Probing exciton propagation and quenching in carbon nanotubes with near-field optical microscopy

We report on near-field optical imaging of single-walled carbon nanotubes (SWNTs), observing photoluminescence (PL) quenching at nanotube ends and defects. The extension of reduced PL reflects the exciton diffusion length of about 100 nm, which can be directly visualized with our technique. Additionally, we model the complete imaging process, including exciton diffusion and tip-induced rate enhancement, for a deeper understanding of the experimental data and the determination of, e.g. diffusion length and tip enhancement from near-field PL images. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim