Method for preparing high-efficiency stable CsPbI3 inorganic perovskite solar cell in atmospheric environment

Abstract

The application discloses a method for preparing a high-efficiency and stable CsPbI3 inorganic perovskite solar cell in an atmospheric environment, and comprises the following steps: using low-temperature SnO2 modified by an alkali metal halide salt as an electron transport layer, dropping a perovskite precursor solution containing a certain amount of benzylamine salt additive on the electron transport layer through a spin coating technology, adopting a two-step annealing method, adjusting the concentration of the additive, and realizing the preparation of a dense and uniform CsPbI3 thin film in a full-air environment, then spin-coating Spiro-OMeTAD as a hole transport layer and vacuum evaporation of an Ag electrode to obtain the preparation of the high-efficiency and stable CsPbI3 inorganic perovskite solar cell. The application realizes the low-energy-consumption preparation of the dense and uniform CsPbI3 inorganic perovskite solar cell under low environmental requirements, and has an excellent photoelectric conversion efficiency of 17.24%.

Description

Technical Field

[0001] This invention relates to the field of thin-film perovskite solar cell materials and devices, specifically to a method for preparing high-efficiency and stable CsPbI3 inorganic perovskite solar cells in an atmospheric environment. Background Technology

[0002] With the continuous advancement of industrial production and social development, people's use of natural resources is increasing. Fossil fuels, as non-renewable resources, are gradually becoming scarce, and the environmental pollution they cause is attracting increasing attention. Solar energy is renewable, clean, and abundant, and can be converted into electrical energy through photovoltaics. Solar cells have developed rapidly since the 1960s, and today, silicon-based solar cells are commercially available. However, the high cost of raw materials and the complexity of processing technology greatly limit the development of silicon-based solar cells. In the past decade, perovskite solar cells (PSCs), representing third-generation photovoltaics, have become a promising future technology. Metal halide perovskite semiconductors exhibit excellent photoelectric properties, such as tunable bandgap, excellent light collection ability, and long charge carrier lifetime. Since 2009, the photoelectric conversion efficiency of organic-inorganic hybrid perovskite solar cells has rapidly increased from 3.8% to 25.7%. However, the organic components in the light-absorbing layer greatly limit the long-term use of organic-inorganic hybrid perovskite solar cells in high-temperature environments. Therefore, researchers have proposed using all-inorganic perovskite as the light-absorbing layer to improve the thermal stability of the cells.

[0003] Currently, the fabrication of most inorganic CsPbI3 perovskite solar cells requires a glove box or dry air chamber, which greatly limits the possibility of industrial production and adds to the complexity of experiments. Furthermore, high-efficiency inorganic CsPbI3 perovskite solar cells all require the use of high-temperature TiO2 as an electron transport layer, which greatly increases the energy loss in the production process. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing high-efficiency and stable CsPbI3 inorganic perovskite solar cells in an atmospheric environment, which enables the CsPbI3 thin film to be uniformly and densely formed in ambient air, greatly reducing the stringent requirements of the preparation process.

[0005] In one aspect of the present invention, a method for preparing a perovskite precursor solution is provided. According to an embodiment of the present invention, the method includes the following steps: dissolving cesium iodide, lead iodide, and dimethylammonium iodide in a molar ratio of 1:1:1 to 1.5 in a DMF solvent, adding benzylamine salt as an additive, and stirring at 60 to 80°C for 2 to 4 hours to obtain the perovskite precursor solution.

[0006] In addition, the method for preparing a perovskite precursor solution according to the above embodiments of the present invention may also have the following additional technical features:

[0007] In some embodiments of the present invention, the concentration of the perovskite precursor solution is 0.6 to 1.0 mol / L, the benzylamine salt is 1,4-phenylenediamine salt, and the concentration of the benzylamine salt is 1 to 6 mg / mL.

[0008] In another aspect, the present invention provides a method for preparing CsPbI3 thin films. According to an embodiment of the present invention, the method includes the following steps:

[0009] (1) An electron transport layer was spin-coated onto a cleaned FTO transparent conductive glass sheet;

[0010] (2) The prepared perovskite precursor solution is spin-coated onto an FTO transparent conductive glass plate with an electron transport layer in ambient air without any treatment. The plate is then subjected to gradient annealing at 70°C for 3-5 minutes and at 100-200°C for 15-20 minutes to obtain a CsPbI3 light absorption layer, which is the CsPbI3 thin film.

