Ferroelectric bismuth-titanate nanoplatelets and nanowires with a new crystal structure.

Two different morphologies of ferroelectric bismuth titanate (BiTiO) nanoparticles, , nanoplatelets and nanowires, were synthesized by changing the concentration of NaOH during a hydrothermal treatment of precipitated Ti and Bi ions. The nanoparticles' crystal structures were characterized using atomic-resolution imaging with a -probe-corrected scanning-transmission electron microscope in combination with X-ray diffractometry and Raman spectroscopy. The nanoplatelets (10 nm thick and from 50 nm to 200 nm wide) exhibit the Aurivillius-type layered-perovskite crystal structure that is characteristic of BiTiO, whereas the nanowires (from 15 nm to 35 nm wide and from several hundreds of nm to several μm long) exhibit an entirely new structure with an orthorhombic unit cell ( = 3.