Showing papers by "Michael Grätzel published in 1995"
TL;DR: In this article, a comparison of optical and photoelectrochemical properties of the TiO2 layer indicates a relative enhancement of light harvesting efficiency due to lowering of reflection losses in the electrolyte.
417 citations
TL;DR: Reference LPI-ARTICLE-1995-007View record in Web of Science Record created on 2006-02-21, modified on 2017-05-12 as discussed by the authors, created on 2016
Abstract: Reference LPI-ARTICLE-1995-007View record in Web of Science Record created on 2006-02-21, modified on 2017-05-12
407 citations
TL;DR: To anchor transition-metal compounds onto metal oxide surfaces 2,2′:6′,2″-terpyridine-4′-phosphonic acid (4′PO3H2-terpy) is synthesized; strong surface adhesion as well as efficient charge-transfer sensitization of nanocrystalline TiO2 films has been observed with a ruthenium complex involving this ligand as discussed by the authors.
Abstract: To anchor transition-metal compounds onto metal oxide surfaces 2,2′:6′,2″-terpyridine-4′-phosphonic acid (4′-PO3H2-terpy) is synthesized; strong surface adhesion as well as efficient charge-transfer sensitization of nanocrystalline TiO2 films has been observed with a ruthenium complex involving this ligand.
214 citations
TL;DR: The formation of an accumulation layer on a nanocrystalline TiO2 (anatase) electrode was studied by cyclic voltammetry in solutions of MCF3SO3 (M = Li, Na, K, Cs, NBu4; Bu = n-butyl) + propylene carbonate as mentioned in this paper.
198 citations
TL;DR: In this paper, the formation of H-aggregates as a function of solution, substrate and ambient variables is considered for the merocyanine dye 3-acetyl-5-12-(3-ethyl-2-benzothiazolydene) rhodanine.
84 citations
TL;DR: A reusable piezoelectric immunosensor was used for the detection of the human hepatitis viruses type A and type B as mentioned in this paper, where the virus specific monoclonal antibodies were immobilized via protein A onto a 16-MHz AT-cut crystal.
55 citations
TL;DR: In this article, thin films on RuO2 were deposited on glass by metalorganic chemical vapor deposition using tristrifluoroacetylacetonate•ruthenium (III) [Ru(tfa)3] as precursor.
Abstract: Conducting thin films on RuO2 were deposited on glass by metalorganic chemical vapor deposition using tris‐trifluoroacetylacetonate‐ruthenium (III) [Ru(tfa)3] as precursor. Smooth, specular, and well adherent films were grown at temperatures as low as 400 °C, if the reaction gas contained water. RuO2 was the only phase detected by x‐ray diffraction. The films were investigated by spectroscopic ellipsometry in the energy range of 1.5 to 5.0 eV. Thereby, the real (e1) and imaginary (e2) parts of the dielectric function were determined at room temperature. The optical constants could be described by three harmonic oscillators in combination with a Drude term for free‐charge carriers.
30 citations
TL;DR: In this paper, the location of the emitting triplet state in heteroleptic RuII polypyridyl complexes has been determined by a new method using deuteriated ligands and emission-lifetime measurements.
Abstract: The location of the emitting triplet state in heteroleptic RuII polypyridyl complexes has been determined by a new method using deuteriated ligands and emission-lifetime measurements, and a new single-step, high yield synthesis of perdeuteriated 2,2′-bipyridyl has been developed.
27 citations
Patent•
25 Sep 1995TL;DR: In this article, the catalytic properties of the platinum on the reduction reaction of triiodide to iodide were improved by applying a thermal treatment at a temperature in the range of about 375 to 400 °C.
Abstract: The present invention aims at improving the catalytic activity of the metallic platinum deposited on the substrate of the counterelectrode (i.e. the cathode), so as to obtain a high value of the catalytic activity on the reduction reaction of triiodide to iodide essentially independant of the nature of the solvent used in the electrolyte. To that effect, the manufacturing process according to the invention is characterized in that said metallic platinum is deposited in the form of a plurality of spheroidal microcrystallite clusters each having a size of less than about 100 nanometers, dispersed over the surface of said substrate, and in that said deposited metallic platinum is submitted to a thermal treatment, carried out at a temperature in the range of about 375 to 400 °C, so as to enhance the catalytic properties of the platinum on the oxido-reduction reaction of iodine and triiodide 3I2 + 2e- ⇐∊ 2I?3?- in the redox system iodine/iodide.
