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Supramolecular Control of Charge‐Transfer Dynamics on Dye‐sensitized Nanocrystalline TiO 2 Films
Author(s) -
Hirata Narukuni,
Lagref JeanJacques,
Palomares Emilio J.,
Durrant James R.,
Nazeeruddin M. Khaja,
Gratzel Michael,
Di Censo Davide
Publication year - 2004
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.200305408
Subject(s) - nanocrystalline material , moiety , electron transfer , molecule , quantum tunnelling , materials science , photochemistry , electron , excitation , chemical physics , chemistry , nanotechnology , stereochemistry , optoelectronics , organic chemistry , physics , engineering , quantum mechanics , electrical engineering
A [Ru(dcbpy) 2 (NCS) 2 ] dye has been chemically modified by the addition of a secondary electron donor moiety, N , N ‐(di‐ p ‐anisylamino)phenoxymethyl. Optical excitation of the modified dye adsorbed to nanocrystalline TiO 2 films shows a remarkably long‐lived charge‐separated state, with a decay half time of 0.7 s. Semiempirical calculations confirm that the HOMO of the modified dye molecule is localised on the electron donor group. The retardation of the recombination dynamics relative to the unmodified control dye is caused by the increase in the spatial separation of the HOMO orbital from the TiO 2 surface. The magnitude of the retardation is shown to be in agreement with that predicted from the non‐adiabatic electron‐tunnelling theory.