The optical phonon spectrum of CdSe colloidal quantum dots
Langue
en
Article de revue
Ce document a été publié dans
Physical Chemistry Chemical Physics. 2014-08-28, vol. 16, n° 32, p. 16957-16961
Royal Society of Chemistry
Résumé en anglais
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 ...Lire la suite >
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.< Réduire
Mots clés en anglais
INTRABAND RELAXATION
NANOCRYSTALS
EXCITON
PHOTOLUMINESCENCE
SPECTROSCOPY
BOTTLENECK
EMISSION
ENERGY
Origine
Importé de halUnités de recherche