Fluorescence blinking, exciton dynamics, and energy transfer domains in single conjugated polymer chains.

Hongzhen Lin, Seyed R Tabaei, Daniel Thomsson, Oleg Mirzov, Per-Olof Larsson, Ivan Scheblykin

Research output: Contribution to journalArticlepeer-review

Abstract

In order to understand exciton migration and fluorescence intensity fluctuation mechanisms in conjugated polymer single molecules, we studied fluorescence decay dynamics at "on" and "off" fluorescence intensity levels with 20 ps time resolution using MEH-PPV [poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] dispersed in PMMA. Two types of intensity fluctuations were distinguished for single chains of conjugated polymers. Abrupt intensity fluctuations (blinking) were found to be always accompanied by corresponding changes in fluorescence lifetime. On the contrary, during "smooth" intensity fluctuations no lifetime change was observed. Time-resolved data in combination with data on fluorescence emission and excitation anisotropy lead to a picture where a single polymer molecule is seen as consisting of several energy transfer domains. Exciton migration is efficient within a domain and not efficient between domains. Each domain can have several emitting low-energy sites over which the exciton continuously migrates until it decays. Emission of individual domains is often highly polarized. Fluorescence from a domain can be strongly quenched by Forster energy transfer to a quencher (hole polaron) if the domain overlaps with the quenching sphere.
Original languageEnglish
Pages (from-to)7042-7051
JournalJournal of the American Chemical Society
Volume130
Issue number22
DOIs
Publication statusPublished - 2008

Bibliographical note

The information about affiliations in this record was updated in December 2015.
The record was previously connected to the following departments: Chemical Physics (S) (011001060), Pure and Applied Biochemistry (LTH) (011001005), Department of Chemistry (011001220)

Subject classification (UKÄ)

  • Biochemistry and Molecular Biology
  • Atom and Molecular Physics and Optics

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