Self assembling of porphyrin-fullerene dyads in the Langmuir and Langmuir-Blodgett films: Formation as well as spectral, electrochemical and vectorial electron transfer studies

Renata Marczak, Krzysztof Noworyta, Robert Nowakowski, Wlodzimierz Kutner, Bernard Desbat, Yasuyaki Araki, Osamu Ito, Suresh Gadde, Melvin E. Zandler, Francis D'Souza

研究成果: Article査読

5 被引用数 (Scopus)

抄録

Donor-acceptor dyads of water-soluble Zn porphyrins and C 60 bearing either pyridine or imidazole ligand were self assembled via axial coordination in Langmuir and Langmuir-Blodgett (LB) films. Compression and surface potential versus area per molecule isotherms as well as ellipsometry and BAM measurements showed that molecules were aggregated in all Langmuir films before compression. The area per molecule in the absence of aggregation was determined by linear extrapolation of the area at the zero surface pressure to infinite adduct dilution. Comparison of the extrapolated and theoretically calculated areas, being dependent on the composition of the subphase solution, indicated that dyads were oriented with their porphyrin macrocycles in plane of the air-solution interface. Calculated by molecular modeling thickness of the Langmuir films was in accord with that determined by ellipsometry. The Langmuir films were transferred, by using the LB technique, onto different solid substrates for spectroscopic, microscopic, electroanalytical, and photochemical characterization. From the IR spectroscopy investigations it followed that the porphyrin macrocycle of the dyad was either nearly parallel or tilted with respect to the substrate plane. Molecularly modeled pseudo-hexagonal packing and thickness of the LB films were in accord with that imaged by STM and determined by ellipsometry, respectively. The electrochemical redox states of the dyads were established by performing simultaneous cyclic voltammetry and piezoelectric microgravimetry measurements of the LB films on Au-quartz electrodes. Both steady-state and time-resolved emission studies of the zinc porphyrin-fullerene LB films revealed efficient quenching of the singlet-excited Zn porphyrin. Based on the free-energy calculations and dyad orientation in the film, this quenching was attributed to vectorial electron transfer within the dyad.

本文言語English
ページ(範囲)1455-1471
ページ数17
ジャーナルJournal of Nanoscience and Nanotechnology
7
4-5
DOI
出版ステータスPublished - 2007 4

ASJC Scopus subject areas

  • バイオエンジニアリング
  • 化学 (全般)
  • 生体医工学
  • 材料科学(全般)
  • 凝縮系物理学

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