Silver tip formation on colloidal CdSe nanorods by a facile phase transfer protocol

A facile phase transfer procedure is described for the formation of uniform silver metal tips on II-VI semiconductor nanorods. Judicious choice of a functional ligand dimethyl phenol (DMP) which binds to the semiconductor rod in the organic phase enables the transfer of metal ions from the aqueous phase and their reduction onto the nanorod. The metal tips initially form as random sub <2 nm particles surrounding the nanorod which ripen to dual tips at the nanorod ends. The nanorod hybrids can be assembled into perpendicularly aligned arrays by simple solvent evaporation. The hybrid nanostructures are characterised by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), photoluminescence (PL), ultraviolet-visible spectroscopy (UV-Vis) and X-ray photoelectron spectroscopy (XPS). A detailed FTIR analysis is also carried out to predict the role of the ligands in the tipping procedure.