Thiol-stabilized CdSe and CdTe nanocrystals in the size quantization regime: Synthesis,optical and structural properties

We report on the recently developed method for the synthesis, optical, and structural properties of CdSe and CdTe nanocrystals. They were formed in aqueous solutions at moderate temperatures by a wet chemical route in the presence of thiol molecules as effective stabilizing agents. The size-selective precipitation technique was applied for the post-preparative nanoparticle fractionation into a series of CdSe and CdTe nanocrystals with extremely narrow size distributions exhibiting mean cluster sizes in the range of 2 to 4 nm. The nature of stabilizing agent (mercaptoalcohols and mercaptoacids) had an important influence on the particle size and determines largely the photoluminescence properties. The nanocrystals were characterized by means of UV-vis absorption and photoluminescence spectroscopy, X-ray diffraction, and high resolution transmission electron microscopy (HRTEM).