Probing Local Structural Distortion for Insights into the Stabilization Mechanism of the Black Phase in MOF-CsPbI3 Perovskite

CsPbI3 is a promising material for multijunction solar cells due to its solar-friendly bandgap (1.7 eV) in the black phase. However, the progression of CsPbI3 based solar cells is hindered by their inherent instability under ambient conditions. Water vapor catalyzes a phase transformation to the less efficient yellow phase. To address this, we've introduced an innovative approach: synthesizing the black-CsPbI3 within a protective Pb-based metal-organic framework (MOF) that maintains stability even after prolonged exposure to air. Understanding the stabilization mechanism is now of paramount importance. In previous studies, we conducted XAFS measurements (Cs-K, I-K, and Pb-L3 edges) on bare γ-and delta-CsPbI3 phases. Now we propose to investigate the same elements for MOF-embedded CsPbI3 phases, this study promises detailed insights about the stabilization mechanism, which could potentially lead to significant advancement in the development of stable, efficient perovskite solar cells.