Effects of types of anions and cosurfactants on ZnS nanoparticles synthesis in microemulsion

Abstract

Now, much attention has been paid to synthesis of group II-VI semiconductor materials due to their excellent properties in catalysis, optical and magnetic functionality, and so on. There are many methodologies available for synthesizing ZnS nanocrystals, however, water-in-oil (w/o) microemulsions technique is one of the most recognized one due to its several advantages, for instance, soft chemistry, demanding no extreme pressure or temperature control, easy to handle, and requiring no special or expensive equipment. In this research, the effects of types of cosurfactants, the molar ratio of water to surfactant, reactant, types of anions and temperature are investigated. From the experimental results, it could be clearly shown that the size and the morphology of the ZnS nanoparticles are dependent upon these parameters. With relatively high reactant concentration and w₀, some certain amount of ZaS nanorod and nanotubes could be successfully synthesized. Moreover, microemulsion with larger molecule of cosurfactant could provide higher possibility to synthesize these morphologies of the nanoparticles. When adding anions such as CI or Br into the microemulsion, the higher population of ZnS nanorods and nanoneedles were obtained, especially when employing n-butanol as a cosurfactant. Moreover, the reaction temperature can greatly effect on the morphology and size of the resulting nanoparticles. The interesting morphologies of ZnS nanoparticles were obtained such as nanotubes and nanowires with very small diameter.