Ion-migration analysis of degradation caused by outdoor exposure and accelerated stress testing in perovskite solar cells

In this study, we conducted outdoor exposure testing and investigated the degradation mechanism of perovskite solar cells deployed in the field. We conducted a detailed failure analysis to identify specific degradation modes induced by outdoor exposure, using current–voltage curve measurements, maximum power evaluation, and mobile-ion analysis. This analysis revealed a significant change in the ion-migration current response of the devices after exposure. These changes suggest that the modification of mobile ions and formation of defects within the perovskite materials are likely the primary causes of degradation. Additionally, we compared the solar cell characteristics observed after the field test with the results of controlled indoor accelerated stress tests, which included exposure to visible light, ultraviolet (UV) irradiation, and thermal stress. Our findings highlight that the degradation patterns induced by UV irradiation at elevated temperatures closely resemble those caused by outdoor stress. We also discuss indoor test conditions that replicate the degradation phenomena experienced during outdoor exposure. This ability to replicate outdoor degradation phenomena under laboratory conditions is crucial for accelerating the development of robust and durable perovskite solar cells.