In situ micelle-template-interface reaction route to CdS nanotubes and nanowires

CdS nanotubes and nanowires have been successfully synthesized via an in situ micelle-template-interface reaction (ISMTIR) route by adjusting the concentration of the surfactant. The whole reaction system is made up of SDS rod-like micelles as the template, CS2 as the oil phase and sulfur source, NH3 as the attacking agent and coordination-agent, and CdCl2 in water. It was found that SDS rod-like micelles were excellent templates for the growth of nanotubes and nanowires of small size. Due to a micelle diameter of 10-20 nm, the CdS nanotubes formed have an outer diameter of 15 nm on average and a wall thickness of ca. 5 nm, within the exciton diameter of bulk CdS. In particular, the formation of CdS nanowires was thought to occur by a "rolling-broken-growth'' (RBG) process, in which the micelles could not support the strain of the CdS produced rolling. Thus, the diameter of as-obtained CdS nanowires was ca. 5 nm, within the exciton diameter, too. The UV-vis absorption spectra show the as-obtained CdS nanotubes and nanowires are well quantum-confined. In the future, this method is expected to be used to prepare other metal sulfide nanotubes and nanowires.