Abstract
The Z-Scheme function within molecular systems has been rarely reported for solar energy conversion although it offers the possibility to achieve higher efficiency than single photon absorber photosystems due to the use of a wider range of visible light. In this study, we synthesized and investigated the electrochemical and spectroscopic properties of two new dyads based on ruthenium and osmium tris-bipyridine complexes covalently linked via a butane bridge to explore their ability to realize the Z-scheme function once immobilized on TiO2. These dyads can be grafted onto a nanocrystalline TiO2 film via the osmium complex bearing two dicarboxylic acid bipyridine ligands, while the ruthenium complex contains either two unsubstituted bipyridine ancillary ligands (RuH-Os) or two (4,4′-bis-trifluoromethyl-bipyridine) ancillary ligands (RuCF3-Os). Transient absorption spectroscopy studies of the Ru(II)-Os(III) dyads with femtosecond and nanosecond lasers were conducted both in solution and on TiO2. For both conditions, the photophysical studies revealed that the MLCT excited state of the ruthenium complex is strongly quenched and predominantly decays by energy transfer to the LMCT of the adjacent Os(III) complex, in spite of the high driving force for electron transfer. This unexpected result, which is in sharp contrast to previously reported Ru(II)-Os(III) dyads, precluded us to achieve the expected Z-scheme function. However, the above results may be a guide for designing new artificial molecular systems reproducing the complex function of a Z-scheme with molecular systems grafted onto a TiO2 mesoporous film.
| Original language | English |
|---|---|
| Pages (from-to) | 4778-4786 |
| Number of pages | 9 |
| Journal | Physical Chemistry Chemical Physics |
| Volume | 19 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - 2017 |
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ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry
Cite this
Tris-bipyridine based dinuclear ruthenium(II)-osmium(III) complex dyads grafted onto TiO2 nanoparticles for mimicking the artificial photosynthetic Z-scheme. / Favereau, Ludovic; Makhal, Abhinandan; Provost, David; Pellegrin, Yann; Blart, Errol; Göransson, Erik; Hammarström, Leif; Odobel, Fabrice.
In: Physical Chemistry Chemical Physics, Vol. 19, No. 6, 2017, p. 4778-4786.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Tris-bipyridine based dinuclear ruthenium(II)-osmium(III) complex dyads grafted onto TiO2 nanoparticles for mimicking the artificial photosynthetic Z-scheme
AU - Favereau, Ludovic
AU - Makhal, Abhinandan
AU - Provost, David
AU - Pellegrin, Yann
AU - Blart, Errol
AU - Göransson, Erik
AU - Hammarström, Leif
AU - Odobel, Fabrice
PY - 2017
Y1 - 2017
N2 - The Z-Scheme function within molecular systems has been rarely reported for solar energy conversion although it offers the possibility to achieve higher efficiency than single photon absorber photosystems due to the use of a wider range of visible light. In this study, we synthesized and investigated the electrochemical and spectroscopic properties of two new dyads based on ruthenium and osmium tris-bipyridine complexes covalently linked via a butane bridge to explore their ability to realize the Z-scheme function once immobilized on TiO2. These dyads can be grafted onto a nanocrystalline TiO2 film via the osmium complex bearing two dicarboxylic acid bipyridine ligands, while the ruthenium complex contains either two unsubstituted bipyridine ancillary ligands (RuH-Os) or two (4,4′-bis-trifluoromethyl-bipyridine) ancillary ligands (RuCF3-Os). Transient absorption spectroscopy studies of the Ru(II)-Os(III) dyads with femtosecond and nanosecond lasers were conducted both in solution and on TiO2. For both conditions, the photophysical studies revealed that the MLCT excited state of the ruthenium complex is strongly quenched and predominantly decays by energy transfer to the LMCT of the adjacent Os(III) complex, in spite of the high driving force for electron transfer. This unexpected result, which is in sharp contrast to previously reported Ru(II)-Os(III) dyads, precluded us to achieve the expected Z-scheme function. However, the above results may be a guide for designing new artificial molecular systems reproducing the complex function of a Z-scheme with molecular systems grafted onto a TiO2 mesoporous film.
AB - The Z-Scheme function within molecular systems has been rarely reported for solar energy conversion although it offers the possibility to achieve higher efficiency than single photon absorber photosystems due to the use of a wider range of visible light. In this study, we synthesized and investigated the electrochemical and spectroscopic properties of two new dyads based on ruthenium and osmium tris-bipyridine complexes covalently linked via a butane bridge to explore their ability to realize the Z-scheme function once immobilized on TiO2. These dyads can be grafted onto a nanocrystalline TiO2 film via the osmium complex bearing two dicarboxylic acid bipyridine ligands, while the ruthenium complex contains either two unsubstituted bipyridine ancillary ligands (RuH-Os) or two (4,4′-bis-trifluoromethyl-bipyridine) ancillary ligands (RuCF3-Os). Transient absorption spectroscopy studies of the Ru(II)-Os(III) dyads with femtosecond and nanosecond lasers were conducted both in solution and on TiO2. For both conditions, the photophysical studies revealed that the MLCT excited state of the ruthenium complex is strongly quenched and predominantly decays by energy transfer to the LMCT of the adjacent Os(III) complex, in spite of the high driving force for electron transfer. This unexpected result, which is in sharp contrast to previously reported Ru(II)-Os(III) dyads, precluded us to achieve the expected Z-scheme function. However, the above results may be a guide for designing new artificial molecular systems reproducing the complex function of a Z-scheme with molecular systems grafted onto a TiO2 mesoporous film.
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U2 - 10.1039/c6cp06679h
DO - 10.1039/c6cp06679h
M3 - Article
VL - 19
SP - 4778
EP - 4786
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
SN - 1463-9076
IS - 6
ER -