Wide-bandgap perovskite solar cells and tandem solar cells based on fullerene derivatives and their fabrication methods

Abstract

This application discloses a wide-bandgap perovskite solar cell based on fullerene derivatives, a tandem solar cell, and a method for fabricating the same, belonging to the field of perovskite solar cell technology. A wide-bandgap perovskite solar cell based on fullerene derivatives includes a conductive substrate, a first hole transport layer, a self-assembled monolayer, a wide-bandgap perovskite light-absorbing layer, a fullerene derivative electron transport layer, a first electron modification layer, and a first metal electrode layer, sequentially stacked. The molecular formula of the wide-bandgap perovskite is FA. 0.5‑1.0 Cs 0.1‑ 0.3 PbI 1.5‑2.0 Br 1.0‑1.5 The fullerene derivative is 5'-Phenyl-5'. H -[5,6]fullereno-C 60 - I h -[1,9:2',3']pyrido[3,2- b [indole. Through the synergistic effect of electron transport, defect passivation, and thin film stability enhancement, the optoelectronic performance and long-term operational stability of wide-bandgap perovskite and all-perovskite stacked devices are significantly improved.]

Description

Technical Field

[0001] This application relates to a wide-bandgap perovskite solar cell based on fullerene derivatives, a tandem solar cell, and a method for preparing the same, belonging to the field of perovskite solar cell technology. Background Technology

[0002] In recent years, the photoelectric conversion efficiency of traditional silicon-based solar cells has gradually approached its theoretical limit. Perovskite solar cells, with their superior photovoltaic performance, low cost, and simple fabrication process, have seen their power conversion efficiency (PCE) rapidly increase from 3.8% to over 27%. All-perovskite tandem solar cells (AP-TSCs) combine the advantages of wide-bandgap (WBG, 1.7-1.8 eV) and narrow-bandgap (NBG, 1.2-1.3 eV) perovskite materials, allowing for full utilization of the solar spectrum. Currently, the efficiency of AP-TSCs has exceeded 30%, providing a new avenue for improving solar cell efficiency.

[0003] In all-perovskite tandem solar cells, wide-bandgap perovskite top cells suffer from the following problems: severe interfacial charge recombination loss, energy level mismatch between the electron transport layer (ETL) and the perovskite active layer, and low mobility and weak passivation ability of traditional fullerene-based electron transport materials (such as PCBMs), which restrict the photoelectric conversion efficiency and long-term stability of the device. Specifically, the wide-bandgap perovskite surface is prone to trap state defects caused by uncoordinated lead ions, leading to intensified nonradiative recombination at the interface and a decrease in carrier collection efficiency. At the same time, fullerene materials such as PCBMs are prone to molecular aggregation and phase separation, making it difficult to form a uniform and dense film. Furthermore, their ability to block water and oxygen is insufficient, failing to effectively prevent the external environment from eroding the perovskite layer, resulting in a significant degradation in the damp-heat stability and long-term operating performance of the tandem device. Summary of the Invention

[0004] To address the aforementioned issues, a wide-bandgap perovskite solar cell and a tandem solar cell based on fullerene derivatives are provided, along with their fabrication methods. Through the synergistic effect of electron transport, defect passivation, and thin film stability enhancement, the photoelectric performance and long-term operational stability of wide-bandgap perovskite and all-perovskite tandem devices are significantly improved.

[0005] The technical solution of this invention is as follows: According to one aspect of this application, a wide-bandgap perovskite solar cell based on fullerene derivatives is provided, comprising a conductive substrate, a first hole transport layer, a self-assembled monolayer, a wide-bandgap perovskite light-absorbing layer, a fullerene derivative electron transport layer, a first electron modification layer, and a first metal electrode layer stacked sequentially. The molecular formula of the wide-bandgap perovskite is FA. 0.5-1.0 Cs 0.1-0.3 PbI 1.5-2.0 Br 1.0-1.5The fullerene derivative is 5'-Phenyl-5'. H -[5,6]fullereno-C 60 - I h -[1,9:2',3']pyrido[3,2- b ]indole.

[0006] Optionally, the conductive substrate comprises glass and an indium tin oxide layer deposited on the glass surface; And / or, the material of the first hole transport layer is nickel oxide; And / or, the material of the self-assembled monolayer is SAM; And / or, the material of the first electronic modification layer is copper bath; And / or, the material of the first metal electrode layer is silver or gold.

[0007] Optionally, the thickness of the conductive substrate is 1-1.2 mm; And / or, the thickness of the first hole transport layer is 15-40 nm; And / or, the thickness of the self-assembled monolayer is 0.8-2.5 nm; And / or, the thickness of the wide-bandgap perovskite light-absorbing layer is 300-450 nm; And / or, the thickness of the fullerene derivative electron transport layer is 20-25 nm; And / or, the thickness of the first electronic modification layer is 5-10 nm; And / or, the thickness of the first metal electrode layer is 90-110 nm.

[0008] According to another aspect of this application, a method for preparing a wide-bandgap perovskite solar cell based on fullerene derivatives as described in any of the preceding claims is provided, comprising the following steps: S1. Coat a conductive substrate with an aqueous nickel oxide solution at a spin coating rate of 1200-1800 rpm for 20-40 s. Anneal at 140-160℃ for 5-15 min. After cooling, transfer to a nitrogen-filled glove box. S2. In a nitrogen atmosphere, the SAM ethanol solution is coated onto nickel oxide at a spin coating rate of 2500-3500 rpm for 20-40 s, and then annealed at 90-110℃ for 5-15 min. S3. In a glove box, the wide-bandgap perovskite precursor solution is coated onto SAM in two steps. The first step is a spin coating rate of 300-800 rpm and a spin coating time of 1-3 s. The second step is a spin coating rate of 3500-4500 rpm and a spin coating time of 50-70 s. During the second step of spin coating, anhydrous diethyl ether is added dropwise at 20-30 s. Then, the mixture is annealed at 90-110℃ for 5-15 min. S4. Coat a fullerene derivative chlorobenzene solution onto a wide-bandgap perovskite substrate at a spin coating rate of 1500-2500 rpm for 20-40 s, and anneal at 60-80℃ for 0.5-1.5 min. S5. Coat the fullerene derivative with a copper-based isopropanol solution at a spin coating rate of 3500-4500 rpm for 20-40 s, and anneal at 90-110℃ for 0.5-1.5 min. S6. Metal is deposited onto the copper bath using a vacuum thermal evaporation method. The vacuum degree inside the vacuum thermal evaporation system is 1×10⁻⁶. -4 With a deposition rate of 0.5-1.0 Å / s, a wide-bandgap perovskite solar cell based on fullerene derivatives is obtained.

