Ensemble and single-molecule spectroscopic study on excitation energy transfer processes in 1,3-phenylene-linked perylenebisimide oligomers

Hee Won Bahng, Min Chul Yoon, Ji Eun Lee, Yuichi Murase, Tomoki Yoneda, Hiroshi Shinokubo, Atsuhiro Osuka, Dongho Kim

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1,3-Phenylene-bridged perylenebisimide dimer (PBI2) and trimer (PBI3) were prepared along with monomer reference (PBI1) using perylene imide-anhydride 5 as a key precursor. 3,3-Dimethylbut-1-yl substituents were introduced at the 2,5-positions of perylenebisimide (PBI) to improve the solubilities of PBI oligomers. Actually, no serious aggregation of PBI2 and PBI3 was detected in their dilute CH2Cl2 solutions. Under these conditions, intramolecular electronic interactions among PBI chromophores have been revealed by measuring the photophysical properties at their ensemble and single-molecule levels. The excitation energy transfer times of PBI2 (0.16 ps) and PBI3 (0.60 ps) were determined from the two different observables, anisotropy depolarization, and singlet-singlet annihilation, respectively, which are considered as the incoherent Förster-type energy hopping (EEH) times as compared with the EEH time constant (1.97 ps) calculated on the basis of the Förster mechanism. The relatively short EEH times compared to similar PBI oligomers can be attributed to 1,3-phenylene linker, which assures a short distance between the chromophores and, as a consequence, makes it hard to treat the PBI unit as a point dipole. The limitation of point-dipole approximation to describe the PBI oligomers and additional through-bond type interactions can be attributed as the causes of the discrepancies in excitation energy transfer times. Considering these photophysical properties, we can suggest that 1,3-phenylene-linked PBI oligomers have potentials as molecular photonic devices including the artificial light-harvesting system.

Original languageEnglish
Pages (from-to)1244-1255
Number of pages12
JournalJournal of Physical Chemistry B
Issue number4
Publication statusPublished - 2012 Feb 2


All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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