A Flexible Piezoelectric-Pyroelectric Hybrid Nanogenerator Based on P(VDF-TrFE) Nanowire Array

The piezoelectric and pyroelectric effects are well known and have been widely used for energy harvesting and self-powered sensing systems. This paper presents a high performance piezoelectric-pyroelectric hybrid nanogenerator based on P(VDF-TrFE) nanowire array that is capable of simultaneously harvesting mechanical and thermal energies. The nanowire array was synthesized by nanoimprinting P(VDF-TrFE) polymer into anodic aluminum oxide (AAO). The ferroelectric beta crystalline phase of the aligned P(VDF-TrFE) nanowires has been demonstrated by Fourier transform infrared spectrum and X-ray diffraction measurements. Under periodic mechanical bending, electric signals are repeatedly generated from the hybrid nanogenerator and the measured piezoelectric output reach 4.0 V/65 nA. The cyclic bending-releasing process and impacts of strain rate on the electrical outputs are thoroughly characterized and analyzed. Besides, upon exposure of heat-cool condition with a temperature range of 8 K around room temperature, pyroelectric output up to 3.2 V/52 nA was obtained. There is a linear relationship between the output and the temperature difference across the device. Because the fast response time of 90 ms and high detected sensitivity of 0.8 K, the hybrid nanogenerator can also use as a self-powered temperature sensor. Finally, the piezoelectric and pyroelectric output voltages were successfully integrated together to obtain an enhanced output. These results demonstrate the great potential of the flexible hybrid nanogenerator for self-powered electronic devices.