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. TiO 2 thin film is a semiconductor with a wide band gap and is usually used as an electron-selective layer (ESL) in PSCs. Although SnO 2 exhibits conductivity higher than that of TiO 2, its use as a compact ESL in PSCs has not been reported. In this study, nanocrystalline SnO 2 thin film was prepared through a sol–gel method and then characterized. The prepared SnO 2 thin film was composed of small tetragonal rutile nanocrystals. We applied the SnO 2 compact ESL into PSCs and compared their performance with that of PSCs based on a TiO 2 thin layer. SnO 2 -ESL-based PSCs (S-PSCs) showed higher short-circuit current density and lower open-circuit voltage, fill factor, and conversion efficiency than the conventional TiO 2 -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.