Broadband-gap perovskite solar cell and preparation method thereof
By introducing sulfamethoxypyrimidine molecules as additives into wide-bandgap perovskite solar cells, the problems of nonradiative recombination and phase separation during crystallization were solved, improving open-circuit voltage and photoelectric conversion efficiency, and enhancing the quality of perovskite thin films.
Patent Information
- Application Number
- CN202512006960.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-29
- Publication Date
- 2026-05-01
AI Technical Summary
Wide-bandgap perovskite solar cells suffer from severe nonradiative recombination losses and phase separation during crystallization, resulting in reduced open-circuit voltage and low photoelectric conversion efficiency. Existing technologies have limited passivation effects from additives and may introduce unstable ions.
By introducing sulfamethoxypyrimidine molecules as a bulk additive, the crystallization process is regulated and defects are passivated through interaction with iodide ions in the perovskite solution, thereby improving the quality of perovskite films.
It significantly improved the open-circuit voltage, increased the photoelectric conversion efficiency by 1.5%~2%, effectively reduced non-radiative recombination, and enhanced the film quality of perovskite thin films.
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Abstract
Description
A wide-bandgap perovskite solar cell and its fabrication method Technical Field
[0001] This invention belongs to the field of perovskite solar cell technology, and in particular relates to a wide-bandgap perovskite solar cell and its preparation method. Background Technology
[0002] In recent years, perovskite solar cells have been regarded as promising candidate materials for next-generation photovoltaic technology due to their excellent photovoltaic performance and simple fabrication process. With the development of research, perovskite solar cells have become a research hotspot in the photovoltaic field. For high-efficiency tandem solar cells, the crystallinity and defect control of the wide-bandgap perovskite absorber layer of the top cell are crucial.
[0003] However, compared to narrow-bandgap perovskites, wide-bandgap perovskites face more severe nonradiative recombination losses. This is mainly because increased bromine content accelerates crystallization, leading to smaller grain size, increased grain boundary defects, and severe phase separation. This affects the quality of the perovskite film, generates numerous defects, reduces the open-circuit voltage of the cell, and consequently impacts the photoelectric conversion efficiency. Therefore, suppressing ion migration and phase separation is crucial for improving the photoelectric conversion efficiency of wide-bandgap perovskites. Existing technologies introduce additives such as Pb(SCN)2 into the perovskite precursor solution to regulate the crystallization process and passivate bulk defects at the source. However, while this method can regulate crystallization to some extent, it still has limited passivation effects on deep defects in wide-bandgap systems and may introduce excessive Pb. 2+ Unstable technical issues, etc. Summary of the Invention
[0004] To address the shortcomings of existing technologies, this invention provides a wide-bandgap perovskite solar cell and its fabrication method. This invention improves the photoelectric conversion efficiency of perovskite solar cells by introducing sulfamethoxypyrimidine molecules as a bulk additive.
[0005] The present invention is achieved by the following technical solution: The present invention provides a wide-bandgap perovskite solar cell, the perovskite solar cell comprising, from bottom to top, a conductive glass substrate layer, a hole transport layer, a wide-bandgap perovskite light-absorbing layer, a passivation layer, an electron transport layer, a blocking layer, and a metal electrode layer; the wide-bandgap perovskite light-absorbing layer is composed of additive molecules, the additive molecules including sulfamethoxypyrimidine and its derivatives.
[0006] Specifically, the additive molecule is represented by any of the following structural formulas: .
[0007] Specifically, the conductive glass substrate is made of fluorine-doped tin oxide (FTO) or indium tin oxide (ITO); the hole transport layer is made of any one of [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz), [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACz), and [4-(9H-carbazole-9-yl)butyl]phosphonic acid (4PACz).
[0008] Furthermore, the passivation layer is obtained by spin-coating a passivation layer stock solution onto the light-absorbing layer. The passivation layer stock solution is a passivation layer material with a concentration of 4 to 6 mg / mL, and the passivation layer material is phenylethyl iodide and / or a phenylethyl iodide derivative.
[0009] Specifically, the material of the electron transport layer is methyl [6,6]-phenyl C61 butyrate (PC). 61 BM), [6,6]-phenyl C71 butyrate methyl ester (PC) 71 Any one of BM); the barrier layer is a BCP barrier layer material; the material of the metal electrode layer is copper or silver.
