Perovskite solar cell based on guanidine sulfamate interface modification in air environment and preparation method thereof

Abstract

The invention relates to the technical field of perovskite solar cells, in particular to a guanidine sulfamate interface modification-based perovskite solar cell in an air environment and a preparation method thereof. By adopting an interface passivation engineering strategy, multifunctional guanidinium sulfamate molecules are customized between the electron transport layer and the perovskite light absorption layer to serve as an interface modification material, efficient and directional extraction and transport of photon-generated carriers are achieved, interface non-radiative recombination is inhibited, and therefore the perovskite thin film with high crystallization quality is obtained in the air environment. And an efficient and stable perovskite solar cell is further prepared in an air environment. Based on this, the optimized device obtains a high open-circuit voltage of 1.157 V, and the photoelectric conversion efficiency is improved to 24.00%.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of perovskite solar cells, in particular to a perovskite solar cell based on guanidinium sulfamate interface modification in an air environment and a preparation method thereof. BACKGROUND

[0002] As a representative of new thin-film photovoltaic technology, perovskite solar cells are regarded as a core technology to revolutionize traditional crystalline silicon cells in the future due to advantages such as high efficiency, low cost and flexibility.

[0003] In the past decade, planar structure perovskite solar cells have attracted the attention of many researchers around the world due to their simple preparation method and ultra-high conversion efficiency, and their power conversion efficiency has increased from 3.8% in 2009 to 27%, reaching a level comparable to crystalline silicon solar cells developed for more than 70 years. However, the electron transport layer, an important component of planar structure perovskite solar cells, is generally prepared by low-temperature solution spin coating process, resulting in a large number of defect states such as dangling bonds and vacancies. In addition, the defect states induced by the electron transport layer and the perovskite film prepared by low-temperature solution method are prone to form high-density defect states and dangling bonds at the electron transport layer / perovskite buried interface and perovskite film, resulting in specific carrier trapping behavior. Improving the film quality and reducing the interface non-radiative recombination are beneficial to the improvement of the photoelectric conversion efficiency of perovskite solar cells. Therefore, it is necessary to develop a convenient and effective electron transport layer / perovskite buried interface defect state passivation process to improve the efficiency of perovskite solar cells. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a perovskite solar cell based on guanidinium sulfamate interface modification in an air environment and a preparation method thereof. The guanidinium sulfamate introduced at the buried interface can interact with the uncoordinated Sn 4 + or oxygen vacancy sites and uncoordinated Pb 2+ or I - in the perovskite, so as to solve the problem that the interface defect passivation of the electron transport layer / perovskite light absorbing layer is difficult to achieve when preparing the perovskite film by the two-step solution spin coating method in the prior art, so as to obtain a perovskite film with high crystalline quality in an air environment, and make the preparation of high-efficiency perovskite solar cells free from the limitation of inert atmosphere and enter an open environment.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: A first technical objective of the present application is to provide a perovskite solar cell based on guanidinium sulfamate interface modification in an air environment, which is an n-i-p type formal planar structure, from bottom to top in turn is transparent conductive substrate, electron transport layer, guanidinium sulfamate modified layer, perovskite light absorbing layer, hole transport layer and metal electrode, the structural formula of guanidinium sulfamate is as follows: .

[0006] Further, the guanidinium sulfamate is a white solid powder.

[0007] Further, the above-mentioned transparent conductive substrate is selected from any one of fluorine-doped tin oxide (FTO) conductive glass, indium-doped tin oxide (ITO) conductive glass, transparent conductive flexible material.

[0008] Further, the above-mentioned electron transport layer is selected from any one of titanium dioxide (TiO2), tin dioxide (SnO2), zinc oxide (ZnO).

[0009] Further, the above-mentioned perovskite light absorbing layer is FA x Cs 1-x PbI3, wherein the value of x is 0-1, the thickness of the perovskite light absorbing layer is 450-700 nm.

[0010] Further, the above-mentioned hole transport layer is selected from any one of 2,2",7,7"-tetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD), nickel oxide (NiO), poly-3-hexylthiophene (P3HT).

[0011] Further, the above-mentioned metal electrode is selected from any one of gold (Au) electrode, silver (Ag) electrode.

[0012] Preferably, the perovskite solar cell comprises ITO glass, SnO2 electron transport layer, guanidinium sulfamate modified layer, FA x Cs 1-x PbI3 perovskite absorbing layer, Spiro-OMeTAD hole transport layer and metal electrode, arranged in turn from bottom to top.

[0013] A second technical objective of the present application is to provide a preparation method of a perovskite solar cell based on guanidinium sulfamate interface modification in an air environment as described above, comprising the following steps: Step 1, clean the transparent conductive substrate ITO and blow dry; Step 2, spin-coat SnO2 nano-dispersion on the ITO glass, and obtain the electron transport layer after annealing; Step 3: coating a guanidinium sulfamate aqueous solution on the SnO2 electron transport layer, and obtaining a guanidinium sulfamate modified layer after annealing; Step 4: spin-coating FA on the guanidinium sulfamate modified layer x Cs 1-x PbI3 perovskite precursor solution, and obtaining FA after annealing x Cs 1-x PbI3 perovskite absorption layer; Step 5: preparing a Spiro-OMeTAD hole transport layer on the FA x Cs 1-x PbI3 perovskite absorption layer; Step 6: vacuum evaporation of a metal electrode on the Spiro-OMeTAD hole transport layer, and obtaining a perovskite solar cell.

[0014] Further, in the above step 1, the cleaning and drying specifically refers to: first, the transparent conductive substrate is sequentially ultrasonically cleaned in deionized water, acetone and isopropanol for 10-30 minutes, and then dried with nitrogen.

[0015] Further, in the above step 2, the mass concentration of the SnO2 nanodispersion liquid is 2.0-5.0 wt%; the spin-coating speed is 2500-3500 rpm, and the time is 30-40 seconds; the annealing temperature is 140-160 ℃, and the time is 20-40 minutes.

[0016] Further, in the above step 3, the guanidinium sulfamate aqueous solution is obtained by dissolving guanidinium sulfamate in water and stirring, and the concentration of the guanidinium sulfamate aqueous solution is 1.5-3.5 mg / mL; the spin-coating speed during coating is 2000-3000 rpm, and the spin-coating time is 10-20 seconds; the annealing temperature is 80-120 ℃, and the time is 10-20 minutes.

[0017] Further, in the above step 4, the FA is prepared on the guanidinium sulfamate modified layer x Cs 1-x The operation steps of the FA a. Preparation of PbI2 thin film: Cesium iodide (CsI) powder and lead iodide (PbI2) powder are weighed, the concentration of CsI is 15-20 mg / mL, the concentration of PbI2 is 620-720 mg / mL, the solvent is a mixture of polar solvents DMF and DMSO, the volume ratio of DMF to DMSO is 9.5:0.5-2:1, wherein DMF is methyl formamide and DMSO is dimethyl sulfoxide; the PbI2 precursor solution is spin-coated on the electron transport layer substrate, the spin-coating time is 25-35 seconds, the rotation speed is 2000-3000 rpm, after spin-coating, the sample is placed on a flat heating table for heating, the heating temperature is 50-80 ℃, and the heating time is 40-80 seconds; b. Preparation of FA x Cs 1-x PbI3 perovskite thin film: an ammonium salt solution is configured, FAI (formamidinium iodide) and MACl (methylamine chloride) are weighed, wherein the concentration of FAI is 70-110 mg / mL, the concentration of MACl is 10-20 mg / mL, and the solvent is isopropanol; the configured ammonium salt solution is spin-coated on the PbI2 thin film to obtain a perovskite thin film, the spin-coating time is 15-30 seconds, the rotation speed is 1500-2500 rpm, after spin-coating, the sample is placed on a flat heating table for heating, the heating temperature is 100-180 ℃, and the heating time is 10-20 minutes; the prepared FA x Cs 1-x The thickness of the PbI3 perovskite thin film is 500-800 nm.

