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Interligand electron transfer determines triplet excited state electron injection in RuN3-sensitized TiO2 films

Benko, Gabor LU ; Kallioinen, J; Myllyperkio, Pasi LU ; Trif, Florentina LU ; Korppi-Tommola, J E I; Yartsev, Arkady LU and Sundström, Villy LU (2004) In The Journal of Physical Chemistry Part B 108(9). p.2862-2867
Abstract
Electron injection from the transition metal complex Ru(dcbpy)(2)(NCS)(2) (dcbpy = 2,2'-bipyridine-4,4'-dicarboxylate) into a titanium dioxide nanoparticle film occurs along two pathways. The dominating part of the electron injection proceeds from the initially excited singlet state of the sensitizer into the conduction band of the semiconductor on the sub-hundred-femtosecond time scale. The slower part of the injection occurs from the thermalized triplet excited state on the picosecond time scale in a nonexponential fashion, as was shown in a previous study (Benko, G.; et al. J. Am. Chem. Soc. 2002, 124, 489). Here we show that the slower channel of injection is the result of the excited state being localized on a ligand of the sensitizer... (More)
Electron injection from the transition metal complex Ru(dcbpy)(2)(NCS)(2) (dcbpy = 2,2'-bipyridine-4,4'-dicarboxylate) into a titanium dioxide nanoparticle film occurs along two pathways. The dominating part of the electron injection proceeds from the initially excited singlet state of the sensitizer into the conduction band of the semiconductor on the sub-hundred-femtosecond time scale. The slower part of the injection occurs from the thermalized triplet excited state on the picosecond time scale in a nonexponential fashion, as was shown in a previous study (Benko, G.; et al. J. Am. Chem. Soc. 2002, 124, 489). Here we show that the slower channel of injection is the result of the excited state being localized on a ligand of the sensitizer that is not attached to the semiconductor; hence, the electron cannot be injected directly from such an excited state into the semiconductor. Before being injected, it has to be transferred from the non-surface-attached ligand to the attached one. The results show that the interligand electron-transfer time is on the picosecond time scale, depends on the relative energies of the two ligands, and controls the electron injection from the excited triplet state of the sensitizer. The findings provide information relevant to the design of molecular-based assemblies and devices. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
The Journal of Physical Chemistry Part B
volume
108
issue
9
pages
2862 - 2867
publisher
The American Chemical Society
external identifiers
  • wos:000220021600018
  • scopus:1542336802
ISSN
1520-5207
DOI
10.1021/jp036778z
language
English
LU publication?
yes
id
601613a5-ad27-4d2f-9ec3-0064802ad799 (old id 139091)
date added to LUP
2007-07-03 10:32:24
date last changed
2017-09-03 04:41:34
@article{601613a5-ad27-4d2f-9ec3-0064802ad799,
  abstract     = {Electron injection from the transition metal complex Ru(dcbpy)(2)(NCS)(2) (dcbpy = 2,2'-bipyridine-4,4'-dicarboxylate) into a titanium dioxide nanoparticle film occurs along two pathways. The dominating part of the electron injection proceeds from the initially excited singlet state of the sensitizer into the conduction band of the semiconductor on the sub-hundred-femtosecond time scale. The slower part of the injection occurs from the thermalized triplet excited state on the picosecond time scale in a nonexponential fashion, as was shown in a previous study (Benko, G.; et al. J. Am. Chem. Soc. 2002, 124, 489). Here we show that the slower channel of injection is the result of the excited state being localized on a ligand of the sensitizer that is not attached to the semiconductor; hence, the electron cannot be injected directly from such an excited state into the semiconductor. Before being injected, it has to be transferred from the non-surface-attached ligand to the attached one. The results show that the interligand electron-transfer time is on the picosecond time scale, depends on the relative energies of the two ligands, and controls the electron injection from the excited triplet state of the sensitizer. The findings provide information relevant to the design of molecular-based assemblies and devices.},
  author       = {Benko, Gabor and Kallioinen, J and Myllyperkio, Pasi and Trif, Florentina and Korppi-Tommola, J E I and Yartsev, Arkady and Sundström, Villy},
  issn         = {1520-5207},
  language     = {eng},
  number       = {9},
  pages        = {2862--2867},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Part B},
  title        = {Interligand electron transfer determines triplet excited state electron injection in RuN3-sensitized TiO2 films},
  url          = {http://dx.doi.org/10.1021/jp036778z},
  volume       = {108},
  year         = {2004},
}