Deciphering the importance of graded poling in piezoelectric materials: A numerical study

Piezoelectric materials play an important role in powering nano and microelectromechanical systems. However, these are often limited by their low sensing, actuation, and power outputs. This study proposes a novel poling direction arrangement theoretically in the piezoelectric materials which enhances the output parameters drastically. The poling angle was graded from bottom to top surface of element in linear fashion which helps in utilizing the bending and shear stresses efficiently. The sensing, actuation and energy harvesting performance of Pb[ZrxTi1-x]O-3 in graded mode was compared with those obtained from operating in transverse and shear modes. It was found from finite element simulations that a maximum sensing voltage of 11.85V was been obtained in graded mode which was around 15 times higher than that obtained in shear mode. Likewise, a maximum strain of 8.2 mu m/m and a tip displacement of 34.3 mu m was observed in the graded mode. Eventually, the maximum power of 0.12W was harvested from graded mode harvester followed by shear mode harvester where only : 1.6x10(-3) W could be harvested. However, the associated challenge with such study is the fabrication and graded poling of piezoelectric which still is an unexplored research area for scientific fraternity.