Spatiotemporal dynamics of excitons in isolated semiconducting single-walled carbon nanotubes are studied using transient absorption microscopy. Differential reflection and transmission of an 810-nm probe pulse after excitation by a 750-nm pump pulse are measured. We observe a bi-exponentially decaying signal with a fast time constant of 0.66 ps and a slower time constant of 2.8 ps. Both constants are independent of the pump fluence. By spatially and temporally resolving the differential reflection, we are able to observe a diffusion of excitons, and measure a diffusion coefficient of 200 cm2/s at room temperature and 300 cm2/s at lower temperatures of 10 K and 150 K.
@article{arxiv.1211.0593,
title = {Exciton diffusion in semiconducting single-wall carbon nanotubes studied by transient absorption microscopy},
author = {Brian A. Ruzicka and Rui Wang and Jessica Lohrman and Shenqiang Ren and Hui Zhao},
journal= {arXiv preprint arXiv:1211.0593},
year = {2013}
}