[0018] Further, in the above step 5, the Spiro-OMeTAD precursor solution is prepared by mixing 72.3 mg of Spiro-OMeTAD powder, 28.8 μL of 4-tert-butylpyridine and 17.5 μL of Li-TFSI (lithium bis-trifluoromethanesulfonimide) acetonitrile solution with a concentration of 500 mg / mL per 1 mL of chlorobenzene, and the spin-coating amount is 10-20 μL / cm 2 ; the rotation speed of spin-coating is 3000-5000 rpm, and the time is 20-40 seconds; the oxidation treatment equipment is a dry cabinet, the humidity is not more than 10% RH, and the time is 12-24 hours.

[0019] Further, in the above step 6, the vacuum degree of vacuum evaporation is 1.0-5.0×10 -4 Pa.

[0020] According to the above technical solution, compared with the prior art, the beneficial effects of the present application are as follows: 1) The present application first proposes to introduce multifunctional guanidinium sulfamate as an interface carrier transport targeting high-speed bridge between the electron transport layer and the perovskite light-absorbing layer. Through theoretical and experimental research, it is proved that guanidinium sulfamate is introduced into the buried interface between the electron transport layer and the perovskite light-absorbing layer, and the interface characteristics are synergistically controlled through its unique bifunctional group. The guanidinium sulfamate molecule contains sulfonic acid group (-SO3 – ) with strong coordination ability and positively charged guanidinium cation (-NH3 + ) at the same time, which can construct an efficient bidirectional passivation mechanism at the electron transport layer / perovskite interface. On the one hand, the lone pair electrons in the sulfonic acid group can form stable coordination bonds with uncoordinated Sn 4+ or oxygen vacancy sites on the surface of the electron transport layer, effectively filling the oxygen vacancy defects in the electron transport layer lattice, thereby inhibiting the interface carrier recombination and enhancing the electron transport capacity; on the other hand, the guanidinium cation is combined with uncoordinated Pb 2+ or I - defects in the perovskite light-absorbing layer through electrostatic interaction, which significantly reduces the deep level defect state density at the interface and improves the crystalline quality of the perovskite film. Finally, the perovskite solar cell based on guanidinium sulfamate interface modification achieves a power conversion efficiency of nearly 24.00%.

[0021] 2) The present application has simple process, low cost and good commercial application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the provided drawings.

[0023] Figure 1 is the structure schematic diagram of the perovskite solar cell described in embodiment 1 of the present application.

[0024] Figure 2 is the interface interaction mechanism diagram of the guanidinium sulfamate small molecule described in the present application at the SnO2 / FA x Cs 1-x PbI3 interface.

[0025] Figure 3 is the steady-state photoluminescence (PL) spectrum of the perovskite film on the surface of the SnO2 electron transport layer without modification and after guanidinium sulfamate modification described in embodiment 1 and comparative example of the present application.

[0026] Figure 4Time-resolved photoluminescence (TRPL) spectra of perovskite films after no modification and modification of guanidinium sulfamate on the surface of SnO2 electron transport layer described in Example 1 of the present application.

[0027] Figure 5 is the conductivity graph of SnO2 electron transport layer prepared in Example 1 and Comparative Example.

[0028] Figure 6 J-V curves of perovskite solar cells after no modification and modification of guanidinium sulfamate on the surface of SnO2 electron transport layer described in Example 1 and Comparative Example of the present application.

[0029] Figure 7 is the scanning electron microscope (SEM) scanning comparison chart of the surface of SnO2 electron transport layer described in Example 1 and Comparative Example 1 of the present application; wherein, (a) is the unmodified, (b) is the perovskite film after modification of guanidinium sulfamate.

[0030] Figure 8 is the environmental stability graph of perovskite solar cells prepared in Example 1 and Comparative Example. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0032] Herein, the special word "embodiment" as "exemplary" explained any embodiment does not have to be interpreted as superior or better than other embodiments. In the performance index test of the embodiments of the present application, unless otherwise specified, the conventional test method in the art is adopted. It should be understood that the terms described in the present application are only for describing the specific embodiments, and are not used to limit the disclosure of the present application.

