Aqueous synthesis of luminescent magic sized CdSe nanoclusters

Highly stable water-soluble CdSe nanoclusters (NCs) with magic size were successfully synthesized using homocysteine (HCY) as capping ligands. Their sizes were tunable between 1.2 and 2.0 nm depending on reflux time. The final products were characterized by UV-vis absorption, steady and time-resolved photoluminescence (PL) spectra, X-ray powder diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). XRD analysis showed that the HCY-capped CdSe NCs were of the cubic structure, UV-vis absorption spectra and HRTEM micrograph exhibited that the NCs were nearly monodisperse and relatively uniform. The as-prepared CdSe NCs had a PL quantum yield of up to 1.4%, almost comparable to the CdSe magic sized clusters prepared by an organometallic route. (C) 2007 Elsevier B.V. All rights reserved.