A carbon nanohorn-porphyrin supramolecular assembly for photoinduced electron-transfer processes

María Vizuete, Maria José Gómez-Escalonilla, José Luis G. Fierro, Atula S.D. Sandanayaka, Taku Hasobe, Masako Yudasaka, Sumio Iijima, Osamu Ito, Fernando Langa

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)

Abstract

A supramolecular assembly of zinc porphyrin-carbon nanohorns (CNHs) was constructed in a polar solvent. An ammonium cation was covalently connected to the CNH through a spacer (sp) (CNH-sp-NH3+) and bound to a crown ether linked to a zinc porphyrin (Crown-ZnP). Nanohybrids CNH-sp-NH 3+;Crown-ZnP and CNHsp-NH3+ were characterized by several techniques, such as high-resolution transmission electron microscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, and Raman spectroscopy. The photoinduced electron-transfer processes of the nanohybrids have been confirmed by using time-resolved absorption and fluorescence measurements by combining the steady-state spectral data. Fluorescence quenching of the ZnP unit by CNH-spNH3+ has been observed, therefore, photoinduced charge separation through the excited singlet state of the ZnP unit is suggested for the hybrid material, CNH-sp-NH3+;Crown-ZnP. As transient absorption spectral experiments reveal the formation of the radical cation of the ZnP unit, electron generation is suggested as a counterpart of the charge-separation on the CNHs; such an electron on the CNHs is further confirmed by migrating to the hexylviologen dication (HV2+). Accumulation of the electron captured from HV+ is observed as electron pooling in solution in the presence of a hole-shifting reagent. Photovoltaic performance with moderate efficiency is confirmed for CNH-sp-NH3+;CrownZnP deposited onto nanostructured SnO2 films.

Original languageEnglish
Pages (from-to)10752-10763
Number of pages12
JournalChemistry - A European Journal
Volume16
Issue number35
DOIs
Publication statusPublished - 2010 Sep 17

Keywords

  • Carbon nanohorns
  • Electron transfer
  • Photovoltaic cells
  • Porphyrinoids
  • Supramolecular chemistry

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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