Microstructure and optical properties of NaTaO3 and TiO2 nanocrystalline low symmetry materials

In this work, in order to study the correlation between the microstructure and optical properties of the low symmetry materials, two different nanopowders i.e. TiO2 (tetragonal) and NaTaO3 (orthorhombic) are synthe-sized by the sol-gel and hydrothermal methods, respectively. Based on the active slip systems in rutile crystals, the contrast factors of dislocations are calculated numerically for TiO2 and then the microstructure behavior is investigated in terms of annealing temperature using the whole powder pattern modeling method. The NaTaO3 is crystallized in perovskite structure with unknown slip systems, therefore the behavior of its microstructure is investigated by the Rietveld method. Furthermore, UV-Vis and photoluminescence spectra were measured for two series samples to find the relation between the optical and microstructure peculiarities.