Solution-Processed Cu:SnO2 as an Efficient Electron Transport Layer for Fabrication of Low-Temperature Planar Perovskite Solar Cell Under Ambient Conditions

Rapid growth in photovoltaic performance of lead-halide-based perovskite solar cells (PSCs) has made them a potential candidate for emerging solar technology. The perovskite material itself can be manufactured at low temperatures, which makes it attractive for low-cost manufacturing. However, PSCs utilizing a low-temperature-processed metal-oxide electron transport layer have exhibited lower device performance due to less conductivity. The inclusion of metal dopant in this layer is a cheap and desirable approach that improves electrical conductivity and enables facilities for better energy band alignment that plays a crucial role in the obtained photovoltaic performance. In this work, a low-temperature solution-processed copper (Cu)-doped tin oxide (SnO2) is demonstrated as an effective electron transport layer, in which, Cu was simply introduced into the SnO2 solution. An optimal Cu concentration of 3.0 mol% exhibited 11.29% power conversion efficiency (PCE) with 73.38% fill factor (FF), whereas the PSCs utilizing undoped SnO2 resulted in 8.32% PCE and 59.9% FF when processed in ambient conditions with an average relative humidity of 62%. Our photovoltaic results indicated low-temperature-processed Cu-doped SnO2 as a potential candidate for device performance, which is also compatible with high throughput and cost-effective manufacturing of PSCs through automation.