Synergistic improvement of piezoelectric and triboelectric responses in thermally exfoliated graphene oxide incorporated poly(vinylidene fluoride) nanocomposite

In this study, we have thoroughly investigated the intrinsic polarity-mediated optimization of multiple parameters, such as the piezoelectric coefficient, surface roughness, and surface work function, through the strategic incorporation of thermally exfoliated graphene oxide (TEGO) in poly(vinylidene fluoride) (PVDF) matrix, and its effect on piezoelectricity and triboelectricity. A higher density of delocalized π-electrons and oxygen-containing functional groups on the surface of TEGO regulated the electrostatic anchoring of -CH₂ dipoles in PVDF through π-dipole, dipole-dipole interaction to simultaneously induce a maximum polar phase content of ~89% at 2 wt.% TEGO concentration and a negative surface potential. This has resulted in a significant dual enhancement of charge generation and charge transfer through mechanical stimuli. The hybrid device yielded an instantaneous output power density of ~43.5 µW/cm², and a maximum external efficiency of ~42.4%, which was utilized to harvest various bio-mechanical energies, followed by the development of a smart health-monitoring system that calculates calories from footsteps in real time.