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Journal Articles Physical Chemistry Chemical Physics Year : 2014

The optical phonon spectrum of CdSe colloidal quantum dots

Mark J. Fernée
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Chiara Sinito
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Paul Mulvaney
Philippe Tamarat
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  • PersonId : 941314
Brahim Lounis
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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.
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hal-01061208 , version 1 (05-09-2014)

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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, 2014, 16 (32), pp.16957-16961. ⟨10.1039/c4cp02⟩. ⟨hal-01061208⟩
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