A method for preparing perovskite film and perovskite battery

Abstract

The present application provides a method for preparing a perovskite film and a perovskite battery, the perovskite battery comprising a battery substrate, a first electrode layer, a first carrier transport layer, a carrier transport passivation layer, a perovskite film, a second carrier transport layer, and a second electrode layer. The present application adds a thickener to the perovskite inorganic salt solution, thereby effectively improving the fluid properties of the perovskite inorganic salt solution, obtaining a first inorganic substrate layer with high viscosity, and the fluidity of the first inorganic substrate layer decreases as the temperature decreases, so that the first inorganic substrate layer can be stably deposited and attached on the battery substrate. By cooling and standing the wet film substrate, the wet film can be uniformly preliminarily cured by a vacuum flash evaporation process, reducing the fluidity of the wet film. The wet film is subjected to two annealing treatments, and the perovskite film prepared after being matched with an organic halogen salt solution has good quality, which helps to improve the photoelectric conversion efficiency and long-term stability of the perovskite battery.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and more specifically, relates to a method for preparing a perovskite film, and a perovskite battery prepared using the method for preparing the perovskite film. Background Art

[0002] In the field of perovskite cells, the processes for wet preparation of perovskite films mainly include one-step and two-step methods. The one-step method is to blend the perovskite precursor material in a solvent to prepare a perovskite precursor solution, and then coat the perovskite precursor solution on a substrate; then use anti-solvent extraction or vacuuming to quickly remove the solvent to achieve rapid supersaturation of the wet film, thereby pre-crystallizing; finally, anneal the pre-crystallized film to obtain a perovskite film. Due to the large number of crystalline defects in the one-step method, the photoelectric conversion efficiency of perovskite cells is relatively low. The two-step method is to first prepare a perovskite inorganic salt solution, and coat it on a substrate to anneal to form an inorganic substrate layer; then the organic halogen salt solution is infiltrated into the inorganic substrate layer and annealed to form a perovskite film. The perovskite film prepared by the two-step method has a high degree of crystallinity and density, and the photoelectric conversion efficiency of the perovskite cell prepared thereby is usually higher.

[0003] In the current two-step method, the inorganic substrate layer is usually formed by coating the perovskite inorganic salt solution on the substrate by slit coating or blade coating, and then annealing. However, the inorganic substrate layer prepared above has defects such as poor uniformity and many holes, resulting in serious defects in the perovskite film formed by the organic halogen salt solution and the inorganic substrate layer, which affects the photoelectric conversion efficiency and long-term stability of the perovskite cell. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a method for preparing a perovskite film and a perovskite cell, so as to solve the problems existing in the related art: the inorganic substrate layer has defects such as poor uniformity and many holes, which lead to serious defects in the perovskite film formed by the organic halogen salt solution and the inorganic substrate layer, thus affecting the photoelectric conversion efficiency and long-term stability of the perovskite cell.

[0005] To achieve the above purpose, the technical solution adopted in the embodiment of the present application is:

[0006] In one aspect, a method for preparing a perovskite film is provided, comprising the following steps:

[0007] Applying a perovskite inorganic salt solution containing a thickener on a battery substrate to form a first inorganic substrate layer, wherein the battery substrate and the first inorganic substrate layer are combined to form a wet film substrate;

[0008] Cooling the wet film substrate and leaving it to stand, removing the organic solvent in the first inorganic substrate layer by vacuum flash evaporation to form a pre-dried film layer, wherein the pre-dried film layer is composed of a perovskite inorganic salt material and the thickener;

[0009] Performing a first annealing treatment on the pre-dried film layer to remove cations in the thickener;

[0010] Performing a second annealing treatment on the pre-dried film layer to remove anions in the thickener and obtain a second inorganic substrate layer;

[0011] The organic halogen salt solution is coated on the second inorganic substrate layer, and the perovskite film is obtained after drying and annealing.

