Synthesis of Na0.5Bi0.5TiO3 whiskers and their nanoscale piezoelectricity

The perovskite structured lead-free system Na0.5Bi0.5TiO3 (NBT) whiskers were synthesized from whiskers of layered tunnel structured Na2Ti6O13 (NT), using a topochemical route. Both NT and NBT whiskers show high aspect ratios with an average length of 15 µm and diameter of 1 µm. By prolonging the reaction time from 2 h to 6 h at 900 °C, NT whiskers with monoclinic phase completely transformed to NBT whiskers with pseudocubic phase. Typical strip-like nanodomains are observed in a NBT whisker, which are parallel to each other. The piezoelectric response amplitude for a NBT whisker indicates a large electric field induced strain, corresponding to a Smax/Emax value of as high as 300 pm/V. This work provides an in-depth instruction to prepare pure NBT whiskers, and gives the detailed piezoelectricity of NBT whiskers to promote their applications in energy harvesting and micro-electromechanical systems.