Temperature Sensitive and Reversible Halide Ion Exchange in Inorganic-Organic Hybrid CH3NH3Pbl3-xBrx Mixed-halide Perovskite

Ion exchange of organic-inorganic hybrid perovskite plays an important role in controlling the performance of materials ant its devices. In this study, we found an interesting phenomenon that the precipitate in the in suspension (CH₃NH₃PbI_3-xBr_x in γ – butyrolactone) presented different colors at high and room temperature. The mechanism study shows that the phenomenon is controlled by temperature sensitive and reversible halide ion exchange in organic-inorganic hybrid CH₃NH₃PbI_3-xBr_x mixed-halide perovskite. The results of structure phase, element composition morphology and band gap indicate that high temperature 55 °C is beneficial to the increasing of I content in MAPbI_3-xBr_x and room temperature or lower is beneficial to increasing of Br content in MAPbI_3-xBr_x.measurement were carried out. Compared with MAPbI_0.76Br_2.24 precipitate obtained at room temperature, MAPbI_1.17Br_1.83 precipitate obtained at high temperature exhibit wider lattice spacing, better crystallinity, better morphology and narrower band gap. The results and findings in this study will arouse the interest of readers or experts in the field of organic-inorganic hybrid perovskite materials and related optoelectronic applications.