Fig. 3From: Enhanced performance of CH3NH3PbI3−x Cl x perovskite solar cells by CH3NH3I modification of TiO2-perovskite layer interface(Color online) Top-view SEM images of the CH3NH3PbI3−x Cl x films deposited on meso-TiO2 films modified by CH3NH3I solutions with different concentrations a 0 mg/ml, b 5 mg/ml, c 10 mg/ml, and d 20 mg/ml, respectively. Scale bar, 500 nmBack to article page