Seed concentration control of metal nanowire diameter.

Gold/silver nanowires (NWs) of controlled diameters were synthesized from catalytic metal seed particles at the substrate/solution interface. Small seed nanoparticles of three different sizes: ~1 nm (11 gold atoms), ~1.4 nm (~55 gold atoms), and homemade nanoparticles of ~2 nm were used. By varying a single type of seed particle concentration in the growth solution, the NW diameters and morphology could be controlled, between bundles of ultrathin NWs of ~2-3 nm diameter to thicker isolated single NWs with a mean diameter of ~16 nm. In addition, the catalytic reduction rate leading to NW growth was found to be seed size dependent at small seed sizes (<2 nm). The two types of metallic NW films were tested for their performance as transparent electrodes after additional metal deposition for their stabilization and conductivity enhancement. The thin NW bundles exhibit superior transparent conductor properties.