Turning “on” and “off” nucleation and growth: Microwave assisted synthesis of CdS clusters and nanoparticles

We report here on the formation of CdS NP from the microwave assisted reaction of Cd(CH3CO2)2 with dimethylsulfoxide (DMSO). DMSO serves as the solvent and a controlled source of sulfide ions to form (CdS)1≤n≤5 clusters at the early stages of the process. The clusters grow into CdS nanoparticles, with diameters that range from 1.6 nm up to over 250 nm, with microwave heating. The time dependence of the onset of light absorption and absorbance are consistent with a concurrent nucleation and growth processes. The formation of clusters and nuclei and their subsequent reactions is controlled by turning on and off the energy supply consistent with an energy barrier to the formation of CdS nanostructures.