A trans perovskite solar cell with a cuprous iodide nanocrystal dispersion liquid as a hole transport layer and a preparation method thereof

Abstract

The application discloses a kind of cuprous iodide nanocrystal dispersion liquid as hole transport layer transverse perovskite solar cell and preparation method thereof, belong to solar cell technical field.The application first proposes that thiol doped CuI dispersion liquid is prepared as the preparation strategy of the hole transport layer of perovskite solar cell, the problems of the roughness increase, the pinhole increase, the thickness unevenness etc. under existing process are solved, so that CuI-SH solution is more dispersed and stable.The transverse perovskite solar cell prepared by the application has excellent surface quality of CuI-SH hole transport layer, and the film is more flat and uniform, without CuI aggregation and other defects, and the overall perovskite solar cell shows excellent scalable preparation capacity, which lays a solid foundation for scalable preparation of transverse perovskite solar cell.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and in particular to an inverted perovskite solar cell with a cuprous iodide nanocrystal dispersion as a hole transport layer and its preparation method. Background Technology

[0002] Against the backdrop of ever-increasing energy demand, the development and utilization of solar energy has always been a research hotspot in the field. Therefore, solar cells, which convert solar energy into electricity, have been extensively studied and developed rapidly. Not only have the types of solar cells become increasingly diverse, but their conversion efficiency has also steadily improved. In just over a decade, the conversion efficiency of novel perovskite solar cells has become comparable to that of silicon-based solar cells, skyrocketing from 3.8% in 2009 to over 27% certified in 2026. Among them, perovskite solar cells with inverted device structures have attracted researchers' attention due to their simple fabrication process and applicability to flexible and large-area fabrication, and possess great development potential in the commercialization of perovskite solar cells.

[0003] In inverted perovskite solar cells, CuI is considered an ideal candidate to replace expensive organic hole transport materials due to its wide bandgap (~3.1 eV), high hole mobility, good optical transmittance, and valence band level matching the perovskite layer. It can be prepared via a low-temperature solution method, which is inexpensive and exhibits excellent chemical and thermal stability, beneficial for the long-term stable operation of the device. For example, in Chinese invention patent publication CN118419963A, the applicant provides a method for preparing cuprous iodide and an inverted perovskite solar cell. This method uses organic cuprous salts and organic iodamine compounds to prepare cuprous iodide, and uses the prepared cuprous iodide as the hole transport layer material in the inverted perovskite solar cell. This reduces the surface roughness of the hole transport layer and makes the nucleation sites on the surface of the hole transport layer more dispersed, which is beneficial for the crystallization of perovskite film and improves the film quality. However, in further research, the inventors found that the low-temperature solution method still has certain drawbacks due to the intrinsic properties of CuI. CuI nanoparticles are prone to agglomeration in precursor dispersions due to their high surface energy, resulting in poor colloidal stability. This leads to problems such as increased roughness, more pinholes, and uneven thickness during film formation, which degrades the interfacial contact with the perovskite layer, exacerbates carrier recombination losses, and severely restricts the uniformity and large-scale manufacturing of large-area devices.

[0004] In summary, providing a novel process to achieve the large-scale preparation of flat, dense, and pinhole-free CuI hole transport layers is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] In view of the above-mentioned defects of the prior art, especially for inverted perovskite solar cells using CuI as the hole transport layer, the purpose of this invention is to solve the problem of easy aggregation of CuI nanoparticle solutions, and to provide CuI-SH as the hole transport layer to solve the above-mentioned problem, and to provide a method for preparing highly efficient and stable inverted perovskite solar cells that can be mass-produced.

[0006] To achieve the above objectives, the technical solution provided by the present invention is as follows: In a first aspect of the present invention, a method for preparing an inverted perovskite solar cell using a cuprous iodide nanocrystal dispersion as a hole transport layer is provided, comprising the following steps: (1) Dissolve the mercapto-containing compound in isopropanol to form a mercapto solution; dope the mercapto solution into the isopropanol dispersion of CuI to obtain a CuI-SH dispersion; (2) The CuI-SH dispersion was coated onto a transparent conductive substrate and then annealed to form a CuI-SH hole transport layer; (3) A perovskite light-absorbing layer, an electron transport layer, an interface modification layer and a metal electrode layer are sequentially stacked on a CuI-SH hole transport layer to form an inverted perovskite solar cell.

