Long-term operating stability in perovskite photovoltaics

Perovskite solar cells have demonstrated the efficiencies needed for technoeconomic competitiveness. With respect to the demanding stability requirements of photovoltaics, many techniques have been used to increase the stability of perovskite solar cells, and tremendous improvements have been made over the course of a decade of research. Nevertheless, the still-limited stability of perovskite solar cells remains to be fully understood and addressed. In this Review, we summarize progress in single-junction, lead-based perovskite photovoltaic stability and discuss the origins of chemical lability and how this affects stability under a range of relevant stressors. We highlight categories of prominent stability-enhancing strategies, including compositional tuning, barrier layers and the fabrication of stable transport layers. In the conclusion of this Review, we discuss the challenges that remain, and we offer a perspective on how the field can continue to advance to 25-year and 30-year stable perovskite solar modules. Although perovskite solar cells now have competitive efficiencies compared with silicon solar cells, their low stability has hindered their commercial application thus far. This Review summarizes the tremendous improvements made over the past decade and offer a perspective on how to reach >25-year stable perovskite solar cells.