Preparation And Photoelectric Properties Of Perovskite Solar Cells Based On CH₃NH₃Sn_xPb_?1-x?I₃

Perovskite solar cells are a new type of battery that has emerged in recent years,which has the advantage of high power conversion efficiency,cheap core materials and easy to use roll to roll technology to achieve large-low-cost manufacturing by solution method.However,the toxicity of heavy metal lead can cause environmental pollution.Tin and lead belong to the same main element,with tin instead of lead to prepare tin-lead binary perovskite solar cells is an effective way to reduce lead toxicity,but the efficiency of tin-based batteries is still lower than that of lead-based batteries.In order to improve the energy conversion efficiency of these batteries,the preparation process of CH₃NH₃Sn_xPb_?1-x?I3 tin-lead binary perovskite thin films was studied,the effects of the doping ratio of tin elements,the effects of solvent cleaning and solvent annealing on the performance of the battery were discussed,which is useful for the development of high efficiency,low cost and low lead perovskite thin film solar cells.The main contents of this thesis include the following two aspects:1.The preparation process of CH₃NH₃Sn_xPb_?1-x?I3 tin-lead binary perovskite active layer,especially the cleaning and soaking process of sec-butanol solvent and the solvent annealing process of dimethylformamide?DMF?were studied.The prepared tin-doped film(X = 0,0.15,_0.25,0.35,1)was tested and characterized and the performance of the 25% tin-doped(CH₃NH₃Sn_0.25Pb_0.75I3)battery is the best.Preferably,the perovskite polycrystalline thin films are homogeneous and compact,with an average particle size of 870 nm,which is larger than the film thickness,and CH₃NH₃SnI3 film has the worst crystallinity.2.The photovoltaic properties of CH₃NH₃Sn_xPb_?1-x?I3 tin-lead binary perovskite were studied,including J-V characteristic,EQE and stability.The results show that CH₃NH₃Sn_0.25Pb_0.75I3 has the best performance.The maximum energy conversion efficiency is 12.08% and the average efficiency is 11.01%.This efficiency has reached a high level in the field of the current reported one-step preparation of tin-lead binary perovskite solar cells.The battery has good repeatability,high stability and no obvious hysteresis phenomenon.