[0010] This invention also provides a method for fabricating a wide-bandgap perovskite solar cell, the method comprising the following steps: S1, coating a hole transport layer on a conductive glass substrate and completing the fabrication of the hole transport layer; S2, coating a wide-bandgap perovskite light-absorbing layer on the hole transport layer and completing the fabrication of the perovskite light-absorbing layer on the hole transport layer; S3, coating a passivation layer on the wide-bandgap perovskite light-absorbing layer; S4, coating an electron transport layer on the passivation layer; S5, depositing a barrier layer material on the substrate using vacuum evaporation or spin coating to form a barrier layer; the barrier layer material includes, but is not limited to, BCP and LiF; S6, evaporating a metal electrode on the barrier layer to obtain the wide-bandgap perovskite solar cell.
[0011] Further, step S1 specifically involves: ultrasonically cleaning the conductive glass substrate sequentially in deionized water, acetone, and ethanol solutions, drying it with nitrogen gas, treating it in an ultraviolet ozone cleaner for 10-30 minutes, coating the hole transport layer on the substrate surface using spin coating or other methods, and annealing it for 10-30 minutes to complete the preparation of the hole transport layer.
[0012] Further, step S2 specifically involves: adding the molecular additive sulfamethoxypyrimidine or its derivative to the perovskite precursor solution to prepare a precursor solution; spin-coating the precursor solution onto the hole transport layer and annealing it at a heating stage at 100~150℃ for 10~30 min to complete the preparation of the perovskite light-absorbing layer; the precursor solution contains additive molecules with a mass concentration of 0.3~1mg / mL.
[0013] Further, the precursor solution is formed by dissolving a perovskite light-absorbing layer material in an organic solvent; the perovskite light-absorbing layer material includes, but is not limited to, at least one of methylamine lead iodide (MAPbI3), formamidinium lead iodide (FAPbI3), methylamine lead bromide (MAPbBr3), formamidinium lead bromide (FAPbBr3), cesium lead iodide (CsPbI3), cesium lead bromide (CsPbBr3), methylamine tin iodide (MASnI3), and methylamine tin bromide (MASnBr3); the solvent of the precursor solution is a mixed solution of N,N-dimethylformamide and dimethyl sulfoxide, wherein the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 7~9:1~3; the precursor solution contains a molecular additive with a mass concentration of 0.3~1 mg / mL.
[0014] Specifically, the spin coating conditions are: spin coater speed of 3000-6000 r / min, time of 20-40 s; the annealing conditions are: annealing temperature of 100-150℃, annealing time of 10-30 min.
[0015] The beneficial effects of this invention are as follows: This invention is the first to apply the molecular sulfamethoxypyrimidine and its derivatives to wide-bandgap perovskites. Its molecular structure effectively improves defect passivation and crystallization regulation. Compared with control devices without this molecular additive, the open-circuit voltage of the device is significantly improved, and the photoelectric conversion efficiency is increased by 1.5% to 2%. The sulfonamide group and pyrimidine in the additive of this invention can coordinate with uncoordinated lead ions in the perovskite, effectively passivating defects and significantly reducing non-radiative recombination, thereby increasing the open-circuit voltage. Simultaneously, the molecular additive interacts with iodide ions in the perovskite solution, regulating the crystallization process, inhibiting ion migration, and improving film quality, thereby enhancing the photoelectric conversion efficiency of the battery. Attached Figure Description
[0016] Figure 1 is a structural diagram of the molecular additives in this invention; wherein, (a) is a molecular structure diagram of molecular additive 1, and (b) is a molecular structure diagram of molecular additive 2; Figure 2 is the JV curve of the perovskite solar cells obtained in Example 1 and Comparative Example 1 of this invention; Figure 3 is a statistical graph of the photovoltaic parameters of the perovskite solar cells obtained in Example 1 and Comparative Example 1 of this invention; Figure 4 is the JV curve of the perovskite solar cells obtained in Example 2 and Comparative Example 2 of this invention; Figure 5 is a statistical graph of the photovoltaic parameters of the perovskite solar cells obtained in Example 2 and Comparative Example 2 of this invention; Figure 6 is the JV curve of the perovskite solar cells obtained in Example 3 and Comparative Example 3 of this invention; Figure 7 is a statistical graph of the photovoltaic parameters of the perovskite solar cells obtained in Example 3 and Comparative Example 3 of this invention; Figure 8 is the JV curve of the perovskite solar cells obtained in Example 4 and Comparative Example 4 of this invention; Figure 9 is a statistical graph of the photovoltaic parameters of the perovskite solar cells obtained in Example 4 and Comparative Example 4 of this invention. Detailed Implementation
[0017] This invention primarily improves the open-circuit voltage of the battery by adding additives, thereby enhancing the photoelectric conversion efficiency of wide-bandgap perovskite solar cells. The following specific embodiments further illustrate the method described in this invention. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more associated listed items.
