Solution-Processed Nb:SnO₂ Electron Transport Layer for Efficient Planar Perovskite Solar Cells

Electron transport layer (ETL), facilitating charge carrier separation and electron extraction, is a key component in planar perovskite solar cells (PSCs). We developed an effective ETL using low-temperature solution-processed Nb-doped SnO₂ (Nb:SnO₂). Compared to the pristine SnO₂, the power conversion efficiency of PSCs based on Nb:SnO₂ ETL is raised to 17.57% from 15.13%. The splendid performance is attributed to the excellent optical and electronic properties of the Nb:SnO₂ material, such as smooth surface, high electron mobility, appropriate electrical conductivity, therefore making a better growth platform for a high quality perovskite absorber layer. Experimental analyses reveal that the Nb:SnO₂ ETL significantly enhances the electron extraction and effectively suppresses charge recombination, leading to improved solar cell performance