Optimization of a 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 the ETL/perovskite interface were passivated by introducing a CeOx interlayer, which also avoids detrimental contact between the perovskite layer and indium tin oxide (ITO). In addition, owing to the suitable energy level positions and high electron mobility of CeOx, its incorporation between SnO2 and perovskite results not only in the formation of an ideal cascade energy level arrangement but also in the creation of two electron transport channels, which promote the extraction and transport of electrons, reduce charge accumulation at the interface, and consequently enhance the 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.