TY - JOUR
T1 - Strong Acoustic Phonon Localization in Copolymer-Wrapped Carbon Nanotubes
AU - Sarpkaya, Ibrahim
AU - Ahmadi, Ehsaneh D.
AU - Shepard, Gabriella D.
AU - Mistry, Kevin S.
AU - Blackburn, Jeffrey L.
AU - Strauf, Stefan
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/6/23
Y1 - 2015/6/23
N2 - 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.
AB - 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.
KW - acoustic phonon localization
KW - carbon nanotubes
KW - dephasing
KW - excitons
KW - isotope effects
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U2 - 10.1021/acsnano.5b01997
DO - 10.1021/acsnano.5b01997
M3 - Article
AN - SCOPUS:84935006382
SN - 1936-0851
VL - 9
SP - 6383
EP - 6393
JO - ACS Nano
JF - ACS Nano
IS - 6
ER -