Mesoporous BaTiO₃/TiO₂ Double Layer for Electron Transport in Perovskite Solar Cells

Abstract

We report on the effect of BaTiO3/TiO2 mesoporous double layer (MDL) in the electron transport layer (ETL) of perovskite solar cells and enhancement of the photovoltaic performance. The conversion efficiency was enhanced from 9.89% for TiO2 mesoporous single layer (MSL) to 12.4% for BaTiO3/TiO2 MDL. The CH3NH3PbI3 crystal size on the BaTiO3/TiO2 MDL was larger. The larger CH3NH3PbI3 crystals resulted in the better light absorption and improved JSC. Moreover, VOC was also improved by suppressing a charge recombination, which is attributable to the fewer CH3NH3PbI3 crystal boundaries and band structure of BaTiO3/TiO2 MDL. The results suggest that using BaTiO3 as the second layer of the TiO2 mesoporous layer is a promising way to boost the performance of perovskite solar cells.