Giant piezoelectric voltage coefficient in grain-oriented modified PbTiO3 material

A rapid surge in the research on piezoelectric sensors is occurring with the arrival of the Internet of Things. 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 report a grain-oriented (with 95% <001> texture) modified PbTiO₃ ceramic that has a high Tc (364 °C) and an extremely large g₃₃ (115 × 10⁻³ Vm N⁻¹) in comparison with other known single-phase oxide materials. Our results 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. The phase field simulations confirm that the large piezoelectric voltage coefficient g₃₃ originates from maximized piezoelectric strain coefficient d₃₃ and minimized dielectric permittivity ɛ₃₃ in [001]-textured PbTiO₃ ceramics where domain wall motions are absent.