Incorporation of Rubidium in the Organic–Inorganic FAPbI3 Structure for Stabilizing the Optically Active Perovskite Phase

Organic–inorganic halide perovskite (OIHP) materials have become the focus of attention in the photovoltaic and other electronic/optoelectronic applications since past few years. The exceptional and fundamental properties of these materials pave the desired state-of-the-art in the perovskite based applications. However, the associated issue of stability must be solved for commercialization. The critical weakness of the OIHPs against moisture originates mainly from the hygroscopic organic cations in the structure. In this work, rubidium (Rb) has been partially substituted at the A-site of formamidinium lead iodide (FAPbI3) structure and found to be suitable for moisture-tolerance. The incorporation of Rb, induced the absorption over the entire visible window, which may lead to various long-term applicability in solar cells, photocatalysis and other optoelectronic devices.