Vibtrational energy harvesting using photo-patternable piezoelectric nanocomposite cantilevers

Abstract

Here we report on fabricating photo-patternable polymer nanocomposite cantilevers for harvesting electrical energy from mechanical vibrations. The optimized piezoelectric polymer nanocomposite enables direct photo patterning and, therefore, easy fabrication of microcantilevers eliminating expensive etching steps. Integrating piezoelectric zinc oxide (ZnO) nanoparticles (NPs) with optimum weight fraction into a photosensitive SU-8 polymer matrix not only retains the highly desired piezoelectric and semiconducting properties of the ZnO, but also combines the photo-patternability and the optical transparency of the SU-8. The maximum output power produced by nanocomposite cantilevers was 0.025 μW across a resistive load of 100 kΩ with peak to peak voltage of ∼140 mV at a resonance frequency of 4 kHz. This inexpensive platform offers design flexibility and ease of fabrication for harvesting mechanical vibrations.