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Surface‐Grafted Multiporphyrin Arrays as Light‐Harvesting Antennae to Amplify Photocurrent Generation
Author(s) -
Morisue Mitsuhiko,
Yamatsu Shigeru,
Haruta Noriko,
Kobuke Yoshiaki
Publication year - 2005
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200500040
Subject(s) - photocurrent , monolayer , electrode , electrolyte , photochemistry , chemistry , substrate (aquarium) , viologen , materials science , nanotechnology , optoelectronics , oceanography , geology
Organized multiporphyrin arrays were developed on the conductive surface by a novel coordination‐directed molecular architecture aiming at efficient photoelectric conversion. The basic strategy employs the mutual coordination of two imidazolylporphyrinatozinc( II ) units to form a cofacial dimer. Thus, meso , meso ‐linked bis(imidazolylporphyrinatozinc) (Zn 2 (ImP) 2 ) was organized onto imidazolylporphyrinatozinc on the gold substrate as a self‐assembled monolayer. The organized Zn 2 (ImP) 2 bearing allyl side chains was covalently linked by ring‐closing olefin metathesis catalyzed with Grubbs catalyst. Alternating coordination/metathesis reactions allow the stepwise accumulation of multiporphyrin arrays on the gold electrode. A successive increase in absorption over a wide wavelength range occurred after each accumulation step of Zn 2 (ImP) 2 on the gold electrode, and cathodic photocurrent generation was enhanced in the aqueous electrolyte system, containing viologen as an electron carrier. The significant increase of the photocurrent indicates that the multiporphyrin array works as a “light‐harvesting antenna” on the gold electrode.