Spontaneous polarization behaviors in hybrid halide perovskite film

Spontaneous polarization behaviors of hybrid perovskite CH3NH3PbI3 film were confirmed by in situ PFM and spectroscopic ellipsometry. The film exhibits uniform spontaneous polarization and ferroelectric domain inversion performance. The fitted dielectric constants spectra agree well with the calculated ones. We attribute the spontaneous polarization behaviors of hybrid perovskite to lone pair electrons, and its outstanding photovoltaic performance partially originates from spontaneous polarization and plasma resonance. This report will facilitate understanding of the instinct physical essence of hybrid perovskite solar cells.