One-pot synthesis of ZnxCd1-xS nanocrystals with tunable optical properties from molecular precursors

We have reported a non-injection one-pot synthesis of the alloyed ZnxCd1-xS semiconductor nanocrystals (SNCs) with controlled shapes and compositions. This non-injection approach involves heating two molecular precursors (cadmium ethylxanthate and zinc ethylxanthate) as metal and S sources in organic solvents at 320 degrees C for 30 min, which results in the thermal decompositions of the molecular precursors to produce ZnxCd1-xS. The effects of solvents and compositions on the shapes and structures of ZnxCd1-xS SNCs have been investigated. The mixture solvent containing oleic acid, paraffin oil and oleylamine (such as a volume ratio: 1/2/1) results in the preparation of uniform ZnxCd1-xS nanoparticles with diameters of 7-13 nm, while pure oleylamine or the mixture of oleylamine and paraffin oil as the solvent leads to the formation of uniform ZnxCd1-xS nanorods. Monodisperse wurtzite ZnxCd1-xS nanorods with different compositions have been prepared in pure oleylamine, and no obvious effects of the compositions on their shapes are found. Their alloying nature is consistently confirmed by the results of high-resolution transmission electron microscopy (HRTEM). X-ray diffraction (XRD) and optical measurements. These alloyed ZnxCd1-xS nanorods exhibit composition-dependent absorption and emission properties, and therefore they can be promising candidates as emitting materials. (C) 2010 Elsevier B.V. All rights reserved.