Structural correlations in the generation of polaron pairs in low-bandgap polymers for photovoltaics

• DOI: 10.1038/ncomms1967
• Publication Date: 2012-07-24T10:40:27Z
• Authors: Raphael Tautz; Enrico Da Como; Thomas Limmer; Jochen Feldmann; Hans-Joachim Egel...; Elizabeth von Hauff; Vincent Lemaur; David Beljonne; Seyfullah Yilmaz; Ines Dumsch; Sybille Allard; Ullrich Scherf
• Keywords: Acceptor

Polymeric semiconductors are materials where unique optical and electronic properties often originate from a tailored chemical structure. This allows for synthesizing conjugated macromolecules with ad hoc functionalities organic electronics. In photovoltaics, donor-acceptor co-polymers, moieties of different electron affinity alternating on the chain, have attracted considerable interest. The low bandgap offers optimal light-harvesting characteristics has inspired work towards record power conversion efficiencies. Here we show first time how structure donor acceptor controls photogeneration polaron pairs. We that co-polymers strong acceptors large yields pair formation up to 24% initial photoexcitations as compared homopolymer (η=8%). π-conjugated spacers, separating centre masses, beneficial role increasing recombination time. results provide useful input into understanding in low-bandgap photovoltaics.