Monitoring the stability and degradation mechanisms of perovskite solar cells by in situ and operando characterization

Solar energy technologies are among the most promising renewable energy sources. The massive growth of global solar generating capacity to multi-terawatt scale is now a requirement to mitigate climate change. Perovskite solar cells (PSCs) are one of the most efficient and cost-effective photovoltaic (PV) technologies with efficiencies reaching the 26% mark. They have attracted substantial interest due to their light-harvesting capacity combined with a low cost of manufacturing. However, unsolved questions of perovskite stability are still a concern, challenging the potential of widespread commercialization. Thus, it is imperative to advance in the understanding of the degradation mechanism of PSCs under in situ and operando conditions where variable and unpredictable stressors intervene, in parallel or sequentially, on the device stability. This review aims to debate the advantages behind in situ and operando characterization to complement stability-testing of PV parameters in the strive to achieve competitive stability and reproducibility in PSCs. We consider the impact of applying single and multi-stressors under constant monitoring of alterations observed in PSC components or complete devices. We outline key future research directions to achieve the long-term stability necessary for the successful commercialization of this promising PV technology.