Self-Passivation at the SnO<sub>2</sub>/Perovskite Interface
Kai-Ping Wang, Dong Xue, Ji-Zhe Yuan, Bo Wen, Jun He, Chuan‐Jia Tong, Oleg V. Prezhdo
Abstract
Interfaces are crucial to the performance of solar cells, as they significantly affect charge transport. Using density functional theory and nonadiabatic molecular dynamics simulations, we reveal a self-passivation mechanism at the SnO 2 /CH 3 NH 3 PbI 3 interface to enhance the stability and efficiency of the device, which is mainly attributed to a benign iodine vacancy (V Iact ). Unlike the typical defects of accelerating the charge recombination and reducing efficiency, this distinctive V Iact facilitates charge transfer and decelerates nonradiative recombination by passivating the potential trap states. Additionally, the benign V Iact at the interface reduces structural distortion and suppresses electron–vibration interactions, which in turn, extends the charge carrier lifetime and enhances the electron injection. Furthermore, V Iact exhibits both thermodynamic and kinetics stability. Our findings rationalize the high performance of SnO 2 -based perovskite solar cells and highlight the importance of the defect self-passivation strategy in optimizing interfacial properties for enhanced solar cell efficiency.