Enhancing ferroelectric photovoltaic effect of BaTiO₃ by the lateral interface

A large bandgap significantly suppress the development of ferroelectric photovoltaic (FE-PV). The bandgap of BaTiO3 decreases to 1.49 eV from 2.46 eV by the formation of the lateral interface structure with BaO based on first principles calculations, which is beneficial to enhance the visible-light adsorption of FE-PV materials. The electronic structures of BaO/BaTiO3 show that the lateral interface plays a very important role. The conduction band minimum (CBM) and the valence band maximum (VBM) of BaO/BaTiO3 mainly originate from the Ba 6s states and the O 2p states in the interface of BaO/BaTiO3, respectively, revealing the strong lateral interface effect. In addition, the polarization of BaO/BaTiO3 decreases to 177.5 mu C/cm(2) from the 59.8 mu C/cm(2) of BaTiO3. The new mechanism provides a feasible way to reduce the bandgap of FE-PV with the wide bandgap (>3.0 eV).