title: Measurement of a reaction-diffusion crossover in exciton-exciton recombination inside carbon nanotubes using femtosecond optical absorption.
abstract: Exciton-exciton recombination in isolated semiconducting single-walled carbon nanotubes was studied using femtosecond transient absorption. Under sufficient excitation to saturate the optical absorption, we observed an abrupt transition between reaction- and diffusion-limited kinetics, arising from reactions between incoherent localized excitons with a finite probability of ~0.2 per encounter. This represents the first experimental observation of a crossover between classical and critical kinetics in a 1D coalescing random walk, which is a paradigm for the study of nonequilibrium systems.
authors.affiliation: Advanced Technology Institute and Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom.
authors.forename: J
authors.initials: J
authors.lastname: Allam
authors.forename: M T
authors.initials: MT
authors.lastname: Sajjad
authors.forename: R
authors.initials: R
authors.lastname: Sutton
authors.forename: K
authors.initials: K
authors.lastname: Litvinenko
authors.forename: Z
authors.initials: Z
authors.lastname: Wang
authors.forename: S
authors.initials: S
authors.lastname: Siddique
authors.forename: Q-H
authors.initials: QH
authors.lastname: Yang
authors.forename: W H
authors.initials: WH
authors.lastname: Loh
authors.forename: T
authors.initials: T
authors.lastname: Brown