Temperature Sensitive and Reversible Halide Ion Exchange in Inorganic–Organic Hybrid CH3NH3PbI3−xBrx Mixed-Halide Perovskite

Ion exchange of organic-inorganic hybrid perovskite plays a significant role in controlling the performance of materials ant its devices. In this study, an interesting phenomenon was observed that the precipitate in suspension (CH 3 NH 3 PbI 3 − x Br x in γ-butyrolactone) brought out different colors at high and room temperature. The mechanism study appears that the phenomenon is controlled by temperature sensitive and reversible halide ion exchange in organic-inorganic hybrid CH 3 NH 3 PbI 3 − x Br x mixed-halide perovskite. The results of structure phase, element composition morphology and band gap illustrate that high temperature 55 °C is beneficial to the increasing of I content in MAPbI 3 − x Br x and room temperature or lower is advantageous to increasing of Br content in MAPbI 3 − x Br x . Compared with MAPbI 0.76 Br 2.24 precipitate acquired at room temperature, MAPbI 1.17 Br 1.83 precipitate got at high temperature illustrate wider lattice spacing, better crystallinity, better morphology and narrower band gap. The results and findings in this study will prompt the interest of readers or experts in the field of organic-inorganic hybrid perovskite materials and related optoelectronic applications.