Generation and Clearance of Superoxide Radicals at Buried Interfaces of Perovskites with Different Crystal Structures

One of the most notorious issues with classic perovskite (MAPbI3) is its rapid degradation caused by generating superoxide radicals (O2•−) on its surface under light and oxygen environments (light/O2). The differences in O2•− generation rate and tolerance to O2•− among perovskite with different structures are pending. For the first time it is validated through solid‐electron paramagnetic resonance (EPR) that MAPbI3 and Cs0.175FA0.75MA0.075PbI3 (PVSK) crystals can generate O2•− in an air atmosphere. The rapid degradation of perovskite buried interfaces caused by O2•− dominates the nonexposed air aging process of SnO2‐based perovskite film, and the degradation rate of MAPbI3 film is faster than that of PVSK film. The fullerene pyridine derivatives (C60OPD), which function as a buffer layer between SnO2 and PVSK to scavenge O2•− and prevent degradation at the buried interface of the PVSK film, reduce the density of defect states, and accelerate the transmission of photogenerated electrons. The photoelectric conversion efficiency (PCE) of perovskite solar cells (PSCs) optimizes with C60OPD increased from 21.15% to 23.11% while significantly improving the stability in light/O2. This work reveals the hidden degradation of perovskite‐buried interfaces caused by O2•− and explores efficient ways for perovskite to resist O2•−. Perovskite crystals can generate superoxide radicals (O2•−) in an air atmosphere, leading to hidden degradation at the buried interface. As an O2•– scavenger, the fullerene pyridine derivatives (C60OPD) eliminate this degradation and improve device efficiency.