[0012] In one embodiment, the perovskite inorganic salt solution is formed by mixing the perovskite inorganic salt material and a solvent; the perovskite inorganic salt material is AX and BX2, A is a monovalent metal cation, including one or more of cesium and rubidium; B is a divalent metal cation, including one or more of lead and tin; X is a monovalent anion, including one or more of iodine, bromine, and chlorine; the solvent includes one or more of dimethyl sulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone.

[0013] In one embodiment, the thickener includes one of ionic surfactants such as methylamine acetate, methylamine formate, and methylamine propionate.

[0014] In one embodiment, the coating method of the perovskite inorganic salt solution includes one of deposition processes such as slit coating, doctor blade coating, screen printing, and spraying.

[0015] In one embodiment, the wet film substrate is cooled and allowed to stand, and the organic solvent in the first inorganic substrate layer is removed by vacuum flash evaporation to form a pre-dried film layer, wherein the pre-dried film layer is composed of a perovskite inorganic salt material and the thickener. In the step: the cooling rate range is 1-30°C / min, the cooling and standing temperature range is -5-20°C, and the standing time range is 0-400min.

[0016] In one embodiment, in the step of performing a first annealing treatment on the pre-dried film layer to remove cations in the thickener: the annealing temperature ranges from 40 to 90° C., and the annealing time ranges from 1 to 800 min.

[0017] In one embodiment, in the step of performing a second annealing treatment on the pre-dried film layer to remove anions in the thickener and obtain a second inorganic substrate layer: the annealing temperature ranges from 120-200° C., and the annealing time ranges from 1-500 min.

[0018] In one embodiment, the organic halogen salt solution is formed by mixing a solute and a solvent; the solvent of the organic halogen salt solution includes one of isopropanol, ethanol, n-butanol, etc.; the solute of the organic halogen salt solution is CX, C is a monovalent organic cation, including one or more of methylamine, formamidinium, and phenylethylamine halide salts; X is a monovalent anion, including one or more of iodine, bromine, and chlorine.

[0019] In one embodiment, in the step of coating an organic halogen salt solution on the second inorganic substrate layer and obtaining a perovskite film after drying and annealing: after coating the organic halogen salt solution on the second inorganic substrate layer, let it stand for 1-5000s, and then dry and anneal.

[0020] In another aspect, a perovskite battery is provided, comprising:

[0021] Battery substrate;

[0022] A first electrode layer disposed on the battery substrate;

[0023] a first carrier transport layer disposed on the first electrode layer;

[0024] A carrier transport passivation layer provided on the first carrier transport layer;

[0025] A perovskite film disposed on the carrier transport passivation layer;

[0026] A second carrier transport layer disposed on the perovskite film;

[0027] a second electrode layer disposed on the second carrier transport layer;

[0028] Wherein, the perovskite film is prepared by using the preparation method of the perovskite film provided in any of the above embodiments.

[0029] The preparation method of the perovskite film and the perovskite battery provided in the embodiments of the present application have at least the following beneficial effects: the present application can effectively improve the fluid properties of the perovskite inorganic salt solution by adding a thickener to the perovskite inorganic salt solution, thereby obtaining a first inorganic substrate layer with high viscosity, and the fluidity of the first inorganic substrate layer decreases as the temperature decreases, so that the first inorganic substrate layer can be stably deposited and attached on the battery substrate. By cooling and standing the wet film substrate, the wet film can be uniformly initially solidified by using a vacuum flash evaporation process to reduce the fluidity of the wet film. The perovskite film prepared by the wet film through two annealing treatments and combining with an organic halogen salt solution has good quality, which helps to improve the photoelectric conversion efficiency and long-term stability of the perovskite battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or exemplary technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 A schematic diagram of a process for preparing a perovskite film provided in an embodiment of the present application;

[0032] Figure 2 A schematic diagram of the structure of a perovskite battery provided in an embodiment of the present application.

