Magnetron Sputtering Zn2SnO4 Electron‐Transport Layer for All Room‐Temperature‐Processed Perovskite Solar Cells

Room‐temperature‐processed (RTP) electron‐transport layer (ETL) is a prerequisite for fabricating fully RTP perovskite solar cells (PSCs). Herein, an RTP‐Zn 2 SnO 4 (ZSO) ETL is deposited for achieving RTP‐PSCs by magnetron sputtering using ZnO and SnO 2 targets. The ZSO ETL exhibits great electrical properties, better band alignment, and yields increased grain size of the perovskite grown on it, thus facilitating electron extraction from the perovskite layer to the ETL. As a result, a champion power conversion efficiency of 21.06% is achieved in the ZSO‐based device, which is the highest value for RTP‐PSCs. The ZSO‐based PSCs also exhibit high device stability. Moreover, the efficiency of a large‐area perovskite module based on ZSO ETL reaches 17.79%.