[0009] Optionally, the method for preparing the wide-bandgap perovskite precursor solution includes: N,N-dimethylformamide and dimethyl sulfoxide were mixed in a volume ratio of (3-5):1 to prepare a mixed solvent. FAI, PbBr2, PbI2, PbCl2, CsI and MACl were then dissolved in the mixed solvent and filtered through a polytetrafluoroethylene membrane to obtain a wide-bandgap perovskite precursor solution with a concentration of 1-1.5 mol / L. And / or, the concentration of the nickel oxide aqueous solution is 8-12 mg / mL; And / or, the concentration of the SAM ethanol solution is 0.2-1.0 mg / mL; And / or, the concentration of the fullerene derivative chlorobenzene solution is 15-25 mg / ml; And / or, the concentration of the copper bath isopropanol solution is 1.0-3.5 mg / mL.

[0010] Optionally, the preparation method of wide-bandgap perovskite solar cells based on fullerene derivatives further includes a pretreatment step of the conductive substrate, specifically: The etched ITO glass substrate was washed sequentially with detergent, deionized water, acetone and isopropanol for 30 minutes, dried with nitrogen, and then treated with air-plasma plasma for 5 minutes.

[0011] According to another aspect of this application, a tandem solar cell is provided, comprising a wide-bandgap perovskite top cell, a metal oxide electron transport layer, a buffer layer, a second hole transport layer, a narrow-bandgap perovskite light-absorbing layer, an interface passivation layer, a fullerene electron transport layer, a second electron modification layer, and a second metal electrode layer, which are sequentially stacked. The wide-bandgap perovskite top solar cell comprises a conductive substrate, a first hole transport layer, a self-assembled monolayer, a wide-bandgap perovskite light-absorbing layer, and a fullerene derivative electron transport layer, which are stacked sequentially. The molecular formula of the wide-bandgap perovskite is FA. 0.5-1.0 Cs 0.1-0.3 PbI 1.5-2.0 Br 1.0-1.5 The fullerene derivative is 5'-Phenyl-5'. H -[5,6]fullereno-C 60 - I h -[1,9:2',3']pyrido[3,2- b indole; The molecular formula of the narrow bandgap perovskite is FA. 0.6 MA 0.3 Cs 0.1 Pb 0.5 Sn 0.5 I3; the fullerene is C 60 .

[0012] Optionally, the conductive substrate comprises glass and an indium tin oxide layer deposited on the glass surface; And / or, the material of the first hole transport layer is nickel oxide; And / or, the material of the self-assembled monolayer is SAM; And / or, the material of the metal oxide electron transport layer is tin oxide; And / or, the material of the buffer layer is gold; And / or, the material of the second hole transport layer is PEDOT:PSS; And / or, the material of the interface passivation layer is ethylenediamine dihydroiodide; And / or, the material of the second electronic modification layer is copper bath; And / or, the material of the second metal electrode layer is silver or gold.

[0013] Optionally, the thickness of the conductive substrate is 1-1.2 mm; And / or, the thickness of the first hole transport layer is 15-40 nm; And / or, the thickness of the self-assembled monolayer is 0.8-2.5 nm; And / or, the thickness of the wide-bandgap perovskite light-absorbing layer is 300-450 nm; And / or, the thickness of the fullerene derivative electron transport layer is 20-25 nm; And / or, the thickness of the metal oxide electron transport layer is 20-30 nm; And / or, the thickness of the buffer layer is 0.5-1.5 nm; And / or, the thickness of the second hole transport layer is 25-50 nm; And / or, the thickness of the narrow bandgap perovskite light-absorbing layer is 600-800 nm; And / or, the thickness of the interface passivation layer is 1.0-3.5 nm; And / or, the thickness of the fullerene electron transport layer is 20-30 nm; And / or, the thickness of the second electronic modification layer is 4-8 nm; And / or, the thickness of the second metal electrode layer is 90-110 nm.

[0014] According to another aspect of this application, a method for fabricating a tandem solar cell as described in any of the preceding claims is provided, comprising the following steps: (1) Coat a conductive substrate with an aqueous nickel oxide solution at a spin coating rate of 1200-1800 rpm for 20-40 s, anneal at 140-160℃ for 5-15 min, and after cooling, transfer to a nitrogen-filled glove box. (2) In a nitrogen atmosphere, the SAM ethanol solution is coated onto nickel oxide at a spin coating rate of 2500-3500 rpm and a spin coating time of 20-40 s. Then, it is annealed at 90-110℃ for 5-15 min. (3) In the glove box, the wide-bandgap perovskite precursor solution is coated on SAM in two steps. The first step is spin-coating at a speed of 300-800 rpm and a spin-coating time of 1-3 s. The second step is spin-coating at a speed of 3500-4500 rpm and a spin-coating time of 50-70 s. During the second step spin-coating, anhydrous diethyl ether is added dropwise at 20-30 s. Then, the mixture is annealed at 90-110℃ for 5-15 min. (4) Coat the fullerene derivative chlorobenzene solution onto the wide-bandgap perovskite at a spin coating rate of 1500-2500 rpm and a spin coating time of 20-40 s, and anneal at 60-80℃ for 0.5-1.5 min. (5) Tin oxide was deposited on the fullerene derivative using ALD atomic layer deposition at a vacuum level of 1×10⁻⁶. -3 -5×10 - 3Torr, with a deposition rate of 0.2-0.4 Å / s, and under a vacuum of not less than 1×10 -4 Under the condition of Pa, gold was deposited on the tin oxide surface by vapor deposition, and then PEDOT:PSS was coated on the gold. The spin coating rate was 3500-4500 rpm and the spin coating time was 20-40 s. The coating was then annealed at 110-130℃ for 10-30 min. (6) In a nitrogen-filled glove box, the narrow band gap perovskite precursor solution is coated in two steps. The first step is a spin coating rate of 800-1200 rpm and a spin coating time of 5-15 s. The second step is a spin coating rate of 3500-4500 rpm and a spin coating time of 20-40 s. Chlorobenzene is added dropwise at 20-40 s. Then, the mixture is annealed at 90-110℃ for 5-15 min. (7) Coat the narrow band gap perovskite with ethylenediamine dihydroiodide isopropanol solution at a spin coating rate of 3500-4500 rpm and a spin coating time of 10-30 s, and anneal at 90-110℃ for 0.5-1.5 min. (8) C is sequentially deposited on ethylenediamine dihydroiodide using a vacuum thermal evaporation method. 60 The vacuum thermal evaporation system for copper bath and metals has a vacuum level of 1×10⁻⁶ within its cavity. -4 With a deposition rate of 0.2-1.0 Å / s, a tandem solar cell can be obtained.

