Synergetic Acceleration on the Degradation of Flexible Perovskite Solar Cells under Light and Stress Cooperation

Metal-halide perovskites represent highly efficient and lightweight photovoltaic technology with promising applications in various scenarios. However, their stability is often deteriorated by various external factors in realistic applications, which is particularly severe for flexible devices. Herein this work, the degradation of flexible perovskite devices is focused on under two substantial factors: light and mechanical stress, where the degradation is surprisingly accelerated with simultaneous existence of these factors. Full-scale analysis demonstrates that the mismatch and charge accumulation at the interfaces are direct causes of this device failure. Theoretical simulations reveal that carrier-localization behavior, which is strongly associated with lattice distortion, is the core microscopic factor that destabilizes the device. This finding poses significant challenges to the stability of flexible perovskite devices and other inner strain-sensitive systems, which cannot be simply mitigated by conventional passivation or encapsulation. It is suggested in theoretical studies that this effect may be suppressed by certain physical modulations, such as external electric fields. In general, a better understanding of the degradation mechanisms of realistic flexible and rigid perovskite devices can be contributed in this study and the development of solutions is facilitated to address those challenges.