Remote light energy harvesting and actuation using shape memory alloy - Piezoelectric hybrid transducer

Shape memory alloys (SMAs) exhibit a memory effect which causes the alloy to return to its original shape when heated beyond the transformation temperature. In this study, we show that SMA can be heated remotely by laser and the resulting deformation can be converted into electricity through a piezoelectric bimorph. In addition, the laser actuated SMA deformation can also be used to provide controlled actuation. We provide experimental results demonstrating both the power harvesting and actuation behavior as a function of laser pulse rate. SMA used in this study exhibited higher absorption in the ultraviolet region which progressively decreased as the absorption wavelength increased. Raman analysis revealed TiO2 formation on the surface of SMA, whose concentration increased irreversibly with temperature. Negligible changes in the surface oxidation were detected in the working temperature range (<150 °C).