Copper iodide induced ambient-air-stable formamidinium lead triiodide thin film

Formamidinium lead iodide (FAPbI3) is an important perovskite material for the photovoltaic industry owing to its excellent light absorbing, emitting tendency, and lower bandgap. However, using FAPbI3 in solar cell fabrication has been quite difficult due to its metastable nature under ambient air conditions. Study on stabilizing FAPbI3 is of great interest and importance. Many approaches have been projected to stabilize the FAPbI3 active layer and demonstrate robust and highly stable devices. Doping leads to lead substitution and improves the stability which helps in the commercialization of solar cells. Here we report on the preparation and investigation of pristine FAPbI3 and cuprous iodide (CuI) incorporated FAPbI3 (FAPbI3CuI(0.1M)) thin films and its stability under ambient condition. Structural, optical, morphological studies are performed on both FAPbI3 and FAPbI3CuI(0.1M) thin films and found that the FAPbI3CuI(0.1M) thin films are quite stable for an extended period of 7 days under ambient air condition.