The dielectric and photochromic properties of defect-rich BaTiO3 microcrystallites synthesized from Ti2O3

We report here the synthesis of barium titanate (BaTiO3) microcrystallites by using Ti2O3 powders as the raw material through a modified hydrothermal method. The BaTiO3 contains abundant (1 1 1) twinned microcrystallites, along with a large amount of oxygen vacancies and Ti3+ cations. It is considered that (1 1 1) twins nucleate and grow from the face-shared TiO octahedra of rhombohedral Ti2O3. This unique BaTiO3 structure presents lower phase transition temperature than normal BaTiO3 and exhibits reversible photochromic effects under UV and NIR irradiation.