[0015] Optionally, the method for preparing the narrow bandgap perovskite precursor solution includes: PbI2, SnI2, FAI, MAI, CsI, SnF2 and NH4SCN were dissolved in N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of (2-4):1, stirred overnight, and filtered through a polytetrafluoroethylene membrane to obtain a narrow bandgap perovskite precursor solution with a concentration of 2-2.5 mol / L. And / or, the method for preparing the wide-bandgap perovskite precursor solution includes: N,N-dimethylformamide and dimethyl sulfoxide were mixed in a volume ratio of (3-5):1 to prepare a mixed solvent. FAI, PbBr2, PbI2, PbCl2, CsI and MACl were then dissolved in the mixed solvent and filtered through a polytetrafluoroethylene membrane to obtain a wide-bandgap perovskite precursor solution with a concentration of 1-1.5 mol / L. And / or, the concentration of the nickel oxide aqueous solution is 8-12 mg / mL; And / or, the concentration of the SAM ethanol solution is 0.2-1.0 mg / mL; And / or, the concentration of the fullerene derivative chlorobenzene solution is 15-25 mg / ml; And / or, the PEDOT:PSS is obtained by diluting PEDOT:PSS stock solution with isopropanol at a volume ratio of 1:(2-4); And / or, the concentration of the ethylenediamine dihydroiodide isopropanol solution is 0.8-1.2 mg / mL.

[0016] Optionally, the fabrication method of tandem solar cells further includes a pretreatment step of the conductive substrate, specifically: The etched ITO glass substrate was washed sequentially with detergent, deionized water, acetone and isopropanol for 30 minutes, dried with nitrogen, and then treated with air-plasma plasma for 5 minutes.

[0017] The beneficial effects of this application include, but are not limited to: 1. The wide-bandgap perovskite solar cell and tandem solar cell based on fullerene derivatives in this application, and their fabrication method, utilize the fullerene derivative (5'-Phenyl- ... H -[5,6]fullereno-C 60 - I h -[1,9:2',3']pyrido[3,2- b Fullerene (FLA) is used as an electron transport layer material for wide-bandgap perovskites. This material achieves efficient electron extraction and transport through the high electron mobility of the fullerene framework. Simultaneously, it utilizes the coordination of nitrogen-containing functional groups with uncoordinated lead ions on the wide-bandgap perovskite surface to passivate interface defects and suppress non-radiative recombination. The significant steric hindrance of its functional groups effectively inhibits fullerene molecule aggregation, forming a uniform and dense film, improving interfacial contact quality and water / oxygen barrier properties. Through these synergistic effects of electron transport, defect passivation, and film stability enhancement, the charge transport efficiency and environmental stability of wide-bandgap perovskite top-cell solar cells are significantly improved, providing key technological support for the fabrication of high-efficiency and stable all-perovskite tandem solar cells.

[0018] 2. The wide-bandgap perovskite solar cells and tandem solar cells based on fullerene derivatives of this application and their preparation methods are easy to operate, have good repeatability, and are suitable for large-scale production. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the wide-bandgap perovskite solar cell based on fullerene derivatives in Example 1 and Comparative Example 1 of this application.

[0020] Figure 2This is an IV curve of the wide-bandgap perovskite solar cell based on fullerene derivatives in Example 1 and Comparative Example 1 of this application.

[0021] Figure 3 The electron mobility test graphs are for wide-bandgap perovskite solar cells based on fullerene derivatives in Example 1 and Comparative Example 1 of this application.

[0022] Figure 4 The graphs show the stability test results of wide-bandgap perovskite solar cells based on fullerene derivatives in Example 1 and Comparative Example 1 of this application.

[0023] Figure 5 This is a schematic diagram of the structure of the stacked solar cell of Embodiment 2 and Comparative Example 2 of this application.

[0024] Figure 6 This is an IV curve diagram of the tandem solar cells of Example 2 and Comparative Example 2 of this application. Detailed Implementation

[0025] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0026] Unless otherwise specified in the examples, the procedures shall be performed under standard conditions or conditions recommended by the manufacturer. Raw materials or instruments whose manufacturers are not specified are all commercially available products.

[0027] In a first aspect, some embodiments of the present invention provide a wide-bandgap perovskite solar cell based on a fullerene derivative, comprising a conductive substrate, a first hole transport layer, a self-assembled monolayer, a wide-bandgap perovskite light-absorbing layer, a fullerene derivative electron transport layer, a first electron modification layer, and a first metal electrode layer, which are sequentially stacked.

[0028] In a first aspect, in some embodiments of the present invention, the conductive substrate includes glass and an indium tin oxide (ITO) layer deposited on the surface of the glass. The thickness of the conductive substrate is 1-1.2 mm; preferably 1.1 mm. In a first aspect, in some embodiments of the present invention, the first hole transport layer is disposed on the surface of a conductive substrate. The first hole transport layer uses nickel oxide (NiO). x )preparation. The thickness of the first hole transport layer is 15-40 nm; preferably 25 nm. In a first aspect, in some embodiments of the present invention, the self-assembled monolayer is disposed on the surface of a first hole transport layer. The material of the self-assembled monolayer is SAM. The thickness of the self-assembled monolayer is 0.8-2.5 nm; preferably 1.6 nm. In a first aspect, in some embodiments of the present invention, the wide-bandgap perovskite light-absorbing layer is disposed on the surface of a self-assembled monolayer. The molecular formula of the wide-bandgap perovskite is FA. 0.5-1.0 Cs 0.1-0.3 PbI 1.5-2.0 Br 1.0-1.5 ; Preferably FA 0.8 Cs 0.2 PbI 1.8 Br 1.2 .

[0029] The thickness of the wide-bandgap perovskite light-absorbing layer is 300-450 nm; preferably 400 nm. In a first aspect, in some embodiments of the present invention, the fullerene derivative electron transport layer is disposed on the surface of a wide-bandgap perovskite light-absorbing layer. The fullerene derivative is 5'-Phenyl-5' H -[5,6]fullereno-C 60 - I h -[1,9:2',3']pyrido[3,2- b ]indole.

[0030] The fullerene derivative, with a purity ≥99%, was purchased from Alpha Chemicals Co., Ltd., and can be directly used in the fabrication of perovskite solar cell devices without further purification. The structural formula is:

[0031] The thickness of the fullerene derivative electron transport layer is 20-25 nm; preferably 23 nm.

