Effect of biocompatible glutathione capping on core–shell ZnS quantum dots

Glutathione capped quantum dots are a potential candidate for different applications like ligand exchange in living cells, cell imaging and detection of glucose levels. Keeping these in mind, glutathione capped ZnS quantum dots were synthesized by using the thiol group of the capping agent by chemical precipitation method. Morphological characterizations were done by XRD and TEM. X-ray diffraction (XRD) measurements showed that the nanocrystals have Zinc Blende structure. Grain size and particle size shows a little variation with glutathione capping. Optical characterizations were done by UV–visible absorption, FTIR and energy resolved photoluminescence. UV–visible studies shows that the band gap also shows a small variation with glutathione capping. FTIR studies confirm glutathione capping on the surface of ZnS quantum dots. Room temperature energy resolved photoluminescence spectrum of samples exhibited a defect-related blue emission band. However, the PL properties seem to start tunability at higher concentration of glutathione which is a very good sign for extending this research further.