Strong Acoustic Phonon Localization in Copolymer-Wrapped Carbon Nanotubes

Ibrahim Sarpkaya, Ehsaneh D. Ahmadi, Gabriella D. Shepard, Kevin S. Mistry, Jeffrey L. Blackburn, Stefan Strauf

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

Understanding and controlling exciton-phonon interactions in carbon nanotubes has important implications for producing efficient nanophotonic devices. Here we show that laser vaporization-grown carbon nanotubes display ultranarrow luminescence line widths (120 μV) and well-resolved acoustic phonon sidebands at low temperatures when dispersed with a polyfluorene copolymer. Remarkably, we do not observe a correlation of the zero-phonon line width with 13C atomic concentration, as would be expected for pure dephasing of excitons with acoustic phonons. We demonstrate that the ultranarrow and phonon sideband-resolved emission spectra can be fully described by a model assuming extrinsic acoustic phonon localization at the nanoscale, which holds down to 6-fold narrower spectral line width compared to previous work. Interestingly, both exciton and acoustic phonon wave functions are strongly spatially localized within 5 nm, possibly mediated by the copolymer backbone, opening future opportunities to engineer dephasing and optical bandwidth for applications in quantum photonics and cavity optomechanics.

Original languageEnglish
Pages (from-to)6383-6393
Number of pages11
JournalACS Nano
Volume9
Issue number6
DOIs
StatePublished - 23 Jun 2015

Keywords

  • acoustic phonon localization
  • carbon nanotubes
  • dephasing
  • excitons
  • isotope effects

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