Investigation of structural, optical and photoluminescence properties of the sol-gel synthesized powder ZnS nanoparticles

Zinc sulphide (ZnS) nanoparticles have been synthesized by using chemical route especially by sol-gel technique and are calcined at different temperatures at 150 degrees C, 200 degrees C and 250 degrees C. The calcined nanoparticles have been analyzed by several analytical and spectroscopic techniques such as, X-ray diffraction, transmission electron microscopy, optical absorption spectroscopy, Fourier-transform infrared spectroscopy and photoluminescence spectroscopy. The crystallite sizes of the nanoparticles in the range of 4-8 nm have been obtained from X-ray diffraction analysis. These are also justified by the transmission electron microscopic analysis, and supported by Williamson-Hall (W-H) analysis. From W-H analysis, it is found that the lattice strain is inversely proportional to particle sizes which are increased with calcined temperatures. The optical absorption study revealed that the value of optical band gap has been found to be in the range 3.76-3.13 eV. Photoluminescence spectra revealed that there might have zinc and sulphur vacancies related with green emission spectra around 550 nm wavelength. The results justified the possibility of tailoring the characteristic of zinc sulphide nanoparticles for various technological aspects.