Doped Bilayer Tin(IV) Oxide Electron Transport Layer for High Open-Circuit Voltage Planar Perovskite Solar Cells with Reduced Hysteresis.

Tin oxide (SnO ) is an emerging electron transport layer (ETL) material in halide perovskite solar cells (PSCs). Among current limitations, open-circuit voltage (V ) loss is one of the major factors to be addressed for further improvement. Here a bilayer ETL consisting of two SnO nanoparticle layers doped with different amounts of ammonium chloride is proposed.