Facilitating the formation of SnO2 film via HfO2-modified FTO electrode for efficient perovskite solar cells

Fabricating a dense and crystalline SnO2 film has been an important step for efficient SnO2-based perovskite solar cells (PSCs). Herein, wide bandgap material, HfO2, was deposited on the surface of FTO to facilitate formation film. It found that HfO2 modification could significantly improve crystallization upper passivate trap states within layer. Moreover, high conduction band level can block backflow electrons suppress nonradiative recombination carriers. Eventually, best PSC with interlayer presented power conversion efficiency (PCE) 21.13% VOC 1.13 V, which are higher than those reference device. This study provides meaningful strategy ETL optimization further increase PSCs.