[0007] Preferably, in step (1), the thiol-containing compound includes at least one of thiol polyethylene glycol thiol, thioglycolic acid, and 3-mercaptopropionic acid; the thiol concentration of the thiol solution is 0.5~1 mg / mL.

[0008] Preferably, in step (1), the preparation method of CuI isopropanol dispersion is as follows: the chemically reacted amounts of organic cuprous salt and organic amine salt are dissolved in isopropanol for reaction, and after the reaction is completed, the product is washed with isopropanol. The obtained product is annealed at 100~120℃ for 30~60 min to obtain CuI powder. Then, the CuI powder is dispersed in isopropanol at a concentration of 4~6 mg / mL to obtain CuI isopropanol dispersion.

[0009] More preferably, the organic cuprous salt includes at least one of cuprous acetate, cuprous diphenyl phosphate, and cuprous trifluoromethanesulfonate toluene complex; the organic amine salt includes at least one of methyl iodine, methyl iodine, and phenethylamine hydroiodate.

[0010] Preferably, in step (1), the thiol solution is doped into the isopropanol dispersion of CuI at a ratio of 1:8 to 1:10 to obtain CuI-SH dispersion.

[0011] Preferably, in step (2), the CuI-SH dispersion is coated onto a transparent conductive substrate by spin coating. The transparent conductive substrate includes ITO conductive glass with dimensions of 1.5 cm × 1.5 cm to 2 cm × 2 cm. The amount of CuI-SH dispersion used is 40 to 60 μL. The spin coating speed is 3000 to 5000 rpm and the time is 30 to 50 s. The annealing temperature is 100 to 120°C and the time is 10 to 15 min.

[0012] Preferably, in step (2), the transparent conductive substrate is cleaned and impurity removed before coating. First, the transparent conductive substrate is rinsed with deionized water and ultrasonically treated. Then, it is placed in anhydrous ethanol, isopropanol, acetone and anhydrous ethanol for ultrasonic treatment in sequence. When in use, it is dried with high-purity nitrogen gas and then treated with ultraviolet ozone.

[0013] Preferably, in step (3), the preparation method of the perovskite light-absorbing layer includes the following steps: FAPbI3 (formamidinium lead triiodide), CsPbI3 (lead triiodide cesium triiodide), and MAPbBr3 (methylamine lead bromide) are dissolved in a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) at a volume ratio of 4:1 to 9:1, respectively, to prepare a solution with a concentration of 1.3 to 1.5 mol / L; after complete dissolution, 3 to 5% molar concentration of CsPbI3 and 3 to 5% molar concentration of MAPbBr3 are added to the FAPbI3 solution to form a perovskite precursor solution, which is then spin-coated onto the CuI-SH hole transport layer. The amount of the perovskite precursor solution is 45 to 60 μL, and the spin coating speed is 4000 to 6000. At rpm for 20-40 seconds, chlorobenzene antisolvent is added dropwise at the 10th-20th second before spin coating. The perovskite mesophase film is then annealed at 100-120℃ for 10-30 minutes to form a perovskite light-absorbing layer.

[0014] Preferably, in step (3), the preparation method of the electron transport layer includes the following steps: dissolving PCBM in chlorobenzene at a concentration of 20~40 mg / mL to obtain a PCBM solution; swirling the PCBM solution onto the perovskite light-absorbing layer, with a PCBM solution volume of 30~35 μL, a swirling speed of 2000~3000 rpm / s, and a time of 20~40 s; and then annealing at 70~100℃ for 10~20 min to form an electron transport layer.

[0015] PCBM is a fullerene derivative that is widely used as an electron acceptor material in the fabrication of electron transport layers in organic photovoltaics and perovskite solar cells.

