MgAc2-Modified SnO2 Electron Transport Layer for Highly Efficient and Thermal Stable Perovskite Solar Cells

There are always defects and oxygen vacancies in SnO 2 prepared by solution methods, hindering efficient carrier transfer between SnO 2 and the perovskite in perovskite solar cells. Thus, we employed MgAc 2 to modify the interface. Carboxyl groups of MgAc 2 filled the oxygen vacancies in SnO 2, reducing its surface defect density, and Mg 2+ partially replaced surface Sn 4+, improving the properties of the SnO 2 layer. Finally, perovskite solar cells modified with MgAc 2 exhibited a significant improvement in open-circuit voltage and fill factor, improving the power conversion efficiency from 20.52% to 22.02%. Moreover, MgAc 2 -devices maintained 80% of the initial efficiency after 1250 h in thermal stability tests at 85 °C and 30% relative humidity compared to control devices. This work provides a method for treating the SnO 2 electron transport layer and demonstrates the synergistic effects of Mg 2+ and acetate ions, which can facilitate the development of efficient and stable perovskite solar cells.