[0033] Unless otherwise specified, the technical and scientific terms used herein have the same meaning as generally understood by those skilled in the art to which the present application belongs; as the test methods and technical means not specially noted in the present application are all the experimental methods and technical means generally used by those skilled in the art.

[0034] In order to better illustrate the content of the present application, a large number of specific details are given in the specific embodiments below. Those skilled in the art should understand that without certain specific details, the present application can also be implemented. In the embodiments, some methods, means, instruments, equipment and the like which are well known to those skilled in the art are not described in detail, in order to highlight the main idea of the present application.

[0035] The technical features disclosed in the embodiments of the present application can be combined arbitrarily without conflicts, and the resulting technical solutions belong to the disclosure of the present application.

[0036] The application discloses a perovskite solar cell based on guanidinium sulfamate interface modification in an air environment and a preparation method thereof.

[0037] The raw materials used in the application are all commercially available chemical pure reagents, and the application will be further described in detail below in combination with the drawings and examples, but the protection scope of the application is not limited to these examples. Based on the examples in the application, all other examples obtained by those skilled in the art without creative labor belong to the protection scope of the application.

[0038] Example 1 Preparation of guanidinium sulfamate modification solution: 2.5 mg of guanidinium sulfamate was dissolved in 1 mL of ultrapure water to obtain a 2.5 mg / mL guanidinium sulfamate modification aqueous solution.

[0039] SnO2 precursor solution: 12 v / v% SnO2 hydrogel dispersion liquid was mixed with deionized water at a volume ratio of 1:3, and ice water was ultrasonicated for 5 minutes.

[0040] Preparation of perovskite precursor solution: 19 mg of CsI and 691.5 mg of PbI2 were dissolved in a mixed solution of 0.05 mL of DMSO and 0.95 mL of DMF, and fully stirred to obtain a CsI / PbI2 solution; 90 mg of FAI and 16 mg of MACL were mixed and dissolved in 1 mL of IPA, and stirred to dissolve to obtain a FAI / MACL solution.

[0041] Preparation of hole transport layer solution: 72.3 mg of Spiro-OMeTAD, 28.8 μL of Li-TFSI salt (520 mg of Li-TFSI dissolved in 1 mL of acetonitrile solvent) and 17.5 μL of 4-tert-butylpyridine (TBP) were added to 1 mL of chlorobenzene (CB), and stirred for 12 hours and then filtered to obtain a hole transport layer (Spiro-OMeTAD) solution.

[0042] Preparation of perovskite solar cell: 2 cm x 2 cm ITO conductive glass was ultrasonically cleaned in deionized water, acetone and isopropanol for 10-30 minutes alternately, and then dried by blowing nitrogen and placed in a culture dish with the conductive surface upward, and then treated with ultraviolet-ozone (UVO) for 20 minutes.

[0043] The prepared SnO2 precursor aqueous solution was spin-coated on the surface of the ITO glass substrate treated by ultraviolet-ozone, the spin-coating speed was 3000 rpm, the time was 30 seconds, then annealing treatment was carried out, the annealing temperature was 150℃, the annealing time was 30 minutes, thereby the SnO2 electron transport layer was prepared; then the SnO2 electron transport layer was treated by UVO for 10 minutes, then 50 μL of the guanidinium sulfamate modification aqueous solution was spin-coated on the SnO2 electron transport layer at a speed of 3000 rpm for 30 seconds, after the spin-coating, the sample was quickly transferred to a high-temperature annealing table at 100℃ for annealing for 10 minutes and then cooling, thereby the guanidinium sulfamate modification layer was formed; then 30 μL of CsI / PbI2 was dropped on the SnO2 substrate under the atmosphere, and spin-coated on the guanidinium sulfamate modification layer at a speed of 1500 rpm for 30 seconds, and then annealed at 70℃ for 1 minute; then 90 μL of FAI / MACL was dropped on the film substrate on which CsI / PbI2 was deposited, and spin-coated at a speed of 1800 rpm for 20 seconds, and then annealed on a 150℃ heating plate for 15 minutes, thereby the perovskite film was obtained; 45 μL of the Spiro-OMeTAD solution was spin-coated on the perovskite light-absorbing layer at a speed of 4000 rpm for 30 seconds, thereby the hole transport layer was formed; finally, the silver electrode with a thickness of 70-120 nm was deposited on the hole transport layer by vacuum thermal evaporation, thereby the perovskite solar cell was prepared.