[0018] The specific embodiments of the present invention are as follows: In the embodiments of the present invention, the molecular structure diagram of molecular additive 1 shown in Figure 1(a) and the molecular structure diagram of molecular additive 2 shown in Figure 1(b) are selected.
[0019] Example 1: This example describes a wide-bandgap perovskite light-absorbing layer obtained by adding 0.4 mg / mL of molecular additive 1 to a perovskite precursor solution. The specific steps are as follows: S1) The FTO glass was ultrasonically cleaned sequentially with deionized water, acetone, and ethanol solutions, then dried with nitrogen gas and treated in a UV ozone cleaner for 25 min. The prepared SAM solution was spin-coated onto the FTO glass surface and annealed on a heating stage at 100 °C for 10 min to form a hole transport layer; S2) 0.8 mg of molecular additive 1 was weighed and added to 2 mL of the prepared perovskite precursor solution, and stirred at 55 °C for 2 h to obtain precursor solution 1. 90 μL of precursor solution 1 was spin-coated onto the surface of the hole transport layer. The spin coater was set to 5000 r / min. After spin-coating for 25 seconds, chlorobenzene was dropped onto the center of the perovskite substrate. After spin-coating at 5000 r / min for 10 seconds, the FTO glass was heated on a 100 ℃ hot stage for 30 minutes to obtain the perovskite light-absorbing layer. S3) A 4.8 mg / mL phenylethyl iodide (PEAI) passivation layer was spin-coated onto the substrate surface. S4) A 20 mg / mL PC... 61 S5) Spin-coat the BM solution onto the perovskite light-absorbing layer to form an electron transport layer, with the spin coater set to 1500 r / min; S6) Spin-coat the 0.5 mg / mL BCP solution onto the electron transport layer to obtain a blocking layer, with the spin coater set to 1500 r / min; S7) Finally, place the substrate in an evaporator and deposit an 80 nm silver film as the back electrode.
[0020] The highest photoelectric conversion efficiency of the wide-bandgap perovskite solar cell obtained in this embodiment is 23.96%.
[0021] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that, in step 2), no molecular additive 1 is added to the perovskite precursor solution 1.
[0022] The highest photoelectric conversion efficiency of the wide-bandgap perovskite solar cell obtained in this comparative example is 21.91%.
[0023] Example 2: This example describes a wide-bandgap perovskite light-absorbing layer obtained by adding 0.6 mg / mL of molecular additive 1 to the perovskite precursor solution. The specific steps are as follows: S1) The FTO glass was ultrasonically cleaned sequentially with deionized water, acetone, and ethanol solutions, then dried with nitrogen gas and treated in a UV ozone cleaner for 30 min. The prepared SAM solution was spin-coated onto the FTO glass surface and annealed on a heating stage at 100 °C for 10 min to form a hole transport layer; S2) 1.2 mg of molecular additive 1 was weighed and added to 2 mL of the prepared perovskite precursor solution, and stirred at 55 °C for 2 h to obtain precursor solution 1. 100 μL of precursor solution 1 was spin-coated onto the surface of the hole transport layer. The spin coater was set to 5000 r / min. After spin-coating for 25 seconds, a drop of chlorobenzene solution was placed on the center of the perovskite substrate. After spin-coating at 5000 r / min for 10 seconds, the FTO glass was heated on a 100 ℃ hot stage for 30 minutes to obtain the perovskite light-absorbing layer. S3) A 4.8 mg / mL phenylethyl iodide (PEAI) passivation layer was spin-coated onto the substrate surface. S4) A 15 mg / mL PC... 61 S5) Spin-coat BM onto the perovskite light-absorbing layer to form an electron transport layer, with the spin coater set to 1500 r / min; S6) Spin-coat a 1 mg / mL BCP solution onto the electron transport layer to obtain a blocking layer, with the spin coater set to 3000 r / min; S7) Finally, place the substrate in an evaporator and deposit an 80 nm silver film as the back electrode.