[0032] The aforementioned fullerene derivatives are used as electron transport layer materials in wide-bandgap perovskite solar cells. By utilizing the combination of the high electron mobility of the fullerene framework and the passivation of defects in nitrogen-containing functional groups, the charge transport efficiency of perovskite devices is enhanced, the dissociation and collection efficiency of photogenerated excitons is improved, and the non-radiative recombination loss at the interface is effectively suppressed. Combining the excellent energy level matching of fullerene materials with the film-forming stability advantages brought by functional group modification, wide-bandgap perovskite solar cells with both high energy conversion efficiency and long-term stability are prepared.

[0033] In a first aspect, in some embodiments of the present invention, the first electron modification layer is disposed on the surface of the fullerene derivative electron transport layer. The first electronic modification layer was prepared using copper bath (BCP). The thickness of the first electronic modification layer is 5-10 nm; preferably 7 nm.

[0034] In a first aspect, in some embodiments of the present invention, the first metal electrode layer is disposed on the surface of the first electronic modification layer. The first metal electrode layer is made of silver (Ag) or gold (Au); preferably Ag. The thickness of the first metal electrode layer is 90-110 nm; preferably 100 nm. In a second aspect, some embodiments of the present invention provide a method for preparing a wide-bandgap perovskite solar cell based on fullerene derivatives as described in any of the preceding claims, comprising the following steps: S1. Coat a conductive substrate with an aqueous nickel oxide solution at a spin coating rate of 1200-1800 rpm for 20-40 s. Anneal at 140-160℃ for 5-15 min. After cooling, transfer to a nitrogen-filled glove box. S2. In a nitrogen atmosphere, the SAM ethanol solution is coated onto nickel oxide at a spin coating rate of 2500-3500 rpm for 20-40 s, and then annealed at 90-110℃ for 5-15 min. S3. In a glove box, the wide-bandgap perovskite precursor solution is coated onto SAM in two steps. The first step is a spin coating rate of 300-800 rpm and a spin coating time of 1-3 s. The second step is a spin coating rate of 3500-4500 rpm and a spin coating time of 50-70 s. During the second step of spin coating, anhydrous diethyl ether is added dropwise at 20-30 s. Then, the mixture is annealed at 90-110℃ for 5-15 min. S4. Coat a fullerene derivative chlorobenzene solution onto a wide-bandgap perovskite substrate at a spin coating rate of 1500-2500 rpm for 20-40 s, and anneal at 60-80℃ for 0.5-1.5 min. S5. Coat the fullerene derivative with a copper-based isopropanol solution at a spin coating rate of 3500-4500 rpm for 20-40 s, and anneal at 90-110℃ for 0.5-1.5 min. S6. Metal is deposited onto the copper bath using a vacuum thermal evaporation method. The vacuum degree inside the vacuum thermal evaporation system is 1×10⁻⁶. -4 With a deposition rate of 0.5-1.0 Å / s, a wide-bandgap perovskite solar cell based on fullerene derivatives is obtained.

[0035] In a second aspect, in some embodiments of the present invention, the method for preparing the wide-bandgap perovskite precursor solution includes: N,N-dimethylformamide and dimethyl sulfoxide were mixed in a volume ratio of (3-5):1 to prepare a mixed solvent. FAI, PbBr2, PbI2, PbCl2, CsI and MACl were then dissolved in the mixed solvent. The solution was filtered through a polytetrafluoroethylene membrane to obtain a wide-bandgap perovskite precursor solution with a concentration of 1-1.5 mol / L.

[0036] In a second aspect, in some embodiments of the present invention, the concentration of the nickel oxide aqueous solution is 8-12 mg / mL; preferably 10 mg / mL.

[0037] In a second aspect, in some embodiments of the present invention, the concentration of the SAM ethanol solution is 0.2-1.0 mg / mL; preferably 0.5 mg / mL.

[0038] In a second aspect, in some embodiments of the present invention, the concentration of the fullerene derivative chlorobenzene solution is 15-25 mg / ml; preferably 20 mg / ml.

[0039] In a second aspect, in some embodiments of the present invention, the concentration of the copper bath isopropanol solution is 1.0-3.5 mg / mL; preferably 2.5 mg / mL.

[0040] In a third aspect, some embodiments of the present invention provide a tandem solar cell, comprising a wide-bandgap perovskite top cell, a metal oxide electron transport layer, a buffer layer, a second hole transport layer, a narrow-bandgap perovskite light-absorbing layer, an interface passivation layer, a fullerene electron transport layer, a second electron modification layer, and a second metal electrode layer, which are sequentially stacked. In a third aspect, in some embodiments of the present invention, the wide-bandgap perovskite top solar cell includes a conductive substrate, a first hole transport layer, a self-assembled monolayer, a wide-bandgap perovskite light-absorbing layer, and a fullerene derivative electron transport layer stacked sequentially. The conductive substrate, the first hole transport layer, the self-assembled monolayer, the wide-bandgap perovskite light-absorbing layer, and the fullerene derivative electron transport layer have the same structure as the aforementioned wide-bandgap perovskite solar cell based on fullerene derivatives.

[0041] In a third aspect, in some embodiments of the present invention, the metal oxide electron transport layer is disposed on the surface of a wide-bandgap perovskite top cell.

[0042] The material of the metal oxide electron transport layer is tin oxide.

[0043] The thickness of the metal oxide electron transport layer is 20-30 nm; preferably 25 nm.

[0044] In a third aspect, in some embodiments of the present invention, the buffer layer is disposed on the surface of the metal oxide electron transport layer.

[0045] The material of the buffer layer is gold.

[0046] The thickness of the buffer layer is 0.5-1.5 nm; preferably 1 nm.

[0047] In a third aspect, in some embodiments of the present invention, the second hole transport layer is disposed on the surface of the buffer layer.

[0048] The material of the second hole transport layer is PEDOT:PSS.

[0049] The thickness of the second hole transport layer is 25-50 nm; preferably 35 nm.

[0050] In a third aspect, in some embodiments of the present invention, the narrow bandgap perovskite light-absorbing layer is disposed on the surface of the second hole transport layer.

[0051] The molecular formula of the narrow bandgap perovskite is FA. 0.6 MA 0.3 Cs 0.1 Pb 0.5 Sn 0.5 I3.

[0052] The thickness of the narrow bandgap perovskite light-absorbing layer is 600-800 nm; preferably 750 nm.

[0053] In a third aspect, in some embodiments of the present invention, the interface passivation layer is disposed on the surface of the narrow bandgap perovskite light-absorbing layer.

[0054] The material of the interface passivation layer is ethylenediamine dihydroiodide.

