Charge-transfer excitons in strongly coupled organic semiconductors
Résumé
Time-resolved and temperature-dependent photoluminescence measurements on one-dimensional sexithiophene lattices reveal intrinsic branching of photoexcitations to two distinct species: self-trapped excitons and dark charge-transfer excitons (CTXs; ≳5% yield), with radii spanning 2–3 sites. The significant charge-transfer exciton (CTX) yield results from the strong charge-transfer character of the Frenkel exciton band due to the large free-exciton bandwidth (∼400 meV) in these supramolecular nanostructures.