Design and fabrication of a double-sided piezoelectric transducer for harvesting vibration power

This investigation examines a means of integrating high-performance ZnO piezoelectric thin films with a flexible stainless steel substrate (SUS304) to fabricate a double-sided piezoelectric transducer for vibration-energy harvesting applications. The double-sided piezoelectric transducer is constructed by depositing ZnO piezoelectric thin films on both the front and the back sides of the SUS304 substrate. The titanium and platinum layers were deposited using a dual-gun DC sputtering system between the ZnO piezoelectric thin film and the back side of the SUS304 substrate. The scanning electron microscopy and X-ray diffraction of ZnO piezoelectric films reveal a rigid surface structure and a highly c-axis-preferring orientation. To fabricate a transducer with a low resonant frequency, a tip-mass of 0.5 g and a vibration-area of 1 cm(2) are designed, based on the cantilever vibration theory. The maximum open circuit voltage of the power transducer is approximately 18 V. After rectification and filtering through a 33 nF capacitor, a specific power output of 1.31 mu W/cm(2) is obtained from the transducers with a load resistance of 6 M Omega. The variation of the power output of +/- 0.001% is obtained after 24-hour continuous test. (C) 2012 Elsevier B.V. All rights reserved.