Simple preparation and characteristics for transparent, conductive thin films of carbon nanotubes

We report a simple process for the fabrication of transparent, electrically conductive thin films of purified single-walled carbon nanotubes (CNTs) on various substrates. CNTs dispersed in a deionized water solution made of 0.5 wt% Triton surfactant and small quantities of gelatin as a spreader was sprayed by using an airbrush onto various substrates, including glass, polycarbonate, and polyester. The as-prepared 100-nm film had a transmittance of nearly 90 % over a wide invisible spectra range, and the sheet resistance of the as-prepared 300-nm films was measured to be about 600 Omega/square. A further improvement in the sheet resistance of the nanotube film was achieved using vacuum-annealed nanotubes during a purification step. Differing from the normal filtration method using mixed cellulose ester filter membranes, our process is adaptable and simpler due to its not using organic solvents such as acetone. In addition, our single-walled carbon nanotube film is more appropriate for flexible displays due to its having a high mechanical strength compared with brittle oxide thin films.