Engineered domain configuration and piezoelectric energy harvesting in 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 single crystals

The performance of cantilever piezoelectric energy harvesters using three types of piezoelectric materials, relaxor ferroelectric 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-PT) single crystals oriented along the 〈110〉 and 〈001〉 directions, and a PZT-based ceramic, were investigated. The 〈110〉 and 〈001〉 oriented PMN-PT single crystals, which have a rhombohedral phase and spontaneous polarization along the 〈111〉 direction, presented electromechanical coupling factor k31’s of 0.78 and 0.42, respectively. The cantilever-type energy harvester operated by 31 resonance mode generated a larger output power of 1.07 mW for the 〈110〉 oriented PMN-PT single crystal compared to those of the other materials. The effective electromechanical coupling factor of the piezoelectric energy harvester with the 〈110〉 oriented crystal also reached 0.25, not achievable with the other piezoelectric materials. These results demonstrate that the domain engineering of the piezoelectric single crystals can provide higher design flexibility for a tiny energy harvester.