[0011] In addition, the method for preparing a CsPbI3 thin film according to the above embodiments of the present invention may also have the following additional technical features:

[0012] In some embodiments of the present invention, the electron transport layer is SnO2 modified with alkali metal halide salts.

[0013] In some embodiments of the present invention, the method for preparing the electron transport layer includes the following steps:

[0014] (1) Dilute a 15% SnO2 aqueous solution with water at a volume ratio of 1:3, add an alkali metal halide AX to the SnO2 aqueous solution, stir at room temperature for 40-50 min, and filter to obtain a SnO2 precursor solution. In the alkali metal halide AX, A is any one of Li, Na, K, Rb, Cs, and X is any one of F, Cl, Br, I.

[0015] (2) Take the SnO2 precursor solution and spin coat it onto a clean FTO conductive glass surface. First, spin coat it at a speed of 800-1500 rpm for 3 seconds, and then spin coat it at a speed of 2500-4000 rpm for 30-40 seconds to obtain the electron transport layer.

[0016] In some embodiments of the present invention, in step (2), the temperature of the FTO transparent conductive glass sheet and the precursor solution is 50-70°C, and the spin coating method is to first spin coat at 800-1000 rpm for 8-10 seconds, and then spin coat at 3000-4000 rpm for 30-40 seconds.

[0017] In another aspect, this invention proposes a method for preparing high-efficiency and stable CsPbI3 inorganic perovskite solar cells under atmospheric conditions. According to an embodiment of the invention, the method includes the following steps:

[0018] (1) A hole transport layer is spin-coated on the CsPbI3 thin film on the FTO transparent conductive glass sheet.

[0019] (2) Vacuum evaporation of metal electrode Ag on hole transport layer to obtain the method for preparing high-efficiency and stable CsPbI3 inorganic perovskite solar cells in an atmospheric environment.

[0020] In addition, the method for preparing high-efficiency and stable CsPbI3 inorganic perovskite solar cells in an atmospheric environment according to the above embodiments of the present invention may also have the following additional technical features:

[0021] In some embodiments of the present invention, in step (1), the hole transport layer is Spiro-OMeTAD, and the method for preparing the hole transport layer includes the following steps:

[0022] (1) Dissolve 70-80 mg of Spiro-OMeTAD in 1-1.1 mL of chlorobenzene to obtain a Spiro-OMeTAD mixed solution;

[0023] (2) Dissolve 500-530 mg of lithium bis(trifluoromethanesulfonate)imide in 1-1.1 mL of acetonitrile solution to obtain a lithium salt solution;

[0024] (3) Add 25-30 μL of TBP solution to the Spiro-OMeTAD mixed solution obtained in step (1);

[0025] (4) Add 15-20 μL of the lithium salt solution obtained in step (2) to the solution obtained in step (3);

[0026] (5) Stir the mixed solution obtained in step (4) at room temperature for 30 to 40 minutes;

[0027] (6) Spin coat the solution after stirring in step (5) onto the CsPbI3 film at a spin speed of 3000-4000 rpm for 30-40 seconds.

[0028] In some embodiments of the present invention, in step (2), at 3*10 -4 An 80 nm thick Ag electrode is vacuum-deposited under a pressure of Pa at a deposition rate of 1–2 A° / s.

[0029] In another aspect of the present invention, a method for preparing high-efficiency and stable CsPbI3 inorganic perovskite solar cells in an atmospheric environment is proposed.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] 1) Most existing all-inorganic CsPbI3 perovskite solar cells require preparation in a drying oven or drying box with a humidity of RH < 30%, which greatly increases the complexity and uncontrollability of cell preparation. However, the CsPbI3 thin film prepared by this invention does not require special control of the ambient humidity. By utilizing the strong hydrophobicity of benzylamine salt, it can resist the erosion of the perovskite layer by moisture during the film formation process, which greatly improves the quality of the film prepared in air. This allows the CsPbI3 thin film to be uniformly and densely formed in ambient air, greatly reducing the stringent requirements of the preparation process.

