Performance enhancement of low temperature processed tin oxide as an electron transport layer for perovskite solar cells under ambient conditions

Most of the SnO2-based perovskite cells (PSC) are either fabricated in a controlled environment or have low energy conversion efficiencies. In this research, we used a low-temperature processed SnO(2)as an electron transport layer (ETL) and fabricated planar PSC via a spin coating technique under ambient condition. By adjusting the concentration of SnO(2)precursor solution, the efficiency of PSC was enhanced from 4% to 9%. Furthermore, different weight ratios of 3D-structured crumpled graphene oxide (CGO), which was synthesized using a one-step furnace aerosol reactor, were introduced into the SnO2ETL to improve the PSC performance. The 0.25% CGO ratio resulted in a cell with highestJ(sc)of 21 mA/cm(2)and the efficiency of 11%. Photoluminescence measurements also showed the benefit of doping SnO(2)layer with CGO in charge transfer in the ETL and from the perovskite layer suppressing carrier recombination. The SnO2-based ETL with the presence of CGO can be a promising ETL for low-cost planar PSCs as well as tandem cells, fabricated under ambient condition.