ISSN: 2996-6701
Authors: SivaSankari J*, Nivethaa EAK and Naseeha EMH
ZnO nanoparticles were synthesized by co-precipitation with no capping agent followed by covering with ZnS using a solutionbased chemical method at low temperature. By varying the solution concentration, it was found that the fully-covering ZnS shell forms by a reaction of Na2S with ZnO NPs followed by the formation of ZnS nano-crystals by the reaction of Na2S with ZnCl2. The mechanism that led to full coverage of the ZnO core is proposed to be the addition of ZnCl2 at a later stage of the growth which guarantees a continuous supply of Zn ions to the core surface. Moreover, the ZnS nano- crystals that uniformly cover the ZnO NPs show no epitaxial relationship between the ZnO core and ZnS shell. The slow atomic mobility at the low reaction temperature is attributed to the non-epitaxial uniform ZnS shell growth. The rough surface of the ZnO grains provides initial nucleation positions for the growth of the ZnS shell nano-crystals. The low growth temperature also inhibits the abnormal growth of ZnS grains and results in the homogeneous coverage of ZnS nano-crystals on the ZnO core surface. The morphology and structure of samples are verified by X-ray diffraction (XRD). Identification of unknown substances and quantitative analysis can be done by FTIR. The absorption and reflectance of the nanoparticles were analyzed by UV Visible spectroscopy.
Keywords: ZnO @ZnS; Core Shell Nanoparticles; Microstrain; Pl; FTIR; Biological Application
