Spectroscopy of Carbon Nanotubes

One of the most active areas of research today is the discovery and understanding of next-generation solar cell materials. Quantum dots, perovskites, conducting polymers and many other materials are being studied in order to understand and harness their energy transfer properties. A promising new class of materials is semi-conducting carbon nanotubes where the nanotubes are used in the photoabsorbing layer, similar to molecular dyes in dye-sensitized solar cells. Isolated carbon nanotubes have extremely large exciton diffusion lengths, large carrier mobilities, low trap densities, high optical cross sections, and excellent air stability (compared to organic photovoltaic dyes) which are all critical properties for solar cells. These purified thin films represent an entirely new class of materials, whose properties need to be understood. Their ultrafast dynamics are especially important because fast exciton transfer is directly linked to solar cell performance. Using transient absorption spectroscopy, we are able to measure the time scale for energy transfer within these solar cell materials. By studying the anistropy of our transient signals, we can also gain insights into how the energy transfer is distributed spatially.

Selected Publications
Son M, Armstrong ZT, Allen RT, Dhavamani A, Arnold MS & Zanni MT. Energy cascades in donor-acceptor exciton-polaritons observed by ultrafast two-dimensional white-light spectroscopy Nat. Commun.
Allen RT, Dhavamani A, Son M, Kéna-Cohen S, Zanni MT, Arnold MS. Population of Subradiant States in Carbon Nanotube Microcavities in the Ultrastrong Light–Matter Coupling Regime. J. Phys. Chem. C.
Mehlenbacher, R. D.; Wu, M.-Y.; Grechko, M.; Laaser, J. E.; Arnold, M. S.; Zanni, M. T. Photoexcitation Dynamics of Coupled Semiconducting Carbon Nanotube Thin Films. Nano Lett. 2013, 13, 1495–1501.
Grechko, M.; Ye, Y.; Mehlenbacher, R. D.; McDonough, T. J.; Wu, M.-Y.; Jacobberger, R. M.; Arnold, M. S.; Zanni, M. T. Diffusion-Assisted Photoexcitation Transfer in Coupled Semiconducting Carbon Nanotube Thin Films. ACS Nano 2014, 8, 5383–5394.
McDonough, T. J.; Zhang, L.; Roy, S. S.; Kearns, N. M.; Arnold, M. S.; Zanni, M. T.; Andrew, T. L. Triplet Exciton Dissociation and Electron Extraction in Graphene-Templated Pentacene Observed with Ultrafast Spectroscopy. Phys. Chem. Chem. Phys. 2017, 19, 4809–4820.