Flexible PbZr0.52Ti0.48O3 Capacitors with Giant Piezoelectric Response and Dielectric Tunability

Abstract

Oxide ferroelectric ceramics and single crystals for flexible wearable device applications significantly suffer from the nature of hardness and brittleness due to their small maximum elastic strain and technological challenge in thinning to micrometer or nanometer scale. Although many oxide films are thin enough to be flexible, their rigid substrates restrain their piezoelectric d(33) coefficient and limit their flexible performance. Here, the large-scale PbZr0.52Ti0.48O3 (PZT) films with SrRuO3 (SRO) buffered layer are grown on the 10 mu m thick flexible mica substrate. An amplified longitudinal piezoelectric d(33) of about 1200 pm V-1 is achieved in an SRO/PZT/Pt capacitor due to the direct mechanical coupling between PZT and flexible mica via the d(31) piezoelectric tensor. The SRO/PZT/Pt capacitor shows a saturated polarization of approximate to 60 mu C cm(-2) and a dielectric tunability of approximate to 90%. Most importantly, the electric properties do not show obvious deterioration after repeatedly bending 10 000 times at a 2.2 mm radius. The flexible ferroelectric capacitors have potential applications in next-generation wearable devices and micro-electromechanical systems.