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2006-01-18 - Article/Dans un journal avec peer-review - Anglais - 9 page(s)

Beckers E.H.A., Meskers S.C.J., Schenning A.P.H.J., Chen Z., Würthner F., Marsal Philippe, Beljonne David , Cornil Jérôme , Janssen R.A.J., "The Influence of the Intermolecular Orientation on the Photoinduced Charge Transfer Kinetics in Self-Assembled Aggregates of Donor-Acceptor Arrays" in Journal of the American Chemical Society, 128, 2, 649-657

  • Edition : American Chemical Society, Washington (DC)
  • Codes CREF : Chimie des surfaces et des interfaces (DI1327), Physique de l'état solide (DI1261), Chimie quantique (DI1321), Spectroscopie [électromagnétisme, optique, acoustique] (DI1255)
  • Unités de recherche UMONS : Chimie des matériaux nouveaux (S817)
  • Instituts UMONS : Institut de Recherche en Science et Ingénierie des Matériaux (Matériaux)
Texte intégral :

Abstract(s) :

(Anglais) The kinetics of photoinduced charge transfer reactions in covalently linked donor-acceptor molecules often undergoes dramatic changes when these molecules self-assemble from a molecular dissolved state into a nanoaggregate. Frequently, the origin of these changes is only partially understood. In this paper, we describe the intermolecular spatial organization of three homologous arrays, consisting of a central perylene bisimide (PERY) acceptor moiety and two oligo(p-phenylene vinylene) (OPV) donor units, in nanoaggregates and identify both face-to-face (H-type) and slipped (J-type) stacking of the OPV and PERY chromophores. For the J-type aggregates, short intermolecular OPV-PERY distances are created that give rise to a charge-transfer absorption band. The proximity of the donor and acceptor groups in the J-type aggregates enables a highly efficient photoinduced charge separation with a rate (kcs > 1012 s-1) that significantly exceeds the rate of the intramolecular charge transfer of the same compounds when molecularly dissolved, even in the most polar media. In the H-type aggregates, on the other hand, the intermolecular OPV-PERY distance is not reduced compared to the intramolecular separation, and hence, the rates of the electron transfer reactions are not significantly affected compared to the molecular dissolved state. Similar to the forward electron transfer, the kinetics of the charge recombination in the aggregated state can be understood by considering the different interchromophoric distances that occur in the H- and J-type aggregates. These results provide the first consistent rationalization of the remarkable differences that are observed for photoinduced charge-transfer reactions of donor-acceptor compounds in molecularly dissolved versus aggregated states.

Notes :
  • (Anglais) Publié le 16 décembre 2005
Identifiants :
  • DOI : 10.1021/ja0568042