Optimization of Zinc Oxide Electron Transport Layers for Cs-based Perovskite Solar Cells

Zinc oxide (ZnO) possesses remarkable semiconductor properties. The compact ZnO (c-ZnO) and ZnO nanorod arrays (ZnO-NAs) are used as ETLs in CsPbI2Br perovskite solar cells (PSCs). It is found that c-ZnO doped with graphene oxide (GO) has an improvement in electron transport efficiency in PSCs. The devices based on c-ZnO:GO ETL exhibit an average power conversion efficiency (PCE) of 9.1%, which is an improvement of 7% compared to PSCs with the undoped ETL.