Improving The Performance Of CsPbBr₃ Perovskite Solar Cells By Solvent Engineering

In order to solve the current increasingly serious energy crisis and achieve sustainable development,the development and utilization of renewable energy has become a top priority.As a kind of new energy,solar energy has the advantages of abundant storage capacity and no transportation problems,so it has attracted wide attention.As a"star"material in recent years,perovskite materials have excellent characteristics such as high absorption coefficient and long carrier life,and are widely used in the absorption layer of solar cells.After more than ten years of development,perovskite solar cells（PSCs）have increased their power conversion efficiency（PCE）to 25.6%of the latest report.However,most of the current high-efficiency perovskite solar cells use organic-inorganic hybrid perovskite materials as the light absorption layer.Due to the existence of organic groups,this material is easily decomposed under water vapor,oxygen or light conditions.Thus,the stability of the equipment is greatly reduced.In contrast,all-inorganic perovskite materials,especially CsPbBr₃,have excellent environmental stability.In this context,this thesis explores and studies the all-inorganic perovskite material CsPbBr₃and its solar cell device application,aiming to improve the quality of CsPbBr₃film and device performance through solvent engineering,and analyze its potential mechanism.The main research contents are as follows:（1）Optimize the preparation process of CsPbBr₃ film and device:Introduce multi-step spin coating process to prepare CsPbBr₃film,and optimize spin coating parameters to improve the quality of CsPbBr₃film and device performance;adopt carbon electrode without hole transport layer structure to replace traditional holes transmission layer and metal electrode structure to optimize the device structure,so that the PCE and stability of the device are significantly improved;the anti-solvent method is used to control the surface morphology of the Pb Br₂layer to promote the full reaction of the CsPbBr₃film,thereby improving the quality of the CsPbBr₃film and the performance of the device,And analyzed its influence mechanism.（2）2-phenylethanamine iodide（PEAI）solvent treatment improves the quality of CsPbBr₃film and device performance:for the first time,PEAI is introduced for solvent treatment in the preparation of all-inorganic CsPbBr₃perovskite film to improve the crystalline quality and surface morphology of the CsPbBr₃film.Finally,a PCE of 8.51%is obtained.The best device has excellent stability over 340 days Studies have found that the introduction of PEAI can not only induce the formation of 2D perovskite materials,passivate grain boundaries and inhibit non-radiative recombination,but also improve the crystallization kinetics of perovskite,including stress release and orientation growth during crystallization,so as to obtain stable Structure of high-quality CsPbBr₃ film.