Chemical Bath Deposited Antimony Oxide Thin Films for Efficient Perovskite Solar Cells

The metal oxide electron transport layers (ETLs) of n-i-p perovskite solar cells (PSCs) are dominated by TiO2 and SnO2, while the efficacy of the other metal oxide ETLs still lags far behind. Herein, an emerging, economical, and environmentally friendly metal oxide, antimony oxide (Sb2Ox, x = 2.17), prepared by chemical bath deposition is reported as an alternative ETL for PSCs. The deposited Sb2Ox film is amorphous and very thin (similar to 10 nm) but conformal on rough fluorine-doped tin oxide substrates, showing matched energy levels, efficient electron extraction, and then reduced nonradiative recombination in PSCs. The champion PSC based on the Sb2Ox ETL delivers an impressive power conversion efficiency of 24.7% under one sun illumination, which represents the state-of-the-art performance of all metal oxide ETL-based PSCs. Additionally, the Sb2Ox-based devices show improved operational and thermal stability compared to their SnO2-based counterparts. Armed with these findings, we believe this work offers an optional ETL for perovskites-based optoelectronic devices.