Chemical and electrochemical routes to DNA-templated rhodium nanowires

Abstract

Two methods for the preparation of rhodium nanowires are described: (i) electroless metal deposition at duplex DNA 'template' molecules in bulk solution and (ii) electrochemical reduction in DNA-containing solution at a modified electrode. Both methods render essentially similar 1D nanostructures with a Rh/Rh-oxide core-shell structure. AFM studies revealed the resulting nanostructures are typically <10 nm in diameter with continuous and smooth metal coatings. However, the latter method was less effective with samples containing an ∼3-fold increase in the bare template DNA remaining. A combination of SPM methods demonstrated the structures to be electrically conducting, hence confirming their nanowire nature. The conductivity was, however, several orders of magnitude lower than that of bulk Rh; a fact attributed to the presence of resistance-increasing mechanisms, such as grain boundaries present in the Rh coatings and electron surface scattering.