The photoinduced charge transfer mechanism in aligned and unaligned carbon nanotubes

Gianluca Galimberti, Stefania Pagliara*, Stefano Ponzoni, Stefano Dal Conte, Federico Cilento, Gabriele Ferrini, Stephan Hofmann, Muhammad Arshad, Cinzia Cepek, Fulvio Parmigiani

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

11 Citations (Scopus)

Abstract

Using time-resolved reflectivity measurements on unaligned and aligned bundled single-wall carbon nanotubes with a pump energy of 1.55 eV, quasi-resonant with the second Van Hoye singularity of semiconducting tubes, a positive sign of the transient reflectivity is detected in unaligned nanotubes. In contrast a negative sign is detected in aligned nanotubes. This discovery addresses a long-standing question showing that in unaligned nanotubes the stronger intertube interactions favor the formation of short-lived free charge carriers in semiconducting tubes. A detailed analysis of the transient reflectivity spectral response shows that the free carriers in the photo-excited state of semiconducting tubes move towards metallic tubes in about 400 fs. (C) 2011 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)5246-5252
Number of pages7
JournalCarbon
Volume49
Issue number15
DOIs
Publication statusPublished - Dec-2011

Keywords

  • ELECTRONIC-STRUCTURE
  • VIBRATIONAL-MODES
  • CARRIER DYNAMICS
  • TIME-DOMAIN
  • ROPES
  • BUNDLES

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