Synthesis and Characterization of Large-Scale Hierarchical Dendrites of Single-Crystal CdS

Large-scale hierarchical CdS dendrites were synthesized by hydrothermal treatment of CdCl 2 and thiourea, using poly(ethylene glycol) (PEG) as a capping agent. The products were characterized by X-ray diffraction, energy-dispersive X-ray spectrometry, transmission electron microscopy, field emission scanning electron microscopy, and selected area electronic diffraction. The individual CdS dendrite is composed of a long central trunk with secondary and tertiary branches, which preferentially grew in a parallel direction with a definite angle to the trunk. The results reveal that the dendrites are single crystalline in nature. The contrast experiments demonstrated that both thiourea and the additive PEG are necessary for building hierarchically self-assembled CdS dendrites in a water system. Moreover, the possible growth process has been discussed based on the analyses of detailed configuration and the effects of surfactants in the system.