The ferroelectric photovoltaic effect of BiCrO3/BiFeO3 bilayer composite films

This work involves an investigation of the structure, ferroelectricity, optical band-gap, photovoltaic spectral response and J-V performance of BiCrO3/BiFeO3 bilayer composite films prepared via the solution-gelation technique. It is shown that the enhanced ferroelectric properties are observed for BiCrO3/BiFeO3 bilayer composite films by interaction resulting from the coupling between BiFeO3 and BiCrO3 layers. The photovoltaic spectral responses of the normalized current for BiCrO3/BiFeO3 bilayer composite films presents a noteworthy red-shift towards visible region compared with the pure BiFeO3 films and the pure BiCrO3 films. Thus photovoltaic response is attributed to the narrow band-gap of BiCrO3/BiFeO3 bilayer composite films. The short circuit current density and open circuit voltage of the BiCrO3/BiFeO3 bilayer composite films under white-light illumination are much higher than the values of BiFeO3 and BiCrO3 films. The present work provides an available way of controlling photovoltaic response of ferroelectric films and accelerating its application in light sensors, light drivers and ferroelectric photovoltaic cells.