MgAc₂‑Modified SnO₂ Electron\nTransport Layer for Highly Efficient and Thermal Stable Perovskite\nSolar Cells

Abstract

There are always defects and oxygen vacancies in SnO₂ prepared by solution methods, hindering efficient carrier\ntransfer\nbetween SnO₂ and the perovskite in perovskite solar cells.\nThus, we employed MgAc₂ to modify the interface. Carboxyl\ngroups of MgAc₂ filled the oxygen vacancies in SnO₂, reducing its surface defect density, and Mg²⁺ partially replaced surface Sn⁴⁺, improving the properties\nof the SnO₂ layer. Finally, perovskite solar cells modified\nwith MgAc₂ exhibited a significant improvement in open-circuit\nvoltage and fill factor, improving the power conversion efficiency\nfrom 20.52% to 22.02%. Moreover, MgAc₂-devices maintained\n80% of the initial efficiency after 1250 h in thermal stability tests\nat 85 °C and 30% relative humidity compared to control devices.\nThis work provides a method for treating the SnO₂ electron\ntransport layer and demonstrates the synergistic effects of Mg²⁺ and acetate ions, which can facilitate the development of\nefficient and stable perovskite solar cells.