Preparation Of Perovskite Solar Cells Based On Green Antisolvent And Their Interface Modification

In recent years,due to the increasing energy consumption and the continuous environmental pollution,the substitution of clean energy for fossil energy is inevitable.With the strong support of industrial policies in various countries around the world,solar energy and photovoltaic industry have developed rapidly.Solar energy,as a clean and sustainable energy,has great prospect and potential.Organic-inorganic perovskite thin-film solar cells?PSCs?,as a new type of high-efficiency photovoltaic device,have attracted great interest in academia in recent years.However,the toxicity of anti-solvent during perovskite preparation process and the instability of device performance still restrict their industrial application.In this paper,a one-step anti-solvent rapid crystallization method was used to control the composition of the light-absorbing layer of a ternary mixed cationic perovskite solar cell.The effect of the ratio of the cation Cs⁺on the microstructure and battery performance of the ternary mixed cationic perovskite thin film was studied.A green,non-toxic anti-solvent diethyl carbonate?DEC?was further developed to assist the perovskite crystallization process,effectively improving the photovoltaic performance of mixed regular and inverted structure mixed cation perovskite solar cells.Finally,polystyrene?PS?hydrophobic material was applied to the structural design of the device,and the passivation effect of the PS buffer layer on the mixed cation perovskite interface and the improvement of stability were studied.The specific research results are as follows:?1?The effects of cationic Cs⁺doping on the microstructure and photoelectric properties of mixed cation perovskite films were studied.The XRD and SEM test results of the film show that with the incorporation of Cs⁺,the yellow phase in the perovskite film can be effectively suppressed,and dense and uniform perovskite crystals are obtained.The UV-Vis and PL spectrum analysis also shows that with the increase of Cs⁺doping amount,the light absorption and PL characteristics of the film are improved,indicating that the film has fewer defects.The analysis of the J-V curve of the battery is consistent with the characterization of the material.Comprehensive analysis of various characterization methods:When the doping amount of Cs⁺is x=10%,the absorption of Cs_0.1(MA_0.17FA_0.83)_0.9Pb(I_0.83Br_0.17)₃ The layer has the best crystalline quality,and the prepared inverted structure solar cell has obtained a conversion efficiency of 10.63%(V_OC=0.74V,J_SC=21.26 mA/cm²,FF=67.39%);The solar cells with normal structure using the same optimal Cs ratio also achieved a conversion efficiency of14.51%.?2?In this paper,diethyl carbonate?DEC?was used as anti-solvent in the preparation process of the mixed cation perovskite thin film Cs_0.1(MA_0.17FA_0.83)_0.9.9 Pb(I_0.83Br_0.17)₃,and the microstructure and the photoelectric characteristics of corresponding solar cells have also been systematically studied.Compared with the perovskite film prepared by traditional chlorobenzene method,DEC anti-solvent treatment effectively increased the grain size of the perovskite film,reduced the pores in the film,and thereby improved the absorption and morphology of the perovskite films.Therefore,after the DEC antisolvent treatment,the PL intensity and carrier lifetime of the thin films are significantly improved.Under light illumination?AM1.5,100mW/cm²?,the short-circuit current,open-circuit voltage,and fill factor of perovskite thin-film photovoltaic devices treated with DEC anti-solvent are significantly improved.The photoelectric conversion efficiency increased from 12.83%?CB?to 14.05%?DEC?,which is nearly 7%.Importantly,compared to organic solvents such as ether and chlorobenzene,pollution-free DEC has more practical and commercial value and can be widely used in large-scale production applications.?3?The effect of the introduction of the tunneling layer PS on the performance and stability of the normal structure perovskite solar cell device was studied,and the effect of PS thickness on the carrier extraction and device stability were systematically investigated.The SEM of the film shows a complete and uniform coverage of PS on the surface of the perovskite sample.At the same time,the structural and optical properties of the perovskite film were not changed before and after the introduction of PS,and the device efficiency was increased from 10.53%to 12.8%after PS treatment.Compared with the perovskite solar cells with a traditional structure,the introduction of the PS layer with a concentration of 10 mg/ml significantly improved the stability of the device.After being left in the atmosphere for 10 days,the device performance still maintained 76%of its original efficiency.