Transparent Piezoelectric Polymer-Based Materials for Energy Harvesting and Multitouch Detection Devices

Abstract

Energy harvesting devices allowing to recover wasted energy from the environment are increasingly being developed. Mechanical energy is one of the most interesting sources for energy harvesting, and piezoelectric materials present excellent overall properties for the scavenging of that energy. Piezoelectric polymers, and, in particular, poly(vinylidene fluoride), show appropriate mechanical properties for large amplitude movements, higher piezoelectric coefficients, and transparency and can be easily integrated into devices. A transparent piezoelectric energy harvesting device has been developed with screen-printed transparent (72%) and conductive (42 Ω/sq) electrodes on PVDF sheets with a d33 = −23 pC/N, generating about P ∼ 12 μW and P ∼ 8 μW under pressing and bending modes, corresponding to an energy per cycle of E∼ 37 nJ and E ∼ 55 nJ, respectively. The piezoelectric energy harvesting characteristics of the materials have been also theoretically evaluated, and the applicability of the materials for touch detection has been demonstrated.