Theory of Primary Photoexcitations in Donor-Acceptor Copolymers

Karan Aryanpour, Tirthankar Dutta, Uyen N.V. Huynh, Zeev Valy Vardeny, Sumit Mazumdar

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


We present a generic theory of primary photoexcitations in low band gap donor-acceptor conjugated copolymers. Because of the combined effects of strong electron correlations and broken symmetry, there is considerable mixing between a charge-transfer exciton and an energetically proximate triplet-triplet state with an overall spin singlet. The triplet-triplet state, optically forbidden in homopolymers, is allowed in donor-acceptor copolymers. For an intermediate difference in electron affinities of the donor and the acceptor, the triplet-triplet state can have a stronger oscillator strength than the charge-transfer exciton. We discuss the possibility of intramolecular singlet fission from the triplet-triplet state, and how such fission can be detected experimentally.

Original languageEnglish (US)
Article number267401
JournalPhysical review letters
Issue number26
StatePublished - Dec 30 2015

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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