[0055] The thickness of the interface passivation layer is 1.0-3.5 nm; preferably 2.5 nm.

[0056] In a third aspect, in some embodiments of the present invention, the fullerene electron transport layer is disposed on the surface of the interface passivation layer.

[0057] The fullerene is C 60 .

[0058] The thickness of the fullerene electron transport layer is 20-30 nm; preferably 25 nm.

[0059] In a third aspect, in some embodiments of the present invention, the second electron modification layer is disposed on the surface of the fullerene electron transport layer.

[0060] The material of the second electronic modification layer is bath copper spirit.

[0061] The thickness of the second electronic modification layer is 4-8 nm; preferably 6 nm.

[0062] In a third aspect, in some embodiments of the present invention, the second metal electrode layer is disposed on the surface of the second electronic modification layer.

[0063] The material of the second metal electrode layer is silver or gold; preferably silver.

[0064] The thickness of the second metal electrode layer is 90-110 nm; preferably 100 nm.

[0065] In a fourth aspect, some embodiments of the present invention provide a method for fabricating a tandem solar cell as described in any of the preceding claims, comprising the following steps: (1) Coat a conductive substrate with an aqueous nickel oxide solution at a spin coating rate of 1200-1800 rpm for 20-40 s, anneal at 140-160℃ for 5-15 min, and after cooling, transfer to a nitrogen-filled glove box. (2) In a nitrogen atmosphere, the SAM ethanol solution is coated onto nickel oxide at a spin coating rate of 2500-3500 rpm and a spin coating time of 20-40 s. Then, it is annealed at 90-110℃ for 5-15 min. (3) In the glove box, the wide-bandgap perovskite precursor solution is coated on SAM in two steps. The first step is spin-coating at a speed of 300-800 rpm and a spin-coating time of 1-3 s. The second step is spin-coating at a speed of 3500-4500 rpm and a spin-coating time of 50-70 s. During the second step spin-coating, anhydrous diethyl ether is added dropwise at 20-30 s. Then, the mixture is annealed at 90-110℃ for 5-15 min. (4) Coat the fullerene derivative chlorobenzene solution onto the wide-bandgap perovskite at a spin coating rate of 1500-2500 rpm and a spin coating time of 20-40 s, and anneal at 60-80℃ for 0.5-1.5 min. (5) Tin oxide was deposited on the fullerene derivative using ALD atomic layer deposition at a vacuum level of 1×10⁻⁶. -3 -5×10 - 3 Torr, with a deposition rate of 0.2-0.4 Å / s, and under a vacuum of not less than 1×10 -4 Under the condition of Pa, gold was deposited on the tin oxide surface by vapor deposition, and then PEDOT:PSS was coated on the gold. The spin coating rate was 3500-4500 rpm and the spin coating time was 20-40 s. The coating was then annealed at 110-130℃ for 10-30 min. (6) In a nitrogen-filled glove box, the narrow band gap perovskite precursor solution is coated in two steps. The first step is a spin coating rate of 800-1200 rpm and a spin coating time of 5-15 s. The second step is a spin coating rate of 3500-4500 rpm and a spin coating time of 20-40 s. Chlorobenzene is added dropwise at 20-40 s. Then, the mixture is annealed at 90-110℃ for 5-15 min. (7) Coat the narrow band gap perovskite with ethylenediamine dihydroiodide isopropanol solution at a spin coating rate of 3500-4500 rpm and a spin coating time of 10-30 s, and anneal at 90-110℃ for 0.5-1.5 min. (8) C is sequentially deposited on ethylenediamine dihydroiodide using a vacuum thermal evaporation method. 60 The vacuum thermal evaporation system for copper bath and metals has a vacuum level of 1×10⁻⁶ within its cavity. -4 With a deposition rate of 0.2-1.0 Å / s, a tandem solar cell can be obtained.

[0066] The preparation method of the wide-bandgap perovskite precursor solution is the same as the preparation method of the wide-bandgap perovskite solar cell based on fullerene derivatives mentioned above.

[0067] In a fourth aspect, in some embodiments of the present invention, the method for preparing the narrow bandgap perovskite precursor solution includes: PbI2, SnI2, FAI, MAI, CsI, SnF2 and NH4SCN were dissolved in N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of (2-4):1, stirred overnight, and filtered through a polytetrafluoroethylene membrane to obtain a narrow bandgap perovskite precursor solution with a concentration of 2-2.5 mol / L.

[0068] In a fourth aspect, in some embodiments of the present invention, the concentration of the nickel oxide aqueous solution is 8-12 mg / mL; preferably 10 mg / mL.

[0069] In a fourth aspect, in some embodiments of the present invention, the concentration of the SAM ethanol solution is 0.2-1.0 mg / mL; preferably 0.5 mg / mL.

[0070] In a fourth aspect, in some embodiments of the present invention, the concentration of the fullerene derivative chlorobenzene solution is 15-25 mg / ml; preferably 20 mg / ml.

[0071] In a fourth aspect, in some embodiments of the present invention, the PEDOT:PSS is obtained by diluting commercially available PH1000 type PEDOT:PSS stock solution with isopropanol at a volume ratio of 1:(2-4); preferably, the volume ratio is 1:3.

[0072] In a fourth aspect, in some embodiments of the present invention, the concentration of the ethylenediamine dihydroiodide isopropanol solution is 0.8-1.2 mg / mL; preferably 1 mg / mL.

