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Stanley, R. P.; Hegarty, J.; Fischer, R.; Feldmann, Jochen; Göbel, E. O.; Feldman, R. D.; Austin, R. F.

doi:10.1103/physrevlett.67.128

Cited by 77 publications

(23 citation statements)

References 18 publications

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“…This explanation is supported by the literature on time resolved luminescence studies, which show that the Stokes shift initially assumes a value close to our prediction, and then slowly increases [18].…”

Section: The Statistical Topographic Modelsupporting

confidence: 78%

Distribution of oscillator strengths for recombination of localised excitons in two dimensions

Wilkinson

Walker

Chinyama

1997

Chaos, Solitons & Fractals

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We investigate the distribution of oscillator strengths for the recombination of excitons in a two dimensional sample, trapped in local minima of the confinement potential: the results are derived from a statistical topographic model of the potential. The predicted distribution of oscillator strengths is very different from the Porter-Thomas distribution which usually characterises disordered systems, and is notable for the fact that small oscillator strengths are extremely rare.

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Section: The Statistical Topographic Modelsupporting

confidence: 78%

Distribution of oscillator strengths for recombination of localised excitons in two dimensions

Wilkinson

Walker

Chinyama

1997

Chaos, Solitons & Fractals

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“…[5][6][7] Excitons initially formed from electron-hole pairs usually still have a large kinetic energy compared to kT L . At low exciton densities, the thermalization and cooling of these socalled ''hot'' excitons to states with a small in-plane wave vector K ʈ is dominated by their interaction with phonons.…”

Section: Direct Observation Of Free-exciton Thermalization In Quantummentioning

confidence: 99%

“…This trapping occurs on a subpicosecond time scale, and leads to a spectrally narrow, nonthermal distribution of localized excitons when the emission of one or several optical phonons leads to the region of the localization tail in the excitonic density of states. [6][7][8] The dynamics within the localized states is mainly determined by the probability for the excitons of finding an energetically lower minimum within their lifetime. 8 Depending on the time constants for the various processes described above, the energy distribution even of the free excitons can be far from thermal equilibrium, not only in a short-laserpulse experiment but also under cw excitation.…”

Section: Direct Observation Of Free-exciton Thermalization In Quantummentioning

confidence: 99%

“…2,[6][7][8][9][10][11][12][13][14][15] But these results are based on time-resolved studies of the zero-phonon line ͑ZPL͒. The population of free-exciton states with large K ʈ is not directly accessible in such experiments, because only excitons with K ʈ Ϸ0 can contribute to the photoluminescence ͑PL͒ by direct emission of a photon.…”

Section: Direct Observation Of Free-exciton Thermalization In Quantummentioning

confidence: 99%

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Direct observation of free-exciton thermalization in quantum-well structures

et al. 1998

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“…7,8 Since a hot exciton is a thermal nonequilibrium state of the system, the measurement of HExEm is a great experimental challenge due to very fast cooling, i.e., a hot exciton always tends to cool rapidly by emission of optical and acoustic phonons toward the (quasi-) equilibrium state with lower energy. Little direct observation has been convincingly made because of this, and all of the previous reports have been made in the frequency domain [9][10][11][12][13][14][15][16] or are masked by resonant Raman scattering (RRS). 7,8,17 The very recent reports show that tailored HExEm 18,19 is still in the frequency domain and uses a very strong quantum confinement effect in combination with a cavity effect.…”

Section: Introductionmentioning

confidence: 99%

Femtosecond hot-exciton emission in a ladder-typeπ-conjugated rigid-polymer nanowire

Dai¹,

Monkman²

2013

Phys. Rev. B

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Publisher's copyright statement:Reprinted with permission from the American Physical Society: Phys. Rev. B 87, 045308 c (2013) by the American Physical Society. Readers may view, browse, and/or download material for temporary copying purposes only, provided these uses are for noncommercial personal purposes. Except as provided by law, this material may not be further reproduced, distributed, transmitted, modied, adapted, performed, displayed, published, or sold in whole or part, without prior written permission from the American Physical Society.Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. A hot exciton is usually the initial elementary excitation product of the solid phase, particularly in lowdimensional photonic materials, which is a bottleneck to all subsequent processes. Measurement of hot-exciton emission (HExEm) is a great challenge due to fast E K relaxation and thus very weak transient emission. Here, we report the unambiguous observation of femtosecond HExEm from thin films of a model quasi-one-dimensional π -conjugated organic rigid-rod quantum nanowire, methyl-substituted ladder-type poly(para-phenylenes), using femtosecond time-resolved fluorescence spectroscopy. The results show clear HExEm from the cooling hot excitons, having a lifetime of ∼500 to ∼800 fs, and concomitant very weak density-dependent singlet-singlet annihilation (SSA) due to this ultrashort dwell time. The ultrafast dispersive migration of the relaxing excitons toward the bottom of the density of states occurs immediately after HExEm, which is simultaneous to the strong density-dependent SSA effect enhanced by the lengthening dwell time.

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Hot-exciton relaxation inCdxZn1−

Cited by 77 publications

References 18 publications

Distribution of oscillator strengths for recombination of localised excitons in two dimensions

Distribution of oscillator strengths for recombination of localised excitons in two dimensions

Direct observation of free-exciton thermalization in quantum-well structures

Femtosecond hot-exciton emission in a ladder-typeπ-conjugated rigid-polymer nanowire

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