Ultraviolet Photocatalytic Degradation of Perovskite Solar Cells: Progress, Challenges, and Strategies

The certified efficiency of perovskite solar cells (PSCs) has reached 25.5% within just around 10 years, approaching the highest reported value of mainstream silicon solar cells. The application of metal–oxide (MO) electron transport layers (ETLs), including TiO 2 and SnO 2 , is crucial for achieving highly efficient PSCs because of their wonderful photoelectrical properties, resulting in n–i–p conventional structure devices, constantly breaking the world record efficiency. However, these MOETLs inevitably lead to the degradation of PSCs due to their photocatalytic activity under actual sunlight which includes ultraviolet (UV) range. Overcoming the UV photocatalytic degradation is still a great challenge for the state‐of‐the‐art PSCs toward practical applications. Herein, the recent progress related to the UV photocatalytic degradation of PSCs induced by the MOETLs based on recent literature reports is reviewed, including the photocatalysis origin, degradation mechanism, challenges, and various strategies. Perspectives for future efforts in overcoming UV photocatalytic degradation are provided. It is believed that this review is advantageous for achieving stable PSCs under actual outdoor sunlight.