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URN to cite this document: urn:nbn:de:bvb:703-epub-4786-5
Title data
Li, Xiaoe ; Nazeeruddin, Mohammad K. ; Thelakkat, Mukundan ; Barnes, Piers R. F. ; Vilar, Ramon ; Durrant, James R.:
Spectroelectrochemical studies of hole percolation on functionalised nanocrystalline TiO2 films : a comparison of two different ruthenium complexes.
In: Physical Chemistry Chemical Physics.
Vol. 13
(2011)
Issue 4
.
- pp. 1575-1584.
ISSN 1463-9076
DOI der Verlagsversion: https://doi.org/10.1039/c0cp01013h
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Abstract
We report the application of spectroelectrochemical techniques to compare the hole percolation dynamics of molecular networks of two ruthenium bipyridyl complexes adsorbed onto mesoporous, nanocrystalline TiO2 films. The percolation dynamics of the ruthenium complex cis-di(thiocyanato)(2,2'-bipyridyl-4,4'-dicarboxylic acid)-(2,2'-bipyridyl-4,4'-tridecyl) ruthenium(II), N621, is compared with those observed for an analogous dye with an additional tri-phenyl amine (TPA) donor moiety, cis-di(thiocyanato)(2,2'-bipyridyl-4,4'-dicarboxylic acid)-(2,2'-bipyridyl-4,4'-bis(vinyltriphenylamine)) ruthenium(II), HW456. The in situ oxidation of these ruthenium complexes adsorbed to the TiO2 films is monitored by cyclic voltammetry and voltabsorptometry, whilst the dynamics of hole (cation) percolation between adsorbed ruthenium complexes is monitored by potentiometric spectroelectrochemistry and chronoabsorptometry. The hole diffusion coefficient, D-eff, is shown to be dependent on the dye loading on the nanocrystalline TiO2 film, with a threshold observed at similar to 60% monolayer surface coverage for both dyes. The hole diffusion coefficient of HW456 is estimated to be 2.6 x 10(-8) cm(2)/s, 20-fold higher than that obtained for the control N621, attributed to stronger electronic coupling between the TPA moieties of HW456 accelerating the hole percolation dynamics. The presence of mercuric ions, previously shown to bind to the thiocyanates of analogous ruthenium complexes, resulted in a quenching of the hole percolation for N621/TiO2 films and an enhancement for HW456/TiO2 films. These results strongly suggest that the hole percolation pathway is along the overlapped neighbouring -NCS groups for the N621 molecules, whereas in HW456 molecules cation percolation proceeds between intermolecular TPA ligands. These results are discussed in the context of their relevance to the process of dye regeneration in dye sensitised solar cells, and to the molecular wiring of wide bandgap inorganic materials for battery and sensing applications.
Further data
| Item Type: | Article in a journal |
|---|---|
| Additional notes (visible to public): | ISI:000286056400038 |
| DDC Subjects: | 500 Science > 530 Physics 500 Science > 540 Chemistry |
| Institutions of the University: | Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Professor Applied Functional Polymers > Professor Applied Functional Polymers - Univ.-Prof. Dr. Mukundan Thelakkat Faculties Faculties > Faculty of Biology, Chemistry and Earth Sciences Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Professor Applied Functional Polymers |
| Language: | English |
| Originates at UBT: | Yes |
| URN: | urn:nbn:de:bvb:703-epub-4786-5 |
| Date Deposited: | 08 Sep 2020 07:24 |
| Last Modified: | 08 Sep 2020 07:24 |
| URI: | https://epub.uni-bayreuth.de/id/eprint/4786 |
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