Temperature-induced Degradation of Perovskite Solar Cells

Poor thermal stability of perovskite solar cells is a drawback currently preventing their commercialisation. In situ heating in the transmission electron microscope is a valuable tool to understand the micro- and nano-scale processes correlated to performance degradation. Here devices are produced according to four common approaches in the literature, and the photovoltaic performance is characterised as they are heated within their operational range. The devices are then analysed using transmission electron microscopy as they are further heated in situ, to monitor changes in morphology and chemical composition using Energy-dispersed X-ray (EDX) elemental mapping. The authors identify mechanisms for structural and local chemical changes, such as iodine and lead migration, which can be correlated to the synthesis conditions.