High-quality and water-soluble near-infrared photolumineseent CdHgTe/CdS quantum dots prepared by adjusting size and composition

In this article, near-infrared (NIR) CdHgTe alloyed quantum dots (QDs) were directly synthesized in water by heating a mixed solution of CdCb, Hg(ClO4)(2) and NaHTe in the presence of thiol stabilizers. The CdHgTe QDs exhibit photoluminescence (PL) ranging from 600 to 830 nm that can be tuned by size and composition. The quantum yields (QYs) of QDs were about 20-50%, associated with their emission wavelength and composition. Compared to other reported NIR QDs such as CdTe/CdHgTe and InAs, the as-prepared CdHgTe alloyed QDs have much narrower emission spectra, and their full widths at half-maximum (fwhm) are only 60-80 nm. Characterization by HRTEM and XRD showed that the CdHgTe QDs have good monodispersity and a nice crystal structure. To improve the photostability and reduce the cytotoxity of the CdHgTe QDs, a CdS nanocrystal shell was added to the surface of the CdHgTe QD core. Furthermore, the CdHgTe/CdS core/shell QDs were successfully applied for the imaging of living animals. Our preliminary results illustrate that our synthesis procedure is very simple and inexpensive and that the as-prepared products CdHgTe/CdS core/shell QDs are water-soluble and photostable and will be an alternative probe in the imaging of living animals.