Facile synthesis and photoluminescence properties of water-soluble CdTe/CdS core/shell quantum dots

A facile route to water-soluble CdTe/CdS core/shell quantum dots (QDs) under mild conditions has been developed. The CdTe/CdS core/shell QDs were prepared in alkaline aqueous solution at 50°C under atmospheric pressure, using Cd(CH₃COO)₂·2H₂O and TeO₂ as starting materials, 3-mercaptopropionic acid as the source of sulphur and a stabiliser as well, and KBH₄ as a reductant. The samples were characterised by means of transmission electron microscopy, ultraviolet-visible (UV-vis) absorption spectroscopy and photoluminescence (PL) spectroscopy, respectively. The results show that the diameters of the QDs are increasing with the increasing reaction time, and that UV-vis absorption onsets and PL emission peak of the QDs both have an obvious red shift. The PL property of the QDs can be controlled by adjusting the reaction time. The growth mechanism of the CdTe/CdS core/shell QDs was proposed.