Method and Composition for Achieving High Piezoelectric Voltage Coefficient

A rapid surge in the research on piezoelectric sensors is occurring with the arrival of the Internet of Things (IoTs). Single-phase oxide piezoelectric materials with giant piezoelectric voltage coefficient (g, induced voltage under applied stress) and high Curie temperature (Tc) are crucial towards providing desired performance for sensing, especially, under harsh environmental conditions. Here, we provide rational design criterion for piezoelectric sensing material incorporating (a) anisotropy/composition/phase structure, (b) microstructure and (c) domain engineering. Using this criterion we report a grain-oriented (with 95% <001> texture) modified-PbTiO3 material that has a high Tc (~364°C) and an extremely large g33 (115 X 10^-3 Vm/N) in comparison to other known single phase oxide materials. Diffraction and scanning probe microscopy studies reveal that self-polarization due to grain orientation along the spontaneous polarization direction plays an important role in achieving large piezoelectric response in a domain-motion-confined material. Domain-level mechanisms were verified quantitatively by simulations using phase field model. The simulations confirm that the large piezoelectric voltage coefficient g33 originates from maximized piezoelectric strain coefficient d33 and minimized dielectric permittivity e33 in [001]- texture PbTiO3 ceramics where domain wall motions are absent.

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Grant Brewer
Senior Licensing Associate
Virginia Tech Intellectual Properties, Inc.
(540) 443-9218
Yongke Yan
Shashank Priya