Atomic layer deposition of SnO using hydrogen peroxide improves the efficiency and stability of perovskite solar cells.

Low-temperature processed SnO is a promising electron transporting layer in perovskite solar cells (PSCs) due to its optoelectronic advantage. Atomic layer deposition (ALD) is suitable for forming a conformal SnO layer on a high-haze substrate. However, oxygen vacancy formed by the conventional ALD process using HO might have a detrimental effect on the efficiency and stability of PSCs. Here, we report on the photovoltaic performance and stability of PSCs based on the ALD-SnO layer with low oxygen vacancies fabricated HO. Compared to the ALD-SnO layer formed using HO vapors, the ALD-SnO layer prepared HO shows better electron extraction due to a reduced oxygen vacancy associated with the highly oxidizing nature of HO. As a result, the power conversion efficiency (PCE) is enhanced from 21.42% for HO to 22.34% for HO mainly due to an enhanced open-circuit voltage. Operational stability is simultaneously improved, where 89.3% of the initial PCE is maintained after 1000 h under an ambient condition for the HO-derived ALD SnO as compared to the control device maintaining 72.5% of the initial PCE.