Wind-power generators based on ZnO piezoelectric thin films on stainless steel substrates

This paper reports a novel means of integrating a high-performance ZnO piezoelectric transducer with a flexible stainless steel substrate (SUS304) to construct a wind-power generator. The stainless steel substrate has a higher Young’s modulus than that of the PET substrate, and will behave the long-term stability under vibration. The transducer includes a ZnO piezoelectric film deposited on the stainless steel substrate at a temperature of 300 °C by an RF magnetron sputtering system. Scanning electron microscopy and X-ray diffraction of ZnO piezoelectric films reveal a rigid surface structure and a high c-axis-preferred orientation. To fabricate a transducer with a resonant frequency of 75 Hz for the natural winding, the cantilever length of 1 cm and a vibration area of 1 cm2 are used, based on cantilever vibration theory. A mass loading of 0.57 g at the front-end of the cantilever is critical to increase the amplitude of vibration and the power generated by the piezoelectric transducer. The maximum open circuit voltage of the power generator is 10.5 V. After rectification and filtering through a 3.3 nF capacitor, the output power of the wind generators exhibited a specific power output of 1.0 μW/cm2 with a load resistance of 5 MΩ.

► Wind-power piezoelectric transducer. ► Flexible piezoelectric transducer. ► Piezoelectric thin films. ► Stainless steel substrates.