Screening effect on photovoltaic performance in ferroelectric CH₃NH₃PbI₃ perovskite thin films

Organic and inorganic hybrid materials of CH₃NH₃PbX₃ with a perovskite crystal structure have been conceived as emerging light absorbing materials for high efficiency photovoltaic devices. Here, we demonstrate the screening effect of polarization states on charge redistribution related to the photovoltaic performance of ferroelectric CH₃NH₃PbI₃ thin films using atomic force microscopy. We show the interplay between polarization and injected charges to have significant effects on charge transfer which potentially influences photovoltaic performance. The obtained results reveal that the direction and the amount of charge transfer can be influenced by the screening of polarization states at the interface. These results could deliver fundamental information regarding the influence of ferroelectricity on CH₃NH₃PbX₃ solar cells.