All-perovskite tandem solar cells (TSCs) have recently surpassed the 30% power conversion efficiency milestone, positioning mixed tin-lead (Sn-Pb) perovskite as indispensable narrow-bandgap absorbers. Their optimal bandgap, reduced lead content, and solution processability make them promising for next-generation photovoltaics. However, their widespread application is hindered by severe stability issues, primarily the facile oxidation of Sn2+ and crystallization mismatch between Sn- and Pb-based phases. Distinct from existing reviews, this short review provides an integrated framework for the two fundamental bottlenecks of Sn-Pb perovskite-Sn2+ oxidation and Sn/Pb crystallization mismatch-linking mechanistic insights across precursor chemistry, thin-film formation, and device operation. We summarize recent advances that enable efficiencies >23% together with thousand-hour operational stability, and we outline future directions toward fully integrated, scalable, and commercialization-relevant stability solutions.
Hu et al. (Thu,) studied this question.