https://doi.org/10.1140/epjb/e2009-00374-1
Long lived photo excitations in (6, 5) carbon nanotubes
1
IIT-Department of Physics, Politecnico di Milano, P.zza L. da Vinci 23, 20133 Milano, Italy
2
Institut für Physikalische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
Corresponding author: calogero.sciascia@mail.polimi.it
Received:
16
July
2009
Revised:
31
August
2009
Published online:
3
November
2009
We study the photo-induced transmission change (ΔT/T) upon quasi-continuum laser excitation, for different modulation frequency and excitation intensity in films of (6, 5) enriched CoMoCat single wall nanotubes (SWNTs) embedded in a polymeric matrix. This technique probes long-lived excited species, with lifetime in the 1 ms–1 s domain. The observed line-shape of ΔT/T spectra that can be assigned to a superposition of ground state bleaching and absorption modulation. We speculate that photo-excitation creates charges which get trapped in the sample, acquiring ms lifetime. This causes bleaching of the ground state absorption due to state filling and possibly a tube diameter expansion, with consequent blue shift of the optical transition.
PACS: 33.20.Ea – Infrared spectra / 33.20.Kf – Visible spectra / 42.62.Fi – Laser spectroscopy
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2009