title: Evidence for long-lived, optically generated quenchers of excitons in single-walled carbon nanotubes.
abstract: The nonlinear dependence of near-infrared photoluminescence (PL) emission on excitation intensity has been measured for individual nanotubes representing six different (n,m) species. Significant deviations from linearity are observed for intensities as low as ~100 W/cm(2), and an approximate inverse correlation is found between nonlinearity and PL action cross section (brightness). A model in which all PL nonlinearity arises from exciton-exciton annihilation is insufficient to account for the experimental data using realistic parameters. It is proposed that additional nonlinear quenching arises from photoinduced quenching states or species with longer lifetimes than emissive excitons. Evidence is also found for metastable photogenerated PL quenchers with lifetimes up to 20 s.
authors.affiliation: Department of Chemistry and Richard E. Smalley Institute for Nanoscale Science and Technology, Rice University, 6100 Main Street, Houston, Texas 77005, USA.
authors.forename: Anni J
authors.initials: AJ
authors.lastname: Siitonen
authors.forename: Sergei M
authors.initials: SM
authors.lastname: Bachilo
authors.forename: Dmitri A
authors.initials: DA
authors.lastname: Tsyboulski
authors.forename: R Bruce
authors.initials: RB
authors.lastname: Weisman
mesh_terms: D000042:Absorption; D003198:Computer Simulation; D008027:Light; D008956:Models, Chemical; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D012031:Refractometry; D012542:Scattering, Radiation
chemical_list: D037742:Nanotubes, Carbon