[0044] Example 2 In this example, 1.5 mg of guanidinium sulfamate was dissolved in 1 mL of ultrapure water to obtain a guanidinium sulfamate modification solution of 1.5 mg / mL, and the other steps were the same as those in Example 1.

[0045] Example 3 In this example, 3.5 mg of guanidinium sulfamate was dissolved in 1 mL of ultrapure water to obtain a guanidinium sulfamate modification solution of 3.5 mg / mL, and the other steps were the same as those in Example 1.

[0046] In order to further prove the beneficial effects of the present application and better understand the present application, the technical features disclosed in the present application are further illustrated by the following comparative examples, but it should not be understood as a limitation of the present application. Other improvements made by those skilled in the art without creative work according to the above invention content are also considered to fall within the protection scope of the present application.

[0047] Comparative Example The guanidinium sulfamate modification solution was not spin-coated on the SnO2 electron transport layer, and the perovskite precursor solution was directly spin-coated to prepare the perovskite light-absorbing layer, and the other steps were the same as those in Example 1.

[0048] As Figure 1is a device structure schematic diagram of the perovskite solar cell, and Glass / ITO, SnO2 electron transport layer, guanidinium sulfamate modification layer, FA x Cs 1-x PbI3perovskite light absorption layer, Spiro-OMeTAD hole transport layer and silver electrode. The concentration of guanidinium sulfamate is 2.5 mg / mL.

[0049] As Figure 2 shown, the characteristics of the multifunctional ligand guanidinium sulfamate can passivate the defects on both sides of the interface, and optimize the interface contact. The-SO3 - and-NH3 + of guanidinium sulfamate can passivate the Sn 4+ and I - of the SnO2 / perovskite buried interface, reduce the interface defect state density, and inhibit non-radiative recombination.

[0050] As Figure 3 shown, compared with the comparative example, the PL emission peak intensity of the perovskite thin film excited from the glass side of the example 1 is significantly reduced, which is due to the synergistic passivation effect of the molecular bridge structure of guanidinium sulfamate on the defect states of the electron transport layer / perovskite thin film, reducing the non-radiative recombination loss.

[0051] As Figure 4 shown, the test results of TRPL show that, compared with the comparative example, the average charge lifetime of the guanidinium sulfamate treated SnO2 / perovskite interface of the example 1 is significantly reduced from 177.66 ns to 89.42 ns, which is due to the reduction of defect density, the acceleration of charge extraction rate, the shortening of charge lifetime, and the enhancement of carrier transport ability.

[0052] As Figure 5 shown, in order to evaluate the influence of guanidinium sulfamate on the carriers of the SnO2 electron transport layer, the difference in conductivity of the SnO2 electron transport layer of the comparative example and the example 1 was analyzed, and the J-V curve was tested by a single electron device of ITO / ETL / Ag structure in a dark environment. The conductivity is calculated by the formula σ=Id / VA, and the conductivity of the device without guanidinium sulfamate modified SnO2 is 3.75×10 -3 mS cm -1 . In contrast, the conductivity of the device using guanidinium sulfamate modified SnO2 is significantly increased to 5.99×10 -3 mS cm -1 .

[0053] As Figure 6The J-V curves of the comparative example (SnO2 electron transport layer surface unmodified) and example 1 (modified by guanidinium sulfamate) perovskite solar cells are shown. It can be seen that, compared with the comparative sample, the open circuit voltage and fill factor of the perovskite solar cell modified by guanidinium sulfamate are obviously improved, from 1.108 V and 78.25% to 1.57 V and 80.22%, respectively, and the highest photoelectric conversion efficiency of 23.96% is obtained for the prepared device.

