Abstract Tandem solar cells (TSCs) employing wide‐bandgap (WBG) perovskite solar cells (PSCs) as the bottom sub‐cell represent a leading research direction in photovoltaics. However, the presence of phase segregation, interfacial losses, and crystallization quality within WBG perovskite films can drive complex compositional evolution and non‐radiative recombination, leading to photovoltage deficits, fill factor ( FF ) degradation, and impaired charge transport characteristics, which fundamentally limit the attainable high power conversion efficiency. From this perspective, this review presents a systematic optimization framework for high‐performance mixed‐halide WBG perovskite photovoltaics, addressing critical challenges in mixed‐halide WBG PSCs through interfacial, solvent, additive, and composition engineering, along with advanced fabrication techniques. Finally, a comprehensive summary and prospective analysis of future research directions for high‐performance mixed‐halide WBG perovskite photovoltaics is presented.
Liu et al. (2025) studied this question.