25 citations
TL;DR: In this paper, a molecular photovoltaic device based on the sensitization of nanocrystalline oxide films by transition metal charge transfer sensitizers has been developed, achieving an overall efficiency of 10% for AM 1.5 solar light to electricity.
Abstract: Solar cells are expected to provide environmentally friendly solutions to the worlds energy supply problem. Learning from the concepts used by green plants we have developed a molecular photovoltaic device whose overall efficiency for AM 1.5 solar light to electricity has already attained 10 %. The system is based on the sensitization of nanocrystalline oxide films by transition metal charge transfer sensitizers. In analogy to photosynthesis, the chemical solar cell achieves the separation of the light absorption and charge carrier transport processes. Extraordinary yields for the conversion of incident photons into electric current are obtained, exceeding 90% for transition metal complexes within the wave-length range of their absorption band. The use of molten salt electrolytes together with coordination complexes of ruthenium as sensitizers has endowed these cells with a remarkable stability making practical applications feasible. Quite aside from their intrinsic merits as photovoltaic device, the mesoscopic oxide semiconductor films developed in our laboratory offer attractive possibilities for a number Of Other applications. Thus, the first example of a briefly discussed.
16 citations
TL;DR: Nanocrystalline TiO2 films were explored for the first time as electrode material for a rechargeable lithium intercalation cell, i.e., Li/LiCF3SO3 as mentioned in this paper.
Abstract: Nanocrystalline TiO2 films were explored for the first time as electrode material for a rechargeable lithium intercalation cell, i.e., Li/LiCF3SO3
TL;DR: In this article, the surface roughness and microstructure of Niobium pentaethoxide precursors with triethylamine (TEA) and Nb(OEt)5 mole ratios of 0.25, 0.4 and 0.8 were discussed.
Abstract: The hydrolysis of niobium pentaethoxide precursor in the presence of triethylamine (TEA) is discussed. Three precursors with TEA/Nb(OEt)5 mole ratios of 0.25, 0.4 and 0.8 were prepared. Niobia colloids with different appearance were obtained after autoclaving the above precursors at 250°C during 12 h. The surface roughness and microstructure of niobia films prepared with the colloids by spread coating method are strongly dependent on the TEA/Nb(OEt)5 mole ratio. At a value of 0.4 TEA/Nb(OEt)5 mole ratio, a niobia film with large surface roughness can be achieved. It is opaque and mechanically stable and has differently ordered needle microstructure. The crystalline structure and photoelectrochemical property of niobia film with the largest surface roughness were examined. The effect of CO2 gas bubbling, reflux and addition of 2-methoxyethanol on the hydrolysis of Nb(OEt)5 and the nature of the Nb2O5 films is also discussed.
TL;DR: In this paper, the modified Ullmann reaction was applied to 2-chloro-3-trifluoromethylpyridine (2,2′-bipyridine).
TL;DR: In this paper, the triplet and singlet state properties of the title compound were investigated and electron transfer from the singlet excited state to methyl viologen in acetonitrile produced the corresponding free radicals which recombine with second-order kinetics.
Abstract: The triplet and singlet state properties of the title compound are reported: nitroxyl free radicals and oxygen enhance the triplet yield significantly; electron transfer from the singlet excited state to methyl viologen in acetonitrile produced the corresponding free radicals which recombine with second-order kinetics.
TL;DR: In this paper, the Ames test was used to evaluate the mutagenic activity of tris-(4,4′-substituted-2,2′-bipyridine) complexes.
Abstract: Five novel tris-(4,4′-substituted-2,2′-bipyridine) complexes of the group VIII metals [Fe(II), Ru(II) and Os(II)] (all having been previously examined electrochemically with respect to their ability to act as electron-transfer mediators for redox enzymes) were assayed in the Ames test to evaluate their mutagenic activity. For the bipyridine complexes, some complexes did exhibit mutagenic activity in the circumstances of this test, whereas others did not. this is comparable to the results known from the literature for ferrocene mediators. There was no specific correlation with the identities of the metal and ligand type; the possible explanations of the results are discussed in this paper. It seems probable that the penetration of the whole compound inside bacterial cells depends on the organic part of a complex, with only then the possible genotoxic activity of the complex being revealed. In view of our mutagenic test results, such complexes found to be mutagenic should not be taken into consideration as components of implanted glucose sensors in future in vivo experiments.