[0032] 2) Most existing high-efficiency all-inorganic CsPbI3 perovskite solar cells require the use of high-temperature TiO2 as the electron transport material. The annealing temperature of nearly 500℃ greatly increases the energy consumption of production. However, this invention uses SnO2, which can be annealed at only 150℃, as the electron transport layer. It is modified with AX (A = Li, Na, K, Rb, Cs, X = F, Cl, Br, I) to prepare a uniform, dense, and highly conductive SnO2 electron transport layer. This greatly improves the carrier transport capability of the low-temperature electron transport layer and realizes the preparation of the electron transport layer and inorganic perovskite layer below 200℃. Finally, a high-efficiency solar cell device is obtained, with the CsPbI3 perovskite solar cell achieving a conversion efficiency of up to 17.24%.

[0033] 3) The CsPbI3 thin film substrate prepared by the present invention has good coverage, good surface morphology, large and uniform grain size, and good stability and repeatability.

[0034] 4) The CsPbI3 thin film prepared by this invention has an optical bandgap of 1.7 eV, which is expected to be used as the top cell of tandem solar cells to further improve the efficiency of commercial crystalline silicon solar cells and promote the development of the photovoltaic industry. Attached Figure Description

[0035] Figure 1 This is a cross-sectional SEM image of a method for preparing high-efficiency and stable CsPbI3 inorganic perovskite solar cells in an atmospheric environment, as described in Embodiment 1 of this invention.

[0036] Figure 2 In the figure, (a) is a surface morphology diagram of the electron transport layer in Comparative Example 3 of the present invention, (b) is a surface morphology diagram of the electron transport layer in Example 1 of the present invention, and (c) is a test diagram of the conductivity of the electron transport layer in Comparative Example 3 and Example 2 of the present invention.

[0037] Figure 3 These are SEM images of the CsPbI3 thin films prepared in Comparative Example 2 and Example 1 of this invention.

[0038] Figure 4 These are contact angle test images of the CsPbI3 thin films prepared in Comparative Example 2 and Example 1 of this invention;

[0039] Figure 5 This is a JV curve of the CsPbI3 inorganic perovskite solar cells prepared in Comparative Examples 1-3 and Example 1 of this invention. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0041] Example 1

[0042] A method for preparing high-efficiency and stable CsPbI3 inorganic perovskite solar cells in an atmospheric environment includes the following steps:

[0043] (1) Preparation of SnO2 solution: Dilute 15% SnO2 aqueous solution with water at a volume ratio of 1:3, add 2mg RbCl to 1ml of SnO2 aqueous solution, stir at room temperature for 50min, and filter for later use.

[0044] (2) Preparation of SnO2 thin film: Take 2 drops of SnO2 precursor solution and add them to the cleaned FTO conductive glass surface (after cleaning with detergent, acetone and isopropanol). Adjust the spin coater parameters to 1000 rpm for 3s and 3000 rpm for 30s. After spin coating, remove the substrate and sinter at 150℃ for 30min to obtain FTO / SnO2 substrate.

[0045] (3) Preparation of CsPbI3 precursor solution: Weigh 368 mg PbI2, 208 mg CsI, 138 mg DMAI and 4 mg 1,4-phenylenediamine iodine and add them to 1 mL LDMF to prepare a 0.8 mol / L CsPbI3 solution. Stir at 70 °C for 2 h until completely dissolved. Filter with a 0.22 μm PTFE filter to obtain a clear and transparent orange-yellow solution, which is used as the CsPbI3 perovskite precursor solution.

[0046] (4) Preparation of CsPbI3 thin film: The FTO transparent conductive glass sheet and the precursor solution were preheated on a heating stage at 50°C. Two drops of the precursor solution obtained in step (3) were dropped onto the glass substrate containing SnO2. The spin coater parameters were adjusted to 1000 rpm for 10 s and 3000 rpm for 30 s. After spin coating, the substrate was removed and annealed on a heating stage at 70°C for 3 minutes. Then the substrate was placed on a heating stage at 190°C for annealing for 18 minutes.