[0024] The highest photoelectric conversion efficiency of the wide-bandgap perovskite solar cell obtained in this embodiment is 23.78%.
[0025] Comparative Example 2: The difference between Comparative Example 2 and Example 2 is that, in step 2), no molecular additive 1 is added to the perovskite precursor solution 1.
[0026] The highest photoelectric conversion efficiency of the wide-bandgap perovskite solar cell obtained in this comparative example is 21.95%.
[0027] Example 3: This example describes a wide-bandgap perovskite light-absorbing layer obtained by adding 0.3 mg / mL of molecular additive 2 to the perovskite precursor solution. The specific steps are as follows: S1) The FTO glass was ultrasonically cleaned sequentially with deionized water, acetone, and ethanol solutions, then dried with nitrogen gas and treated in a UV ozone cleaner for 25 min. The prepared SAM solution was spin-coated onto the FTO glass surface and annealed at 110 °C for 5 min to form a hole transport layer. S2) 0.6 mg of molecular additive 2 was weighed and added to 2 mL of the prepared perovskite precursor solution, and heated at 55 °C for 4 h to obtain precursor solution 2. Take 90 μL of precursor solution 2 and spin-coat it onto the surface of the hole transport layer. Set the spin coater speed to 5000 r / min. After spin-coating for 20 seconds, drop chlorobenzene onto the center of the perovskite substrate. After spin-coating at 5000 r / min for 10 seconds, place the FTO glass on a hot stage at 110 ℃ and heat for 15 min to obtain the perovskite light-absorbing layer; S3) Spin-coat a passivation layer with a concentration of 4.5 mg / mL of phenylethyl iodide (PEAI) onto the substrate surface.
[0028] S4) PC at a concentration of 20 mg / mL 61 S5) Spin-coat BM onto the perovskite light-absorbing layer to form an electron transport layer, with the spin coater set to 1500 r / min; S6) Spin-coat 0.5 mg / mL BCP solution onto the electron transport layer to obtain a blocking layer, with the spin coater set to 3000 r / min; S7) Finally, place the substrate in an evaporator to deposit an 80 nm silver film as the back electrode.
[0029] The photoelectric conversion efficiency of the wide-bandgap perovskite solar cell obtained in this embodiment is 24.03%.
[0030] Comparative Example 3: The difference between Comparative Example 3 and Example 3 is that, in step 2), no molecular additive 2 is added to the perovskite precursor solution 2.
[0031] The photoelectric conversion efficiency of the wide-bandgap perovskite solar cell obtained in this comparative example is 22.22%.
[0032] Example 4: This example describes a wide-bandgap perovskite light-absorbing layer obtained by adding 0.5 mg / mL of molecular additive 2 to the perovskite precursor solution. The specific steps are as follows: S1) The FTO glass was ultrasonically cleaned sequentially with deionized water, acetone, and ethanol solutions, then dried with nitrogen gas and treated in a UV ozone cleaner for 25 min. The prepared SAM solution was spin-coated onto the FTO glass surface and annealed at 100°C for 10 min to form a hole transport layer; S2) 1 mg of molecular additive 2 was weighed and added to 2 mL of the prepared perovskite precursor solution, and heated at 55°C for 4 h to obtain precursor solution 2. 100 μL of precursor solution 2 was spin-coated onto the surface of the hole transport layer. The spin coater was set to 5000 r / min. After spin-coating for 20 seconds, chlorobenzene was dropped onto the center of the perovskite substrate. After spin-coating at 5000 r / min for 10 seconds, the FTO glass was heated on a 100℃ hot stage for 30 minutes to obtain the perovskite light-absorbing layer. S3) A 4.5 mg / mL phenylethyl iodide (PEAI) passivation layer was spin-coated onto the substrate surface. S4) A 15 mg / mL PC... 61 S5) Spin-coat BM onto the perovskite light-absorbing layer to form an electron transport layer, with the spin coater set to 1500 r / min; S6) Spin-coat a 1 mg / mL BCP solution onto the electron transport layer to obtain a blocking layer, with the spin coater set to 1500 r / min; S7) Finally, place the substrate in an evaporator and deposit an 80 nm silver film as the back electrode.
