 perovskite CH3NH3PBI3 light absorber is deposited on the mesoporous TiO2 layer via 1-step and 2-step coding methods and their photovoltaic performances are compared. 1-step coding using a solution containing CH3NH3I and PBI2 shows average power conversion efficiency, PCE, of 7.5%, while higher average PCE of 13.9% is obtained from 2-step coding method, mainly due to higher voltage and fill factor. The coverage, poor filling, and morphology of the deposited perovskite are found to be critical in photovoltaic performance of the mesoporous TiO2 based perovskite solar cells. This article was authored by Jong Hyak Kim, Hwee Siang Kim, and Nombu Park.