Overcoming Phase Segregation in Wide‐Bandgap Perovskites: from Progress to Perspective

Abstract Wide‐bandgap (WBG) perovskite solar cells (PSCs) are recognized as promising candidates for diversified photovoltaics (PVs), such as tandem devices, indoor PVs, and semitransparent building‐integrated PVs. However, these WBG perovskites made from a mixed‐halides strategy suffer from severe phase segregation under continuous illumination, leading to exacerbated non‐radiative recombination, and consequently decreased open‐circuit voltage and efficiency. In this review, the generation and reversal processes of phase segregation in WBG perovskites are meticulously introduced. Additionally, the major characterization techniques for phase segregation are presented. A detailed summary of recent progress in enhancing photostability of WBG PSCs through various strategies is provided. These strategies primarily concentrate on composition regulation, crystallization modulation, inhibition of ion migration, and strain regulation. Finally, perspectives and potential directions are carefully discussed to promote the further development of high‐efficiency and photostable WBG PSCs.