SnO2 : A Wonderful Electron Transport Layer for Perovskite Solar Cells.

The highest power conversion efficiency of perovskite solar cells is beyond 22%. Charge transport layers are found to be critical for device performance and stability. A traditional electron transport layer (ETL), such as TiO2 , is not very efficient for charge extraction at the interface, especially in planar structure. In addition, the devices using TiO2 suffer from serious degradation under ultraviolet illumination. SnO2 owns a better band alignment with the perovskite absorption layer and high electron mobility, which is helpful for electron extraction. In this Review, recent progresses in efficient and stable perovskite solar cells using SnO2 as ETL are summarized.