[0016] Preferably, in step (3), the method for preparing the interface modification layer includes the following steps: dissolving BCP in trifluoroethanol at a concentration of 0.5~1 mg / mL to obtain a BCP solution; spin-coating the BCP solution onto the electron transport layer, with a BCP solution volume of 30~50 μL, a spin-coating speed of 5000~6000 rpm / s, and a time of 20~40 s, followed by annealing at 70~100℃ for 5~10 min to form an interface modification layer.

[0017] BCP, or dimethyl-4,7-diphenyl-1,10-phenanthroline, is widely used in the field of solar cells as an electron transport layer and an exciton / hole blocking material.

[0018] Preferably, in step (3), the preparation method of the metal electrode layer includes the following steps: depositing a metal thin film on the electron transport layer by thermal evaporation under vacuum conditions, the thickness of the metal thin film being controlled at 150~200 nm, and the metal type including silver.

[0019] In a second aspect of the present invention, an inverted perovskite solar cell is provided, comprising a transparent conductive substrate and a CuI-SH hole transport layer, a perovskite light-absorbing layer, an electron transport layer, an interface modification layer and a metal electrode layer sequentially stacked thereon, and is fabricated using the preparation method of the first aspect of the present invention.

[0020] Preferably, the transparent conductive substrate comprises ITO conductive glass; the CuI-SH hole transport layer comprises thiol-doped CuI; and the perovskite light-absorbing layer comprises an APbX3 thin film, wherein A represents Cs. + methylammonium ion (MA) + ), methyl etheramine ion (FA) + One of them, X represents I. - or Br - The electron transport layer includes PCBM; the interface modification layer includes BCP; and the metal electrode layer includes a silver electrode layer.

[0021] Based on the above technical solutions, the design concept and principle of this invention are as follows: Addressing the key bottlenecks in existing CuI nanoparticle technologies, this invention designs a method to incorporate thiol-containing (-SH) functional molecules into a CuI dispersion, utilizing the interaction between the thiol groups and the surface Cu... +Strong Cu-S coordination bonds are formed, creating steric hindrance and electrostatic repulsion on the particle surface, thereby effectively suppressing aggregation and significantly improving the stability and shelf life of the dispersion. Based on this modification process, a smooth, dense, and pinhole-free CuI hole transport layer was prepared, successfully realizing the large-scale fabrication of high-efficiency, large-area devices. Furthermore, as presented in one or more embodiments of this invention, the feasibility of the thiol molecule modification strategy in promoting the industrial application of CuI-based perovskite batteries is verified.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects: This invention provides an inverse perovskite solar cell with a cuprous iodide nanocrystal dispersion as the hole transport layer and its preparation method. It proposes for the first time a strategy for preparing a perovskite solar cell with a thiol-doped CuI dispersion as the hole transport layer, which solves the problems of increased roughness, increased pinholes, and uneven thickness existing in the existing process, making the CuI-SH solution more dispersed and stable.

[0023] This invention provides an inverted perovskite solar cell with an excellent surface quality of its CuI-SH hole transport layer, which is flat, uniform, and free from defects such as CuI agglomeration, laying a solid foundation for the large-scale fabrication of inverted perovskite solar cells. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the device structure of an inverted perovskite solar cell; Figure 2 The images show a comparison of the hole transport layer solution before and after aging experiments in the preparation methods of Example 1 and Comparative Example 1. Figure 3 Comparison of the microstructures of the hole transport layers prepared by the methods of Example 1 and Comparative Example 1; Figure 4 The failure rate results for the fabrication methods of Example 1 and Comparative Example 1 used in the fabrication of large-area devices are shown. Detailed Implementation

[0025] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0026] In the following embodiments: Copper(I) trifluoromethanes μLfonatetoluene complex (molecular formula (CF3SO3Cu)2C6H5CH3) is manufactured by Aladdin; Methylamine Hydroiodide (molecular formula CH5N.HI) is manufactured by Greatcell; and thiol-based polyethylene glycol thiol (molecular formula HSCH2CH2(OCH2CH2)) is manufactured by [company name missing]. n SH-mercaptoacetic acid (molecular formula C2H4O2S) and 3-mercaptopropionic acid (molecular formula C3H6O2S) are both produced by Aladdin.

