Stepwise decrease of fluorescence versus sequential photobleaching in a single multichromophoric system

Abey Issac, Richard Hildner, Catharina Hippius, Frank Würthner, Jürgen Köhler

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

For individual molecules from the newly synthesized calix[4]arene tethered perylene bisimide (PBI) trimer, we studied the emitted fluorescence intensity as a function of time. Owing to the zigzag arrangement of PBI dyes in these trimers, the polarization state of the emission provides directly information about the emitting subunit within the trimer. Interestingly, we observed emission from all neutral subunits within a trimer rather than exclusively from the subunit with the lowest site energy. This can be understood in terms of thermally activated uphill energy transfer that repopulates the higher energetic chromophores. Together with the simultaneously recorded polarization-resolved emission spectra, this reveals that the emission from a multichromophoric system is governed by a complex interplay between the temporal variations of the photophysical parameters of the subunits, bidirectional hopping processes within the trimer, and unavoidable photobleaching. Moreover, it is demonstrated that the typically observed stepwise decrease of the signal from a multichromophoric system does not necessarily reflect sequential bleaching of the individual chromophores within the macromolecule.

Original languageEnglish
Pages (from-to)1708-1717
Number of pages10
JournalACS Nano
Volume8
Issue number2
DOIs
Publication statusPublished - Feb 25 2014

Keywords

  • excitation energy transfer
  • multichromophore
  • photobleaching
  • polarization-resolved emission spectra
  • single-molecule spectroscopy
  • uphill energy transport

ASJC Scopus subject areas

  • Engineering(all)
  • Materials Science(all)
  • Physics and Astronomy(all)

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