Optimizing TiO(2) through Water-Soluble Ti Complexes as Raw Material for Controlling Particle Size and Distribution of Synthesized BaTiO(3) Nanocubes

[Image: see text] Barium titanate (BaTiO(3)) nanocubes with a narrow particle size distribution were synthesized using a three-step approach. First, a water-soluble Ti complex was synthesized using a hydrolysis method. Next, the titanium dioxide (TiO(2)) raw material was synthesized via a hydrothermal method using various water-soluble titanium (Ti) complexes. The TiO(2) exhibited various particle sizes and crystal structures (anatase, rutile, or brookite) depending on the water-soluble Ti complex and the hydrothermal conditions used in its synthesis. Finally, BaTiO(3) nanocubes were subsequently created through a hydrothermal method using the synthesized TiO(2) particles and barium hydroxide octahydrate [Ba(OH)(2)·8H(2)O] as raw materials. The present study clarifies that the particle size of the BaTiO(3) nanocubes depends on the particle size of the TiO(2) raw material. BaTiO(3) particles with a narrow size distribution were obtained when the TiO(2) particles exhibited a narrow size distribution. We found that the best conditions for the creation of BaTiO(3) nanocubes using TiO(2) involved using lactic acid as a complexing agent, which resulted in a particle size of 166 nm on average. This particle size is consistent with an average of the width of the cubes measured from corner to corner diagonally, which corresponds to a side length of 117 nm. In addition, surface reconstruction of the BaTiO(3) was clarified via electron microscopy observations, identifying the outermost surface as a Ti layer. Electron tomography using high-angle annular dark-field (HAADF)-scanning transmission electron microscopy (STEM) confirmed the three-dimensional (3D) structure of the obtained BaTiO(3) nanocubes.