Ultrafast charge separation in organic photovoltaics enhanced by charge delocalization and vibronically hot exciton dissociation

Hiroyuki Tamura, Irene Burghardt

    Research output: Contribution to journalArticlepeer-review

    216 Citations (Scopus)

    Abstract

    In organic photovoltaics, the mechanism by which free electrons and holes are generated, overcoming the Coulomb attraction, is a currently much debated topic. To elucidate this mechanism at a molecular level, we carried out a combined electronic structure and quantum dynamical analysis that captures the elementary events from the exciton dissociation to the free carrier generation at polymer/fullerene donor/acceptor heterojunctions. Our calculations show that experimentally observed efficient charge separations can be explained by a combination of two effects: First, the delocalization of charges which substantially reduces the Coulomb barrier, and second, the vibronically hot nature of the charge-transfer state which promotes charge dissociation beyond the barrier. These effects facilitate an ultrafast charge separation even at low-band-offset heterojunctions.

    Original languageEnglish
    Pages (from-to)16364-16367
    Number of pages4
    JournalJournal of the American Chemical Society
    Volume135
    Issue number44
    DOIs
    Publication statusPublished - 2013 Nov 6

    ASJC Scopus subject areas

    • Catalysis
    • Chemistry(all)
    • Biochemistry
    • Colloid and Surface Chemistry

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