Impact of Electrode Materials on Process Environmental Stability of Efficient Perovskite Solar Cells

Summary For commercializing perovskite solar cells (PSCs), moisture-tolerant materials are required because a moisture-free environment cannot be maintained on an actual production line (large scale). Recently, PSCs with efficiency exceeding 22% have been fabricated using Li-doped mesoporous TiO2 as an electron transport layer (ETL). However, the use of Li can negatively influence device stability during the fabrication process under humid air because of its hydroscopic property. Here, we report a strategy for improving processing stability without sacrificing the power conversion efficiency (PCE) under a humid atmospheric environment by employing a mesoporous BaSnO3 as an ETL. Using the mesoporous BSO ETL, we achieved a certified efficiency of 21.3% and stabilized efficiency of 21.7%. Furthermore, the BSO-based PSCs also exhibited better processing stability than Li-doped TiO2-based PSCs under humid air. We believe that this strategy of introducing BSO into PSCs will accelerate the commercialization of PSCs.