Insight into Perovskite Solar Cells Based on SnO2 Compact Electron-Selective Layer

Considering the remarkable progress in photovoltaic performance, scholars have focused on perovskite solar cells (PSCs) over the recent two years. TiO2 thin film is a semiconductor with a wide band gap and is usually used as an electron-selective layer (ESL) in PSCs. Although SnO2 exhibits conductivity higher than that of TiO2, its use as a compact ESL in PSCs has not been reported. In this study, nanocrystalline SnO2 thin film was prepared through a sol–gel method and then characterized. The prepared SnO2 thin film was composed of small tetragonal rutile nanocrystals. We applied the SnO2 compact ESL into PSCs and compared their performance with that of PSCs based on a TiO2 thin layer. SnO2-ESL-based PSCs (S-PSCs) showed higher short-circuit current density and lower open-circuit voltage, fill factor, and conversion efficiency than the conventional TiO2-ESL-based PSCs. Furthermore, the photovoltaic performance of S-PSCs was highly dependent on measurement means, and this relationship was investigated and is discussed in detail.