title: Band gap fluorescence from individual single-walled carbon nanotubes.
abstract: Fluorescence has been observed directly across the band gap of semiconducting carbon nanotubes. We obtained individual nanotubes, each encased in a cylindrical micelle, by ultrasonically agitating an aqueous dispersion of raw single-walled carbon nanotubes in sodium dodecyl sulfate and then centrifuging to remove tube bundles, ropes, and residual catalyst. Aggregation of nanotubes into bundles otherwise quenches the fluorescence through interactions with metallic tubes and substantially broadens the absorption spectra. At pH less than 5, the absorption and emission spectra of individual nanotubes show evidence of band gap-selective protonation of the side walls of the tube. This protonation is readily reversed by treatment with base or ultraviolet light.
authors.affiliation: Department of Chemistry, Rice Quantum Institute, Rice University, 6100 Main Street, Houston, TX 77005, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: O'Connell
authors.forename: Sergei M
authors.initials: SM
authors.lastname: Bachilo
authors.forename: Chad B
authors.initials: CB
authors.lastname: Huffman
authors.forename: Valerie C
authors.initials: VC
authors.lastname: Moore
authors.forename: Michael S
authors.initials: MS
authors.lastname: Strano
authors.forename: Erik H
authors.initials: EH
authors.lastname: Haroz
authors.forename: Kristy L
authors.initials: KL
authors.lastname: Rialon
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Boul
authors.forename: William H
authors.initials: WH
authors.lastname: Noon
authors.forename: Carter
authors.initials: C
authors.lastname: Kittrell
authors.forename: Jianpeng
authors.initials: J
authors.lastname: Ma
authors.forename: Robert H
authors.initials: RH
authors.lastname: Hauge
authors.forename: R Bruce
authors.initials: RB
authors.lastname: Weisman
authors.forename: Richard E
authors.initials: RE
authors.lastname: Smalley