Monday, 14 May 2018
Ballroom 6ABC (Washington State Convention Center)
The successful utilization of Pb-free piezoelectric materials for the most useful cantilever-type energy-harvesters has been a critical interest for better performance. Here, we introduce the piezoelectric energy-harvesting characteristics of Bi0.5Na0.5TiO3-BaTiO3 (BNT-BT) thin films. The BNT-based thin films have not been reported so far for the energy-harvesting applications. 0.94BNT-0.06BT thin films, which are in the morphotropic phase boundary, showed the best dielectric and piezoelectric performance. The poling effect on the 0.94BNT-0.06BT thin films was also investigated by varying poling electric field, poling temperature and poling time. The 0.94BNT-0.06BT with poling process showed the improved piezoelectric constant of 3.13 C/m2 in the poling condition of 700 kV/cm, 60 oC and 20 min, compared to that of 3.04 C/m2 for films without poling process. XRD patterns showed the increased intensity of (002) peak indicating the increase in the volume fraction of the c-domain of BNT-BT film by applied external electric field, and thus the figure of merit (FOM) values were improved with increased poling field. As a result, the cantilever type energy harvester showed the output power of 2.22 µW from the vibration source with 42 Hz.