Facile synthesis of water-soluble ZnS quantum dots with strong luminescent emission and biocompatibility

ZnS quantum dots (QDs) are among the most promising emerging fluorescent materials for biolabeling. High-quality colloidal ZnS QDs were synthesized via a new facile chemical precipitation method using the mixture of ethylene glycol (EG) and water as the solvent. The phase structure and morphology of the ZnS QDs were characterized by X-ray powder diffraction and high resolution transmission electron microscopy. The synthesized ZnS QDs have a cubic zinc blende structure with monodispered and small particles. ZnS QDs easily dispersed in water to form stable and clear colloids and the strong tunable trap state emissions from 452 to 516 nm were achieved by varying the reaction time. The hemolysis assay was performed to evaluate the biocompatibility of the ZnS QDs.