Origin of the X-Ray-Induced Damage in Perovskite Solar Cells

Perovskite solar cells (PSCs) are promising candidates for not only terrestrial but also space applications. The remarkable power-per-weight of nearly 30 W/g makes them attractive to be deployed on a spacecraft. However, the high-energy radiation in outer space could damage the PSCs, making it crucial to understand their degradation mechanism. Here, we investigated the PSCs' response to X-ray radiation, and proposed that the X-ray-induced damage was attributed to the displacement of $\text{I}^{-}$ , creating lattice defects by the radiation-generated secondary electrons. We verified the hypothesis by simulating the energy deposition of X-rays in PSCs and investigating the PSCs' in situ electronic responses to the X-ray and electron beam. Furthermore, we studied the variation in spatial distribution of trap densities under X-ray radiation, which revealed that the defect-abundant perovskite/Poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) interface was the most rapidly degraded site in PSCs.