The Voltage Loss in Tin Halide Perovskite Solar Cells: Origins and Perspectives

Abstract Exploring stable and efficient lead‐free perovskite solar cells (PSCs) is critical to solving the environmental concerns caused by lead. Recently, tin halide perovskites (THPs) have become a promising candidate due to its low toxicity and similar electronic configuration to lead counterparts. Currently, the power conversion efficiency of tin‐based PSCs (TPSCs) has been pushed over 14%. However, there is still a considerable gap compared to lead PSCs due to the non‐negligible open‐circuit voltage loss ( V loss ). Therefore, understanding the origins and regulation strategies of V loss for TPSCs is of great importance. Herein, the nature of THPs is first reviewed from the crystal structure, electronic structure, and phase transition. Subsequently, the origins and determinants of V loss are discussed in TPSCs. Besides the intrinsic low bandgap, the bulk recombination of tin perovskite, and the non‐radiative recombination of the associated interfaces induce the V loss of the TPSCs devices. Then, some recently emerged strategies to suppress the V loss in TPSCs are introduced. Finally, a perspective on the further suppression of V loss in TPSCs including purifying the precursor solution, suppressing the oxidation Sn 2+ , and optimizing the device structure is outlined.