[0073] Example 1 A method for preparing a wide-bandgap perovskite solar cell based on fullerene derivatives includes the following steps: S1. The etched ITO glass substrate was washed with detergent, deionized water, acetone and isopropanol in sequence for 30 min, dried with nitrogen, and then treated with air-plasma plasma for 5 min. Then, a layer of nickel oxide aqueous solution (10 mg / mL) was coated on the ITO glass substrate by spin coating at a speed of 1500 rpm for 30 s. After annealing at 150 °C for 10 min, it was cooled and transferred to a nitrogen-filled glove box. S2. In a nitrogen-filled glove box (O2<0.01ppm, H2O<0.01ppm), SAM (Me-4PACz) ethanol solution was coated onto nickel oxide at a spin coating rate of 3000rpm for 30s, and then annealed at 100℃ for 10min. S3. Mix N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) at a volume ratio of 4:1 to prepare a mixed solvent. Then, dissolve FAI (165.1 mg), PbBr2 (264.2 mg), PbI2 (221.3 mg), PbCl2 (6.67 mg), CsI (62.4 mg), and MACl (1.62 mg) in 1 mL of the mixed solvent, respectively, and pass the solution through a 0.22 μm polytetrafluoroethylene (PTFE) filter. (PTFE) membrane filtration was used to form a wide-bandgap perovskite precursor solution with a concentration of 1.2 mol / L. The wide-bandgap perovskite precursor solution was coated on SAM (Me-4PACz) in a glove box in two steps. The first step was spin-coating at a speed of 500 rpm for 2 s, and the second step was spin-coating at a speed of 4000 rpm for 60 s. During the second spin-coating process, anhydrous diethyl ether was added dropwise at 25 s, and then annealed at 100 °C for 10 min. S4, 5'-Phenyl-5' H -[5,6]fullereno-C 60 - I h -[1,9:2',3']pyrido[3,2- b Indole was dissolved in chlorobenzene to obtain a fullerene derivative chlorobenzene solution (20 mg / ml). The fullerene derivative chlorobenzene solution was coated onto a wide-bandgap perovskite at a spin coating rate of 2000 rpm for 30 s and then annealed at 70 °C for 1 min. S5. Coat the fullerene derivative with a copper bath (BCP) isopropanol solution at a spin coating rate of 4000 rpm for 30 s, and anneal at 100 °C for 1 min. S6. Silver (Ag) is deposited on the BCP using a vacuum thermal evaporation method. The vacuum degree inside the vacuum thermal evaporation system is 1×10⁻⁶. -4 At a deposition rate of 0.8 Å / s, a wide-bandgap perovskite solar cell based on fullerene derivatives was obtained. See details... Figure 1 .

[0074] The wide-bandgap perovskite solar cell based on fullerene derivatives prepared in Example 1 (see the post-processing curves for details) was assembled into a single-junction wide-bandgap perovskite solar cell device, and its forward and reverse sweep IV performance was tested within the voltage range of 0V to 1.4V. In this experiment, a perovskite solar cell using a conventional PCBM ([6,6]-phenyl-C61-butyrate methyl ester) fullerene derivative as the electron transport layer was used as the control example 1 device, and comparative tests were conducted under the exact same fabrication process and testing conditions. The test results are as follows: Figure 2 As shown, the device using a novel fullerene derivative as an electron transport layer has significantly improved photoelectric conversion efficiency and the hysteresis effect has been significantly suppressed, demonstrating that the nonradiative recombination loss at the device interface is effectively reduced.

[0075] Electron mobility tests were performed on the fullerene derivative electron transport layer of Example 1, and the results are as follows: Figure 3 As shown, the electron mobility is significantly improved compared to traditional materials, indicating that the material has excellent electron extraction and transport capabilities, which can efficiently promote the separation and collection of photogenerated charges.

[0076] Air stability tests were conducted on the wide-bandgap perovskite solar cell based on fullerene derivatives prepared in Example 1. The device was stored and characterized in an environment with 30% humidity. The results are as follows: Figure 4 As shown, the battery device using this novel fullerene derivative as the electron transport layer exhibits significantly improved environmental stability, demonstrating that the fullerene derivative possesses excellent water and oxygen barrier properties, which can effectively improve the environmental tolerance and long-term stability of wide-bandgap perovskite batteries.

[0077] Comparative Example 1 The difference from Example 1 is as follows: 5'-Phenyl-5' H -[5,6]fullereno-C 60 - I h -[1,9:2',3']pyrido[3,2- b ]indole is replaced with the fullerene derivative PCBM ([6,6]-phenyl-C61-butyrate methyl ester).

[0078] Example 2 A method for fabricating a tandem solar cell includes the following steps: (1) The etched ITO glass substrate was washed with detergent, deionized water, acetone and isopropanol for 30 min in sequence, dried with nitrogen, and then treated with air-plasma plasma for 5 min; then a layer of nickel oxide aqueous solution (10 mg / mL) was coated on the ITO glass substrate, the spin coating rate was 1500 rpm and the time was 30 s, annealed at 150 °C for 10 min, cooled and transferred to a nitrogen-filled glove box; (2) In a nitrogen-filled glove box (O2<0.01ppm, H2O<0.01ppm), SAM (Me-4PACz) ethanol solution was coated onto nickel oxide at a spin coating rate of 3000rpm and a spin coating time of 30s, and then annealed at 100℃ for 10min. (3) N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) were mixed in a volume ratio of 4:1 to prepare a mixed solvent. Then, FAI (165.1 mg), PbBr2 (264.2 mg), PbI2 (221.3 mg), PbCl2 (6.67 mg), CsI (62.4 mg), and MACl (1.62 mg) were dissolved in 1 mL of the mixed solvent and passed through a 0.22 μm polytetrafluoroethylene (PTFE) filter. (PTFE) membrane filtration was used to form a wide-bandgap perovskite precursor solution with a concentration of 1.2 mol / L. The wide-bandgap perovskite precursor solution was coated on SAM (Me-4PACz) in a glove box in two steps. The first step was spin-coating at a speed of 500 rpm for 2 s, and the second step was spin-coating at a speed of 4000 rpm for 60 s. During the second spin-coating process, anhydrous diethyl ether was added dropwise at 25 s, and then annealed at 100 °C for 10 min. (4) 5'-Phenyl-5' H -[5,6]fullereno-C 60 - I h -[1,9:2',3']pyrido[3,2- b Indole was dissolved in chlorobenzene to obtain a fullerene derivative chlorobenzene solution (20 mg / ml). The fullerene derivative chlorobenzene solution was coated onto a wide-bandgap perovskite at a spin coating rate of 2000 rpm for 30 s and then annealed at 70 °C for 1 min. (5) Tin oxide was deposited on fullerene derivatives using ALD atomic layer deposition at a vacuum level of 3×10⁻⁶. -3 Torr, with a deposition rate of 0.3 Å / s, and under a vacuum of not less than 1 × 10⁻⁶. -4Under the condition of Pa, gold (Au) was vapor deposited on the tin oxide surface, and then PEDOT:PSS was coated on the gold. The spin coating rate was 4000 rpm and the spin coating time was 30 s. The coating was then annealed at 120℃ for 20 min. (6) PbI2 (507.10 mg), SnI2 (409.77 mg), FAI (224.56 mg), MAI (104.92 mg), CsI (57.16 mg), SnF2 (17.23 mg) and NH4SCN (3.14 mg) were dissolved in N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of 3:1. The mixture was stirred overnight and filtered through a 0.22 μm polytetrafluoroethylene membrane to obtain a narrow bandgap perovskite precursor solution with a concentration of 2.2 mol / L. The narrow bandgap perovskite precursor solution was coated in two steps in a nitrogen-filled glove box. The first step was a spin coating rate of 1000 rpm and a spin coating time of 10 s. The second step was a spin coating rate of 4000 rpm and a spin coating time of 30 s. Chlorobenzene was added dropwise at the 30 s. The mixture was then annealed at 100 °C for 10 min. (7) A 1.0 mg / mL solution of ethylenediamine dihydroiodide (EDAI2) in isopropanol was coated onto a narrow band gap perovskite. The spin coating rate was 4000 rpm and the spin coating time was 20 s. The coating was then annealed at 100 °C for 1 min. (8) C was sequentially deposited on EDAI2 using a vacuum thermal evaporation method. 60 The vacuum thermal evaporation system for copper bath and silver (Ag) has a vacuum level of 1×10⁻⁶. -4 With a deposition rate of 0.6 Å / s, a tandem solar cell is obtained. See details... Figure 5 .

