Haris, Muhammed P. U.Xia, JianxingKazim, SamranMolenda, ZuzannaHirsch, LionelBuffeteau, ThierryBassani, Dario M.Nazeeruddin, Mohammad KhajaAhmad, Shahzada2023-05-082023-05-082023-05-082023-03-1510.1016/j.xcrp.2023.101304https://infoscience.epfl.ch/handle/20.500.14299/197499WOS:000972924400001Formamidinium lead iodide-based solar cells show promising device reliability. The grain imperfection can be further suppressed by developing powder methodology. The water uptake capability is critical for the stability of a-formamidinium lead triiodide (FAPbI3) thin films, and elucidating the migration of hydrogen species is chal-lenging using routine techniques such as imaging or mass spectros-copy. Here, we decipher the proton diffusion to quantify indirect monitoring of H migration by following the N-D vibration using transmission infrared spectroscopy. The technique allows a direct assessment of the perovskite degradation associated with moisture. The inclusion of Cs in FAPbI3, reveals significant differences in pro-ton diffusion rates, attesting to its impact. CsFAPbI3's ability to block the active layer access by water molecules is five times higher than a-FAPbI3, which is significantly higher than methylammonium lead triiodide (MAPbI3). Our protocol directly probes the local environment of the material to identify its intrinsic degradation mechanisms and stability, a key requirement for optoelectronic applications.Chemistry, MultidisciplinaryEnergy & FuelsMaterials Science, MultidisciplinaryPhysics, MultidisciplinaryChemistryMaterials SciencePhysicslead iodide perovskitedegradation mechanismsolar-cellsformamidiniumperformancerelaxationtext::journal::journal article::research article