Chloride incorporation for the stability improvement of the MAPI hybrid perovskite

In recent years, perovskite thin films have attracted much attention in various industries due to their versatile applications. However, the stability problem of perovskite-based solar cells, caused by the susceptibility to degradation due to UV light and moisture, remains a persistent challenge despite the efforts made. This study focuses on the deterioration of CH₃NH₃PbI₃ perovskite thin films, and examines the impact of UV irradiation on their structural, morphological and optical characteristics. For that many CH₃NH₃Pb(I_1−xCl_x)₃ samples with different Cl contents have been synthesized and analyzed by XRD, SEM, UV–Vis Spectroscopy and FTIR technics. The main finding of this study is to demonstrate that it is possible to improve the stability of MAPbI₃ under UV light by integration of adequate chloride concentration into the perovskite structure. In fact, experimental observations approve clearly that the stability of CH₃NH₃Pb(I_1−xCl_x)₃ perovskite is significantly improved when the chloride doping concentration is above 20%. Furthermore, the XRD analysis show clearly that the observed UV stability improvement is directly attributed to a structural transition from the tetragonal to the more stable cubic phase.