Electronic interplay on illuminated aqueous carbon nanohorn-porphyrin ensembles

Georgia Pagona, Atula S.D. Sandanayaka, Yasuyuki Araki, Jing Fan, Nikos Tagmatarchis, Masako Yudasaka, Sumio Iijima, Osamu Ito

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84 Citations (Scopus)


Tetracationic water-soluble porphyrin (H2P4+) has been immobilized by π-π stacking interactions onto the skeleton of carbon nanohorns (CNH), without disrupting their π-electronic network. The stable aqueous solution of the CNH-H2P4+ nanoensemble was examined by both electron microscopy and spectroscopic techniques. The efficient fluorescence quenching of the H2P4+ moiety in the CNH-H2P4+ nanoensemble was probed by steady-state as well as time-resolved fluorescence emission spectroscopy, suggesting charge separation from the photoexcited H2P4+ to CNH. In the presence of methyl viologen dication (MV2+) and a hole trap, accumulation of the reduced species of methyl viologen was observed by the photoillumination of CNH-H2P4+, suggesting that the electron migration from the initially formed charge-separated state takes place. Transient absorption spectroscopy gave further insights on the transient species such as the charge-separated state (CNH.-)-(H 2P4+).+, which was consumed in the presence of MV2+ and hole shifter, leaving the reduced methyl viologen.

Original languageEnglish
Pages (from-to)20729-20732
Number of pages4
JournalJournal of Physical Chemistry B
Issue number42
Publication statusPublished - 2006 Oct 26

ASJC Scopus subject areas

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


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