Effect of solvent medium on the structural, morphological and optical properties of ZnS nanoparticles synthesized by solvothermal route

• ZnS was prepared at low temperature using solvothermal method.
• The phase transformation and shape evolution processes were studied.
• The role of solvent (EN/W) has been discussed for formation of ZnS nanostructures with different morphology.
• The properties and growth mechanism of ZnS nanoparticles were investigated.
• Optical band gap of ZnS powder were investigated using UV vis spectroscopy.

Different morphologies of ZnS have been synthesized by a facile solvothermal approach in a mixed solvent made of Ethylenediamine (EN) and distilled water. The effect of solvent medium on the structural, morphological and optical properties of ZnS nanoparticles were investigated. The formation mechanism of different morphologies was proposed based on the experiment results. The as-prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectrometer (EDS), Raman spectroscopy and UV-Vis-IR spectrophotometer. The results show that phase transformation is easily induced and there is a strong correlation between morphology and structure of the ZnS nanocrystals by changing the solvent. The results also show that we have successfully produced hexagonal phase ZnS nanorods with mixed solvent. The grain sizes in the range of 17–22 nm were obtained according to elaboration conditions. Raman spectra show the intense peak at 346 cm−1, which is a typical Raman peak of bulk ZnS crystal, no signature of secondary phases. The band gap of ZnS increased from 3.49 to 3.74 eV with an increase in the EN composition in the solvent, implying that the optical properties of these materials are clearly affected by the synthesis medium.