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 system...
