Atomic layer deposition of SnO2 using hydrogen peroxide improves the efficiency and stability of perovskite solar cells

Low-temperature processed SnO2 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 SnO2 layer on a high-haze substrate. However, oxygen vacancy formed by the conventional ALD process using H2O 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-SnO2 layer with low oxygen vacancies fabricated via H2O2. Compared to the ALD-SnO2 layer formed using H2O vapors, the ALD-SnO2 layer prepared via H2O2 shows better electron extraction due to a reduced oxygen vacancy associated with the highly oxidizing nature of H2O2. As a result, the power conversion efficiency (PCE) is enhanced from 21.42% for H2O to 22.34% for H2O2 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 H2O2-derived ALD SnO2 as compared to the control device maintaining 72.5% of the initial PCE.

Automated summary

ALD-SnO2 prepared with H2O2 shows improved photovoltaic performance and stability compared to H2O. It has reduced oxygen vacancies, leading to better electron extraction and enhanced power conversion efficiency. The operational stability is also improved, with higher PCE maintained after 1000 hours under ambient conditions.