Opto-structural characterization of Mg(OH)2 and MgO nanostructures synthesized through a template-free sonochemical method

In this study, we proposed a cost-effective and simple one-step sonochemical route to synthesize Mg(OH)2 and MgO nanostructures by using natural brine. The structure, morphology, and chemical composition of as-synthesized nanostructures were confirmed by XRD, FESEM, TEM, EDS, and FT-IR spectroscopy. The possible growth mechanism of Mg(OH)2 nanoplates and MgO nanoparticles (with an average crystallite size of 22.59 nm and 19.86 nm, respectively) was investigated, and the effect of ultrasound waves on the morphologies was described. The optical properties of nanoparticles were studied by utilizing UV–Vis spectroscopy. The optical energy band gap of the samples (Eg(Mg(OH)2) = 4.8 eV, Eg(MgO) = 4.9 eV) was estimated and used for calculating refractive index (n) and dielectric constant (e∞) parameters via three known models (Ravindra et al., Herve and Vandamme, and Ghosh et al.), in which Ravindra et al. model was selected as acceptable for enhancing their efficiency of dye-sensitized solar cells and other optical applications. The emission peaks for Mg(OH)2 (400 nm) and MgO (380 nm) nanopowders at photoluminescence (PL) measurements indicated that despite obtained from cheap and available impure precursor, the products have potential applications in opto-electronic devices.