Quasi‐2D Sn‐Pb Perovskites: Advances in Optoelectronic Engineering and Device Applications

Abstract Tin‐lead (Sn‐Pb) mixed perovskites are promising candidates for single‐junction and tandem photovoltaic devices due to their tunable bandgap, enabling efficient light absorption. However, the advancement of these materials is impeded by significant challenges, particularly the poor quality of films resulting from the facile oxidation of Sn 2+ to Sn 4+ and the inherent difficulties in controlling crystallization kinetics. To mitigate these issues, the design of low‐dimensional (LD) Sn‐Pb perovskites has gained considerable attention, as 2D structures are associated with improved stability and distinctive optoelectronic properties. This review systematically investigates the optoelectronic characteristics of 2D Sn‐Pb perovskites arising from dimensional reduction while elucidating the intricate relationship between their microstructure and optoelectronic behavior. Additionally, the substantial progress made in applying 2D Sn‐Pb perovskites within single‐junction and heterojunction perovskite solar cells (PSCs) is highlighted. Emerging applications in fields such as near‐infrared (NIR) detection, circularly polarized light detection, and memristors are also discussed. Given the current understanding, further exploration of diverse ligands and Sn‐Pb compositions in 2D systems is crucial for realizing their full potential in practical applications.