Effect of polarization rotation on the optical and photovoltaic properties of BiFeO3 thin films

Visible-light-active ferroelectric materials are gaining increasing attention due to the unique ferroelectric photovoltaic effect. To boost the light harvesting capability, vast research is devoted to band gap engineering by chemical substitutions, regardless of the side effect on ferroelectric polarization. Here, we focus on how polar order affects the optical and photovoltaic properties. Using BiFeO3 as the model system, we induce the polarization rotation by A-site La substitution, which results in continuous reduction of optical anisotropy of the samples, as revealed by the concerted optical characterizations. This further causes the decrease of angular dependence of ferroelectric photovoltaic effect on the light polarization. The results demonstrate the inner connection of the ferroelectric polarization and optical anisotropy via the lattice degree of freedom.

Automated summary

This study focuses on the effect of polar order on the optical and photovoltaic properties of ferroelectric materials, using BiFeO3 as the model system. By inducing polarization rotation through A-site La substitution, the optical anisotropy of the samples is continuously reduced, leading to a decrease in the angular dependence of the ferroelectric photovoltaic effect on light polarization. This highlights the inner connection between ferroelectric polarization and optical anisotropy through lattice degree of freedom.