Facile aqueous synthesis of ZnInS quantum dots and its application for selective detection of Co2+ Ions

The synthesis of ZnInS (ZIS) quantum dots (QDs) in aqueous medium using thioglycolic acid (TGA) and sodium citrate as dual capping agents has been reported. The as-synthesized ZIS QDs were water soluble, emitting at 512 nm and nearly spherical in shape with average particle size of 8.9 +/- 1.4 nm. The as-synthesized ZIS QDs were tested for its fluorescence response against different metal ions and the results revealed that ZIS QDs were selectively quenched by Co2+ ions compared to other ions. The fluorescence sensing experiment showed that ZIS QDs has a linear response against the concentration of Co2+ ions (0.1-100 mu M ) with the detection limit of 0.099 mu M. Based on the transmission electron microscope and absorption spectroscopy analyzes, the fluorescence quenching is attributed to the formation of surface ligand-metal complex (TGA-Co2+ ions) which caused aggregation of the QDs. The present method explores the synthesis of zero-dimentional ZIS QDs and its potential in the selective detection of Co2+ ions in aqueous solution.

Automated summary

This study reported the synthesis of ZnInS (ZIS) quantum dots using thioglycolic acid and sodium citrate as dual capping agents, which showed selective quenching of fluorescence response to Co2+ ions. The findings suggest the potential of ZIS QDs in selective detection of Co2+ ions in aqueous solution.