Halide Homogenization in Wide-Bandgap Perovskite Solar Cells: A Perspective

Wide-bandgap (WBG) perovskite solar cells (PSCs) have received significant attention as an important component of tandem solar cells (TSCs). Nevertheless, open-circuit voltage (V_OC) deficit and phase segregation remain severe challenges, affecting the photovoltaic performance and stability, which impedes the commercialization of TSCs. The photoinduced phase segregation will lead to forming iodine-rich phase becoming the carrier recombination center, thereby reducing the device performance. In this perspective, it is proposed that achieving halogen homogenization is a promising strategy for obtaining high-performance WBG PSCs based on the recent advancements. The significant research progress of multifunctional additive strategies in regulating crystallization kinetics is emphasized to achieve halogen homogenization. Moreover, the perspective discusses the effect of halogen homogenization on the stability of perovskite materials and devices. This perspective proposes the challenges and potential research directions of halogen homogenization in WBG perovskites.