[0033] Among them, the main marks of the drawings in the figure are:

[0034] 1. Battery substrate; 11. Battery base plate; 12. First electrode layer; 13. First carrier transport layer; 14. Carrier transport passivation layer; 2. Perovskite film; 3. Second carrier transport layer; 4. Second electrode layer. DETAILED DESCRIPTION

[0035] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and 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.

[0036] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0037] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "multiple" means two or more, unless otherwise clearly and specifically defined. "Several" means one or more, unless otherwise clearly and specifically defined.

[0038] In the description of the present application, it should be understood that the terms "center", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0039] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0040] Reference throughout the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, when the phrases "in one embodiment" or "in some embodiments" appear in various places throughout the specification, not all references are to the same embodiment. Furthermore, in one or more embodiments, the particular features, structures, or characteristics may be combined in any suitable manner.

[0041] At present, for the perovskite film prepared by the two-step method, in the process of preparing the inorganic substrate layer, the perovskite inorganic salt solution is coated on the substrate by slit coating or blade coating, and the inorganic substrate layer is formed after annealing. Since the solvent fluid characteristics in the perovskite inorganic salt solution do not match the coating process, the inorganic substrate layer prepared by the large-area coating process has poor quality, poor uniformity, many holes and other defects, resulting in serious defects in the perovskite film formed by the reaction with the organic halogen salt solution, affecting the photoelectric conversion efficiency and long-term stability of the perovskite battery.

[0042] In order to solve the above problems, the embodiments of the present application provide a method for preparing a perovskite film and a perovskite battery. For the convenience of description, the specific structure of the perovskite battery is now described in detail.

[0043] See also Figure 2The specific structure of the perovskite battery includes, from bottom to top, a battery substrate 11, a first electrode layer 12 disposed on the battery bottom sheet, a first carrier transport layer 13 disposed on the first electrode layer 12, a carrier transport passivation layer 14 disposed on the first carrier transport layer 13, a perovskite film 2 disposed on the carrier transport passivation layer 14, a second carrier transport layer 3 disposed on the perovskite film 2, and a second electrode layer 4 disposed on the second carrier transport layer 3. Now, in combination with the specific structure of the perovskite battery, the preparation direction of the perovskite battery is described in detail. The preparation method of the perovskite battery specifically includes the following steps:

[0044] Step 1: Provide a battery substrate 11. The battery substrate 11 may be a glass transparent bottom plate.

[0045] Step 2: preparing a first electrode layer 12 on the battery substrate 11 .

[0046] Step 3: Prepare a first carrier transport layer 13 on the first electrode layer 12. Optionally, the first carrier transport layer 13 includes but is not limited to one or more of NiO, SnO2, TiO2, 2PACz, and is deposited by magnetron sputtering, evaporation, spraying, slit coating and other process methods. Specifically, in the embodiment of the present application, NiO can be selected as the material of the first carrier transport layer 13, and magnetron sputtering is used as the deposition method. The film thickness of the prepared first carrier transport layer 13 is 50nm.

[0047] Step 4: preparing a carrier transport passivation layer 14 on the first carrier transport layer 13 .

[0048] Step 5: Prepare a perovskite film 2 on the carrier transport passivation layer 14. Here, the perovskite film 2 is prepared by the preparation method of the perovskite film provided in the embodiment of the present application. Figure 1 The method for preparing the perovskite film provided in the embodiment of the present application specifically comprises the following steps:

[0049] S1. Applying a perovskite inorganic salt solution containing a thickener on a battery substrate 1 to form a first inorganic substrate layer, the battery substrate 1 and the first inorganic substrate layer are combined to form a wet film substrate. The battery substrate 1 can be a sheet prepared by the above steps 1 to 4, and its specific structure includes a battery substrate 11, a first electrode layer 12, a first carrier transport layer 13 and a carrier transport passivation layer 14.

