Hybrid organic–inorganic halides are considered as outstanding materials when used as the absorber layer in perovskite solar cells (PSCs) because of its efficiency, relieve of fabrication and low‐cost materials. However, the content of lead (Pb) in the material may origin a dramatic after effect on human's health caused by its toxicity. Here, we investigate replacing the lead in MAPbI3 with tin (Sn) to show its influence on the growth of the film nucleation and stability of the solar device based on MASnI3. By analysing the manufactured perovskite films by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), UV–visible absorption, photoluminescence (PL) and atomic force microscopy (AFM), the properties of the thin films when lead is replaced by tin are reported. The simulation run for the case of MAPbI3 is reported, where Voc = 0.856 V, Jsc = 25.65 mA cm−2, FF = 86.09%, and ETA = 18.91%, and for MASnI3, Voc = 0.887 V, Jsc = 14.02 mA cm−2, FF = 83.72%, and ETA = 10.42%. In perovskite‐based devices using MASnI3 as absorber, it was found to be more stable despite of its lower efficiency, which could be improved by enhancing the bandgap alignment of MaSnI3. The results of this paper also allow the development of a new, reliable production system for PSCs.