Enhanced energy harvesting performance via interfacial polarization in ternary piezoelectric composites for self-powered flexible pressure sensing application

Abstract

Nonhazardous and self-powered flexible pressure sensors based on piezoelectric effect are promising in the field of health monitoring, human-machine interfaces, soft robots and so on. Here, lead-free self-powered flexible pressure sensors with coaxial nanofiber structure are prepared, where Nb2CTx doped poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] and BaTiO3 (BTO) doped P(VDF-TrFE) are core and shell, respectively. Impressive piezoelectric output of ∼28 V and ∼8.2 μA was obtained for the device prepared by the nanofiber membranes under repeated mechanical force of 25 N at a frequency of 2 Hz. More importantly, the assembled self-powered pressure sensor possesses an ultrafast response time of 215 μs and a good linear relation between voltage and pressure. An interfacial polarization model based on the coaxial nanofibers has been proposed, in which the charge density calculation was carried out to understand the enhanced piezoelectric output of the piezoelectric pressure sensors. Moreover, the sensors are sensitive to various human motions and are suitable for movement monitoring.