[0054] The J-V curves of the comparative example (SnO2 electron transport layer surface unmodified) and example 1 (modified by guanidinium sulfamate) perovskite solar cells are shown. It can be seen that, compared with the comparative sample, the open circuit voltage and fill factor of the perovskite solar cell modified by guanidinium sulfamate are obviously improved, from 1.108 V and 78.25% to 1.57 V and 80.22%, respectively, and the highest photoelectric conversion efficiency of 23.96% is obtained for the prepared device. Figure 7 The J-V curves of the comparative example (SnO2 electron transport layer surface unmodified) and example 1 (modified by guanidinium sulfamate) perovskite solar cells are shown. It can be seen that, compared with the comparative sample, the open circuit voltage and fill factor of the perovskite solar cell modified by guanidinium sulfamate are obviously improved, from 1.108 V and 78.25% to 1.57 V and 80.22%, respectively, and the highest photoelectric conversion efficiency of 23.96% is obtained for the prepared device.

[0055] Figure 8 In order to analyze the influence of guanidinium sulfamate modification on the environmental stability of the device, the change in PCE was monitored in an atmospheric environment of relative humidity (RH: 30%~40%) and ambient temperature (T: 20~30°C). The perovskite solar cell prepared in example 1 after modification by guanidinium sulfamate still maintained 79% of the initial efficiency after 800 hours of storage, while the comparative example maintained only 63% of the initial efficiency after 600 hours of storage.

[0056] Table 1 is the photovoltaic performance parameters of the perovskite cells prepared in the comparative example and examples 1-3, including open circuit voltage, short circuit current, fill factor and cell power conversion efficiency.

[0057] Table 1 photovoltaic performance parameters of the perovskite cells of the comparative example and examples 1-3

[0058] The above description of disclosed examples enables one of ordinary skill in the art to make or use the application. Various modifications to these examples will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other examples without departing from the spirit or scope of the application. Accordingly, the application is not to be limited to these examples as shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.​

Claims

1. A perovskite solar cell based on guanidine sulfonate interface modification in an air environment, wherein the solar cell has a nip-type planar structure and mainly comprises, from bottom to top, a transparent conductive substrate, an electron transport layer, a perovskite light-absorbing layer, a hole transport layer, and a metal electrode; characterized in that, An aminosulfonate guanidine salt modified layer is constructed between the electron transport layer and the perovskite light-absorbing layer using aminosulfonate guanidine salt; The structural formula of the guanidine aminosulfonate is as follows: 。 2. The perovskite solar cell based on guanidine aminosulfonate interface modification in an air environment according to claim 1, characterized in that, The transparent conductive substrate is selected from any one of fluorine-doped tin oxide (FTO) conductive glass, indium-doped tin oxide (ITO) conductive glass, and transparent conductive flexible material, and the electron transport layer is selected from any one of titanium dioxide (TiO2), tin dioxide (SnO2), and zinc oxide (ZnO).

3. The perovskite solar cell based on guanidine aminosulfonate interface modification in an air environment according to claim 1, characterized in that, The perovskite light-absorbing layer is FA. x Cs 1-x PbI3, where x takes the value of 0 to 1, the thickness of the perovskite light-absorbing layer is 450 to 700 nm, the hole transport layer is selected from any one of 2,2" ,7 ,7"-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), nickel oxide (NiO), and poly-3-hexylthiophene (P3HT), and the metal electrode is selected from any one of gold (Au) electrode and silver (Ag) electrode.