[0079] The forward and reverse sweep IV performance was tested within the voltage range of 0V to 2.2V. The test results are as follows. Figure 6 As shown, compared with the tandem device using traditional electron transport materials (Comparative Example 2 PCBM), the photoelectric conversion efficiency of the all-perovskite tandem solar cell prepared in Example 2 (see the post-processing curve for details) is significantly improved. At the same time, the open-circuit voltage and fill factor are significantly optimized. This confirms that the fullerene derivative, through efficient electron transport, interface defect passivation, and excellent water and oxygen barrier properties, synergistically improves the charge matching and interlayer compatibility of the wide bandgap top cell and the narrow bandgap bottom cell, and greatly reduces the non-radiative recombination loss within the device. This provides key technical support for achieving a balance between high efficiency and high stability in all-perovskite tandem solar cells.

[0080] Comparative Example 2 The difference from Example 2 is that: 5'-Phenyl-5' H -[5,6]fullereno-C 60- I h -[1,9:2',3']pyrido[3,2- b ]indole is replaced with the fullerene derivative PCBM ([6,6]-phenyl-C61-butyrate methyl ester).

[0081] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A wide-bandgap perovskite solar cell based on fullerene derivatives, characterized in that, It includes a conductive substrate, a first hole transport layer, a self-assembled monolayer, a wide-bandgap perovskite light-absorbing layer, a fullerene derivative electron transport layer, a first electron modification layer, and a first metal electrode layer, which are stacked sequentially. The molecular formula of the wide-bandgap perovskite is FA. 0.8 Cs 0.2 PbI 1.8 Br 1.2 The fullerene derivative is 5'-Phenyl-5'. H -[5,6]fullereno-C 60 - I h -[1,9:2',3']pyrido[3,2- b indole; The structural formula of the fullerene derivative is shown below: 。 2. The wide-bandgap perovskite solar cell based on fullerene derivatives according to claim 1, characterized in that, The conductive substrate includes glass and an indium tin oxide layer deposited on the surface of the glass; And / or, the material of the first hole transport layer is nickel oxide; And / or, the material of the self-assembled monolayer is SAM; And / or, the material of the first electronic modification layer is copper bath; And / or, the material of the first metal electrode layer is silver or gold.

3. The wide-bandgap perovskite solar cell based on fullerene derivatives according to claim 1, characterized in that, The thickness of the conductive substrate is 1-1.2 mm; And / or, the thickness of the first hole transport layer is 15-40 nm; And / or, the thickness of the self-assembled monolayer is 0.8-2.5 nm; And / or, the thickness of the wide-bandgap perovskite light-absorbing layer is 300-450 nm; And / or, the thickness of the fullerene derivative electron transport layer is 20-25 nm; And / or, the thickness of the first electronic modification layer is 5-10 nm; And / or, the thickness of the first metal electrode layer is 90-110 nm.

4. A method for preparing a wide-bandgap perovskite solar cell based on fullerene derivatives as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Coat a conductive substrate with an aqueous nickel oxide solution at a spin coating rate of 1200-1800 rpm for 20-40 s. Anneal at 140-160℃ for 5-15 min. After cooling, transfer to a nitrogen-filled glove box. S2. In a nitrogen atmosphere, the SAM ethanol solution is coated onto nickel oxide at a spin coating rate of 2500-3500 rpm for 20-40 s, and then annealed at 90-110℃ for 5-15 min. S3. In a glove box, the wide-bandgap perovskite precursor solution is coated onto SAM in two steps. The first step is a spin coating rate of 300-800 rpm and a spin coating time of 1-3 s. The second step is a spin coating rate of 3500-4500 rpm and a spin coating time of 50-70 s. During the second step of spin coating, anhydrous diethyl ether is added dropwise at 20-30 s. Then, the mixture is annealed at 90-110℃ for 5-15 min. S4. Coat a fullerene derivative chlorobenzene solution onto a wide-bandgap perovskite substrate at a spin coating rate of 1500-2500 rpm for 20-40 s, and anneal at 60-80℃ for 0.5-1.5 min. S5. Coat the fullerene derivative with a copper-based isopropanol solution at a spin coating rate of 3500-4500 rpm for 20-40 s, and anneal at 90-110℃ for 0.5-1.5 min. S6, vacuum thermal evaporation method is used to evaporate metal on bath copper spirit, the vacuum degree in the cavity of vacuum thermal evaporation system is 1x10 - 4 Pa, the deposition rate is 0.5-1.0 angstrom / s, that is, a wide-bandgap perovskite battery based on fullerene derivative is obtained.

5. The method for preparing a wide-bandgap perovskite solar cell based on fullerene derivatives according to claim 4, characterized in that, The preparation method of the wide-bandgap perovskite precursor solution includes: N,N-dimethylformamide and dimethyl sulfoxide were mixed in a volume ratio of (3-5):1 to prepare a mixed solvent. FAI, PbBr2, PbI2, PbCl2, CsI and MACl were then dissolved in the mixed solvent and filtered through a polytetrafluoroethylene membrane to obtain a wide-bandgap perovskite precursor solution with a concentration of 1-1.5 mol / L. And / or, the concentration of the nickel oxide aqueous solution is 8-12 mg / mL; And / or, the concentration of the SAM ethanol solution is 0.2-1.0 mg / mL; And / or, the concentration of the fullerene derivative chlorobenzene solution is 15-25 mg / ml; And / or, the concentration of the copper bath isopropanol solution is 1.0-3.5 mg / mL.

