The optical phonon spectrum of CdSe colloidal quantum dots

Mark J. Fernée 1 Chiara Sinito 1 Paul Mulvaney 2 Philippe Tamarat 1 Brahim Lounis 1
1 lp2n-01,lp2n-12
LP2N - Laboratoire Photonique, Numérique et Nanosciences
2 School of Chemistry
Abstract : The direct coupling of excited electronic states to optical phonons in single CdSe colloidal quantum dots is explored using both photoluminescence emission and excitation spectroscopies. We find a broad optical phonon spectrum associated with a single fine structure state. Multiple peaks in the optical phonon sideband are ascribed to different optical phonon types emanating from both the core and shell layers. A mixed emission process that involves the simultaneous generation of two different types of optical phonon is also observed. In general, rather than a single mode, each designated phonon type is associated with a dispersed family of modes. Narrow optical phonon sidebands, consistent with the dominant LO mode, are observed in some nanocrystals. A linewidth analysis indicates that optical phonon lifetimes are in the 10 picosecond range. We demonstrate the ability to selectively excite a specific band-edge state by directly exciting its LO phonon sideband.
Keywords : INTRABAND RELAXATION NANOCRYSTALS EXCITON PHOTOLUMINESCENCE SPECTROSCOPY BOTTLENECK EMISSION ENERGY
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Journal articles
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https://hal-iogs.archives-ouvertes.fr/hal-01061208
Contributor : Philippe Tamarat <>
Submitted on : Friday, September 5, 2014 - 12:34:58 PM
Last modification on : Thursday, September 6, 2018 - 3:12:04 PM

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Mark J. Fernée, Chiara Sinito, Paul Mulvaney, Philippe Tamarat, Brahim Lounis. The optical phonon spectrum of CdSe colloidal quantum dots. Physical Chemistry Chemical Physics, Royal Society of Chemistry, 2014, 16 (32), pp.16957-16961. ⟨10.1039/c4cp02⟩. ⟨hal-01061208⟩

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