Perovskite solar cells have risen rapidly in power conversion efficiency over the past six years, surpassing 22%. However, stability issues remain a key barrier to commercialization. The Group for Molecular Engineering of Functional Materials at EPFL Valais Wallis in Switzerland, led by Prof. Mohammad Khaja Nazeeruddin, is working to advance perovskite solar cell stability through several approaches: developing new hole transport materials and surface passivation layers, growing high-quality films through vacuum sublimation, and unveiling fundamental photophysical properties to guide device design. The group aims to realize highly efficient, stable and non-toxic perovskite solar cells for low-cost renewable energy applications.