[0027] Example 1 The preparation method of inverse perovskite solar cells using cuprous iodide nanocrystal dispersion as a hole transport layer is as follows: (1) Substrate cleaning: The large transparent conductive substrate ITO was cut into uniform sizes of 1.5 cm × 1.5 cm using a glass cutter. The surface of the ITO was then rinsed with deionized water and ultrasonically treated. Subsequently, it was placed in anhydrous ethanol, isopropanol, acetone and anhydrous ethanol for cleaning in sequence. After cleaning, it was placed in anhydrous ethanol solution for storage. When used, it was dried with high-purity nitrogen and treated with ultraviolet ozone to obtain a clean transparent conductive substrate. First, the copper(II) trifluoromethanesulfonate toluene complex and iodine methylamine were mixed and stirred in an isopropanol solution. The reaction product was then washed three times with isopropanol by centrifugation. The product was then dried in a drying oven at 120°C to obtain CuI nanoparticle powder. The CuI powder was then dispersed and dissolved in a clean isopropanol solution to prepare a 2 mg / mL CuI isopropanol dispersion. A 0.5 mg / mL thiol solution was prepared by dissolving thiol molecules (thiol polyethylene glycol thiol in this example) in isopropanol solution. Then, the solution was doped into the isopropanol dispersion of CuI at a ratio of 1:10 to obtain CuI-SH dispersion. (2) Spin-coating 50 μL of CuI-SH dispersion onto a transparent conductive substrate (3000 rpm, 30 s), and annealing at 120℃ for 10 min to obtain a CuI-SH hole transport layer; (3) Preparation of perovskite light-absorbing layer: FAPbI3, CsPbI3 and MAPbBr3 were dissolved in a mixed solvent of DMF and DMSO at a volume ratio of 9:1 to prepare a solution with a concentration of 1.3 mol / L. After complete dissolution, 3% molar concentration of CsPbI3 and 3% molar concentration of MAPbBr3 were added to the FAPbI3 solution and stirred at a constant speed until uniformly mixed to obtain perovskite precursor solution. Then, 45 μL of perovskite precursor solution was pipetted evenly onto the hole transport layer in step (2) and spin-coated using a spin coater at a speed of 5000 rpm / s for 30 s. At the 10th to 20th s from the end, 200 μL of chlorobenzene antisolvent solution was quickly and evenly added. Then, the solution was transferred to a heating plate and annealed at 100℃ for 30 min to obtain perovskite light-absorbing layer. Preparation of the electron transport layer: First, weigh 30 mg of PCBM powder sample, then add 1 mL of chlorobenzene solution, stir evenly and filter to prepare a 30 mg / mL PCBM solution; then use a pipette to take 35 μL and evenly drop it onto the prepared perovskite light-absorbing layer, spin coat it using a spin coater at 3000 rpm / s for 30 s, and then transfer it to a hot plate and anneal at 100℃ for 10 min to obtain the PCBM electron transport layer; Interface modification layer: First, weigh 0.5 mg of BCP powder sample, then add 1 mL of trifluoroethanol solution, stir evenly and filter to prepare a 0.5 mg / mL BCP solution; then use a pipette to take 50 μL and evenly drop it onto the prepared electron transport layer, spin coat it using a spin coater at 5000 rpm / s for 30 s, and then transfer it to a hot plate and anneal at 70℃ for 5 min to obtain the BCP interface modification layer; Electrode evaporation: A silver metal electrode layer is uniformly deposited above the electron transport layer under vacuum conditions by thermal evaporation using a vacuum coating instrument. The film thickness monitor shows that the electron layer thickness is in the range of 150 to 200 nm.

