Effect of Au Doping and Defects on the Conductivity of Single-Walled Carbon Nanotube Transparent Conducting Network Films

Abstract

We examined the electrical conductivity and transmittance of six types of SWNT network films, developed for potential use in transparent conductive films, to investigate the effect of Au doping on single-walled carbon nanotube (SWNT) defects: (i) SWNT network films without Au doping (as-produced (AP-SWNTs), purified (P-SWNTs), and cut (C-SWNTs)) and (ii) Au-doped films of AP-SWNTs (Au/AP SWNTs), P-SWNTs (Au/P-SWNTs), and C-SWNTs (Au/C-SWNTs). The density of SWNT network films was varied systematically by controlling the SWNT concentration and mediating defect formation. The electrical conductivity of each SWNT film was found to be significantly enhanced upon Au doping, with a negligible loss of optical transmittance. The effects of Au doping differed depending on the type of nanotube network present: the electrical conductivity of Au/C-SWNTs was found to be similar to that of Au/AP-SWNTs for a given transmittance, whereas the conductivity of C-SWNTs is much lower than that of the AP-SWNTs prior to Au doping. Therefore, the electrical conductivity was enhanced by the hybridization of gold nanoparticles to a larger degree in the defect-containing SWNT networks than in the AP-SWNT networks. This unusual electrical behavior of SWNT network films may be attributed to an increased number of gold nanoparticles deposited onto C-SWNT surfaces, which are formed from C-SWNTs containing an abundance of carboxylic groups. These results highlight an important consideration in the fabrication of efficient transparent conducting SWNT films for applications in optoelectronic devices.

Highly Doped Carbon Nanotubes with Gold Nanoparticles and Their Influence on Electrical Conductivity and Thermopower of Nanocomposites

“…This causes nanotubes to donate electrons to gold, thereby increasing hole carrier concentrations [23], [24]. The work functions of SWCNTs (4.5∼5.0 eV) [25], [26] and MWCNTs (4.3∼4.95 eV) [25], [27] are also smaller than that of gold (5.1∼5.47 eV [28], [29]), making electrons transferred from nanotubes to gold nanoparticles.…”

Interactions of Gold Nanoparticles with the Interior of Hollow Graphitized Carbon Nanofibers

“…In this study, we investigate the interactions of small gold NPs with the internal surface of GNFs and report the first example of an ordered arrangement of preformed NPs inside carbon nanostructures. Gold nanoparticles adsorbed on carbon nanostructures have been employed for a wide variety of applications, specifically in catalytic,25, 26 electronic,27, 28 and photonic devices;29 however, due to the lack of reported methods for the selective confinement of gold NPs in carbon nanostructures, the potential applicability of these novel materials in such devices has yet to be appraised. Our fundamental study reported here may soon make this a possibility.…”

Carbon nanotube based transparent conductive films: progress, challenges, and perspectives

“…Two examples for fabricating CNT-based TCFs: (b) vacuum filtration and alumina membrane transfer to make CNT films (reprinted with permission from [80] Copyright 2010 American Chemical Society); and (c) spray coating and post treatments of CNT films (reprinted with permission from [101], copyright 2010 Royal Society of Chemistry. )…”