[0033] The photoelectric conversion efficiency of the perovskite solar cell obtained in this embodiment is 23.61%.
[0034] Comparative Example 4: The difference between Comparative Example 4 and Example 4 is that, in step 2), no molecular additive 2 is added to the perovskite precursor solution 2.
[0035] The photoelectric conversion efficiency of the wide-bandgap perovskite solar cell obtained in this comparative example is 21.66%.
[0036] The JV curve test and photovoltaic parameter statistics of the perovskite solar cells obtained by using Examples 1-4 and Comparative Examples 1-4 of the present invention were carried out respectively. The process and results are as follows: (1) JV curve test: The battery IV curve was tested using a 3A-level solar simulator, and the test was carried out from -0.2V to 1.3V.
[0037] The JV curves are shown in Figures 2, 4, 6, and 8.
[0038] The photoelectric conversion efficiency is shown in Table 1 below; Table 1 As shown in Figure 2 and Table 1 above, the perovskite solar cell prepared by adding 0.4 mg / mL of molecular additive 1 to the perovskite precursor solution has a maximum photoelectric conversion efficiency of 23.96% (Example 1), with corresponding current density Jsc, onset voltage Voc, and fill factor FF of 22.44 mA / cm². 2 The photoelectric conversion efficiency of Example 1 was 1.25V and 85.39%. Compared to Comparative Example 1, Example 1 showed a 2.05% improvement in photoelectric conversion efficiency.
[0039] Table 2 shows the photoelectric conversion efficiency. As can be seen from Figure 4 and Table 2 above, the addition of molecular additive 1 at a concentration of 0.6 mg / mL resulted in a battery device conversion efficiency of 23.78% (Example 2), which is 1.83% higher than that of Comparative Example 2.
[0040] Table 3 shows the photoelectric conversion efficiency; Table 3 As shown in Figure 6 and Table 3 above, the perovskite solar cell prepared by adding 0.3 mg / mL of molecular additive 2 to the perovskite precursor solution has a maximum photoelectric conversion efficiency of 24.03% (Example 3), with corresponding current density Jsc, turn-on voltage Voc, and fill factor FF of 22.28 mA / cm². 2 The photoelectric conversion efficiency of Example 3 was 1.25V and 86.20% compared to Comparative Example 3.
[0041] Table 4 shows the photoelectric conversion efficiency. As can be seen from Figure 8 and Table 4 above, the addition of molecular additive 2 at a concentration of 0.5 mg / mL resulted in a battery device conversion efficiency of 23.61% (Example 4), which is 1.95% higher than that of Comparative Example 2.
[0042] (2) Statistical distribution diagram of photovoltaic parameters.
[0043] Figures 3, 5, 7, and 9 show the photovoltaic parameter statistics. From the four sub-figures in Figures 3, 5, 7, and 9 concerning "turn-on voltage, current density, fill factor, and cell efficiency," it can be seen that the turn-on voltage, fill factor, and cell efficiency of Examples 1-4 are significantly higher than those of Comparative Examples 1-4. Therefore, the perovskite solar cells prepared using the molecular additives described in this invention have a significant effect on improving the photoelectric conversion efficiency of the cells.
[0044] Other embodiments of this application will readily conceive of by those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is not limited to the embodiments described above, and is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein.
Claims
1. A wide-bandgap perovskite solar cell, characterized in that: The perovskite solar cell comprises, from bottom to top, a conductive glass substrate, a hole transport layer, a wide-bandgap perovskite light-absorbing layer, a passivation layer, an electron transport layer, a blocking layer, and a metal electrode layer; the wide-bandgap perovskite light-absorbing layer contains additive molecules, including sulfamethoxypyrimidine and its derivatives.
