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

Abstract

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.