[0028] Example 2 This embodiment provides a method for preparing an inverse perovskite solar cell using a cuprous iodide nanocrystal dispersion as a hole transport layer. The method is essentially the same as in Example 1, except that mercaptoacetic acid is used in this embodiment for hole transport layer preparation. The concentration of the mercapto solution remains unchanged; with an optional mercapto source, this embodiment also achieves the preparation of an inverse perovskite solar cell.

[0029] Example 3 This embodiment provides a method for preparing an inverse perovskite solar cell using a cuprous iodide nanocrystal dispersion as a hole transport layer. The method is essentially the same as in Example 1, except that 3-mercaptopropionic acid is used in this embodiment for hole transport layer preparation. The concentration of the thiol solution remains unchanged; with an optional thiol source, this embodiment also achieves the preparation of an inverse perovskite solar cell.

[0030] Example 4 This embodiment provides the inverse perovskite solar cell fabricated in the above embodiments, with the structure as follows: Figure 1 As shown, it includes a transparent conductive substrate and a CuI-SH hole transport layer, a perovskite light-absorbing layer, an electron transport layer, an interface modification layer, and a metal electrode layer stacked thereon in sequence.

[0031] Those skilled in the art can select appropriate parameter combinations within the preferred parameter range of this invention according to actual conditions or needs, and can thus achieve the fabrication of inverted perovskite solar cells and obtain the target inverted perovskite solar cells.

[0032] Comparative Example 1 This comparative example provides an inverted perovskite solar cell, whose fabrication method is basically the same as that of Example 1, except that the hole transport layer in this comparative example does not use thiol doping. The specific steps are as follows: First, a mixture of copper(II) trifluoromethanesulfonate toluene complex and methyl iodide was stirred and reacted in isopropanol solution. The reaction product was then washed three times with isopropanol by centrifugation, followed by drying at 120°C in a drying oven to obtain CuI nanoparticle powder. The CuI powder was then dispersed and dissolved in a clean isopropanol solution to prepare a 2 mg / mL CuI isopropanol dispersion. 50 μL of this dispersion was then pipetted evenly onto a transparent conductive substrate and spin-coated at 4000 rpm for 30 s. The substrate was then annealed at 100°C for 30 min to obtain a CuI hole transport layer. A 1.5 mg / mL KI solution was prepared by dissolving KI in an aqueous solution and then spin-coating 50 μL onto the CuI film (3000 rpm for 30 s). The solution was annealed at 120°C for 10 min, followed by immersion in an aqueous solution for 2 min and annealing at 120°C for 10 min to obtain the CuI film.

[0033] Test Example 1 This test example uses the JV test to perform performance testing on the inverted perovskite solar cells of Example 3 and Comparative Example 1. This test example can also be considered as an application embodiment of the inverted perovskite solar cell of the present invention.

[0034] JV test results for Comparative Example 1: At AM1.5, the effective area of ​​the active layer is 0.06 cm².2 Under these conditions, the battery was tested and found to have an open-circuit voltage of 1,128 V and a short-circuit current density of 23.46 mA·cm⁻¹. -2 The fill factor is 0.779 and the photoelectric conversion efficiency is 20.56%.

[0035] JV test results for Example 3: At AM1.5, the effective area of ​​the active layer is 0.06 cm². 2 Under these conditions, the battery was tested and found to have an open-circuit voltage of 1,128 V and a short-circuit current density of 23.88 mA·cm⁻¹. -2 The fill factor is 0.805 and the photoelectric conversion efficiency is 21.53%.

[0036] Furthermore, this test example compares the hole transport layer solutions prepared in the preparation processes of Example 1 and Comparative Example 1. The CuI-SH dispersion and the CuI isopropanol dispersion were placed together in an air environment (25°C, 30% RH) for an aging experiment for one week. The results are as follows... Figure 2 As shown in the figure, it can be clearly seen that after one week of aging, the isopropanol dispersion of CuI showed obvious agglomeration, while the CuI-SH dispersion almost maintained its original state, which confirms the practicality of the thiol doping process.

