A Scalable Nanogenerator Based on Self-Poled Piezoelectric Polymer Nanowires with High Energy Conversion Efficiency

摘要

Nanogenerators based on piezoelectric materials convert ever-presentmechanical vibrations into electrical power for energetically autonomouswireless and electronic devices. Nanowires of piezoelectric polymers areparticularly attractive for harvesting mechanical energy in this way, as theyare flexible, lightweight and sensitive to small vibrations. Previous studieshave focused exclusively on nanowires grown by electrospinning, but thisinvolves complex equipment, and high voltages of $\approx$ 10 kV thatelectrically pole the nanowires and thus render them piezoelectric. Here wedemonstrate that nanowires of poly(vinylidene fluoride-trifluoroethylene)(P(VDF-TrFE)) grown using a simple and cost-effective template-wettingtechnique, can be successfully exploited in nanogenerators without poling. Atypical nanogenerator comprising $\approx$ 10$^{10}$ highly crystalline,self-poled, aligned nanowires spanning $\approx$ 2 cm$^2$ is shown to produce apeak output voltage of 3 V at 5.5 nA in response to low-level vibrations. Themechanical-to-electrical conversion efficiency of 11% exhibited by ourtemplate-grown nanowires is comparable with the best previously reportedvalues. Our work therefore offers a scalable means of achievinghigh-performance nanogenerators for the next generation of self-poweredelectronics.