[0050] The perovskite inorganic salt solution can be formed by mixing the perovskite inorganic salt material and the solvent. The perovskite inorganic salt material can be AX and BX2, wherein A is a monovalent metal cation, including but not limited to one or more of cesium and rubidium. B is a divalent metal cation, including but not limited to one or more of lead and tin. X is a monovalent anion, including but not limited to one or more of iodine, bromine, chlorine or halogen. The solvent includes but is not limited to one or more of dimethyl sulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone.

[0051] The thickener includes, but is not limited to, one or more of ionic surfactants such as methylamine acetate (MAAC), methyl methylamine formate (MAFA), and methylamine propionate (MAPA).

[0052] The coating method of the perovskite inorganic salt solution includes but is not limited to slit coating, doctor blade coating, screen printing, spraying and other deposition processes.

[0053] Specifically, in the embodiment of the present application, the perovskite inorganic salt material can be made of PbI2, PbBr2, CsI, and FAI mixed in a certain proportion. The solvent in the perovskite inorganic salt solution can be dimethyl sulfoxide (DMSO). The thickener can be methylamine acetate (MAAC). A 1 mol / L perovskite inorganic salt solution is prepared according to a volume ratio of DMSO:MAAC of 1:50. The above perovskite inorganic salt solution is printed on the battery substrate 1 by screen printing to form a first inorganic substrate layer. Among them, the printing screen can use a 240-420 mesh polyester screen or a stainless steel screen, and the tension range is 10-24N. In the embodiment of the present application, a 300 mesh polyester screen is used for the coating operation of the perovskite inorganic salt solution.

[0054] S2, cool the wet film substrate and let it stand, remove the organic solvent in the first inorganic substrate layer by vacuum flash evaporation to form a pre-dried film layer, the pre-dried film layer is composed of a perovskite inorganic salt material and a thickener. The organic solvent in the first inorganic substrate layer can be the solvent in the above-mentioned perovskite inorganic salt solution. Optionally, the cooling rate range is 1-30℃ / min, the cooling and standing temperature range is -5-20℃, and the standing time range is 0-400min. The air pressure of the vacuum box needs to drop to 1.0×10 within 1-1.5s. -2 -1.0×10 -5 kPa. Specifically, in the embodiment of the present application, the cooling rate may be 5°C / min, the cooling stand temperature may be 5°C, and the stand time may be 5 min. The air pressure of the vacuum box drops to 3.5×10 -2 kPa. In this structure, due to the presence of the thickener, the fluidity of the first inorganic substrate layer decreases as the temperature decreases, so that the first inorganic substrate layer can be stably deposited and attached on the battery substrate 1.

[0055] S3, the pre-dried film layer is subjected to a first annealing treatment to remove the cations in the thickener. It is understood that the first inorganic substrate layer after vacuuming is subjected to a first annealing treatment to remove the anions in the thickener, such as Ac - ,PA - , FA - etc., the cations in the remaining thickener and the perovskite inorganic salt material. Optionally, the annealing temperature ranges from 40 to 90° C., and the annealing time ranges from 1 to 800 min. Specifically, in the embodiment of the present application, the annealing temperature may be 60° C., and the annealing time may be 200 min.

[0056] S4. Perform a second annealing treatment on the pre-dried film layer to remove the anions in the thickener and obtain a second inorganic substrate layer. The second annealing treatment can completely heat and decompose the thickener, that is, remove the anions in the thickener, and the remaining perovskite inorganic salt material can form a uniform high-purity perovskite inorganic substrate layer. Optionally, the annealing temperature ranges from 120-200°C, and the annealing time ranges from 1-500min. Specifically, in an embodiment of the present application, the annealing temperature can be 140°C and the annealing time can be 60min.