[0037] The microstructure of the hole transport layer fabricated in the inverse perovskite solar cells of Example 3 and Comparative Example 1 was observed, and the results are as follows: Figure 3 As shown in the figure, the comparison reveals that the surface of CuI-SH is smoother and more uniform, with no obvious agglomeration; while agglomerated particles were observed in CuI.

[0038] Based on this, the preparation methods of Example 1 and Comparative Example 1 were used to prepare large-area devices (5.1 cm²). 2 12cm 2 60 cm 2 The failure rate of devices prepared with different solutions was tested, and the efficiency of the devices was measured. The calculated efficiency was then statistically analyzed (i.e., experiments were conducted on the same batch of two devices, but some cells failed; the failure rate was the percentage of cells that failed). The failure rates of large-area devices prepared with different hole transport layers are shown below. Figure 4 As shown, the results indicate that the large-area failure rate of the CuI-SH hole transport layer is significantly reduced.

[0039] The test results above show that, based on CuI-SH as the hole transport layer, the success rate of large-scale fabrication of inverted perovskite solar cells is significantly increased, giving them greater potential in practical applications.

[0040] In summary, this invention utilizes thiol groups and surface Cu +Strong Cu-S coordination bonds are formed, creating steric hindrance and electrostatic repulsion on the particle surface, effectively suppressing agglomeration and significantly improving the stability and storage life of the dispersion. Based on this modification strategy, a smooth, dense, and pinhole-free CuI hole transport layer was successfully fabricated, and the overall perovskite solar cell exhibited excellent scalability and broad application prospects.

[0041] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for preparing an inverted perovskite solar cell with a cuprous iodide nanocrystal dispersion as a hole transport layer, characterized in that, Includes the following steps: (1) Dissolve the mercapto-containing compound in isopropanol to form a mercapto solution; dope the mercapto solution into the isopropanol dispersion of CuI to obtain a CuI-SH dispersion; (2) The CuI-SH dispersion was coated onto a transparent conductive substrate and then annealed to form a CuI-SH hole transport layer; (3) A perovskite light-absorbing layer, an electron transport layer, an interface modification layer and a metal electrode layer are sequentially stacked on a CuI-SH hole transport layer to form an inverted perovskite solar cell.

2. The method for preparing an inverted perovskite solar cell using cuprous iodide nanocrystal dispersion as a hole transport layer according to claim 1, characterized in that, The thiol-containing compound includes at least one of thiol polyethylene glycol thiol, thioglycolic acid, and 3-mercaptopropionic acid; the thiol concentration of the thiol solution is 0.5~1 mg / mL; the preparation method of CuI isopropanol dispersion is as follows: the chemically reactant amounts of organic cuprous salt and organic amine salt are dissolved in isopropanol for reaction, and after completion, the mixture is washed with isopropanol. The resulting product is annealed at 100~120℃ for 30~60 min to obtain CuI powder. Then, the CuI powder is dispersed in isopropanol at a concentration of 4~6 mg / mL to obtain CuI isopropanol dispersion; the thiol solution is doped into CuI isopropanol dispersion at a molar ratio of 1:8~1:10 to obtain CuI-SH dispersion.

3. The method for preparing an inverted perovskite solar cell using cuprous iodide nanocrystal dispersion as a hole transport layer according to claim 2, characterized in that: The organic cuprous salt includes at least one of cuprous acetate, cuprous diphenyl phosphate, and cuprous trifluoromethanesulfonate toluene complex; the organic amine salt includes at least one of iodomethylamine, iodomethylammonium, and phenethylamine hydroiodate.

