Synthesis of BaTiO 3 -CaTiO 3 and BaTiO 3 -SrTiO 3 Core-Shell Nanocubes via the Surface Reconstruction of BaTiO 3 Nanocubes

BaTiO -CaTiO and SrTiO -BaTiO core-shell nanocubes were synthesized through the surface reconstruction of BaTiO nanocubes, which involved the reaction of titanium oxide with Ca(OH) , Sr(OH) , or Sr(OH) ·8H O in water at 100 °C. The core-shell structure comprised a BaTiO nanocube core and a CaTiO or SrTiO shell. The outermost layer with a perovskite structure also comprised CaTiO or SrTiO , and its thickness was several hundred picometers. The thinnest layer was constructed of only one layer of CaTiO or SrTiO . This is the first presented work on a core-shell nanocube with the outermost layer consisting of only CaTiO or SrTiO surrounding the BaTiO nanocube. The shells of CaTiO and SrTiO comprise a layer thickness of only one unit cell of ∼0.4 nm (400 pm). Thus, we demonstrate new research on nanocube surfaces on the picometer scale.