Highly conductive and transparent single-walled carbon nanotube thin films fabricated by gel coating

Abstract

Transparent and conductive single-walled carbon nanotube (SWCNT) films were fabricated through gel coating. A gel was formed by directly dispersing a large amount of SWCNTs in a liquid nonionic surfactant like polyoxyethylene (12) tridecyl ether without a solvent by mechanical grinding and subsequent ultrasonication. SWCNT films were obtained by coating the gels on glass substrates and subsequently removing the surfactant through heating. The SWCNT films became very thin and transparent after heating at a temperature between 480 and 520 °C. They exhibited good uniformity and a high transmittance-to-sheet resistance ratio which is attributed to the long SWCNTs dispersed in the gels. Films with a sheet resistance of around 250 Ω □⁻¹ at 80% transmittance were obtained. The films can be easily transferred from rigid substrates like glass to flexible polymer substrates like polyethylene terephthalate.