Piezoelectric Vibrational Energy Harvester Using Lead-Free Ferroelectric BiFeO3 Films

We have proposed that BiFeO3 films are suitable for piezoelectric vibrational energy harvester (VEH) applications, because BiFeO3 has high spontaneous polarization and low dielectric permittivity. We demonstrated that energy can be harvested by a micromachined VEH using a BiFeO3 film deposited using a sol-gel process. A VEH with a resonant frequency of similar to 98 Hz produced an output voltage of 1.5 V.G(-1) and electrical power of 2.8 mu W.mm(-3).G(-2) (G = 9.8 m/s(2)) at a load resistance of 1 M Omega. Using the analytical model for VEH, the generalized electromechanical coupling factor was estimated to be 0.41%. These results were comparable to those of the best-performing VEHs using other piezoelectric films. (C) 2013 The Japan Society of Applied Physics