Enhanced Electrical Conductivities of Transparent Double-Walled Carbon Nanotube Network Films by Post-treatment

We investigated the electrical conductivities of double-walled carbon nanotube (DWNT) network films upon post-treatment via HNO3 or gold ions, particularly with respect to their potential use as transparent conducting films. Post-treatment of DWNT films with HNO3 and deposition of gold nanoparticles, respectively, resulted in a significant decrease of the electrical resistance, while the initial value of the transmittance of pristine-DWNT films was maintained. The DWNT-Au nanoparticle hybrid films exhibited the best transmittance-conductivity performance among the evaluated network films, i.e., pristine-SWNT films, pristine-DWNT films, SWNT-Au nanoparticle hybrid films, and HNO3-treated DWNT films. The electrical behaviors of the gold nanoparticle-coated and HNO3-treated DWNT films were examined by an analysis of the work functions of the DWNT films. The DWNT-Au nanoparticle hybrid films are expected to be applicable to transparent electrodes of various optoelectronic devices such as solar cells, light-emitting diodes, sensors, and field-effect transistors.