Coupled In Situ Electrical and Optical Characterization to Assess the Accelerated Aging of Perovskite Solar Cells

While perovskite (PVK)-based solar cells exhibit excellent efficiencies and require a relatively simple synthesis process, stability issues during operation severely limit their commercial development. Therefore, degradation studies have drawn much attention, but the plethoric literature highlights the complexity of the topic. Thus far, in most studies, pre- and postmortem analyses are performed and the system's performances before and after aging are compared, severely limiting the understanding of degradation pathways. By contrast, in situ characterization allows the degradation to be tracked in real time and the pathways to be fully explored. To this end, a coupled current–voltage (IV)–photoluminescence (PL) characterization bench is set up inside a climate chamber, allowing for the periodic acquisition of PL spectra and IV curves during accelerated aging. In this study, the International Summit on Organic Photovoltaic Stability protocol damp–heat test (65 °C, 85% relative humidity) is applied to several PVK solar cells with various transport layer combinations. By following the evolution kinetics of PL spectra and IV curves, insights into the nature of the degradation mechanisms are obtained. Notably, it becomes possible to distinguish performance losses due to degradation of the PVK absorber from those where extracting layers are the cause.