The Preparation And Process Exploration Of Tin-based Perovskite Solar Cells

Organic-inorganic hybrid perovskite solar cells（PSCs）have undergone a dramatic development over the past few years.Nowadays,the latest record of PCE has reached 24.2%which means it has a very broad development prospect.However,the majority of high-performance PSCs are based on lead halide perovskite materials which may pose a threat to the ecological environment and human health.Tin-based PSCs are currently the most promising candidate for lead-free PSCs,but the uncontrollable film morphology and fast oxidation of Sn²⁺severely limits their applications.In this thesis,we mainly study the influence of preparation process and material composition on the quality of tin-based perovskite film and device performance.This work is based on FASnI₃ PSCs and the specific work is as follows:1.Based on the device structure of ITO/PEDOT:PSS/FASnI₃/C₆₀/BCP/Al,the fabrication of FASnI₃ PSCs was studied.The experiment results show that using 10 mol%SnF₂ as an additive is the optimal dose for the preparation of devices.The perovskite film was prepared by adjusting the ratio of the mixed solvent composed of DMSO and DMF.When the volume ratio of DMF to DMSO is 4:1 and chlorobenzene is used as anti-solvent,the best device performance was obtained.The optimized device under AM 1.5（100 mW/cm²）radiation achieved a PCE of 6.82%.2.Mixed-organic-cation tin-based FA_xMA_1-xSnI₃ PSCs were presented.The effects of three anti-solvents of diethyl ether,toluene and chlorobenzene on the perovskite film quality and device performance during spin coating were investigated.The perovskite film quality is of great important to the final device performance.By choosing appropriate anti-solvent,the film quality can be optimized which greatly improve the device performance.The optimal ratio is x=0.75 and the best perovskite film was obtained with chlorobenzene as anti-solvent.The best device has an PCE of9.06%and the encapsulated one can maintain 70%of the original PCE after being stored in nitrogen atmosphere for 30 days.3.Low-dimensional tin-based perovskite PEA₂FA₈Sn₉I₂₈ was fabricated by introducing PEA in FASnI₃ to improve the stability of device.Results indicated that in the case of doping with 10%PEA,the best perovskite film was prepared with toluene and the corresponding device performance had been improved to 8.26%.The semiconductor characteristic test was also performed and the results show that the trap-assisted recombination rate in device with toluene as anti-solvent is the lowest,which is agree with the perovskite film morphology.The encapsulated cell can maintain more than 90%of the initial PCE after being stored in a nitrogen glove box for 30 days,indicating that it has a very good stability.