[0047] (5) Preparation of Spiro-OMeTAD solution: Dissolve 72.3 mg of Spiro-OMeTAD in 1 mL of chlorobenzene, dissolve 520 mg of lithium bis(trifluoromethanesulfonate)imide in 1 mL of acetonitrile solution, add 17.5 μL of the resulting lithium salt solution to the Spiro-OMeTAD chlorobenzene solution, add 28.0 μL of LBP solution to the Spiro-OMeTAD solution, stir at room temperature for 40 minutes until completely dissolved, filter with a 0.22 μm PTFE filter to obtain a clear, transparent yellow solution.

[0048] (6) Preparation of Spiro-OMeTAD thin film: Take 1 drop of the precursor solution obtained in step (5) and drop it onto the surface of CsPbI3 thin film. Adjust the spin coater parameters to 4000 rpm for 30 s. The hole transport layer thickness is 100 nm.

[0049] (7) Electrode preparation: at 3*10 -4 Under a pressure of Pa, the evaporation rate was set to 1 A° / s, and an 80 nm metal Ag electrode was vacuum-deposited onto the hole transport layer, thereby completing the fabrication of a perovskite solar cell.

[0050] like Figure 1 As shown in the device structure diagram, the entire inorganic CsPbI3 perovskite solar cell device structure is FTO / SnO2 / CsPbI3 / Spiro-OMeTAD / Ag, with thicknesses of 400nm, 20nm, 350nm, 100nm, and 80nm, respectively.

[0051] Comparative Example 1

[0052] A method for developing a CsPbI3 inorganic perovskite solar cell includes the following steps:

[0053] (1) Preparation of SnO2 solution: Dilute the SnO2 aqueous solution with a mass ratio of 15% with water at a volume ratio of 1:3, stir at room temperature for 50 min, and filter for later use.

[0054] (2) Preparation of SnO2 thin film: Take 2 drops of SnO2 precursor solution and add them to the clean FTO conductive glass surface. Adjust the spin coater parameters to 1000 rpm for 3s and 3000 rpm for 30s. After spin coating, remove the substrate and sinter at 150℃ for 30min to obtain FTO / SnO2 substrate.

[0055] (3) Preparation of CsPbI3 precursor solution: Weigh 368 mg PbI2, 208 mg CsI and 138 mg DMAI (dimethylammonium iodide) and add them to 1 mL DMSO to prepare a 0.8 mol / L CsPbI3 solution. Stir at 70 °C for 2 h until completely dissolved. Filter with a 0.22 μm PTFE filter to obtain a clear and transparent orange-yellow solution, which is used as the CsPbI3 perovskite precursor solution.

[0056] (4) Preparation of CsPbI3 thin film: The FTO transparent conductive glass sheet and the precursor solution were preheated on a heating stage at 50°C. Two drops of the precursor solution obtained in step (3) were dropped onto the glass substrate containing SnO2. The spin coater parameters were adjusted to 1000 rpm for 10 s and 3000 rpm for 30 s. After spin coating, the substrate was removed and annealed on a heating stage at 70°C for 3 minutes. Then the substrate was placed on a heating stage at 190°C for annealing for 18 minutes.

[0057] (5) Preparation of Spiro-OMeTAD solution: Dissolve 72.3 mg of Spiro-OMeTAD in 1 mL of chlorobenzene, dissolve 520 mg of lithium bis(trifluoromethanesulfonate)imide in 1 mL of acetonitrile solution, add 17.5 μL of the resulting lithium salt solution to the Spiro-OMeTAD chlorobenzene solution, add 28.0 μL of LBP solution to the Spiro-OMeTAD solution, stir at room temperature for 40 minutes until completely dissolved, filter with a 0.22 μm PTFE filter to obtain a clear and transparent yellow solution;

[0058] (6) Preparation of Spiro-OMeTAD thin film: Take 1 drop of the precursor solution obtained in step (5) and drop it onto the surface of CsPbI3 thin film. Adjust the spin coater parameters to 4000 rpm for 30 s. The hole transport layer thickness is 30 nm.

[0059] (7) Electrode preparation: at 3*10 -4 Under a pressure of Pa, the evaporation rate was set to 1 A° / s, and an 80 nm metal Ag electrode was vacuum-deposited onto the hole transport layer, thereby completing the fabrication of a perovskite solar cell.

