Ultrafast Exciton Hopping Observed in Bare Semiconducting Carbon Nanotube Thin Films with Two-Dimensional White-Light Spectroscopy

TitleUltrafast Exciton Hopping Observed in Bare Semiconducting Carbon Nanotube Thin Films with Two-Dimensional White-Light Spectroscopy
Publication TypeJournal Article
Year of Publication2016
AuthorsMehlenbacher RD, Wang J, Shea MJ, Flach JT, McDonough TJ, Wu M-Y, Arnold MS, Zanni M T.
Secondary TitleThe Journal of Physical Chemistry Letters
Volume7
Pagination2024-2031
Date Published05/2016
PublisherThe Journal of Physcial Chemistry Letters
Abstract

We observe ultrafast energy transfer between bare carbon nanotubes in a thin film using two-dimensional (2D) white-light spectroscopy. Using aqueous two-phase separation, semiconducting carbon nanotubes are purified from their metallic counterparts and condensed into a 10 nm thin film with no residual surfactant. Cross peak intensities put the time scale for energy transfer at <60 fs, and 2D anisotropy measurements determine that energy transfer is most efficient between parallel nanotubes, thus favoring directional energy flow. Lifetimes are about 300 fs. Thus, these results are in sharp contrast to thin films prepared from nanotubes that are wrapped by polymers, which exhibit picosecond energy transfer and randomize the direction of energy flow. Ultrafast energy flow and directionality are exciting properties for next-generation photovoltaics, photodetectors, and other devices.

URLhttp://pubs.acs.org/doi/abs/10.1021/acs.jpclett.6b00650
DOI10.1021/acs.jpclett.6b00650