[0057] S5. Apply the organic halogen salt solution on the second inorganic substrate layer, and obtain the perovskite film 2 after drying and annealing. First, prepare an organic halogen salt solution. Optionally, the organic halogen salt solution is formed by mixing a solute and a solvent. Among them, the solvent of the organic halogen salt solution includes but is not limited to volatile solvents such as isopropanol, ethanol, and n-butanol, and will not dissolve the second inorganic substrate layer. The solute of the organic halogen salt solution may be CX, where C is a monovalent organic cation, including but not limited to one or more cations of methylamine or methylammonium, phenylethylamine halide salts; X is a monovalent anion, including but not limited to one or more anions of iodine, bromine, chlorine or halogen-like. Specifically, in an embodiment of the present application, the solvent of the organic halogen salt solution may be n-butanol, and the solute of the organic halogen salt solution may be a mixture of FAI, MAI, and FABr in a certain proportion to form a 15 mg / mL organic halogen salt solution.

[0058] Secondly, the organic halogen salt solution is coated on the second inorganic substrate layer to form an organic halogen salt solution film, and after it fully reacts with the second inorganic substrate layer, the organic halogen salt solution film is pre-crystallized and dried by a drying process to form a perovskite pre-crystallization thin film nucleation. Optionally, the method of coating the organic halogen salt solution on the second inorganic substrate layer includes but is not limited to slit coating, scraping, screen printing, spraying and other processes. After the organic halogen salt solution is coated on the second inorganic substrate layer, it is necessary to wait for a reaction time of 1-5000s. The drying process includes but is not limited to natural drying, blowing drying, infrared drying and other processes; the drying time ranges from 1-5000s. Specifically, in an embodiment of the present application, the organic halogen salt solution is coated on the second inorganic substrate layer by a slit coating process, and after waiting for 20s, it is blown dry by a 5mm / s fan.

[0059] Finally, the perovskite pre-crystallized film is annealed to obtain the perovskite film 2. Optionally, the annealing temperature ranges from 70 to 300° C., and the annealing time ranges from 1 to 600 min. Specifically, in the embodiment of the present application, the annealing temperature may be 140° C., and the annealing time may be 300 min.

[0060] Step 6: Prepare a second carrier transport layer 3 on the perovskite film 2. Optionally, the second carrier transport layer 3 may be made of C 60 Specifically, C is deposited on the perovskite film 2 in sequence by evaporation. 60 and SnO2 film. Among them, C 60 The thickness of the film layer can be 34nm, and the thickness of the SnO2 film layer can be 20nm.

[0061] Step 7: Prepare the second electrode layer 4 on the second carrier transport layer 3. Optionally, the second electrode layer 4 can be made of copper material. Specifically, the copper material is deposited on the second carrier transport layer 3 by evaporation, and the film thickness of the second electrode layer 4 can be 150nm.

[0062] In order to verify the performance of the perovskite battery prepared by the method for preparing the perovskite film provided in the examples of the present application, the examples of the present application provide four groups of experiments for comparative demonstration, namely, Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3.

[0063] The preparation method of the perovskite battery provided in Example 1 is prepared by the above steps 1 to 7.

[0064] The difference between the preparation method of the perovskite battery provided in Comparative Example 1 and the preparation method of the perovskite battery provided in Example 1 is that the preparation method of the perovskite film in step 5 is different. Comparative Example 1 uses a one-step method to prepare the perovskite film 2, and the specific steps are:

[0065] In the first step, DMF / DMSO is used as a solvent, and CsI, PbI2, PbBr2, and FAI are used as perovskite precursor materials. The perovskite precursor materials are blended in the solvent to prepare a perovskite precursor solution.

[0066] In the second step, a perovskite wet film is prepared on the battery substrate 1 by blade coating, and the solvent in the perovskite wet film is quickly removed by vacuum flash evaporation to form a pre-crystallized dry film.

[0067] In the third step, the pre-crystallized dry film is annealed to form a perovskite film 2.

[0068] The other steps of the method for preparing a perovskite battery provided in Comparative Example 1 are the same as the corresponding steps of the method for preparing a perovskite battery provided in Example 1, and are not described again herein.