[0060] Comparative Example 2

[0061] A method for developing a CsPbI3 inorganic perovskite solar cell includes the following steps:

[0062] (1) Preparation of SnO2 solution: Dilute the SnO2 aqueous solution with a mass ratio of 15% with water at a volume ratio of 1:3, add 2mgAX (A=Li, Na, K, Rb, Cs, X=F, Cl, Br, I) to 1ml of SnO2 aqueous solution, stir at room temperature for 50min, filter and set aside.

[0063] (2) Preparation of SnO2 thin film: Take 2 drops of SnO2 precursor solution and add them to the clean FTO conductive glass surface. Adjust the spin coater parameters to 1000 rpm for 3s and 3000 rpm for 30s. After spin coating, remove the substrate and sinter at 150℃ for 30min to obtain FTO / SnO2 substrate.

[0064] (3) Preparation of CsPbI3 precursor solution: Weigh 368 mg PbI2, 208 mg CsI and 138 mg DMAI and add them to 1 mL LDMF to prepare a 0.8 mol / L CsPbI3 solution. Stir at 70 °C for 2 h until completely dissolved. Filter with a 0.22 μm PTFE filter to obtain a clear and transparent orange-yellow solution, which is used as the CsPbI3 perovskite precursor solution.

[0065] (4) Preparation of CsPbI3 thin film: The FTO transparent conductive glass sheet and the precursor solution were preheated on a heating stage at 50°C. Two drops of the precursor solution obtained in step (3) were dropped onto the glass substrate containing SnO2. The spin coater parameters were adjusted to 1000 rpm for 10 s and 3000 rpm for 30 s. After spin coating, the substrate was removed and annealed on a heating stage at 70°C for 3 minutes. Then the substrate was placed on a heating stage at 190°C for annealing for 18 minutes.

[0066] (5) Preparation of Spiro-OMeTAD solution: Dissolve 72.3 mg of Spiro-OMeTAD in 1 mL of chlorobenzene, dissolve 520 mg of lithium bis(trifluoromethanesulfonate)imide in 1 mL of acetonitrile solution, add 17.5 μL of the resulting lithium salt solution to the Spiro-OMeTAD chlorobenzene solution, add 28.0 μL of LBP solution to the Spiro-OMeTAD solution, stir at room temperature for 40 minutes until completely dissolved, filter with a 0.22 μm PTFE filter to obtain a clear and transparent yellow solution;

[0067] (6) Preparation of Spiro-OMeTAD thin film: Take 1 drop of the precursor solution obtained in step (5) and drop it onto the surface of CsPbI3 thin film. Adjust the spin coater parameters to 4000 rpm for 30 s. The hole transport layer thickness is 30 nm.

[0068] (7) Electrode preparation: at 3*10 -4Under a pressure of Pa, the evaporation rate was set to 1 A° / s, and an 80 nm metal Ag electrode was vacuum-deposited onto the hole transport layer, thereby completing the fabrication of a perovskite solar cell.

[0069] Comparative Example 3

[0070] A method for developing a CsPbI3 inorganic perovskite solar cell includes the following steps:

[0071] (1) Preparation of SnO2 solution: Dilute the SnO2 aqueous solution with a mass ratio of 15% with water at a volume ratio of 1:3, stir at room temperature for 50 min, and filter for later use.

[0072] (2) Preparation of SnO2 thin film: Take 2 drops of SnO2 precursor solution and add them to the clean FTO conductive glass surface. Adjust the spin coater parameters to 1000 rpm for 3s and 3000 rpm for 30s. After spin coating, remove the substrate and sinter at 150℃ for 30min to obtain FTO / SnO2 substrate.

[0073] (3) Preparation of CsPbI3 precursor solution: Weigh 368 mg PbI2, 208 mg CsI, 138 mg DMAI and 4 mg 1,4-phenylenediamine iodine and add them to 1 mL LDMF to prepare a 0.8 mol / L CsPbI3 solution. Stir at 70 °C for 2 h until completely dissolved. Filter with a 0.22 μm PTFE filter to obtain a clear and transparent orange-yellow solution, which is used as the CsPbI3 perovskite precursor solution.

[0074] (4) Preparation of CsPbI3 thin film: The FTO transparent conductive glass sheet and the precursor solution were preheated on a heating stage at 50°C. Two drops of the precursor solution obtained in step (3) were dropped onto the glass substrate containing SnO2. The spin coater parameters were adjusted to 1000 rpm for 10 s and 3000 rpm for 30 s. After spin coating, the substrate was removed and annealed on a heating stage at 70°C for 3 minutes. Then the substrate was placed on a heating stage at 190°C for annealing for 18 minutes.

