Energy Transport along Conjugated Polymer Chains: Through-Space or Through-Bond?

Authors


  • This work was supported by the European Commission through the STREP project MODECOM (NMP-CT-2006-016434). The authors gratefully acknowledge the Belgian National Fund for Scientific Research (FNRS-FRFC) for its financial support. E. H. and D. B. are FNRS Postdoctoral Research Fellow and Research Associate, respectively. B. V. A. acknowledges a grant from FRIA (‘Fonds pour la Formation à la Recherche dans l'Industrie et dans l'Agriculture’).

Abstract

On the basis of a quantum-chemical description of the lowest singlet electronic excited states of bi-chromophoric model systems, we have disentangled the through-bond (TB) from the through-space (TS) contributions to the electronic interactions mediating energy hopping in rigid-rod conjugated polymers. While TB interactions lead to significant mixing between local and charge-transfer excitations in the ground-state (acceptor) configuration, this effect is reduced in the excited-state (donor) configuration as a result of the self-confinement induced by geometric relaxation phenomena. Thus, an improved Förster-type hopping model retaining only long-range TS contributions between donors and acceptors but accounting for excited-state delocalization among acceptors (possibly driven by TB interactions) appears as a minimal model to treat excitation transport along polymer chains.

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