Langmuir-Blodgett assembly of densely aligned single-walled carbon nanotubes from bulk materials

Abstract

Single-walled carbon nanotubes (SWNTs) exhibit advanced electrical and surface properties useful for high performance nanoelectronics. Important to future manufacturing of nanotube circuits is a large-scale assembly of SWNTs into aligned forms. Despite progress in assembly and oriented synthesis, pristine SWNTs in aligned and close-packed form remain elusive and needed for high-current, -speed, and -density devices through collective operations of parallel SWNTs. Here, we develop a Langmuir-Blodgett (LB) method achieving monolayers of aligned SWNTs with dense packing, central to which is a noncovalent polymer functionalization by poly(m-phenylenevinylene-co-2,5-dioctoxy-p-phenylenevinylene) (PmPV) imparting high solubility and stability of SWNTs in an organic solvent 1,2-dichloroethane (DCE). Pressure cycling or "annealing" during LB film compression reduces hysteresis and facilitates high-degree alignment and packing of SWNTs characterized by microscopy and polarized Raman spectroscopy. The monolayer SWNTs are readily patterned for device integration by microfabrication, enabling the highest currents (∼3mA) through the narrowest regions packed with aligned SWNTs thus far. Copyright © 2007 American Chemical Society.