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Electron transfer dynamics of peptide‐derivatized Ru II ‐polypyridyl complexes on nanocrystalline metal oxide films
Author(s) -
Hanson Kenneth,
Wilger Dale J.,
Jones Sean T.,
Harrison Daniel P.,
Bettis Stephanie E.,
Luo Hanlin,
Papanikolas John M.,
Waters Marcey L.,
Meyer Thomas J.
Publication year - 2013
Publication title -
peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.22152
Subject(s) - chemistry , electron transfer , nanocrystalline material , chromophore , excited state , quenching (fluorescence) , photochemistry , cyclic voltammetry , oxide , tin oxide , crystallography , electrode , fluorescence , electrochemistry , organic chemistry , atomic physics , physics , quantum mechanics
The performance of dye‐sensitized solar and photoelectrochemical cells is strongly dependent on the electron transfer events at the electrode‐sensitizer interface. Surface‐bound peptides derivatized with chromophores have not been used in dye‐sensitized solar and photoelectrochemical cells, but they have properties for these applications that could be advantageous by exploiting secondary structure and the attachment of multiple chromophores. In this manuscript, we have investigated structure–property relationships for three metallopeptide‐based assemblies to solution and chemically bound to nanocrystalline MO 2 (M = Ti, Zr) films. A particular interest was exploring the influence of increasing separation distance between a common chromophore, [Ru(bpy) 2 (4‐Me‐4′‐(NHCO)bpy)] 2+ , and the underlying oxide substrate on excited and ground state electron transfer. Rates of Ru(II) oxidation to Ru(III) at the interface were measured by cyclic voltammetry on fluorine‐doped tin oxide and cross‐surface electron transfer on TiO 2 . Excited state injection by [Ru III (bpy) 2 (bpy − )] 2+ was monitored by transient absorption and time‐resolved emission. There are discernible trends in the electron transfer rate data with approximated, fully extended distances between the [Ru(bpy) 2 (4‐Me‐4′‐(NHCO)bpy)] 2+ sites and the interface. However, the distance dependences that are observed are smaller than anticipated, a result consistent with a lack of ordered secondary structure in the surface‐bound peptide chains and a distribution of local orientations. For the surface‐bound excited states, only a small fraction undergo quenching by electron transfer to TiO 2 , presumably from those oriented near the surface. © 2012 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 100: 25–37, 2013.