title: Sorting carbon nanotubes by electronic structure using density differentiation.
abstract: The heterogeneity of as-synthesized single-walled carbon nanotubes (SWNTs) precludes their widespread application in electronics, optics and sensing. We report on the sorting of carbon nanotubes by diameter, bandgap and electronic type using structure-discriminating surfactants to engineer subtle differences in their buoyant densities. Using the scalable technique of density-gradient ultracentrifugation, we have isolated narrow distributions of SWNTs in which >97% are within a 0.02-nm-diameter range. Furthermore, using competing mixtures of surfactants, we have produced bulk quantities of SWNTs of predominantly a single electronic type. These materials were used to fabricate thin-film electrical devices of networked SWNTs characterized by either metallic or semiconducting behaviour.
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208-3108, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Arnold
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Green
authors.forename: James F
authors.initials: JF
authors.lastname: Hulvat
authors.forename: Samuel I
authors.initials: SI
authors.lastname: Stupp
authors.forename: Mark C
authors.initials: MC
authors.lastname: Hersam
mesh_terms: D004581:Electronics / Q000295:instrumentation*; D004867:Equipment Design; D008422:Materials Testing; D008670:Metals / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation*; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure*; D012666:Semiconductors
chemical_list: D008670:Metals; D037742:Nanotubes, Carbon