title: Diffusion limited photoluminescence quantum yields in 1-D semiconductors: single-wall carbon nanotubes.
abstract: Photoluminescence quantum yields and nonradiative decay of the excitonic S(1) state in length fractionated (6,5) single-wall carbon nanotubes (SWNTs) are studied by continuous wave and time-resolved fluorescence spectroscopy. The experimental data are modeled by diffusion limited contact quenching of excitons at stationary quenching sites including tube ends. A combined analysis of the time-resolved photoluminescence decay and the length dependence of photoluminescence quantum yields (PL QYs) from SWNTs in sodium cholate suspensions allows to determine the exciton diffusion coefficient D = 10.7 ± 0.4 cm(2)s(-1) and lifetime τ(PL) for long tubes of 20 ± 1 ps. PL quantum yields Φ(PL) are found to scale with the inverse diffusion coefficient and the square of the mean quenching site distance, here l(d) = 120 ± 25 nm. The results suggest that low PL QYs of SWNTs are due to the combination of high-diffusive exciton mobility with the presence of only a few quenching sites.
authors.affiliation: Institute of Physical and Theoretical Chemistry & Department of Chemistry and Pharmacy, University of Würzburg, D-97074 Würzburg, Germany. tobias.hertel@uni-wuerzburg.de
authors.forename: Tobias
authors.initials: T
authors.lastname: Hertel
authors.forename: Sabine
authors.initials: S
authors.lastname: Himmelein
authors.forename: Thomas
authors.initials: T
authors.lastname: Ackermann
authors.forename: Dominik
authors.initials: D
authors.lastname: Stich
authors.forename: Jared
authors.initials: J
authors.lastname: Crochet