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

Abstract

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.