Journal Article Research Support, Non-U.S. Gov't nanogenerators 2D materials 7782-42-5 Graphite Hydrocarbons, Fluorinated Polymers Vinyl Compounds active matrix atomic stacking contact electrification electronic skin electronic skins ferroelectric polarization graphene field-effect transistors graphene transistors graphene tribotronics hybrid materials kelvin probe force microscopy optoelectronic devices photovoltaic devices piezoelectricity piezopotential powering poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) poly(vinylidenefluoride-co-trifluoroethylene) poly(vinylidenefluoride-trifluoroethylene) self-assembly skin strain sensors