Piezoelectric Nanogenerators for Self-Powered Nanosystems and Nanosensors

Abstract : In this project, intensive research effort has been invested in the development of self-powered MNSs, and various prototypes have been built up. Flexible piezotronic device based on RF-sputtered piezoelectric ZnO thin film is a great UV sensor. A nanogenerator based on the hydrothermal growth of a ZnO nanowire film on a spring shows a stable output and both the output voltage and current, displaying a linear relationship with the weight loaded on the spring. Thus, the nanogenerator can be utilized as an active mechanical sensor for measuring the weight applied onto the spring. A flexible thermoelectric nanogenerator (TENG) can be used as a wearable energy harvester by using human body temperature as the energy source. At the same time, the TENG can work as a self-powered temperature sensor with a response time of 17 s and a reset time of 9 s. The detection sensitivity of the sensor can reach 0.15 K in ambient atmosphere. The single output peak from a pyroelectric nanogenerator (PENG) based on a lead zirconate titanate (PZT) film can be used to directly drive a LCD. Further, a homemade Li-ion battery can be charged by the PENG under different working frequencies from 0.005 to 0.02 Hz, which can be used to drive a green LED. An integrated module in the form of a combination of a nanoparticle-WO3 film electrochromic device and a nanogenerator demonstrates the potential of monochrome self-powered displays. This self-powered electrochromic device showed desirable electrochromic response times and high coloration efficiency values. A transparent flexible nanogenerators made by growing ZnO nanowires on flexible polydimethylsiloxane (PDMS) substrate is a self-powered sensor for monitoring vehicle speed and detecting vehicle weight. Using two kinds of piezoelectric material, ZnO and poly-(vinylidene fluoride) (PVDF), we fabricate a composite structure for a nanogenerator (NG) or active-sensor for mechanical energy harvesting and vortex-based gas/liquid flow measurements.