title: Exciton-exciton annihilation and relaxation pathways in semiconducting carbon nanotubes.
abstract: We present a thorough analysis of one- and two-color transient absorption measurements performed on single- and double-walled semiconducting carbon nanotubes. By combining the currently existing models describing exciton-exciton annihilation-the coherent and the diffusion-limited ones-we are able to simultaneously reproduce excitation kinetics following both E11 and E22 pump conditions. Our simulations revealed the fundamental photophysical behavior of one-dimensional coherent excitons and non-trivial excitation relaxation pathways. In particular, we found that after non-linear annihilation a doubly-excited exciton relaxes directly to its E11 state bypassing the intermediate E22 manifold, so that after excitation resonant with the E11 transition, the E22 state remains unpopulated. A quantitative explanation for the observed much faster excitation kinetics probed at E22 manifold, comparing to those probed at the E11 band, is also provided.
authors.affiliation: Department of Theoretical Physics, Faculty of Physics, Vilnius University, Saulėtekio Ave. 9, LT-10222 Vilnius, Lithuania. leonas.valkunas@ff.vu.lt.
authors.forename: Jevgenij
authors.initials: J
authors.lastname: Chmeliov
authors.affiliation: Department of Theoretical Physics, Faculty of Physics, Vilnius University, Saulėtekio Ave. 9, LT-10222 Vilnius, Lithuania. leonas.valkunas@ff.vu.lt.
authors.forename: Jonas
authors.initials: J
authors.lastname: Narkeliunas
authors.affiliation: Department of Physics, Oregon State University, 301 Weniger Hall, Corvallis, Oregon 97331, USA.
authors.forename: Matt W
authors.initials: MW
authors.lastname: Graham
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.
authors.forename: Graham R
authors.initials: GR
authors.lastname: Fleming
authors.affiliation: Department of Theoretical Physics, Faculty of Physics, Vilnius University, Saulėtekio Ave. 9, LT-10222 Vilnius, Lithuania. leonas.valkunas@ff.vu.lt and Institute of Physics, Center for Physical Sciences and Technology, Goštauto 11, LT-01108 Vilnius, Lithuania.
authors.forename: Leonas
authors.initials: L
authors.lastname: Valkunas