduction in trap density, the carrier lifetime can also be extended, the PL intensity can also be significantly enhanced, and the open circuit voltage of the perovskite battery can also be increased. In addition, this preparation method can be applied to both wet and dry two-step preparation of perovskite films.

[0061] Another aspect of the present invention provides a perovskite cell, comprising a substrate and a perovskite thin film disposed on the substrate, wherein the perovskite thin film is prepared using the above-described method for preparing a perovskite thin film. Since the specific preparation steps and technical effects of the perovskite thin film preparation method, as well as the structure of the substrate, have been described in detail above, they will not be further elaborated herein.

[0062] Example 1

[0063] This embodiment adopts the following steps to prepare the perovskite cell.

[0064] 1) Prepare a hole transport layer by spin coating on glass with ITO. The material of the hole transport layer is PTAA.

[0065] 2) The structure obtained in step 1) is placed in a vacuum coating device, and a 300 nm mixed layer containing PbI2 is evaporated as a metal halide skeleton layer using an evaporation rate ratio of PbI2:CsBr of 10:1.

[0066] 3) Place the device obtained in step 2) on a spin coater and take 100 μL of an organic amine salt solution, wherein the organic amine salt solution is a mixed solute formed by formamidine hydrobromide and formamidine hydroiodide at a molar ratio of 1.75:1; the solvent is isopropanol. PhenHCl is added to the organic ammonium salt solution, with the concentration of PhenHCl ranging from 0.2 mg / ml to 2.0 mg / ml. The organic amine salt solution containing PhenHCl is dropwise applied to the surface of the device obtained in step 2) and spin-coated at 3000 rpm for 30 seconds. After the spin coating is completed, the resulting device is annealed on a hot plate at 150°C for 30 minutes to complete the preparation of the perovskite film.

[0067] 4) Place the structure obtained in step 3) in a vacuum coating device, first using The evaporation rate is 20nm, and the C60 is further The evaporation rate was set to 7 nm for BCP as a buffer layer. Finally, a 150 nm copper electrode was deposited on the BCP film using a mask method to obtain a perovskite cell.

[0068] Example 2

[0069] This embodiment adopts the following steps to prepare the perovskite solar cell.

[0070] 1) Prepare a hole transport layer by spin coating on glass with ITO. The material of the hole transport layer is PTAA.

[0071] 2) Dissolve 691.5 mg of PbI2 powder and 18 mg of CsI powder in 1 mL of a 9:1 (volume ratio) DMF:DMSO mixture and stir at 70°C to dissolve. Place the structure obtained in step 1) on a spin coater, take 50 μL of the PbI2 solution, add it dropwise to the surface of the device obtained in step 1), and spin coat at 2500 r / s for 30 seconds. After spin coating, anneal the device on a 70°C hot plate for 1 minute to complete the preparation of the metal halide skeleton layer.

[0072] 3) Place the device obtained in step 2) on a spin coater and take 100 μL of an organic amine salt solution, wherein the organic amine salt solution is a mixed solute formed by formamidine hydrobromide and formamidine hydroiodide at a molar ratio of 1.75:1; the solvent is isopropanol. PhenHCl is added to the organic ammonium salt solution, with the concentration of PhenHCl ranging from 0.2 mg / ml to 2.0 mg / ml. The organic amine salt solution containing PhenHCl is dropwise applied to the surface of the device obtained in step 2) and spin-coated at 3000 rpm for 30 seconds. After the spin coating is completed, the resulting device is annealed on a hot plate at 150°C for 30 minutes to complete the preparation of the perovskite film.

[0073] 4) Place the structure obtained in step 3) in a vacuum coating device, first using The evaporation rate is 20nm, and the C60 is further The evaporation rate was set to 7 nm for BCP as a buffer layer. Finally, a 150 nm copper electrode was deposited on the BCP film using a mask method to obtain a perovskite cell.

[0074] Comparative Example 1

[0075] The comparative example adopts the following steps to prepare the perovskite solar cell.

[0076] 1) Prepare a hole transport layer by spin coating on glass with ITO. The material of the hole transport layer is PTAA.

[0077] 2) The structure obtained in step 1) is placed in a vacuum coating device, and a 300 nm mixed layer containing PbI2 is evaporated as a metal halide skeleton layer using an evaporation rate ratio of PbI2:CsBr of 10:1.

[0078] 3) Place the device obtained in step 2) on a spin coater and take 100 μL of an organic amine salt solution. The organic amine salt solution is a mixed solute of formamidine hydrobromide and formamidine hydroiodide at a molar ratio of 1.75:1; the solvent is isopropanol. The removed organic amine salt solution is dropwise added to the surface of the device obtained in step 2) and spin-coated at 3000 rpm for 30 seconds. After the spin coating is complete, the device is annealed on a hot plate at 150°C for 30 minutes to complete the preparation of the perovskite film.

[0079] 4) Place the structure obtained in step 3) in a vacuum coating device, first using The evaporation rate is 20nm, and the C60 is further The evaporation rate was set to 7 nm for BCP as a buffer layer. Finally, a 150 nm copper electrode was deposited on the BCP film using a mask method to obtain a perovskite cell.

[0080] Comparative Example 2

[0081] The comparative example adopts the following steps to prepare the perovskite solar cell.

[0082] 1) Prepare a hole transport layer by spin coating on glass with ITO. The material of the hole transport layer is PTAA.

