Abstract
Mesoscopic barium titanate (BaTiO3) single crystals with dimensions of 10-15nm that incorporated a cuboid-shaped hollow core were synthesized by a sol-gel method using a highly-concentrated Ba-Ti alkoxide precursor solution combined with a surfactant templating approach. In this synthesis route, perovskite BaTiO3 nanocrystals were formed directly by a polycondensation reaction of the gel framework during aging at room temperature. Hollow-core nanocrystals were contained in the product, which was obtained by firing the crystalline gel at 500 degrees C in flowing oxygen. The cuboid-shaped hollow cores of the nanocrystals were about 0.2nm in size and had {1 0 0} inner surfaces. In addition, it was also found that some kind of ordered structure was formed on a mesoscale with an interplaner spacing of 14nm before and after firing at 500 degrees C. (C) 2004 Elsevier B. V. All rights reserved.