Spray-coated SnO2 electron transport layer with high uniformity for planar perovskite solar cells

SnO2 has been proven to be an effective electron transport layer (ETL) material for perovskite solar cells (PSCs) owing to its excellent electrical and optical properties. Here, we introduce a viable spray coating method for the preparation of SnO2 films. Then, we employ a SnO2 film prepared using the spray coating method as an ETL for PSCs. The PSC based on the spray-coated SnO2 ETL achieves a power conversion efficiency of 17.78%, which is comparable to that of PSCs based on conventional spin-coated SnO2 films. The large-area SnO2 films prepared by spray coating exhibit good repeatability for device performance. This study shows that SnO2 films prepared by spray coating can be applied as ETLs for stable and high-efficiency PSCs. Because the proposed method involves low material consumption, it enables the low-cost and large-scale production of PSCs.