Issues of phase segregation in wide-bandgap perovskites

Perovskite solar cells have attracted tremendous attention due to their rapid increase in efficiency and convenience of preparation. Among them, wide bandgap (WB) perovskites show advantages for tandem solar cell development and have become the most promising candidate for commercialization. However, stability issues crucially restrict the further development of WB perovskites. Due to their ionic nature, WB perovskites suffer severe photo-induced segregation and degradation under illumination. Therefore, in view of the above problems, we summarize the reasons for the instability of WB perovskites and discuss strategies for stability improvement. Finally, we provide prospects for the future development of WB perovskites.