Percolation in Transparent and Conducting Carbon Nanotube Networks

Ultrathin, uniform single-walled carbon nanotube networks of varying densities have been fabricated at room temperature by a vacuum filtration method. Measurements of the sheet conductance as a function of nanotube network density show 2D percolation behavior. In addition, the network transparency in the visible spectral range was examined and the results are in agreement with a standard thin-film model: fits to the standard theory indicate σac = σdc for transmission measurements at 550 nm. Transmission measurements also indicate the usefulness of nanotube network films as a transparent, conductive coating. Avenues for improvement of the network conductance are discussed.