Mechanochemical synthesis, characterization and optical properties of zinc sulphide nanoparticles

Nanosized zinc sulphide (ZnS) was synthesized by the mechanochemical route using zinc acetate and sodium sulphide as source materials in a high energy planetary ball mill (Retsch PM 400/2) for 30-90 min at rotation speed of 300 rpm and vial rotation speed of 600 rpm with ball to powder ratio 5:1. The milled powder was washed with methanol to remove impurity and heat treated at 100-400 °C. ZnS nanoparticles then characterized by using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), UV-Vis-NIR spectrophotometer and fluorescence spectrophotometer. The crystallite size of the synthesized ZnS nanoparticles is found to be in 3-9 nm range. FESEM morphology shows the formation of nanostructure of ZnS samples. The value of optical band gap has been found to be in the range 3.87-4.66 eV. Room temperature photoluminescence spectrum of ZnS samples exhibit a blue emission peaked at 466 nm under UV excitation.