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 (Sb₂O, x = 2.17), prepared by chemical bath deposition is reported as an alternative ETL for PSCs. The deposited Sb₂O film is amorphous and very thin (∼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 Sb₂O 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 Sb₂O-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.