Intrinsic diffusion length of excitons in long single-walled carbon nanotubes from photoluminescence spectra

Xie, Jianping; Inaba, Takumi; Sugiyama, Ryohei; Homma, Yoshikazu

doi:10.1103/physrevb.85.085434

Cited by 27 publications

(38 citation statements)

References 27 publications

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“…21,28,29 Figure 2c inset shows a wide-field PL image of an individual SWCNT at room temperature. Different from diffraction-limited emission at low temperature (Figure 1c inset), elongated emission along the tube can be observed.…”

Section: Resultsmentioning

confidence: 99%

Influence of Exciton Dimensionality on Spectral Diffusion of Single-Walled Carbon Nanotubes

Roslyak

Wang

et al. 2014

ACS Nano

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We study temporal evolution of photoluminescence (PL) spectra from individual single-walled carbon nanotubes (SWCNTs) at cryogenic and room temperatures. Sublinear and superlinear correlations between fluctuating PL spectral positions and line widths are observed at cryogenic and room temperatures, respectively. We develop a simple model to explain these two different spectral diffusion behaviors in the framework of quantum-confined Stark effect (QCSE) caused by surface charges trapped in the vicinity of SWCNTs. We show that the wave function properties of excitons, namely, localization at cryogenic temperature and delocalization at room temperature, play a critical role in defining sub- and superlinear correlations. Room temperature PL spectral positions and line widths of SWCNTs coupled to gold dimer nanoantennas on the other hand exhibit sublinear correlations, indicating that excitonic emission mainly originates from nanometer range regions and excitons appear to be localized. Our numerical simulations show that such apparent localization of excitons results from plasmonic confinement of excitation and an enhancement of decay rates in the gap of the dimer nanoantennas.

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Section: Resultsmentioning

confidence: 99%

Influence of Exciton Dimensionality on Spectral Diffusion of Single-Walled Carbon Nanotubes

Roslyak

Wang

et al. 2014

ACS Nano

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“…Before the excitons interact with each other, the optically excited exciton does not have the center-of-mass momentum because of the energy-momentum conservation, and thus we need some more additional time (sub-picoseconds) after the excitation to obtain the finite diffusion constant which affects the coherent phonon dynamics. In a micelle-encapsulated nanotube sample, excitons typically diffuse by about 2 nm (every 1 ps), 24 while the average separation between two excitons is one order of magnitude larger. Although in a pristine nanotube sample the excitons can diffuse up to the same order as the average separation between two excitons, 25 the exciton diffusion mostly contributes to the decay of the exciton lifetime.…”

Section: Coherent Phonon Modelmentioning

confidence: 99%

Excitonic effects on coherent phonon dynamics in single-wall carbon nanotubes

et al. 2013

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We discuss how excitons can affect the generation of coherent radial breathing modes in the ultrafast spectroscopy of single-wall carbon nanotubes. Photoexcited excitons can be localized spatially and give rise to a spatially distributed driving force in real space which involves many phonon wave vectors of the exciton-phonon interaction. The equation of motion for the coherent phonons is modeled phenomenologically by the Klein-Gordon equation, which we solve for the oscillation amplitudes as a function of space and time. By averaging the calculated amplitudes per nanotube length, we obtain time-dependent coherent phonon amplitudes that resemble the homogeneous oscillations that are observed in some pump-probe experiments. We interpret this result to mean that the experiments are only able to see a spatial average of coherent phonon oscillations over the wavelength of light in carbon nanotubes and the microscopic details are averaged out. Our interpretation is justified by calculating the time-dependent absorption spectra resulting from the macroscopic atomic displacements induced by the coherent phonon oscillations. The calculated coherent phonon spectra including excitonic effects show the experimentally observed symmetric peaks at the nanotube transition energies, in contrast to the asymmetric peaks that would be obtained if excitonic effects were not included.

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“…The reduced screening of optical excitations in the single rolled layer of graphene leads to an exciton binding energy which is approximately one third of the single particle bandgap [1,2]. Consequently, excitons are stable even at room temperature where thermal energy enables exceedingly long diffusion lengths [3][4][5]. The diffusion-reaction of excitons in SWCNTs results in many body interactions which leads to strong nonlinear optical properties [6,7], even at very low excitation fluences [8].…”

Section: Introductionmentioning

confidence: 99%

Independence of optical absorption on Auger ionization in single-walled carbon nanotubes revealed by ultrafast e–h photodoping

et al. 2016

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Auger-ionized free-carriers in a one-dimensional semiconductor are predicted to result in a strong band-gap renormalization. Isolated single-walled carbon nanotubes (SWCNT) under high-intensity laser irradiation exhibit strong nonlinear photoluminescence (PL) due to exciton-exciton annihilation (EEA). The presence of exciton disassociation during the rapid Auger-ionization caused by EEA would lead to a strong nonlinear absorption. By simultaneously measuring SWCNT-PL and optical absorption of isolated SWCNT clusters in the PL saturation regime, we give evidence that Augerionized excitons do not disassociate but remain bound.

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Intrinsic diffusion length of excitons in long single-walled carbon nanotubes from photoluminescence spectra

Cited by 27 publications

References 27 publications

Influence of Exciton Dimensionality on Spectral Diffusion of Single-Walled Carbon Nanotubes

Influence of Exciton Dimensionality on Spectral Diffusion of Single-Walled Carbon Nanotubes

Excitonic effects on coherent phonon dynamics in single-wall carbon nanotubes

Independence of optical absorption on Auger ionization in single-walled carbon nanotubes revealed by ultrafast e–h photodoping

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