F-doping-Enhanced Carrier Transport in the SnO2/Perovskite Interface for High-Performance Perovskite Solar Cells

SnO2 is widely used as the electron transport layer (ETL) in n-i-p perovskite solar cells. However, the deep-level defects at the interface between SnO2 and the perovskite film will lead to energy loss, reducing the open-circuit voltage. Therefore, the interface optimization is essential to raise the efficiency and enhance the stability of perovskite solar cells. In this work, we introduce NH4F into the SnO(2 )electron transport layers, and the optimized SnO2 films reduce the interface defect density, improve the charge extraction, and reveal a better energy-level arrangement. Compared to the conventional SnO2 perovskite solar cell, the average V-oc is improved by 70 mV with the champion efficiency up to 22.12%. Moreover, the unencapsulated F-doped SnO2 perovskite solar cells show better thermal stability (maintained 86.2%) and humidity stability (maintained 80.8%) after 35 days.

Automated summary

In this study, the addition of NH4F to the SnO2 electron transport layer improved the interface defect density, charge extraction, and energy-level arrangement. The optimized SnO2 films resulted in a significant improvement in the open-circuit voltage and champion efficiency of perovskite solar cells. Additionally, the F-doped SnO2 perovskite solar cells exhibited enhanced thermal and humidity stability.