ORALS

Semiconductor nanostructures due to their size tunable photo-physical and photo-chemical behaviour have attracted great interest. CuS nanostructures (NSs) have been synthesized by facile chemical co-precipitation technique in variable solvent media concentrations of water: ethylene glycol (100:0; 75:25; 50:50; 25:75; 0:100). Crystallographic and morphological studies carried with X-ray diffraction (XRD) and High Resolution Transmission Electron Microscope (HR-TEM), respectively; reveal the formation of highly crystalline wurtzite structured CuS nanostructures having spherical morphology. It has been observed from the recorded diffractograms and micrographs that the average crystallite size, particle size and particle size distribution strongly depend on the solvent concentrtaion in variable solvent media. Average crystallite size values calculated for CuS nanostructures synthesized in variable solvent media are 6.62 nm, 8.04 nm, 7.93 nm, 6.64 nm and 6.62 nm for water: ethylene glycol concentration ratios of 100:0; 75:25; 50:50; 25:75 and 0:100, respectively. Morphological studies indicate that monodispersity in the particle size augments with increasing concentration of ethylene glycol. Pristine ethylene glycol solvent gives highly monodisperse nanospheres, whereas pristine aqueous solvent media causes the formation of heterogenous size distribution in synthesized CuS nanostructures. UV-Visible absorption spectra have been recorded to find the optical band gap values of the synthesized NSs. Calculated optical band gap values of NSs synthesized in variable solvent media are 2.29 eV, 2.18 eV, 2.28 eV, 2.33 eV and 2.39 eV for water: ethylene glycol concentration ratios of 100:0; 75:25; 50:50; 25:75 and 0:100, respectively. Photo-catalytic activity potential of synthesized NSs has been tested in aqueous media by the detoxification of test contaminant; methylene blue (MB) dye under visible light irradiation. Recorded results reveal that the synthesized nanostructures have excellent photo-catalytic activity, which strongly depends on the nanostructure morphology.