A flexible self-poled piezoelectric nanogenerator based on a rGO–Ag/PVDF nanocomposite

Here we demonstrate the mechanical energy harvesting performance of a poly(vinylidene-fluoride) (PVDF) device which is loaded with reduced graphene oxide-silver nanoparticles (rGO-Ag). The current results show that the addition of rGO-Ag enhances the polar beta and gamma piezoelectric phases in PVDF, which is capable of generating a greater piezoelectric output, thereby eliminating the requirement of any external poling process. X-ray diffraction (XRD) and Fourier transform infra-red spectroscopy (FT-IR) characterizations were employed for the identification and quantification of the piezoelectric polar phases of the nanocomposite films. Raman spectroscopy confirmed the interactions between rGO-Ag and PVDF. Polarization vs. electric field (P-E) loop testing was performed and it was found that on the application of an external electric field of 148 kV cm(-1) the nanocomposite showed an energy density value of approximate to 0.26 J cm(-1), which indicates its potential for energy storage applications. The fabricated energy harvesting device, a piezoelectric nanogenerator (PNG), could charge up capacitors and light up to 20 commercial blue light-emitting diodes. The PNG was tested to harvest biomechanical energy from pulsing mechanical energy by fixing it to fingers on the human palm. The PNG was also fixed to flip-flops in order to demonstrate its footwear connected energy harvesting application. The PNG showed a peak output open circuit voltage of approximate to 18 V and a short circuit current of approximate to 1.05 A, with a peak power density of 28 W m(-3) across a 1 M resistor. The PNG shows a moderate efficiency of 0.65%.