Room-temperature synthesis and characterization of nanocrystalline CdS, ZnS, and CdxZn1-xS

A novel and simple chemical reduction route at room temperature is described to synthesize nanocrystalline CdS, ZnS, and CdxZn1-xS. In the method, anhydrous CdCl2, or ZnCl2, S, and KBH4 powders react at room temperature in various organic solvents, and the effect of the solvent on the quality of the nanoparticle product is investigated. Among the solvents used, tetrahydrofuran is shown to produce the highest quality single-phase nanoparticles. The nanoparticles are characterized by X-ray diffraction, transmission electron microscopy, UV-vis absorption, and photoluminescence. The particle size ranges from 4 to 8 nm. In the CdxZn1-xS, the lattice structure gradually changes from cubic to hexagonal with increasing percentage of Zn in the ternary compound CdxZn1-xS. The nanoparticles exhibit broad emission peaks that shift. to shorter wavelength with increasing percentage of Zn in the ternary compound CdxZn1-xS. The control of the composition of CdxZn1-xS nanoparticles may lead to the development of ideal materials for short wavelength diode laser applications.