Bipolaron Formation in Organic Solar Cells Observed by Pulsed Electrically Detected Magnetic Resonance

J. Behrends, A. Schnegg, K. Lips, E. A. Thomsen, A. K. Pandey, I. D. W. Samuel, D. J. Keeble

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    Abstract

    We report the observation of a spin-dependent dark transport current, exhibiting spin coherence at room temperature, in a pi-conjugated polymer-fullerene blend using pulsed electrically detected magnetic resonance. The resonance at g = 2.0028(3) is due to polarons in the polymer, and exhibits spin locking at high microwave fields. The presence of an excess of fullerene, and the operating voltage (1 V) used, suppresses negative polaron formation in the polymer. It is concluded that spin-dependent transport is due to the formation of positive bipolarons.

    Original languageEnglish
    Article number176601
    Pages (from-to)-
    Number of pages4
    JournalPhysical Review Letters
    Volume105
    Issue number17
    DOIs
    Publication statusPublished - 19 Oct 2010

    Keywords

    • RADICAL PAIRS
    • MEH-PPV
    • SEMICONDUCTORS
    • POLYMER
    • MAGNETORESISTANCE
    • EXCITONS
    • EPR

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