Low temperature combustion synthesized indium oxide electron transport layer for high performance and stable perovskite solar cells

Abstract

Planar halide perovskite solar cells (PSCs) have undergone rapid development in last decade due to their excellent optoelectronic properties. An electron transport layer (ETL) with high electron mobility is crucial to achieve high power conversion efficiency (PCE). TiO2 is one of the most common ETLs in n-i-p planar PSCs. But the low electron mobility and high annealing temperature of TiO2 hamper the device performance and applications. In2O3 has a higher electron mobility and wider bandgap compared with TiO2 ETL. Herein, we report a low-temperature combustion synthesized In2O3 as ETL for PSCs. The electron mobilities of In2O3 films are investigated by the thin film transistors (TFTs) under annealing at different temperatures. By optimizing the In2O3 layer, a power conversion efficiency of 18.12% is obtained, and is among the highest values for PSCs based on In2O3 ETL. Meanwhile, the unencapsulated devices exhibit a remarkable stability, retaining 75% of the initial value after over 120 days’ storage.