Charge transfer in single chains of a donor-acceptor conjugated tri-block copolymer

Emma N Hooley, David John Jones, Neil C Greenham, Kenneth Philip Ghiggino, Toby Desmond Maynard Bell

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11 Citations (Scopus)

Abstract

The photophysics of a conjugated triblock copolymer comprising poly(9,9-dioctylfluorene-co-bis-N,N′-(4-methylphenyl)-bis-N,N′-phenyl-1,4-phenylenediamine) (PFM) electron donor and poly(4-(9,9-dioctyl-9H-fluoren-2-yl)benzo[c][1,2,5]-thiadiazole) (F8BT) electron acceptor blocks has been studied in solution, in films, and as single chains. While an additional long-wavelength emission apparent in neat films of the copolymer is attributed to interchain exciplex formation, no such long-wavelength emission is apparent in solution or from single molecules. However, in these cases, time-resolved fluorescence measurements indicate the presence of a delayed fluorescence. The kinetics of the delayed emission can be interpreted in terms of an equilibrium between a locally excited and a charge-transfer state at the interface of the copolymer block components. Rate constants and thermodynamic quantities associated with these processes have been evaluated. The single-molecule results allow the assignment of an intramolecular charge-transfer state in an isolated conjugated block copolymer chain.
Original languageEnglish
Pages (from-to)7266-7274
Number of pages9
JournalJournal of Physical Chemistry B
Volume119
Issue number24
DOIs
Publication statusPublished - 2015

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