SnO₂/BaSnO₃ electron transport materials for stable and efficient perovskite solar cells

TiO₂ is one of the most widely used electron transport layer (ETL) materials for the fabrication of perovskite solar cells (PSCs). However, TiO₂ has limitations of low electron mobility and poor photo-stability under UV exposure. To solve this issue, we explored SnO₂/BaSnO₃ (BSO) ETL for a stable and efficient n-i-p PSC with FTO/c-SnO₂/mp-BSO/CH₃NH₃I/Spiro-OMeTAD/Au configuration. It was found that the compact layer plays an important role in electron transport in ETL, leading to better device performance overall. Compared to the TiO₂ based ETL devices, the champion devices with c-SnO₂/mp-BSO ETL showed a power conversion efficiency over 15.54%, which is comparable or even better than the previously reported. More importantly, the champion device showed remarkable enhancement of thermal- and photo-stability and long-term air stability.