title: Chirality dependence of the absorption cross section of carbon nanotubes.
abstract: 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 chirality dependence of the optical absorption with an original method involving ultraefficient energy transfer in porphyrin-nanotube compounds that allows uniform photoexcitation of all chiral species. We measure the absolute absorption cross section of a wide range of semiconducting nanotubes at their S22 transition and show that it varies by up to a factor of 2.2 with the chiral angle, with type I nanotubes showing a larger absorption. In contrast, the luminescence quantum yield remains almost constant.
authors.affiliation: Laboratoire Pierre Aigrain, École Normale Supérieure, UPMC, Université Paris Diderot, CNRS, 75005 Paris, France.
authors.forename: Fabien
authors.initials: F
authors.lastname: Vialla
authors.forename: Cyrielle
authors.initials: C
authors.lastname: Roquelet
authors.forename: Benjamin
authors.initials: B
authors.lastname: Langlois
authors.forename: Géraud
authors.initials: G
authors.lastname: Delport
authors.forename: Silvia Morim
authors.initials: SM
authors.lastname: Santos
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Deleporte
authors.forename: Philippe
authors.initials: P
authors.lastname: Roussignol
authors.forename: Claude
authors.initials: C
authors.lastname: Delalande
authors.forename: Christophe
authors.initials: C
authors.lastname: Voisin
authors.forename: Jean-Sébastien
authors.initials: JS
authors.lastname: Lauret