 The two-step coding method of CH3NH3PBI3 light absorber on mesoporous TiO2 layer results in higher average power conversion efficiency, 13.9%, compared to the one-step coding method, 7.5%, due to better voltage and fill factor, while coverage, poor filling, and morphology of the deposited parafskite are crucial for photovoltaic performance of mesoporous TiO2-based parafskite solar cells. This article was authored by Jong Hyak Kim, Whee Seon Kim, and Nam Gea Park.