Carrier Transport in Low‐Dimensional Tin Perovskite Solar Cells

Recently, the emerging of low‐dimensional tin perovskite solar cells (TPSCs) by introducing bulky organic spacers has attracted extensive attention. It can not only inhibit the oxidation of Sn 2+ , but also reduce the ion migration and self‐doping effect. Thanks to these advantages, the TPSCs have achieved an impressive power conversion efficiency (PCE) of over 15% recently. However, the introduction of organic spacers impedes the carrier transport and thus limits the attainable PCE. Therefore, it is important to understand the carrier‐transport mechanism in low‐dimensional perovskite to develop more efficient and stable TPSCs. In this review, the latest progress of carrier transport in low‐dimensional TPSCs is summarized in detail. First, the characteristics of carrier transport in low‐dimensional tin perovskites are discussed. Then, the strategies to improve carrier transport are discussed, mainly from the aspects of crystal orientation, crystallization kinetics, defects, interface energy level alignment, quantum well effect, and exciton binding energy. Finally, the future challenges and prospects are expounded to prepare high‐performance and stable low‐dimensional TPSCs.