Ferroelectric oxides have recently attracted much attention as a candidate class of materials for use in photovoltaic devices, and for the coupling of light absorption with other functional properties. In these materials, the strong inversion symmetry breaking that is due to spontaneous electric polarization promotes the desirable separation of photo-excited carries and allows voltages higher than the band gap, which may enable efficiencies beyond the maximum possible in a conventional p-n junction solar cell. However, further improvements in photovoltaic efficiency have been inhibited by their wide band gaps (>2.7 eV), which allow the use of only 8-20% of the solar spectrum. Furthermore, in a material with broken inversion symmetry the charge can be separated by the bulk through the shift current mechanism, where the relation between the structure, electronic structure and the shift current response is still unclear. The shift current response of the conventional ferroelectrics is relatively small. Therefore, study of the effects of structural and electronic properties on the shift current response and design of new materials with stronger shift current response are of great importance for ferroelectric photovoltaics.
展开▼
