An effective flexible wireless energy harvester/sensor based on porous electret piezoelectric polymer

A flexible sponge-like nanogenerator (FSNG) based on ZnO nanoparticles (NPs) etched porous electret poly (vinylidene fluoride–hexafluoropropylene) (P(VDF-HFP)) film is spotlighted without any electrical poling treatment. It possesses improved dielectric and ferroelectric properties than neat P(VDF-HFP) film. The FSNG harvests an open-circuit voltage (V_oc) of 9 V and short circuit current (I_sc) of 1.3 μAcm⁻² under repeated mechanical impact of 0.36 MPa stress amplitude on the top surface. With the power density (P) of 1.21 mW/cm² and energy conversion efficiency of 0.3% it directly operates several consumer electronics. The highly sensitive (∼1 μVPa⁻¹) FSNG is demonstrated as a self-powered wireless sensor with 3.0% efficiency for detecting some tiny human activities including finger movements. - Highlights: • ZnO nanoparticles etched porous electret P(VDF-HFP) film is spot lighted. • Superior dielectric and ferroelectric properties without any poling are observed. • It harvests 9 V output voltage with 4.7 μA current under 0.36 MPa stress. • It shows superior power density and energy conversion efficiency of same stress. • It also acts as self-powered wireless sensor for detecting tiny human activities.