Synthesis of Titanium-doped MgO heteronanostructures with tunable band gap

Ti x Mg1−x O heteronanostructures (x = 0.02 to 0.50) have been synthesized by a novel thermal decomposition route, and the effect of concentration of titanium and calcination temperature on optical properties of the heteronanostructures has been investigated. Phase analysis using powder X-ray diffraction demonstrates the formation of mixture of MgO and MgTiO3 when x = 0.02 to 0.20 and pure MgTiO3 when x = 0.33 to 0.50. Scanning electron microscopy studies show that the Ti x Mg1−x O samples with x = 0.02 to 0.20 consist of particles with a mixture of flower- and rod-like morphology, whereas the Ti x Mg1-x O samples with x = 0.33 to 0.50 possess rod-like morphology. Transmission electron microscopy studies show that the flowers are in turn formed by assembly of nanoparticles and the hollow rods are formed by aggregation of dumbbell-shaped nanoparticles. Diffuse reflectance spectroscopic studies show that band gap of the Ti x Mg1−x O heteronanostructures can be tuned from 3.2 to 4.2 eV by varying the concentration of titanium and the calcination temperature. Photoluminescence spectra show emission bands in visible and near-infrared regions due to defects present in the Ti x Mg1−x O heteronanostructures.