UC Berkeley

Colloidal metal nanowire based transparent conductors are excellent candidates to replace indium-tin-oxide (ITO) owing to their outstanding balance between transparency and conductivity, flexibility, and solution-processability. Copper stands out as a promising material candidate due to its high intrinsic conductivity and earth abundance. Here, we report a new synthetic approach, using tris(trimethylsilyl)silane as a mild reducing reagent, for synthesizing high-quality, ultrathin, and monodispersed copper nanowires, with an average diameter of 17.5 nm and a mean length of 17 μm. A study of the growth mechanism using high-resolution transmission electron microscopy reveals that the copper nanowires adopt a five-fold twinned structure and evolve from decahedral nanoseeds. Fabricated transparent conducting films exhibit excellent transparency and conductivity. An additional advantage of our nanowire transparent conductors is highlighted through reduced optical haze factors (forward light scattering) due to the small nanowire diameter.