Halide Segregation in Mixed Halide Perovskites: Visualization and Mechanisms

Photoinduced halide segregation in mixed halide perovskites is an intriguing phenomenon and simultaneously a stability issue. In-depth probing this effect and unveiling the underpinning mechanisms are of great interest and significance. This article reviews the progress in visualized investigation of halide segregation, especially light-induced, by means of spatially-resolved imaging techniques. Furthermore, the current understanding of photoinduced phase separation based on several possible mechanisms is summarized and discussed. Finally, the remained open questions and future outlook in this field are outlined