Flexo-phototronic effect in centro-symmetric BiVO₄ epitaxial films

With exciting functionality, topological defects in ferroic system have attracted significant attention. Under proper design, the emergence of polar domain walls in non-polar ferroelastics enables a flexo-phototronic effect. In this study, we revealed ferroelastic twin texture with localized flexoelectric effect in centrosymmetric epitaxial BiVO₄ film. Supported by photodeposition and localized photocurrent analysis, we found the flexoelectric effect confined at domain wall area facilitates the photocarrier transport and the flexo-phototronic mechanism was further supported by dye-degradation and generation of reactive radicals. This work not only provides new insights into the introduction of flexo-phototronic effects in non-polar materials, but also sheds light on the use of material inhomogeneity for acquiring multifunctionality.