Piezoelectric voltage constant and sensitivity enhancements through phase boundary structure control of lead-free (K,Na)NbO3-based ceramics

The piezoelectric voltage constant (g33) is a material parameter critical to voltage-type sensors for detecting vibrations or strains. Here, we report lead-free (K,Na)NbO3 (KNN)-based accelerometer with sensitivity enhanced by taking advantage of high g33. To achieve g33, the magnitudes charge d33 and dielectric permittivity εr KNN were best coupled manipulating intrinsic polymorphic phase boundaries effectively help Bi-based perovskite oxide additives. For composition that derives benefit from combination d33, value g33 was found be 46.9 × 10−3 V·m/N, which significantly higher than those (20 – 30 V·m/N) in well-known polycrystalline lead-based ceramics including commercial Pb(Zr,Ti)O3 (PZT). Finally, sensor prototype built using modified demonstrated (183 mV/g) when measuring vibrations, showing 29% increase against PZT-based (142 mV/g).