Semiconducting carbon nanotubes are an exciting new material for solar cells. Mesoscale films can now be assebled and made into devices in which the semiconducting tubes are the photoactive layer, analogous to organic dyes or quantum dots in dye-sensitized solar cells. In order to understand their exciton transport properties, we are studying the photophysics of these films. Obtaining a comprehensive picture of the pathways, rates, and bottlenecks is challenging because in many cases this relaxation spans a wide range of energies. The standard approach to study such a wide frequency range is to use a tunable pump pulse to excite each electronic transition in turn, one after another. We have developed two-dimensional white light spectroscopy (2D WL) which allows us to simultaneously examine a spectral range spanning roughly 500-1400 nm. The spectra resolve energy transfer between all possible combinations of excitonic states in the chirality-selected nanotubes, thereby providing an instantaneous and comprehensive snapshot of the dynamical pathways. The new physics we uncover has important implications in the development of carbon nanotube electronics and optoelectronics.

Date Published: 9 September 2014
PDF: 4 pages
Proc. SPIE 9165, Physical Chemistry of Interfaces and Nanomaterials XIII, 91650J (9 September 2014); doi: 10.1117/12.2063327

Published in SPIE Proceedings Vol. 9165:
Physical Chemistry of Interfaces and Nanomaterials XIII
Natalie Banerji; Sophia C. Hayes; Carlos Silva, Editor(s)