6. A tandem solar cell, characterized in that, It includes a wide-bandgap perovskite top cell, a metal oxide electron transport layer, a buffer layer, a second hole transport layer, a narrow-bandgap perovskite light-absorbing layer, an interface passivation layer, a fullerene electron transport layer, a second electron modification layer, and a second metal electrode layer, which are stacked sequentially. The wide-bandgap perovskite top solar cell comprises a conductive substrate, a first hole transport layer, a self-assembled monolayer, a wide-bandgap perovskite light-absorbing layer, and a fullerene derivative electron transport layer, which are stacked sequentially. The molecular formula of the wide-bandgap perovskite is FA. 0.8 Cs 0.2 PbI 1.8 Br 1.2 The fullerene derivative is 5'-Phenyl-5'. H -[5,6]fullereno-C 60 - I h -[1,9:2',3']pyrido[3,2- b indole; The structural formula of the fullerene derivative is shown below: ； The molecular formula of the narrow bandgap perovskite is FA. 0.6 MA 0.3 Cs 0.1 Pb 0.5 Sn 0.5 I3; the fullerene electron transport layer is C 60 .

7. The tandem solar cell according to claim 6, characterized in that, The conductive substrate includes glass and an indium tin oxide layer deposited on the surface of the glass; And / or, the material of the first hole transport layer is nickel oxide; And / or, the material of the self-assembled monolayer is SAM; And / or, the material of the metal oxide electron transport layer is tin oxide; And / or, the material of the buffer layer is gold; And / or, the material of the second hole transport layer is PEDOT:PSS; And / or, the material of the interface passivation layer is ethylenediamine dihydroiodide; And / or, the material of the second electronic modification layer is copper bath; And / or, the material of the second metal electrode layer is silver or gold.

8. The tandem solar cell according to claim 6, characterized in that, The thickness of the conductive substrate is 1-1.2 mm; And / or, the thickness of the first hole transport layer is 15-40 nm; And / or, the thickness of the self-assembled monolayer is 0.8-2.5 nm; And / or, the thickness of the wide-bandgap perovskite light-absorbing layer is 300-450 nm; And / or, the thickness of the fullerene derivative electron transport layer is 20-25 nm; And / or, the thickness of the metal oxide electron transport layer is 20-30 nm; And / or, the thickness of the buffer layer is 0.5-1.5 nm; And / or, the thickness of the second hole transport layer is 25-50 nm; And / or, the thickness of the narrow bandgap perovskite light-absorbing layer is 600-800 nm; And / or, the thickness of the interface passivation layer is 1.0-3.5 nm; And / or, the thickness of the fullerene electron transport layer is 20-30 nm; And / or, the thickness of the second electronic modification layer is 4-8 nm; And / or, the thickness of the second metal electrode layer is 90-110 nm.

9. A method for preparing a tandem solar cell as described in any one of claims 6-8, characterized in that, Includes the following steps: (1) Coat a conductive substrate with an aqueous nickel oxide solution at a spin coating rate of 1200-1800 rpm for 20-40 s, anneal at 140-160℃ for 5-15 min, and after cooling, transfer to a nitrogen-filled glove box. (2) In a nitrogen atmosphere, the SAM ethanol solution is coated onto nickel oxide at a spin coating rate of 2500-3500 rpm and a spin coating time of 20-40 s. Then, it is annealed at 90-110℃ for 5-15 min. (3) In the glove box, the wide-bandgap perovskite precursor solution is coated on SAM in two steps. The first step is spin-coating at a speed of 300-800 rpm and a spin-coating time of 1-3 s. The second step is spin-coating at a speed of 3500-4500 rpm and a spin-coating time of 50-70 s. During the second step spin-coating, anhydrous diethyl ether is added dropwise at 20-30 s. Then, the mixture is annealed at 90-110℃ for 5-15 min. (4) Coat the fullerene derivative chlorobenzene solution onto the wide-bandgap perovskite at a spin coating rate of 1500-2500 rpm and a spin coating time of 20-40 s, and anneal at 60-80℃ for 0.5-1.5 min. (5) Tin oxide was deposited on the fullerene derivative using ALD atomic layer deposition at a vacuum level of 1×10⁻⁶. -3 -5×10 -3 Torr, with a deposition rate of 0.2-0.4 Å / s, and under a vacuum of not less than 1×10 -4 Under the condition of Pa, gold was deposited on the tin oxide surface by vapor deposition, and then PEDOT:PSS was coated on the gold. The spin coating rate was 3500-4500 rpm and the spin coating time was 20-40 s. The coating was then annealed at 110-130℃ for 10-30 min. (6) In a nitrogen-filled glove box, the narrow band gap perovskite precursor solution is coated in two steps. The first step is a spin coating rate of 800-1200 rpm and a spin coating time of 5-15 s. The second step is a spin coating rate of 3500-4500 rpm and a spin coating time of 20-40 s. Chlorobenzene is added dropwise at 20-40 s. Then, the mixture is annealed at 90-110℃ for 5-15 min. (7) Coat the narrow band gap perovskite with ethylenediamine dihydroiodide isopropanol solution at a spin coating rate of 3500-4500 rpm and a spin coating time of 10-30 s, and anneal at 90-110℃ for 0.5-1.5 min. (8) C is sequentially deposited on ethylenediamine dihydroiodide using a vacuum thermal evaporation method. 60 The vacuum thermal evaporation system for copper bath and metals has a vacuum level of 1×10⁻⁶ within its cavity. -4 With a deposition rate of 0.2-1.0 Å / s, a tandem solar cell can be obtained.

10. The method for preparing a tandem solar cell according to claim 9, characterized in that, The method for preparing the narrow bandgap perovskite precursor solution includes: PbI2, SnI2, FAI, MAI, CsI, SnF2 and NH4SCN were dissolved in N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of (2-4):1, stirred overnight, and filtered through a polytetrafluoroethylene membrane to obtain a narrow bandgap perovskite precursor solution with a concentration of 2-2.5 mol / L. And / or, the method for preparing the wide-bandgap perovskite precursor solution includes: N,N-dimethylformamide and dimethyl sulfoxide were mixed in a volume ratio of (3-5):1 to prepare a mixed solvent. FAI, PbBr2, PbI2, PbCl2, CsI and MACl were then dissolved in the mixed solvent and filtered through a polytetrafluoroethylene membrane to obtain a wide-bandgap perovskite precursor solution with a concentration of 1-1.5 mol / L. And / or, the concentration of the nickel oxide aqueous solution is 8-12 mg / mL; And / or, the concentration of the SAM ethanol solution is 0.2-1.0 mg / mL; And / or, the concentration of the fullerene derivative chlorobenzene solution is 15-25 mg / ml; And / or, the PEDOT:PSS is obtained by diluting PEDOT:PSS stock solution with isopropanol at a volume ratio of 1:(2-4); And / or, the concentration of the ethylenediamine dihydroiodide isopropanol solution is 0.8-1.2 mg / mL.

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