Continuous and Scalable Fabrication of Transparent Conducting Carbon Nanotube Films

We report an industrially scalable, fast, and simple process for the large scale fabrication of optically transparent and electrically conducting thin films of single-walled carbon nanotubes (SWNT). Purified, pristine HiPco SWNTs were dispersed in water at high concentrations with the help of surfactants, rod-coated into uniform thin films, and doped by various acids. We show how to combine different surfactants to make uniform dispersions with high concentration of SWNTs and optimal rheological behavior for coating and drying, including preventing dewetting and film rupture that has plagued earlier attempts. Doping by fuming sulfuric acid yielded the films with best performance (sheet resistance of 100 and 300 Ω/sq for respective transparency of 70% and 90%). We use a figure of merit (FOM) plot for an immediate evaluation and comparison of the performance and microstructure of CNT films produced by different methods. Further scientific engineering will pave the way to the deployment of CNT films in commercial applications.