Multistep Deposition of Gold Nanoparticles on Single-Walled Carbon Nanotubes for High-Performance Transparent Conducting Films

We report a dual-coating method for the deposition of gold nanoparticles on single-walled carbon nanotubes (SWNTs) to improve the electrical conductivities of SWNT network films. The deposition is achieved via a two-step process: (i) pretreatment, mixing gold precursor (HAuCl4 center dot 3H(2)O) with a dispersion of SWNTs containing sodium cholate or sodium dodecyl sulfate surfactants, and (ii) post-treatment, immersion of SWNT network films functionalized with gold ions (Au3+) in a gold salt solution. SWNT films doubly hybridized with gold nanoparticles exhibited a 20% reduced sheet resistance in comparison with SWNT films that were post-treated with Au alone. Optical spectroscopy and UPS results show that such enhanced electrical properties can be attributed to additional p-type doping of the SWNTs upon treatment with gold. These results are important for the development of efficient transparent conducting SWNT films for optoelectronic device applications.