Dynamics within the exciton fine structure of colloidal CdSe quantum dots

Vanessa M. Huxter, Vitalij Kovalevskij, Gregory D. Scholes

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

Evidence for an interaction between the quantum dot exciton fine structure states F = ±1 is obtained by measuring the dynamics of transitions among those states, exciton spin relaxation or flipping. An ultrafast transient grating experiment based on a crossed-linear polarization grating is reported. By using the quantum dot selection rules for absorption of circularly polarized light, it is demonstrated that it is possible to detect transitions between nominally degenerate fine structure states, even in a rotationally isotropic system. The results for colloidal CdSe quantum dots reveal a strong size dependence for the exciton spin relaxation rate from one bright exciton state (F = ±1) to the other in CdSe colloidal quantum dots at 293 K, on a time scale ranging from femtoseconds to picoseconds, depending on the quantum dot size. The results are consistent with an interaction between those states attributed to a long-range contribution to the electron-hole exchange interaction.

Original languageEnglish (US)
Pages (from-to)20060-20063
Number of pages4
JournalJournal of Physical Chemistry B
Volume109
Issue number43
DOIs
StatePublished - Nov 3 2005
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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