Flexible PbZr_0.52Ti_0.48O₃ 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 PbZr 0.52 Ti 0.48 O 3 (PZT) films with SrRuO 3 (SRO) buffered layer are grown on the 10 µm 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 ≈60 µC cm −2 and a dielectric tunability of ≈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.