Shape controlled synthesis of CdS nanostructures in tungstosilicate acid solution by a novel approach

In this study, we attempt to combine gas diffusion and hydrothermal method for the synthesis of cadmium sulfide (CdS) assemblies with keggin type tungstosilicate acid (TSA) as scaffold. It is found that slow diffusion rate of H2S gas leads to a flowerlike morphology and fast diffusion rate leans to a spherical morphology. The evolution of CdS microsphere to flowerlike structure can be modulated by tuning the diffusion rate of H2S gas, which is dominated by the reaction temperature. A possible mechanism for the evolution is proposed that slow diffusion rate of H2S gas favors the diffusion controlled growth, and fast diffusion rate promotes a reaction controlled growth. The optical properties of the flowerlike CdS assemblies in the temperature range of 35–300 K were studied.