Defect mediated losses and degradation of perovskite solar cells: Origin, impacts and reliable characterization techniques

The rapid advancement of halide-based hybrid perovskite materials has garnered significant research attention, particularly in the domain of photovoltaic technology. Owing to their exceptional optoelectronic properties, they demonstrated power conversion efficiency (PCE) of over 25% in single junction solar cells. Despite the notable progress in PCE over the past decade, the inherent high defect density presenting in perovskite materials gives rise to several loss mechanisms and associated ion migration in perovskite solar cells (PSCs) during operational conditions. These factors collectively contribute to a significant stability challenge in PSCs, placing their longevity far behind for commercialization. While numerous reports have explored defects, ion migration, and their impacts on device performance, a comprehensive correlation between the types of defects and the degradation kinetics of perovskite materials and PSCs has been lacking. In this context, this review aims to provide a comprehensive overview of the origins of defects and ion migration, emphasizing their correlation with the degradation kinetics of perovskite materials and PSCs, leveraging reliable characterization techniques. Furthermore, these characterization techniques are intended to comprehend loss mechanisms by different passivation approaches to enhance the durability and PCE of PSCs.