[0069] The difference between the preparation method of the perovskite battery provided in Comparative Example 2 and the preparation method of the perovskite battery provided in Example 1 is that the preparation method of the perovskite film in step 5 is different. The specific steps of preparing the perovskite film 2 in Comparative Example 2 are:

[0070] In the first step, DMF / NMP is used as a solvent, and CsI, PbI2, PbBr2, and FAI are used as perovskite precursor materials. The perovskite precursor materials are blended in the solvent to prepare a perovskite inorganic salt solution.

[0071] In the second step, the perovskite inorganic salt solution is coated on the battery substrate 1 by scraping, and annealed to form an inorganic substrate layer.

[0072] The other steps of the method for preparing a perovskite battery provided in Comparative Example 2 are the same as the corresponding steps of the method for preparing a perovskite battery provided in Example 1, and are not described again herein.

[0073] The difference between the preparation method of the perovskite battery provided in Comparative Example 3 and the preparation method of the perovskite battery provided in Example 1 is that the preparation method of the perovskite film in step 5 is different. The specific steps of preparing the perovskite film 2 in Comparative Example 3 are:

[0074] In the first step, CsI, PbI2, PbBr2, and FAI were used as perovskite inorganic salt materials, DMSO was used as the solvent of the perovskite inorganic salt solution, and MAAC was used as the thickener. A 1 mol / L perovskite inorganic salt solution was prepared according to a DMSO:MAAC volume ratio of 1:50.

[0075] In the second step, the perovskite inorganic salt solution is printed onto the battery substrate 1 by screen printing to form an inorganic substrate layer. The printing screen can be a 240-420 mesh polyester screen or a stainless steel screen, and the tension range is 10-24 N. Specifically, Comparative Example 3 uses a 300 mesh polyester screen to coat the perovskite inorganic salt solution.

[0076] The other steps of the method for preparing a perovskite battery provided in Comparative Example 3 are the same as the corresponding steps of the method for preparing a perovskite battery provided in Example 1, and are not described again herein.

[0077] The viscosity characteristics of the perovskite inorganic salt solution in Example 1, the viscosity characteristics of the perovskite precursor solution in Comparative Example 1, and the viscosity characteristics of the perovskite inorganic salt solution in Comparative Example 2 were tested at 20-40° C. using a rheometer. The test results are shown in Table 1 below.

[0078] Table 1 Viscosity of the perovskite inorganic salt solution in Example 1, Comparative Example 1 and Comparative Example 2

[0079]

[0080] From the data comparison in Table 1 above, it can be seen that the viscosity of the perovskite inorganic salt solution provided in Example 1 is significantly higher than the viscosity of the perovskite precursor solution provided in Comparative Example 1, and the viscosity of the perovskite inorganic salt solution provided in Comparative Example 2. It can be concluded that the viscosity of the perovskite inorganic salt solution provided in Example 1 is significantly improved due to the addition of a thickener. When the volume ratio of DMSO:MAAC is 1:50, the fluid requirements of the screen printing process can be met.

[0081] A solar simulator was used to calibrate the intensity of a standard sun and to measure the intensity of a standard sun with an area of ​​1.0 cm. 2 The perovskite battery was subjected to a long-term IV test, with the starting voltage set to 0V, the cut-off voltage set to 1.3V, and the range set to 100mA. The test results are shown in Table 2 below.

[0082] Table 2 Test results of perovskite cells provided in Example 1 and Comparative Examples 1-3

[0083]

[0084] From the data comparison in Table 2 above, we can see that:

[0085] 1. By comparing Example 1 with Comparative Example 1, it can be seen that the performance of the perovskite battery obtained by preparing the perovskite film 2 using the one-step method is significantly lower than the performance of the perovskite battery obtained by preparing the perovskite film 2 using the two-step method.

[0086] 2. By comparing Example 1 with Comparative Example 2, it can be seen that the performance of the perovskite battery obtained by preparing the perovskite film 2 with the addition of a thickener is significantly higher than the performance of the perovskite battery obtained by preparing the perovskite film 2 without using a thickener.