2. The wide-bandgap perovskite solar cell according to claim 1, characterized in that: The additive molecule is represented by any of the following structural formulas: 。 3. The wide-bandgap perovskite solar cell according to claim 1, characterized in that: The conductive glass substrate is made of fluorine-doped tin oxide (FTO) or indium tin oxide (ITO); the hole transport layer is made of any one of [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz), [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACz), or [4-(9H-carbazole-9-yl)butyl]phosphonic acid (4PACz).
4. The wide-bandgap perovskite solar cell according to claim 1, characterized in that: The passivation layer is obtained by spin-coating a passivation layer stock solution onto the light-absorbing layer. The passivation layer stock solution is a passivation layer material with a concentration of 4 to 6 mg / mL, and the passivation layer material is phenylethyl iodide and / or a phenylethyl iodide derivative.
5. The wide-bandgap perovskite solar cell according to claim 1, characterized in that: The electron transport layer is made of methyl [6,6]-phenyl C61-butyrate (PC) 61 BM), [6,6]-phenyl C71 butyrate methyl ester (PC) 71 Any one of BM); the barrier layer is a BCP barrier layer material; the material of the metal electrode layer is copper or silver.
6. A method for preparing a wide-bandgap perovskite solar cell as described in any one of claims 1 to 7, characterized in that: The preparation method includes the following steps: S1, coating a hole transport layer on a conductive glass substrate and completing the preparation of the hole transport layer; S2, coating a wide-bandgap perovskite light-absorbing layer on the hole transport layer and completing the preparation of the perovskite light-absorbing layer on the hole transport layer; S3, coating a passivation layer on the wide-bandgap perovskite light-absorbing layer; S4, coating an electron transport layer on the passivation layer; S5, depositing a barrier layer material on the substrate using vacuum evaporation or spin coating to form a barrier layer; the barrier layer material includes, but is not limited to, BCP and LiF; S6, evaporating a metal electrode on the barrier layer to obtain the wide-bandgap perovskite solar cell.
7. The method for fabricating a wide-bandgap perovskite solar cell according to claim 6, characterized in that: Step S1 specifically involves: ultrasonically cleaning the conductive glass substrate sequentially in deionized water, acetone, and ethanol solutions, drying it with nitrogen, treating it in an ultraviolet ozone cleaner for 10-30 minutes, coating the hole transport layer on the substrate surface using spin coating or other methods, and annealing it for 10-30 minutes to complete the preparation of the hole transport layer.
8. The method for fabricating a wide-bandgap perovskite solar cell according to claim 6, characterized in that: Step S2 specifically involves: adding the molecular additive sulfamethoxypyrimidine or its derivative to the perovskite precursor solution to prepare a precursor solution; spin-coating the precursor solution onto the hole transport layer and annealing it at a heating stage of 100-150℃ for 10-30 min to complete the preparation of the perovskite light-absorbing layer; the precursor solution contains additive molecules with a mass concentration of 0.3-1 mg / mL.
9. The method for preparing a wide-bandgap perovskite solar cell according to claim 8, characterized in that: The precursor solution is formed by dissolving a perovskite light-absorbing layer material in an organic solvent; the perovskite light-absorbing layer material includes, but is not limited to, at least one of methylamine lead iodide (MAPbI3), formamidinium lead iodide (FAPbI3), methylamine lead bromide (MAPbBr3), formamidinium lead bromide (FAPbBr3), cesium lead iodide (CsPbI3), cesium lead bromide (CsPbBr3), methylamine tin iodide (MASnI3), and methylamine tin bromide (MASnBr3); the solvent of the precursor solution is a mixed solution of N,N-dimethylformamide and dimethyl sulfoxide, wherein the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 7~9:1~3; the precursor solution contains a molecular additive with a mass concentration of 0.3~1 mg / mL.
10. The method for preparing a wide-bandgap perovskite solar cell according to claim 8, characterized in that: The spin coating conditions are: spin coater speed of 3000-6000 r / min, time of 20-40 s; the annealing conditions are: annealing temperature of 100-150℃, annealing time of 10-30 min.