2008 Nanowire conductive polymer gas sensor patterned using self-assembled block copolymer lithography

Nanostructured conjugated organic thin films are essential building blocks for highly integrated organic devices. We demonstrate the large-area fabrication of an array of well-ordered 15 nm wide conducting polymer nanowires by using an etch mask consisting of self-assembled patterns of cylinder-forming poly(styrene-b-dimethylsiloxane) diblock copolymer confined in topographic templates. The poly(3,4-ethylenedi-oxythiophene):poly(styrenesulfonate) nanowires operated as an ethanol vapor sensor, suggesting that the electronic properties of the organic film were preserved during the patterning processes. The higher sensitivity to ethanol vapor, compared to an unpatterned film with the same thickness, was attributed to the enhanced surface-to-volume ratio of the nanowire array. A molecular rectifier, theoretically proposed by Ratner and Aviram in 1974, was the starting point for a boom in molecular electronics research that has persisted for the last three decades.1 Later, single-molecule field-effect transistors and logic gates were also conceptually proposed,2 and Reed et al. first reported single-molecule conductance measure-ments through benzene-1,4-dithiol.3 The development of conductive polymers has continued to attract interest fo