[0075] (5) Preparation of Spiro-OMeTAD solution: Dissolve 72.3 mg of Spiro-OMeTAD in 1 mL of chlorobenzene, dissolve 520 mg of lithium bis(trifluoromethanesulfonate)imide in 1 mL of acetonitrile solution, add 17.5 μL of the resulting lithium salt solution to the Spiro-OMeTAD chlorobenzene solution, add 28.0 μL of LBP solution to the Spiro-OMeTAD solution, stir at room temperature for 40 minutes until completely dissolved, filter with a 0.22 μm PTFE filter to obtain a clear, transparent yellow solution.

[0076] (6) Preparation of Spiro-OMeTAD thin film: Take 1 drop of the precursor solution obtained in step (5) and drop it onto the surface of CsPbI3 thin film. Adjust the spin coater parameters to 4000 rpm for 30 s. The hole transport layer thickness is 30 nm.

[0077] (7) Electrode preparation: at 3*10 -4 Under a pressure of Pa, the evaporation rate was set to 1 A° / s, and an 80 nm metal Ag electrode was vacuum-deposited onto the hole transport layer, thereby completing the fabrication of a perovskite solar cell.

[0078] The cross-sectional morphology of the CsPbI3 thin film prepared in Example 1 is as follows: Figure 3 As shown in b, the thickness of the perovskite layer is approximately 350 nm. The morphology of the CsPbI3 thin film prepared in Comparative Example 2 is as follows. Figure 3 As shown in a, by Figure 3 It can be seen that the thin film of Example 1 has larger and more uniform grain size, fewer pinholes, and fewer surface defects.

[0079] Figure 2 Image a shows the surface morphology of the electron transport layer in Comparative Example 3, and image 2b shows the surface morphology of the electron transport layer in Example 1. The IV test of the electron transport layer is as follows: Figure 2 As shown in c, a larger slope demonstrates better electron extraction and transport capabilities.

[0080] Under standard test conditions (AM1.5G illumination), the performance parameters of the perovskite solar cell device prepared in Example 1 are as follows: energy conversion efficiency 17.24%, open-circuit voltage 1.08V, and short-circuit current 20.14mA / cm². 2 The fill factor was 79.18%. The performance parameters of the perovskite solar cell device prepared in Comparative Example 3 were: energy conversion efficiency of 16.40%, open-circuit voltage of 1.09V, and short-circuit current of 20.06mA / cm². 2 The fill factor is 74.34%. The performance parameters of the perovskite solar cell device prepared in Comparative Example 2 are as follows: energy conversion efficiency 15.05%, open-circuit voltage 1.05V, and short-circuit current 19.52mA / cm². 2 The fill factor is 73.42%. The performance parameters of the perovskite solar cell device prepared in Comparative Example 1 are as follows: energy conversion efficiency 14.85%, open-circuit voltage 1.03V, and short-circuit current 19.21mA / cm². 2 The fill factor is 74.39%. The above data shows that improving the electron transport layer with alkali metal salts enhances the device's carrier extraction capability, leading to an increase in short-circuit current. The perovskite film optimized with aniline salts exhibits significantly improved quality, resulting in reduced leakage current and increased open-circuit voltage.

[0081] Figure 4a and 4b are the contact angle tests of the CsPbI3 films of Comparative Example 2 and Example 1, respectively. The film optimized with 1,4-phenylenediamine salt has stronger moisture resistance and improved humidity stability. Figure 5 The JV curve of the device shows that the photoelectric conversion efficiency of the optimized device has been greatly improved from 14.85% to 17.24%, realizing the fabrication of an all-inorganic high-efficiency solar cell for ambient air, and providing a possibility for promoting the industrialization of inorganic perovskite solar cells.

[0082] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the present invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for preparing a perovskite precursor solution, characterized in that, Includes the following steps: Cesium iodide, lead iodide, and dimethylammonium iodide are dissolved in DMF solvent at a molar ratio of 1:1:1~1.5, and benzylamine salt is added as an additive. The mixture is stirred at 60~80°C for 2~4 hours to obtain the perovskite precursor solution, wherein the benzylamine salt is 1,4-phenylenediamine salt.

