Fabrication of carbon nanotube based transparent conductive thin films using layer-by-layer technology

This paper presents a simple and convenient process for the fabrication of carbon nanotube based optically transparent and electrically conductive thin films. Single-walled carbon nanotubes (SWNTs) are chemically treated to introduce negatively charged carboxylic groups on their surfaces, so that a stable SWNT aqueous dispersion can be obtained without any surfactant. The substrate surface is modified by a layer-by-layer nanoassembly technique, in which a positively charged hydrophilic polymer molecular layer is formed on the top of the substrate. This helps the SWNT dispersion to be cast onto the substrate using convenient wet coating techniques and increases the bonding force between the thin films and the substrates. Using the developed process, large sizes of conductive pure SWNT thin films that are uniform and highly transparent have been fabricated. (c) 2007 Elsevier B.V. All rights reserved.