Processing and Doping of Carbon Nanotube Network Transistors on Polymer Substrates

Networks of polymer-sorted, purely semiconducting single-walled carbon nanotubes (SWCNTs) that can be processed from dispersion in organic solvents by various printing techniques have become a competitive semiconducting material with high electron and hole mobilities while also being intrinsically stretchable and flexible. However, reproducible network formation and reliable p- and n-doping to create complementary and low-voltage circuits on a larger scale are still challenging. Here, we introduce a method for improved stabilization of nanotube inks without excess polymer using the molecular additive 1,10-phenanthroline for the reproducible deposition of highly uniform SWCNT networks for field-effect transistors. The successful n-doping of semiconducting nanotubes with different diameters to create purely n-type transistors with excellent on/off ratios will be discussed together with the application of self-assembled monolayers of alkyl phosphonic acids as dielectrics for low-voltage SWCNT-based circuits on thin polyimide substrates.