Abstract
A promising approach to influence and control the photophysical properties of conjugated polymers is directing their molecular conformation by templating. We explore here the templating effect of single-stranded DNA oligomers (ssDNAs) on cationic polythiophenes with the goal to uncover the intermolecular interactions that direct the polymer back-bone conformation. We have comprehensively characterized the optical behavior and structure of the polythiophenes in conformationally distinct complexes depending on the sequence of nucleic bases and addressed the effect on the ultrafast excited-state relaxation. This, in combination with molecular dynamics simulations, allowed us a detailed atomistic-level understanding of the structure-property correlations. We find that electrostatic and other non-covalent interactions direct the assembly with the polymer and we identify that optimal templating is achieved with (ideally 10-20) consecutive cytosine bases through numerous π-stacking interactions with the thiophene rings and side groups of the polymer, leading to a rigid assembly with ssDNA, with highly ordered chains and unique optical signatures. Our insights are an important step forward in an effective approach to structural templating and optoelectronic control of conjugated polymers and organic materials in general.
Funding Information
  • Université de Montpellier
  • University of Cyprus
  • Centre National de la Recherche Scientifique
  • University of Bern
  • Fonds De La Recherche Scientifique - FNRS (EOS 30650939, MIS/F.4532.16)
  • H2020 European Research Council (714586)

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