Acoustic phonon contributions to the emission spectrum of single CdSe nanocrystals

Abstract

Narrow zero-phonon emission lines are observed in single CdSe/CdZnS core/shell colloidal nanocrystals over a range of cryogenic temperatures up to 40 K. These nanocrystals display dramaticaly improved spectral stability enabling the observation of acoustic phonon sidebands accompanying most zero-phonon lines. A discrete phonon mode is attributed to the electron coupling to the l = 0 acoustic breathing mode via the deformation coupling. The Huang-Rhys parameter, Sac, for this interaction is found to vary from 0.0016 to 0.09, demonstrating a wide dispersion in exciton-phonon coupling between different nanocrystals. Indeed, we observe single nanocrystals in which all acoustic phonon sidebands v..