High-symmetry epitaxial growth under solvothermal conditions: A strategy for architectural growth of tubular and nontubular CaTiO3 microstructures with regular geometrical morphologies and tunable dimensions

This paper reports on the architectural growth of CaTiO3 microstructures with regular geometrical morphologies and tunable dimensions under simple solvothermal conditions by using a mixture of ethanol and water as solvent, calcium nitrate and tetrabutyltitanate as starting materials, and NaOH as mineralizer. The microstructures can be divided into tubular and nontubular types, both of which can be further divided into one-, two-, and three-dimensional microstructures. The tubular/nontubular structures and the dimensions of the microstructures can be achieved by adjusting the initial NaOH concentration and the volume ratio of ethanol to water, respectively. The growth mechanism responsible for the formation of the CaTiO3 microstructures was investigated. A high-symmetry epitaxial growth process confers regular geometrical morphologies on the CaTiO3 microstructures: the fast stacking interplay of the {111} planes results in a rectangular structure, and the epitaxial growth limited in the three perpendicular directions forms a perpendicular structure, thus generating the regular geometrical microstructures. The results suggest that high-symmetry epitaxial growth under solvothermal conditions should be a convenient and effective approach for the growth of regular geometrical CaTiO3 microstructures, which may find importance in many fields.