Sonochemical synthesis and measurement of optical properties of zinc sulfide quantum dots

A facile sonochemical method has been developed to prepare very small zinc sulfide nanoparticles (ZnS NPs) of extremely small size about 1 nm in diameter using a set of ionic liquids based on the bis (trifluoromethylsulfonyl) imide anion and different cations of 1-alkyl-3-methyl-imidazolium. The structural features and optical properties of the NPs were determined in depth with X-ray powder diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS) analysis, and UV–vis absorption spectroscopy. The energy band gap measurements of ZnS NPs were calculated by UV–vis absorption spectroscopy. One of the interesting features of the present work is that the wide band gap semiconductor ZnS nanocrystals were prepared which are used in the fabrication of photonic devices.

► Wide band gap ZnS NPs were prepared which can be used in the photonic devices.
► Ionic liquids based on the imidazolium cation were used for the synthesis of ZnS NPs.
► The method is found to be convenient and environmentally friendly.
► No surfactant was used in the synthesis of ZnS NPs.