Kuba, Austin G.Sahli, FlorentOthman, MostafaArtuk, KeremJeangros, QuentinHessler-Wyser, AïchaBallif, ChristopheWolff, Christian M.2025-05-142025-05-142025-05-132025-05-1210.1021/acsenergylett.4c03395https://infoscience.epfl.ch/handle/20.500.14299/250135Vapor phase deposition of formamidinium-rich perovskites is hampered by the decomposition of formamidine in the vapor phase. We use the reversibility of this reaction to establish a dynamic equilibrium that enables the vapor-phase synthesis of formamidinium iodide from the “degradation products” s-triazine, ammonia, and hydrogen iodide and thereby convert lead halide thin films to lead halide perovskites. Finally, we produce the first proof of concept solar cells via this innovative process.entext::journal::journal article::research article