Exciton-phonon coupling and disorder in the excited states of CdSe colloidal quantum dots

Mayrose R. Salvador, Matthew W. Graham, Gregory D. Scholes

Research output: Contribution to journalArticle

103 Scopus citations

Abstract

We study the origin of the spectral line shape in colloidal CdSe nanocrystal quantum dots. The three-pulse photon echo peak shift (3PEPS) data reveal a temperature-independent fast decay, obscuring the quantification of the homogeneous linewidth. The optical gap and Stokes shift are found to have an anomalous behavior with temperature, which is size, capping group, and surrounding polymer matrix independent. Using these results and combining them with simulations, we discuss the role of exciton-phonon coupling, static inhomogeneity, exciton fine structure, and exciton state disorder in the linewidth of the nanocrystal. In particular, our analysis shows that the disorder due to surface imperfections and finite temperature effects, as well as the relaxation within the fine structure, can have significant impact on the steady-state absorption spectrum, 3PEPS data, and dephasing processes.

Original languageEnglish (US)
Article number184709
JournalJournal of Chemical Physics
Volume125
Issue number18
DOIs
StatePublished - Nov 20 2006
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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