Disorder Limited Exciton Transport in Colloidal Single-Wall Carbon Nanotubes

Jared J. Crochet (1) , Juan G. Duque (1) , James H. Werner (2) , Brahim Lounis (3) , Laurent Cognet (4) , Stephen K. Doorn (2)

1 Physical Chemistry and Applied Spectroscopy
2 Center for Integrated Nanotechnologies
3 lp2n-01,lp2n-12
4 LP2N - Laboratoire Photonique, Numérique et Nanosciences

We present measurements of S1 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 dif- fusion constant of approximately 7.5 cm2s-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 non-equilibrium 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 observedtransport 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 wavefunction, defined by the strength of the electron-hole Coulomb interaction.

Mots clés: carbon nanotube; exciton; dephasing; transport; exchange interaction

Domaines: Autre [cond-mat.other]

Jared J. Crochet, Juan G. Duque, James H. Werner, Brahim Lounis, Laurent Cognet, et al.. Disorder Limited Exciton Transport in Colloidal Single-Wall Carbon Nanotubes. Nano Letters, 2012, in press. ⟨10.1021/nl301739d⟩. ⟨hal-00735016⟩