Optimisation of carbon nanotube ink for large-area transparent conducting films fabricated by controllable rod-coating method

Single-walled carbon nanotubes (SWCNTs) were dispersed in water with the help of surfactants to achieve high concentration SWCNT ink. SWCNT transparent conducting films (TCFs) were fabricated by rod coating using the SWCNT ink. A combination of two surfactants provided optimal rheological behaviour, which produced uniform films by preventing dewetting and rupture of SWCNTs during drying. The combination led to a dramatic increase of shear viscosities but no change of their wettability. The viscosity of SWCNT ink was controlled by the ratio of two surfactants. The thickness of SWCNT films could be easily varied by controlling both the concentration of SWCNT ink and the size of the wire-wound rod. The produced uniform SWCNT-TCFs treated by nitric acid have a relatively low sheet resistance of ∼80 Ω sq−1 at 80% transmittance. The performance has a wide range of applied interest for touch screen and flexible electronics.