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Michael Grätzel

Bio: Michael Grätzel is an academic researcher from École Polytechnique Fédérale de Lausanne. The author has contributed to research in topics: Dye-sensitized solar cell & Perovskite (structure). The author has an hindex of 248, co-authored 1423 publications receiving 303599 citations. Previous affiliations of Michael Grätzel include University of California, Berkeley & Siemens Energy Sector.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a statistical model describing the distribution of solubilizate molecules in micellar systems is developed on the basis of their kinetic interaction with the host aggregates.
Abstract: A statistical model describing the distribution of solubilizate molecules in micellar systems is developed on the basis of their kinetic interaction with the host aggregates. The distribution function obtained corresponds to a Poisson law governing the occupancies of individual micelles by quest molecules. This model provides the basis for the development of a theory which treats the behavior of pyrene fluorescence emission in micellar systems. Solutions of this fluorophore in cetyltrioxyethylene sulfate micelles were examined experimentally both by steady‐state and time‐resolved fluorescence techniques. The results obtained are in excellent agreement with the predictions of the model. From this analysis the rate constant for the intramicellar encounter of two pyrene molecules was derived as ke=9×106 s−1. The aggregation number of CTOES was determined as 96 surfactant molecules/micelle.

131 citations

Book ChapterDOI
01 Jan 2007
TL;DR: In this article, the authors discuss the historical background of sensitization phenomenon, operating principles of dye-sensitized solar cells, tuning of photophysical and electrochemical properties of sensitizers, and evolution of photovoltaic performance.
Abstract: The aim of this chapter is to give an in-depth analysis of transition metal complexes that areuseful in conversion of solar energy into electricity, and in organic light emitting diodes. In thefirst part we discuss the historical background of sensitization phenomenon, operating principlesof dye-sensitized solar cells, tuning of photophysical and electrochemical properties of sensitizers,evolution of photovoltaic performance, present status and future prospects for dye-sensitized solarcells. In the second part, we elucidate the modulation of phosphorescent color and quantum yieldsin neutral, cationic, and anionic iridium complexes and their application in light emitting devices.

131 citations

Journal ArticleDOI
TL;DR: In this paper, an unsymmetrical alkoxy zinc phthalocyanine based on push-pull concept was synthesized and fully characterized by CHN, MALDI-TOF, UV-Vis, fluorescence spectroscopies and cyclic voltammetry.

131 citations

Journal ArticleDOI
TL;DR: In this paper, a TiO2-protected Cu2O photocathode paired with a rhenium bipyridyl catalyst was used to accelerate CO2 reduction to CO2.
Abstract: Photoelectrochemical reduction of CO2 to CO was driven by a TiO2-protected Cu2O photocathode paired with a rhenium bipyridyl catalyst. Efficient and selective CO evolution was shown to be stable over several hours. The use of protic solution additives to overcome severe semiconductor-to-catalyst charge transfer limitations provided evidence of a modified catalytic pathway.

130 citations

Journal ArticleDOI
TL;DR: In this paper, a low molecular weight amphiphilic organogelator capable of forming intermolecular hydrogen bonds and well-organized supramolecular structures was found to efficiently gel low-viscosity binary mixtures of ionic liquids at low concentrations.
Abstract: A low molecular weight amphiphilic organogelator capable of forming intermolecular hydrogen bonds and well-organized supramolecular structures was found to efficiently gel low-viscosity binary mixtures of ionic liquids at low concentrations. With this gelator it is possible to prepare stable quasi-solid-state dye-sensitized solar cells (DSCs). At a gelator concentration of only 2 wt%, the sol–gel transition temperature (Tgel) based on the lowest viscosity ionic liquid mixture was at 108 °C, well above the service temperature. Due to the thermoreversible nature of the system, the cells can be conveniently filled with a low-viscosity liquid. Upon cooling and formation of the gel a mechanically stable quasi-solid-state electrolyte was obtained. We successfully employed this quasi-solid ionic liquid electrolyte in DSCs and obtained an efficiency of 6.3% at full sunlight irradiation and maintained its stability during the light soaking accelerating stress test at 60 °C over 1000 h.

130 citations


Cited by
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Journal ArticleDOI

[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

01 May 1993
TL;DR: Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems.
Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

29,323 citations

Journal ArticleDOI
24 Oct 1991-Nature
TL;DR: In this article, the authors describe a photovoltaic cell, created from low-to medium-purity materials through low-cost processes, which exhibits a commercially realistic energy-conversion efficiency.
Abstract: THE large-scale use of photovoltaic devices for electricity generation is prohibitively expensive at present: generation from existing commercial devices costs about ten times more than conventional methods1. Here we describe a photovoltaic cell, created from low-to medium-purity materials through low-cost processes, which exhibits a commercially realistic energy-conversion efficiency. The device is based on a 10-µm-thick, optically transparent film of titanium dioxide particles a few nanometres in size, coated with a monolayer of a charge-transfer dye to sensitize the film for light harvesting. Because of the high surface area of the semiconductor film and the ideal spectral characteristics of the dye, the device harvests a high proportion of the incident solar energy flux (46%) and shows exceptionally high efficiencies for the conversion of incident photons to electrical current (more than 80%). The overall light-to-electric energy conversion yield is 7.1-7.9% in simulated solar light and 12% in diffuse daylight. The large current densities (greater than 12 mA cm-2) and exceptional stability (sustaining at least five million turnovers without decomposition), as well as the low cost, make practical applications feasible.

26,457 citations

28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

18,940 citations

Journal ArticleDOI
TL;DR: The slow pace of hazardous waste remediation at military installations around the world is causing a serious delay in conversion of many of these facilities to civilian uses as discussed by the authors, which is a serious problem.
Abstract: The civilian, commercial, and defense sectors of most advanced industrialized nations are faced with a tremendous set of environmental problems related to the remediation of hazardous wastes, contaminated groundwaters, and the control of toxic air contaminants. For example, the slow pace of hazardous waste remediation at military installations around the world is causing a serious delay in conversion of many of these facilities to civilian uses. Over the last 10 years problems related to hazardous waste remediation have emerged as a high national and international priority.

17,188 citations