Chem. Commun., 2025, Advance Article DOI: 10.1039/D5CC05230K, Communication Jorim Okoth Obila, Chunging Li, Masatoshi Yanagida, Yasuhiro Shirai, Yuko Takeoka Modulation of lower dimensional phases in quasi-2D tin perovskite using ethylenediamine dihydroiodide (EDAI2) improves the performance of quasi-2D Ruddlesden–Popper tin perovskite solar cells.