4. A method for preparing a perovskite solar cell based on guanidine aminosulfonate interface modification in an air environment as described in claim 1, characterized in that, Includes the following steps: Step 1: Clean and dry the transparent conductive substrate ITO; Step 2: Spin-coating SnO2 nano-dispersion onto ITO glass, followed by annealing to obtain an electron transport layer; Step 3: Coat the SnO2 electron transport layer with an aqueous solution of guanidine sulfonate salt, and obtain the guanidine sulfonate salt modified layer after annealing. Step 4: Spin-coat FA onto the guanidine aminosulfonate modified layer. x Cs 1-x FA was prepared by annealing a PbI3 perovskite precursor solution. x Cs 1-x PbI3 perovskite absorber layer; Step 5, in FA x Cs 1-x Spiro-OMeTAD hole transport layer was prepared on PbI3 perovskite absorber layer; Step 6: Vacuum evaporation of metal electrodes onto the Spiro-OMeTAD hole transport layer to obtain a perovskite solar cell.

5. The method for preparing perovskite solar cells based on guanidine aminosulfonate interface modification in an air environment according to claim 4, characterized in that, In step 2, the mass concentration of the SnO2 nano-dispersion is 2.0–5.0 wt%; the spin coating speed is 2500–3500 rpm and the time is 30–40 seconds; the annealing temperature is 140–160 ℃ and the time is 20–40 minutes.

6. The method for preparing perovskite solar cells based on guanidine aminosulfonate interface modification in an air environment according to claim 4, characterized in that, In step 3, the concentration of guanidine aminosulfonate in the aqueous solution is 1.5–3.5 mg / mL, the spin coating speed of the guanidine aminosulfonate salt aqueous solution is 2000–3000 rpm, the spin coating time is 10–20 seconds, and the annealing temperature is 80–120 °C for 10–20 minutes.

7. The method for preparing perovskite solar cells based on guanidine aminosulfonate interface modification in an air environment according to claim 4, characterized in that, In step 4, FA is prepared on the guanidine aminosulfonate modified layer. x Cs 1-x The operation steps for the PbI3 perovskite absorber layer are as follows: a. Preparation of PbI2 thin film: Weigh cesium iodide (CsI) powder and lead iodide (PbI2) powder, with CsI concentration of 15-20 mg / mL and PbI2 concentration of 620-720 mg / mL. The solvent is a mixture of polar solvents DMF and DMSO, with a volume ratio of DMF to DMSO of 9.5:0.5-2:1, where DMF is methylformamide and DMSO is dimethyl sulfoxide. Spin-coat the PbI2 precursor solution onto the electron transport layer substrate for 25-35 seconds at a speed of 2000-3000 rpm. After spin-coating, place the substrate on a flat heating plate and heat it at 50-80 °C for 40-80 seconds. b. Preparation of FA x Cs 1-x PbI3 perovskite thin film: Prepare an ammonium salt solution by weighing FAI (formamidinium iodide) and MACl (methylamine chloride), where the concentration of FAI is 70–110 mg / mL and the concentration of MACl is 10–20 mg / mL, using isopropanol as the solvent; spin-coat the prepared and dispersed ammonium salt solution onto a PbI2 film to obtain a perovskite thin film. The spin-coating time is 15–30 seconds, and the rotation speed is 1500–2500 rpm. After spin-coating, place the film on a flat heating plate and heat it at a temperature of 100–180 °C for 10–20 minutes; the prepared FAI... x Cs 1-x The thickness of the PbI3 perovskite film is 500–800 nm.

8. The method for preparing perovskite solar cells based on guanidine aminosulfonate interface modification in an air environment according to claim 4, characterized in that, In step 5, the Spiro-OMeTAD precursor solution was prepared by mixing 72.3 mg Spiro-OMeTAD powder, 28.8 μL of 4-tert-butylpyridine, and 17.5 μL of a 500 mg / mL Li-TFSI (lithium bis(trifluoromethanesulfonylimide)) acetonitrile solution with 1 mL of chlorobenzene, with a spin-coating amount of 10–20 μL / cm. 2 Spin coating is performed at a speed of 3000–5000 rpm for 20–40 seconds; oxidation treatment is performed in a drying cabinet with a humidity not exceeding 10% RH for 12–24 hours.

9. The method for preparing perovskite solar cells based on guanidine aminosulfonate interface modification in an air environment according to claim 4, characterized in that, In step 6, the vacuum degree of vacuum evaporation is 1.0~5.0×10⁻⁶. -4 Pa.

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