Effect of plasma-nitric acid treatment on the electrical conductivity of flexible transparent conductive films

A flexible transparent electrically conductive film (FTCF) was formed on a poly(ethylene terephthalate) film by spraying single-walled carbon nanotubes dispersed with sodium dodecyl benzene sulfonate in water and, to improve the electrical conductivity of FTCF, the effect on plasma treatment followed by nitric acid treatment was investigated. The Ar plasma treatment was effective in dissociating the surfactant and removing impurities attached to the surface of the carbon nanotubes (CNTs). Therefore, through a cyclic treatment composed of an Ar plasma treatment and nitric acid treatment, more effective removal of surfactant and impurities attached to the spray-coated CNTs could be obtained than a cyclic treatment without the plasma treatment. With the optimized cyclic treatment, the sheet resistance (s) of the spray-coated CNTs could be decreased up to 45% by removing most of the surfactant and impurities. Using the repeated cyclic treatment, the FTCF having the of 160/at 81.5% optical transmittance at the wavelength of 550nm could be obtained.