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- Aranyos, Viviane
(författare)
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Dyes and their adsorption onto nanocrystalline TiO2 electrodes : Synthesis, characterisation and applications
- 2000
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The syntheses of two type of dyes (phthalocyanine and ruthenium tris-bipyridyl) are presented here. Their characterisation involves the use of cyclic voltammetry, NMR- and UV-visible spectroscopy. Once adsorbed on nanocrystalline TiO2 electrodes, their electrochemical, spectroelectrochemical and photoelectrochemical properties were investigated.In the first part, the syntheses of aryl-substituted phthalocyanines are described. The key intermediate, an aryl-substituted phthalonitrile, was prepared by a Pd(0)-catalysed Stille-coupling. The physical properties of tetra-(2,5-dirnetoxyphenyl)phthalocyanine (1a), tetraphenylphthalocyanine (1b) are discussed, An interesting display behaviour was characterised by spectroelectrochemistry in the case of 1b. Considering the system, unexpectedly high efficiencies of the resulting solar cells are observed for both dyes.The second part deals with two types of ruthenium tris-bipyridyl complexes. Syntheses of three carboxylated heteroleptic ruthenium complexes [Ru(bpy)2(bpy-R)](PF6)2 (bpy-R, R= (COOLi)n, n= 1, 2, 4) were synthesised for a study of the influence of the number of carboxylic groups on solar cell efficiencies. A lateral electron transfer mechanism for the dyes adsorbed on TiO2, is observed. Homoleptic and heteroleptic ruthenium complexes possessing the polymerisable groups vinyl, methoxyphenyl or thiophene were prepared for an investigation of the substituent effect on the dye-monolayer in the solar cell, both by electrochemistry and absorption spectroscopy. The methoxyphenyl-substituted complexes showed good polymerisation behaviour both at negative and at positive potentials. They also showed good resistance towards water when adsorbed onto TiO2 electrodes.
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| 2. |
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| 3. |
- Aranyos, Viviane, et al.
(författare)
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Electropolymerisable bipyridine ruthenium(II) complexes: synthesis, spectroscopic and electrochemical characterisation of 4-((2-thienyl)ethenyl)-and 4,4'-di((2-thienyl) ethenyl)-2,2'-bipyridine ruthenium complexes
- 2004
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Ingår i: Polyhedron. ; 23, s. 589-598
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Tidskriftsartikel (refereegranskat)abstract
- Four new ruthenium polypyridyl complexes with mono- or di-((2-thienyl) ethenyl) substituted bipyridines have been synthesized. The complexes were characterized by NMR, elemental analysis, UV-Vis absorption and electrochemistry (differentioal pulse and cyclic voltammetry). Electroactive polymer films of these complexes have been prepared by oxidative electropolymerisation and characterized by UV-Vis absorption spectroscopy and electrochemistry. The electrochemically induced polymerisation of the complexes resulted in a significant shift of the oxidation potential of the Ru(II)-Ru(III) process towards more positive potentials. Also, MLCT absorption band of the polymeric complexes is shifted towards shorter wavelengths. These results are interpreted in terms of an interrupiton of the conjugated system of the (2-thienyl)ethenyl-substituted bipyridine ligands due to a radical polymerisation mechanism affecting rather the ethenyl part of the ligand than the thienyl.
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| 4. |
- Aranyos, Viviane, et al.
(författare)
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Free-base tetra-arylphthalocyanines for dye-sensitised nanostructured solar cell applications
- 2001
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Ingår i: JOURNAL OF PORPHYRINS AND PHTHALOCYANINES. - : JOHN WILEY & SONS LTD. - 1088-4246. ; 5:8, s. 609-616
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Tidskriftsartikel (refereegranskat)abstract
- Adsorption of phthalocyanines lacking conventional attaching substituents onto nanostructured TiO2 electrodes has been studied, and some of the important factors for sensitisation have been identified. Tetra-dimethoxyphenyl phthalocyanine (2) and tetra-ph
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| 6. |
- Figgemeier, Egbert, et al.
(författare)
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Modification of electron transfer properties in photoelectrochemical solar cells by substituting {Ru(terpy)(2)}(2+) dyes with thiophene
- 2004
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Ingår i: Inorganic Chemistry Communications. - : Elsevier BV. - 1387-7003 .- 1879-0259. ; 7:1, s. 117-121
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Tidskriftsartikel (refereegranskat)abstract
- A comparison of the properties of the 2-thienyl-substituted carboxyphenyl {RuII(terpy)2} dyes with their non-substituted analogues has enabled us to gain insight into the electronic properties that are prerequisite for efficient electron injection into the TiO2 conduction band in photoelectrochemical solar cells. Introducing the thienyl group has a profound effect upon the efficiency of photoinduced electron injection. This effect can be explained by a significant shift in the LUMO position from the terpy ligand anchored on the TiO2 surface towards the 2-thienyl substituted ligand, which is shown by means of electrochemistry and semiempirical calculations.
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