Aqueous-synthesis of CuInS2 core and CuInS2/ZnS core/shell quantum dots and their optical properties

The water-soluble CuInS2 quantum dots (CIS QDs) have been successfully synthesized by a one-pot aqueous-phase synthesis method using indium chloride and copper chloride as reactants. The type-I structure CIS/ZnS core/shell QDs were synthesized in situ for surface passivation, which led to a dramatic enhancement of fluorescence intensity. The CIS/ZnS QDs exhibited a tunable emission in the range of 500-680 nm by changing the ratio of Cu:In without the variation of size. And the corresponding fluorescent color changed from green to red. The QDs with uniform diameter could be assigned to a typical chalcopyrite structure according to XRD analysis. The as-prepared CIS/ZnS QDs have a good potential to be applied in biomedical fluorescence label and probes due to their low toxicity and excellent optical features.