4. The method for preparing an inverted perovskite solar cell using cuprous iodide nanocrystal dispersion as a hole transport layer according to claim 1, characterized in that: In step (2), the CuI-SH dispersion is coated onto a transparent conductive substrate by spin coating. The transparent conductive substrate includes ITO conductive glass with dimensions of 1.5 cm × 1.5 cm to 2 cm × 2 cm. The amount of CuI-SH dispersion used is 40 to 60 μL. The spin coating speed is 3000 to 5000 rpm and the time is 30 to 40 s. The annealing temperature is 100 to 120℃ and the time is 10 to 15 min. The transparent conductive substrate is cleaned and impurities removed before coating. First, the transparent conductive substrate is rinsed with deionized water and ultrasonically treated. Then, it is placed in anhydrous ethanol, isopropanol, acetone and anhydrous ethanol for ultrasonic treatment in sequence. When using, it is dried with high-purity nitrogen and then treated with ultraviolet ozone.

5. The method for preparing an inverted perovskite solar cell using cuprous iodide nanocrystal dispersion as a hole transport layer according to claim 1, characterized in that, In step (3), the preparation method of the perovskite light-absorbing layer includes the following steps: FAPbI3, CsPbI3 and MAPbBr3 are dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of 4:1 to 9:1, respectively, to prepare a solution with a concentration of 1.3 to 1.5 mol / L; after complete dissolution, 3 to 5% molar concentration of CsPbI3 and 3 to 5% molar concentration of MAPbBr3 are added to the FAPbI3 solution to form a perovskite precursor solution, which is then spin-coated onto the CuI-SH hole transport layer. The amount of perovskite precursor solution is 45 to 60 μL, the spin coating speed is 4000 to 6000 rpm, and the time is 20 to 40 s. Chlorobenzene antisolvent is added dropwise at the 10th to 20th s before spin coating. Subsequently, the perovskite mesophase film is annealed at 100 to 120°C for 10 to 30 seconds. min, forming a perovskite light-absorbing layer.

6. The method for preparing an inverted perovskite solar cell using cuprous iodide nanocrystal dispersion as a hole transport layer according to claim 1, characterized in that, In step (3), the preparation method of the electron transport layer includes the following steps: dissolving PCBM in chlorobenzene at a concentration of 20~40 mg / mL to obtain a PCBM solution; swirling the PCBM solution onto the perovskite light-absorbing layer, with a volume of 30~35 μL of PCBM solution, a swirling speed of 2000~3000 rpm / s, and a time of 20~40 s; and then annealing at 70~100℃ for 10~20 min to form an electron transport layer.

7. The method for preparing an inverted perovskite solar cell using cuprous iodide nanocrystal dispersion as a hole transport layer according to claim 1, characterized in that, In step (3), the preparation method of the interface modification layer includes the following steps: dissolving BCP in trifluoroethanol at a concentration of 0.5~1 mg / mL to obtain a BCP solution; spin-coating the BCP solution onto the electron transport layer, with a BCP solution volume of 30~50 μL, a spin-coating speed of 5000~6000 rpm / s, and a time of 20~40 s, followed by annealing at 70~100℃ for 5~10 min to form an interface modification layer.

8. The method for preparing an inverted perovskite solar cell using cuprous iodide nanocrystal dispersion as a hole transport layer according to claim 1, characterized in that, In step (3), the preparation method of the metal electrode layer includes the following steps: depositing a metal thin film on the electron transport layer by thermal evaporation under vacuum conditions, with the thickness of the metal thin film controlled at 150~200 nm, and the metal type including silver.

9. A reverse perovskite solar cell, characterized in that: It comprises a transparent conductive substrate and a CuI-SH hole transport layer, a perovskite light-absorbing layer, an electron transport layer, an interface modification layer, and a metal electrode layer stacked thereon, and is prepared by the preparation method according to any one of claims 1 to 8.

10. The inverted perovskite solar cell according to claim 9, characterized in that: The transparent conductive substrate comprises ITO conductive glass; the CuI-SH hole transport layer comprises thiol-doped CuI; the perovskite light-absorbing layer comprises an APbX3 thin film, where A represents Cs. + One of methylammonium ion and methyl etheramine ion, where X represents I. - or Br - The electron transport layer includes PCBM; the interface modification layer includes BCP; and the metal electrode layer includes a silver electrode layer.

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