Flexophotovoltaic Effect in Potassium Sodium Niobate/Poly(Vinylidene Fluoride-Trifluoroethylene) Nanocomposite

Flexoelectricity is an electromechanical coupling effect in which electric polarization is generated by a strain gradient. In this investigation, a potassium sodium niobite/poly(vinylidene fluoride-trifluoroethylene) (KNN/PVDF-TrFE)-based nanocomposite is fabricated, and the flexoelectric effect is used to enhance the photovoltaic current (I _pv) in the nanocomposite. It is found that both a pyroelectric current and photovoltaic current can be generated simultaneously in a light illumination process. However, the photovoltaic current (I _pv) in this process contributes ≈85% of the total current. When assessing the effect of flexoelectricity with a curvature of 1/20, the I _pv of the curved KNN/PVDF-TrFE (20%) (K/P-20) composite increased by ≈13.9% compared to that of the flat K/P-20 nanocomposite. Similarly, at a curvature of 1/20, the I _pv of the K/P-20 nanocomposite is 71.6% higher than that of the PVDF-TrFE film. However, the photovoltaic effect induced by flexoelectricity is much higher than the increased polarization from flexoelectricity, so this effect is called as the flexophotovoltaic effect. Furthermore, the calculated energy conversion efficiency of the K/P-20 film is 0.017%, which is comparable to the previous research result. This investigation shows great promise for PVDF-based nanocomposites in ferroelectric memory device applications.