A simple chemical route to synthesis the CuS nanocrystal powder at room temperature and phase transition

The CuS nanocrystal powders were prepared by a simple chemical route at room temperature and the effect of the solution concentration on properties of CuS nanocrystal were investigated. These CuS nanocrystals were prepared from the solution in which the ratios of copper to thiosulphate were varied from 1:1 to 1:5. X-ray diffraction patterns suggests that the prepared CuS nanocrystals of ratios 1:3–1:5 were very close to the covellite form of copper sulphide. The optical spectra reveal that the powder 1:3, 1:4 and 1:5 shows high absorbance in the visible region. Raman spectra confirmed the covellite form of the copper sulphide nanocrystal. Scanning electron microscopy revealed the formation of agglomerated CuS hexagonal and flex with significant morphological deviation through sulphur concentration. Photoluminescence spectra indicate the concentrations of sulphur increases then the PL emission intensity is also increased. From TEM images, the morphology of the Copper sulphide powder get changes with increasing volumetric ratio of Cu/S. Mechanism of the CuS nanocrystal formation and phase transition is also discussed.