The regulation of ferroelectric photovoltaics by non–compensated doping engineering

By absorbing and transferring the photons (nearby bandgap) to photoelectrons, non–compensated (Ce4+ dopants) doping Bi5Ti3FeO15 ferroelectric films present switchable and stable photovoltaics. The defect dipole attraction in non–compensated doping films not only narrows the bandgap effectively by the creation of tunable intermediate sub–band (gap state), but enhances separation of electron–hole pairs in the visible–light region. The concept is proved by dramatic redshift of optical absorbance and intense photovoltaics. Subsequently, contrast investigations of equivalent–compensated doping films offer solid experimental evidences. Furthermore, the intensity of Coulomb attraction between defect dipoles can be destroyed by thermal perturbation, which is empirically supported by the abrupt drop of temperature dependent photovoltage at 340 K. These results demonstrate that non–compensated doping can be a promising route to construct more efficient energy transfer devices.