Facilitating Electron Transport in Perovskite Solar Cells Through Tailored SnO2 Film Composition

The ratio of Sn 2+ to Sn 4+ plays an essential role in influencing the characteristics of SnO 2 film, which is commonly used in the normal structure of perovskite solar cells (PSCs). It is identified that different sequences of addition lead to varying concentrations of Sn 2+ and Sn 4+ within the SnO 2 film. Through this strategic approach, an enhanced SnO 2 film with improved electron transport capabilities, a smoother surface texture, and more suitable energy levels are successfully engineered. Consequently, the efficiency of PSCs has seen a notable increase from 22.58% for the control device to 24.16% for the target PSC. Furthermore, PSCs utilizing the optimized SnO 2 have demonstrated superior long‐term environmental stability when compared to the control devices. Specifically, PSCs incorporating optimized SnO 2 expose to approximately 30% humidity in ambient air for 41 days without encapsulation retain 87% of their initial efficiency. In contrast, the control devices under the same conditions only maintain 77% of their original value.