Solution assembly of organized carbon nanotube networks for thin-film transistors

Ultrathin, transparent electronic materials consisting of solution-assembled nanomaterials that are directly integrated as thin-film transistors or conductive sheets may enable many new device structures. Applications ranging from disposable autonomous sensors to flexible, large-area displays and solar cells can dramatically expand the electronics market. With a practical, reliable method for controlling their electronic properties through solution assembly, submonolayer films of aligned single-walled carbon nanotubes (SWNTs) may provide a promising alternative for large-area, flexible electronics. Here, we report SWNT network TFTs (SWNTntTFTs) deposited from solution with controllable topology, on/off ratios averaging greater than 10(5), and an apparent mobility averaging 2 cm(2)/V.s, without any pre- or postprocessing steps. We employ a spin-assembly technique that results in chirality enrichment along with tunable alignment and density of the SWNTs by balancing the hydrodynamic force (spin rate) with the surface interaction force controlled by a chemically functionalized interface. This directed nanoscale assembly results in enriched semiconducting nanotubes yielding excellent TFT characteristics, which is corroborated with mu-Raman spectroscopy. Importantly, insight into the electronic properties of these SWNT networks as a function of topology is obtained.