title: Disorder limited exciton transport in colloidal single-wall carbon nanotubes.
abstract: We present measurements of S(1) exciton transport in (6,5) carbon nanotubes at room temperature in a colloidal environment. Exciton diffusion lengths associated with end quenching paired with photoluminescence lifetimes provide a direct basis for determining a median diffusion constant of approximately 7.5 cm(2)s(-1). Our experimental results are compared to model diffusion constants calculated using a realistic exciton dispersion accounting for a logarithmic correction due to the exchange self-energy and a nonequilibrium distribution between bright and dark excitons. The intrinsic diffusion constant associated with acoustic phonon scattering is too large to explain the observed diffusion length, and as such, we attribute the observed transport to disorder-limited diffusional transport associated with the dynamics of the colloidal interface. In this model an effective surface potential limits the exciton mean free path to the same size as that of the exciton wave function, defined by the strength of the electron-hole Coulomb interaction.
authors.affiliation: Physical Chemistry and Applied Spectroscopy, Los Alamos National Laboratory, New Mexico, USA. jcrochet@lanl.gov
authors.forename: Jared J
authors.initials: JJ
authors.lastname: Crochet
authors.forename: Juan G
authors.initials: JG
authors.lastname: Duque
authors.forename: James H
authors.initials: JH
authors.lastname: Werner
authors.forename: Brahim
authors.initials: B
authors.lastname: Lounis
authors.forename: Laurent
authors.initials: L
authors.lastname: Cognet
authors.forename: Stephen K
authors.initials: SK
authors.lastname: Doorn