Crystallization Modulation for Stable Wide‐Bandgap Perovskite Solar Cells and Modules

As the power conversion efficiency (PCE) of single-junction perovskite solar cells (PSCs) approaches the Shockley-Queisser theoretical limit, perovskite-based tandem solar cells (TSCs) have been widely recognized as a key pathway to surpass single-junction PSCs and enable next-generation high-performance photovoltaics. However, wide-bandgap (WBG) perovskites, particularly mixed-halide systems, still face significant challenges, including photoinduced phase segregation, high defect densities, and interfacial mismatches. These issues largely stem from their complex crystallization processes. This review describes how inhomogeneous crystallization of WBG perovskites underlies the following challenges: initial phase segregation, defect formation, and stability issues. Following this, a comprehensive review of recent advances in crystallization modulation was carried out. Strategies such as interface engineering, composition engineering, solvent engineering, process optimization, and additive engineering are discussed, with a focus on precisely modulating nucleation and growth to achieve high-quality WBG perovskites. Finally, the development of large-area fabrication of WBG perovskites and stability issues are summarized, and future research directions are outlined.