Characterization of Direct Piezoelectric Properties for Vibration Energy Harvesting

Direct piezoelectric effect of Pb(Zr,Ti)O-3 (PZT) thin films was investigated to discuss the application of ferroelectric films to vibration energy harvesting. From the model of the piezoelectric vibration energy harvester, it was found that the figure of merit (FOM) is proportional of the square of the effective transverse piezoelectric coefficient e(31,f). The e(31,f) coefficient of PZT films were measured by substrate bending method. Furthermore, it was found that the e(31,f) coefficient increases with increasing strain, which is favourable for the vibration energy harvesting.