 perovskite containing solar cells were fabricated using a two-step process involving the deposition of lead iodide, PBI2, followed by conversion into the CH3 and H3 PBI3 perovskite. The device performance was found to be optimized when the dipping time was kept under 15 minutes, with the best results achieved after 15 minutes. This was attributed to the presence of Rennet PBI2, which acted as a blocking layer between the titanium dioxide semiconductor and the perovskite, thereby reducing charge recombination. Additionally, the presence of larger perovskite crystals at the interface between the whole transporting material and the perovskite was observed, which was also attributed to the Rennet PBI2. This article was authored by D&H Chow, Konstantinos C. Stumpos, Christos D. Maliakas, and others.