Effect of lithium bis(trifluoromethane)sulfonimide treatment on titanium dioxide-based electron transporting layer of perovskite solar cells

In recent years, perovskite solar cells (PSCs) have attracted considerable research attention owing to their ease of fabrication, high photovoltaic performance, and reasonable cost compared to conventional photovoltaic devices. These PSCs consist of four main interfaces between the conductive oxide such as fluorine-doped tin oxide and indium tin oxide, compact titanium dioxide electrode (cp-TiO2) layer, mesoporous titanium dioxide electrode (mp-TiO2) layer, perovskite layer, hole transporting layer, and metallic electrode. Among these interfaces, the electron transporting layer and perovskite layers such as cp-TiO2 and mp-TiO2 play a significant role in blocking holes and transporting electrons, which is important for realizing high power conversion efficiency (PCE). Various approaches have been employed to modify TiO2 to improve PCE. In this study, the effect of chemical surface activation on the TiO2 electrode via lithium bis(trifluoromethane)sulfonimide treatment were investigated, and the performances of the PSCs were evaluated. The experimental results help understand the effect of surface activation on the PSCs.