Shape memory effect based thermal cycling induced flexoelectricity for energy harvesting

Different from traditional flexoelectric effect derived from converting mechanical energy into electricity, the present letter provide a new design of composites mode to achieve converting thermal energy into electricity. The composites consist of shape memory alloy (SMA) substrate pre-deformed under indentation, and ZnO film with centimeter scale deposited on the SMA by magnetron sputtering. The experimental results indicated pronounced flexoelectric effect, corresponds to output short-circuit current reached up to 0.3μA/cm² under thermal cycling condition, could be derived in the ZnO film with high strain gradient induced by the pre-deformed SMA substrate, pathing a new way to achieve flexoelectric effect for thermal energy harvesting.