Synthesis, Characterization and Physical Properties of Nano-Antimony Oxyhalides

Abstract

The novel synthesis routes have been developed for the synthesis of nanorods and nanosheets of antimony oxychloride (Sb4O5Cl2) in the dimension range of 55-90 nm by using single precursor. Nanostructures, microstructures and bulk single phase materials have been synthesized. X-ray powder diffraction analysis have confirmed the monoclinic crystal symmetry in space group no.14 with structure type Sb4O5Cl2 for the single phase nanorods, nanosheets, microstructures and the bulk materials. Rietveld refinement and the crystallite size investigations of the powder patterns revealed the lattice parameters and crystallite size increment in case of nanorods in comparison to the nanosheets. Through scanning electron microscopy, a composition near to the Sb4O5Cl2 (at %) and the averaged dimensions; dia. ~ 50-90 nm, l ~ 2 m for nanorods, dia. ~ 50-150 nm, l ~ 2 m for nanosheets and thickness ~ 2-3 m, l ~ 2 m for microstructures have been observed. The PNCs have also been synthesized by using PVA as matrix with various compositions (1, 3 and 5 w/w%) of Sb4O5Cl2 nanorods and -sheets. IR analysis has verified the PNCs synthesis in form of uniform films. The optical properties of the nano and bulk materials have also been studied through DRS UV-Vis spectroscopy, the band gap widening has been observed while moving from bulk to nanoregime, i.e. 3.25, 3.31 and 3.34 eV, for bulk, nanosheets, and nanorods, respectively due to quantum confinement. In the case of nanosheets, highest value of dielectric constant has been observed, i.e. 87, as compared to nanorods 40 and the bulk 35.5, respectively. The nanosheets have also shown the highest value of dielectric and tangent loss with increase in frequency due to the least crystallite size of this material. Nanosheets have depicted the higher AC conductivity at low frequency due to the alignment of the charges but its value decreases at the higher frequency due to lack of time for alignment of the charges. However, nanorods and bulk material had no change throughout the frequency range. The hopping phenomenon has been observed in all three cases with most prominent one in bulk case at higher frequencies.