Perovskite Solar Cells and Devices at EPFL Valais Wallis.

Stability required! Perovskite solar cells have emerged as one of the most exciting fields of research, owing to their impressive rise in power conversion efficiency surpassing 22% in six short years of research. Current research is focused on ways to improve stability of perovskite-based devices, a key characteristic required to bring this technology from the lab into the market. In this Editorial, guest editor Prof. Mohammad Khaja Nazeeruddin describes the context of this Special Issue, and summarizes the work being performed in his research group toward this low-cost near-future photovoltaic technology.