Mechano-chemical synthesis and optical properties of ZnS nanoparticles

In the present work, we report the synthesis and optical properties of ZnS nanoparticles produced by the mechano-chemical route. We used zinc acetate and sodium sulphide as source materials in a high energy planetary ball mill at rotation speed of 300 rpm and vial rotation speed of 600 rpm with ball to powder (BPR or charge ratio CR) 5:1 for 30 and 90 min. The milled powders were washed with methanol to remove impurity and dried at 300 °C for 1 h. The prepared nanoparticles have been characterized using X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), UV–vis–NIR spectrophotometer and Fluorescence spectroscopy. The crystallite size of the synthesized ZnS nanoparticles is found to be in the range 7–8 nm which was calculated using Debye–Scherer's formula. The value of optical band gap has been found to be in the range 3.80–4.15 eV. Room temperature photoluminescence (PL) spectrum of ZnS samples exhibit a blue emission peaked at 466 nm under UV excitation.