Tin oxide (SnO2) is used as an electron transport layer (ETL) in perovskite solar cells with a planar
structure due to its good transparency and energy level alignment with the perovskite layer. The modification
interface of the electron transport layer and the perovskite absorber layer plays an important role in the efficient
charge extraction process at the interface. In this study, planar perovskite solar cells with configuration
(FTO/SnO2/mixed-cation perovskite/CuInS2/Au) were prepared to investigate the effect of UV-Ozone (UVO) treated
SnO2 as ETL on the performance of devices. ETL treatment was performed at different times (0 to 60 min). It is
shown that surface wetting was improved by UVO treating the SnO2 films prior to deposition of the perovskite layer.
The latter improves the contact between the ETL and the perovskite layer, allowing more efficient electron transport
at the interface. Contact angle, SEM, photoluminescence spectra, and the current density-voltage tests were
conducted to characterize the photovoltaic of the cells. The best PSC performance with a power conversion
efficiency of 10.96% was achieved using UVO-treated SnO2 ETL for 30 min, whereas the power conversion
efficiency of the perovskite solar cells with SnO2 ETL without UVO treatment was only 4.34%.
