Optimization of SnO2‑Based Electron Transport Layer Using Cerium Oxide for Efficient and Stable Perovskite Solar Cells

Abstract

Electron transport layer (ETL)/perovskite interface engineering is an effective strategy to improve the performance of perovskite solar cells. In this work, the surface morphology of SnO2 was improved, and defects at ETL/perovskite interface were passivated by introducing a CeOx interlayer, which also avoids detrimental contact between perovskite layer and indium tin oxide (ITO). In addition, owing to suitable energy level positions and high electron mobility of CeOx, the introduction of CeOx between SnO2 and perovskite results not only in the formation of ideal cascade energy level arrangement but also in the creation of two electron transport channels, which promotes the extraction and transport of electrons, reduces charge accumulation at the interface, and thus improves optoelectronic performance of the device. Finally, an efficiency of 20.23% was obtained for the optimized device based on CeOx/SnO2 under ambient conditions, with negligible hysteresis and enhanced long-term stability.