Aqueous phase synthesis of biostabilizer capped CdS nanocrystals with bright emission

In this manuscript, we present a facile approach for the synthesis of highly luminescent CdS nanocrystals (maximum quantum yield of 36%) by the reaction of Cd2+ and thiourea in the presence of glutathione (GSH) as capping reagent. The influence of various experimental variables, including pH value, S-to-Cd ratio, as well as Cd-to-ligand ratio, on the growth rate and optical properties of the obtained CdS nanocrystals has been systematically investigated. Experimental results indicate that the pH value and Cd-to-ligand molar ratio play a crucial role in determining luminescent properties of the obtained CdS nanocrystals. Furthermore, the luminescence intensity can be enhanced significantly when the nanocrystals sample is illuminated by room light. The mechanism for the resulting high-quality optical properties of the obtained CdS nanocrystals is also elucidated.