Fabien Vialla, Cyrielle Roquelet, Benjamin Langlois, Géraud Delport, Silvia Morim Santos, Emmanuelle Deleporte, Philippe Roussignol, Claude Delalande, Christophe Voisin, Jean-Sébastien Lauret
The variation of the optical absorption of carbon nanotubes with their geometry has been a long standing question at the heart of both metrological and applicative issues, in particular because optical spectroscopy is one of the primary tools for the assessment of the chiral species abundance of samples. Here, we tackle the chiral dependence of the optical absorption with an original method involving ultra-efficient energy transfer in porphyrin/nanotube compounds that allows uniform photo-excitation of all chiral species. We measure the absolute absorption cross-section of the second excitonic transition (S22) of a wide range of semiconducting nanotubes and show that it varies by up to a factor of 3 with the chiral angle, with type I nanotubes showing a larger absorption. In contrast, the luminescence quantum yield remains almost constant.
View original:
http://arxiv.org/abs/1306.3337
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