2. The method for preparing a perovskite precursor solution according to claim 1, characterized in that: The concentration of the perovskite precursor solution is 0.6~1.0 mol / L, and the concentration of the benzylamine salt is 1~6 mg / mL.

3. A method for preparing a CsPbI3 thin film, characterized in that, Includes the following steps: (1) An electron transport layer is spin-coated onto a cleaned FTO transparent conductive glass sheet; (2) The perovskite precursor solution prepared according to the method of claim 1 is spin-coated onto an FTO transparent conductive glass sheet with an electron transport layer in ambient air without any treatment. The perovskite precursor solution is then subjected to gradient annealing at 70°C for 3-5 minutes and at 100-200°C for 15-20 minutes to obtain a CsPbI3 light absorption layer, which is the CsPbI3 thin film.

4. The method for preparing a CsPbI3 thin film according to claim 3, characterized in that: The electron transport layer is SnO2 modified with alkali metal halide salts.

5. The method for preparing a CsPbI3 thin film according to claim 4, characterized in that, The method for preparing the electron transport layer includes the following steps: (1) Dilute the SnO2 aqueous solution with a mass ratio of 15% with water at a volume ratio of 1:3, add the alkali metal halide AX to the SnO2 aqueous solution, stir at room temperature for 40-50 min, and filter to obtain the SnO2 precursor solution. In the alkali metal halide AX, A is any one of Li, Na, K, Rb, Cs, and X is any one of F, Cl, Br, I. (2) Take the SnO2 precursor solution and spin coat it onto a clean FTO conductive glass surface. First, spin coat it at a speed of 800~1500 rpm for 3 seconds, and then spin coat it at a speed of 2500~4000 rpm for 30~40 seconds. After spin coating, anneal it on a heating stage at 130~160℃ for 30~40 minutes to obtain the electron transport layer.

6. The method for preparing a CsPbI3 thin film according to claim 3, characterized in that: In step (2), the temperature of the FTO transparent conductive glass sheet and the precursor solution is 50~70℃, and the spin coating method is to first spin coat at 800~1000 rpm for 8~10 seconds, and then spin coat at 3000~4000 rpm for 30~40 seconds.

7. A method for preparing high-efficiency and stable CsPbI3 inorganic perovskite solar cells in an atmospheric environment, characterized in that, Includes the following steps: (1) A hole transport layer is spin-coated on a CsPbI3 thin film on an FTO transparent conductive glass sheet according to any one of claims 3-6; (2) Vacuum evaporation of metal electrode Ag on hole transport layer to obtain the high-efficiency and stable CsPbI3 inorganic perovskite solar cell prepared in ambient air with low energy consumption.

8. The method for preparing high-efficiency and stable CsPbI3 inorganic perovskite solar cells in an atmospheric environment according to claim 7, characterized in that: In step (1), the hole transport layer is Spiro-OMeTAD, and the preparation method of the hole transport layer includes the following steps: (1) Dissolve 70-80 mg of Spiro-OMeTAD in 1-1.1 mL of chlorobenzene to obtain a Spiro-OMeTAD mixed solution; (2) Dissolve 500~530 mg of lithium bis(trifluoromethanesulfonate)imide in 1~1.1 mL of acetonitrile solution to obtain lithium salt solution; (3) Add 25~30 μL of TBP solution to the Spiro-OMeTAD mixed solution obtained in step (1); (4) Add 15~20 μL of the lithium salt solution obtained in step (2) to the solution obtained in step (3); (5) Stir the mixed solution obtained in step (4) at room temperature for 30-40 minutes; (6) Spin coat the solution after stirring in step (5) onto the CsPbI3 film at a spin speed of 3000~4000 rpm and a spin time of 30~40 seconds.

9. The method for preparing high-efficiency and stable CsPbI3 inorganic perovskite solar cells in an atmospheric environment according to claim 7, characterized in that: In step (2), in 3*10 -4 An 80 nm thick Ag electrode is vacuum-deposited under a pressure of Pa at a deposition rate of 1~2 A° / s.

10. A method for preparing a high-efficiency and stable CsPbI3 inorganic perovskite solar cell in an atmospheric environment according to the method described in claim 7.

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