Piezo-phototronic Effect in centro-symmetric BiVO₄

Pao-Wen Shao^1*, Ying-Hao Chu¹

¹Materials Science and Engineering, National Chiao Tung University, Hsinchu, Taiwan

* Presenter:Pao-Wen Shao, email:crag418@gmail.com

The internal field in ferroelectrics has been used to promote photovoltaic and photoelectrochemical effects, delivering a different approach for the efficiency enhancement. However, not much attention was paid to ferroelastics. In this study, we revealed ferroelastic twin texture with localized piezoelectric effect in epitaxial BiVO₄ film. The piezoresponse and thickness dependent twin domain width were probed by piezoresponse force microscopy. A second order phase transition was confirmed by monitoring the structural and domain changes as a function of temperature. We found the flexoelectricity near domain wall was induced due to the domain formation and then enhanced photogenerated charge separation. Such a phenomenon was confirmed by the experimental results of photoconductivity and Au photoreduction. This work not only broadens the understanding of ferroelastics, but also expands potential application of using ferroelastics especially in photoelectrochemistry.

Keywords: Piezo-phototronics, flexoelectricity, phase transition, ferroelasticity, centro-symmetry