[0087] 3. By comparing Example 1 with Comparative Example 3, it can be seen that the step of adding a thickener to prepare the perovskite film 2 in Comparative Example 3 has not been subjected to cooling and solidification, vacuum flash evaporation and other treatments, and the quality of the obtained inorganic substrate layer is poor, resulting in low photoelectric conversion efficiency of the prepared perovskite battery.

[0088] The above description is only an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing a perovskite film, characterized in that: The following steps are involved: A perovskite inorganic salt solution containing a thickener is applied to a battery substrate to form a first inorganic substrate layer, and the battery substrate and the first inorganic substrate layer are combined to form a wet film substrate; the perovskite inorganic salt solution is formed by mixing a perovskite inorganic salt material and a solvent, the perovskite inorganic salt material is a mixture of PbI2, PbBr2, CsI, and FAI in a certain proportion, the solvent in the perovskite inorganic salt solution is dimethyl sulfoxide, the thickener is methylamine acetate, and the perovskite inorganic salt solution is configured to be 1 mol / L according to a volume ratio of dimethyl sulfoxide:methylamine acetate of 1:50; Cooling the wet film substrate and leaving it to stand, removing the organic solvent in the first inorganic substrate layer by vacuum flash evaporation to form a pre-dried film layer, wherein the pre-dried film layer is composed of a perovskite inorganic salt material and the thickener; Performing a first annealing treatment on the pre-dried film layer to remove cations in the thickener; Performing a second annealing treatment on the pre-dried film layer to remove anions in the thickener and obtain a second inorganic substrate layer; An organic halogen salt solution is coated on the second inorganic substrate layer, and a perovskite film is obtained after drying and annealing. The organic halogen salt solution is formed by mixing a solute and a solvent; the solvent of the organic halogen salt solution is n-butanol, and the solute of the organic halogen salt solution is a mixture of FAI, MAI, and FABr in a certain proportion. The concentration of the organic halogen salt solution is 15 mg / mL.

2. The method for preparing a perovskite thin film according to claim 1, wherein: The coating method of the perovskite inorganic salt solution includes one of slit coating, scraper coating, screen printing, and spray deposition processes.

3. The method for preparing a perovskite thin film according to claim 1 or 2, characterized in that: In the step of cooling and standing the wet film substrate, removing the organic solvent in the first inorganic substrate layer by vacuum flash evaporation to form a pre-dried film layer, wherein the pre-dried film layer is composed of a perovskite inorganic salt material and the thickener: the cooling rate range is 1-30°C / min, the cooling and standing temperature range is -5-20°C, and the standing time range is 0-400min.

4. The method for preparing a perovskite thin film according to claim 1 or 2, characterized in that: In the step of performing a first annealing treatment on the pre-dried film layer to remove cations in the thickener, the annealing temperature ranges from 40 to 90° C. and the annealing time ranges from 1 to 800 min.

5. The method for preparing a perovskite thin film according to claim 1 or 2, characterized in that: In the step of performing a second annealing treatment on the pre-dried film layer to remove anions in the thickener and obtain a second inorganic substrate layer: the annealing temperature ranges from 120 to 200° C., and the annealing time ranges from 1 to 500 min.

6. The method for preparing a perovskite thin film according to claim 1 or 2, characterized in that: In the step of coating the organic halogen salt solution on the second inorganic substrate layer, and obtaining the perovskite film after drying and annealing: after coating the organic halogen salt solution on the second inorganic substrate layer, let it stand for 1-5000s, and then dry and anneal.

7. A perovskite battery, characterized in that: include: Battery substrate; A first electrode layer disposed on the battery substrate; a first carrier transport layer disposed on the first electrode layer; A carrier transport passivation layer provided on the first carrier transport layer; A perovskite film disposed on the carrier transport passivation layer; A second carrier transport layer disposed on the perovskite film; a second electrode layer disposed on the second carrier transport layer; Wherein, the perovskite film is prepared by the method for preparing a perovskite film according to any one of claims 1 to 6.

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