Using Piezoelectric Generator to Estimate Energy Harvesting with Graphene

Recent STM studies suggest graphene membranes exhibits spontaneous mirror buckling, a phenomenon which can be exploited to harvest ambient energy. This behavior compels us to investigate into different mechanical to electrical energy converters that can be used to harvest low power energy from graphene. One mechanism is to attach a piezoelectric cantilever on a graphene mesh and convert its mechanical energy to electricity. To understand power output from such device, we conduct experimental studies on a hand-shakable piezoelectric device. The generator comprises of multiple PVDF cantilevers connected in parallel, a full-bridge rectifier to change AC signal to DC, a dielectric capacitor to store harvested charges, and an LED for power consumption. We measure the power output and the efficiency of the device. Our results show a low maximum power output after 10 minutes of shaking and efficiency values lower than expected. With a piezoelectric intrinsic capacitor of and an external charge storing capacitance of , the system behaves as a charge source damping . We attribute these low values to high impedance of the intrinsic capacitor due to low frequency domain and its low capacitance. We think these results can be improved with graphene, which vibrates at high frequency.