[0083] 2) Dissolve 691.5 mg of PbI2 powder and 18 mg of CsI powder in 1 mL of a 9:1 (volume ratio) DMF:DMSO mixture and stir at 70°C to dissolve. Place the structure obtained in step 1) on a spin coater, take 50 μL of the PbI2 solution, add it dropwise to the surface of the device obtained in step 1), and spin coat at 2500 r / s for 30 seconds. After spin coating, anneal the device on a 70°C hot plate for 1 minute to complete the preparation of the metal halide skeleton layer.

[0084] 3) Place the device obtained in step 2) on a spin coater and take 100 μL of an organic amine salt solution. The organic amine salt solution is a mixed solute of formamidine hydrobromide and formamidine hydroiodide at a molar ratio of 1.75:1; the solvent is isopropanol. The removed organic amine salt solution is dropwise added to the surface of the device obtained in step 2) and spin-coated at 3000 rpm for 30 seconds. After the spin coating is complete, the device is annealed on a hot plate at 150°C for 30 minutes to complete the preparation of the perovskite film.

[0085] 4) Place the structure obtained in step 3) in a vacuum coating device, first using The evaporation rate is 20nm, and the C60 is further The evaporation rate was set to 7 nm for BCP as a buffer layer. Finally, a 150 nm copper electrode was deposited on the BCP film using a mask method to obtain a perovskite cell.

[0086] The main conditions of the above embodiments and comparative examples are shown in Table 1.

[0087] Table 1

[0088] Whether to add crystallization regulator Concentration of crystallization modifier Example 1 yes 0.2-2mg / ml Example 2 yes 0.2-2mg / ml Comparative Example 1 no none Comparative Example 2 no none

[0089] The performance of the perovskite cells prepared in the above examples and comparative examples was measured, and the measurement results are shown in Table 2.

[0090] Table 2

[0091]

[0092] Please refer to Figure 3 and Figure 4 ,in, Figure 3 The surface SEM image of the perovskite film prepared in Comparative Example 1 is shown. Figure 4 The surface SEM image of the perovskite film prepared in Example 1 is shown in FIG. Figure 3 and Figure 4From the comparison, it can be seen that the grain size of the perovskite film prepared by the preparation method provided by this application after adding a crystallization modifier is significantly larger and the surface is smoother. This proves that the perovskite solar cell prepared by the method of the embodiment of the present invention can significantly change the morphology of the perovskite film.

[0093] Figure 5 The IV curves of the perovskite cells prepared in Example 1, Example 2, Comparative Example 1 and Comparative Example 2 of the present invention under strong irradiation of AM1.5G sunlight are shown. Figure 5 It can be seen that the short-circuit current of the perovskite battery prepared in Example 1 is 19.48 mA / cm 2 The open circuit voltage is 1.25V, the fill factor is 77.26%, and the final cell conversion efficiency is 18.78%. The voltage of the perovskite solar cell prepared in Example 1 is significantly better than that of the cell in Comparative Example 1.

[0094] The foregoing description is merely an optional embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

[0095] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A method for preparing a perovskite thin film, characterized in that: include: forming a mixed layer containing PbI2 as a metal halide skeleton layer on a substrate; Applying an organic ammonium salt solution containing a crystallization modifier to the metal halide skeleton layer to obtain a first device; wherein the crystallization modifier contains a guanidine group; The first device is annealed to obtain a perovskite film.

2. The method for preparing a perovskite thin film according to claim 1, wherein: The step of forming a mixed layer containing PbI2 on the substrate as a metal halide skeleton layer comprises: A mixed layer containing PbI2 was evaporated as the metal halide skeleton layer using an evaporation rate ratio of PbI2:CsBr of 10:

1.

3. The method for preparing a perovskite thin film according to claim 1, wherein: The step of forming a mixed layer containing PbI2 on the substrate as a metal halide skeleton layer comprises: Dissolving PbI2 powder and CsI powder in a mixed solvent and stirring to dissolve to obtain a mixed solution, wherein the mixed solvent includes DMF and DMSO; Adding the mixed solution dropwise to the surface of the substrate and coating it evenly; The substrate coated with the mixed solution is subjected to annealing treatment to obtain a metal halide skeleton layer.

4. The method for preparing a perovskite thin film according to claim 1, wherein: The annealing treatment is performed on the first device to obtain a perovskite film, comprising: The first device is annealed on a hot stage at a temperature between 120° C. and 170° C. for 10 to 40 minutes to obtain a perovskite thin film.

5. The method for preparing a perovskite thin film according to claim 1, wherein: The solute of the organic ammonium salt solution includes formamidine hydrobromide and formamidine hydroiodide; and the solvent of the organic ammonium salt solution is isopropyl alcohol.

6. The method for preparing a perovskite thin film according to claim 5, wherein: The molar ratio of the formamidine hydrobromide to the formamidine hydroiodide is between 1:1 and 2:

1.

7. The method for preparing a perovskite thin film according to claim 1, wherein: The concentration of the crystallization modifier is between 0.2 mg / ml and 2.0 mg / ml.

8. The method for preparing a perovskite thin film according to claim 1 or 7, wherein: The crystallization regulator is any one of guanidine chloride, aminoguanidine chloride, 1,3-diaminoguanidine, phenformin, metformin and buformin, or a mixture of multiple thereof.

9. A perovskite battery, characterized in that: The invention comprises a substrate and a perovskite film provided on the substrate, wherein the perovskite film is prepared by the method for preparing a perovskite film according to any one of claims 1 to 8.

10. The perovskite cell according to claim 9, characterized in that The base includes a substrate and a hole transport layer coated on the substrate.

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