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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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TL;DR: In this paper, a rapid dismantling process is proposed to recover all major components, saving raw materials, energy and production time in the fabrication of recycled perovskite solar cells.
Abstract: Perovskite solar cells based on CH3NH3PbI3 and related materials have reached impressive efficiencies that, on a lab scale, can compete with established solar cell technologies, at least in short-term observations. Despite frequently voiced concerns about the solubility of the lead salts that make up the absorber material, several life cycle analyses have come to overall positive conclusions regarding the environmental impact of perovskite solar cell (PSC) production. Their particularly short energy payback time (EBPT) in comparison to other established PV technologies makes them truly competitive. Several studies have identified valuable components such as FTO, gold and high temperature processes as the most significant contributors to the environmental impact of PSCs. Considering these findings, we have developed a rapid dismantling process allowing the recovery of all major components, saving raw materials, energy and production time in the fabrication of recycled PSCs. We demonstrate that the performance of PSCs fabricated from recycled substrates can compete with that of devices fabricated from virgin materials.

97 citations

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TL;DR: In this paper, metal-free organic donor-π acceptor dyes were synthesized using electron-rich 10-butyl-(2-methylthio)-10H-phenothiazine as a donor and cyanoacrylic acid as an acceptor.
Abstract: Two novel metal-free organic donor–π–acceptor dyes were synthesized using electron-rich 10-butyl-(2-methylthio)-10H-phenothiazine as a donor and cyanoacrylic acid as an acceptor. The spectral response of the dye was tuned by introducing a vinylene thiophene π-bridge. Obtained optical and electrochemical properties of the dyes seemed to be promising in terms of employing them as light harvesters in dye-sensitized solar cells (DSCs). The efficiencies of the devices under standard AM 1.5G (100 mW cm−2) conditions reached 7.3% with volatile electrolyte. The differences in the photovoltaic parameters of these DSCs were explained by comparing the results of electrochemical impedance spectroscopy (EIS) measurements and transient photovoltage and photocurrent decay experiments.

96 citations

Journal ArticleDOI
TL;DR: In this paper, quasi type-II PbSe/PbS quantum dots (QDs) are employed in a solid state high efficiency QD/TiO2 heterojunction solar cell.
Abstract: Quasi type-II PbSe/PbS quantum dots (QDs) are employed in a solid state high efficiency QD/TiO2 heterojunction solar cell. The QDs are deposited using layer-by-layer deposition on a half-micrometer-thick anatase TiO2 nanosheet film with (001) exposed facets. Theoretical calculations show that the carriers in PbSe/PbS quasi type-II QDs are delocalized over the entire core/shell structure, which results in better QD film conductivity compared to PbSe QDs. Moreover, PbS shell permits better stability and facile electron injection from the QDs to the TiO2 nanosheets. To complete the electrical circuit of the solar cell, a Au film is evaporated as a back contact on top of the QDs. This PbSe/PbS QD/TiO2 heterojunction solar cell produces a light to electric power conversion efficiency () of 4% with short circuit photocurrent (Jsc) of 17.3 mA/cm2. This report demonstrates highly efficient core/shell near infrared QDs in a QD/TiO2 heterojunction solar cell.

96 citations

Journal ArticleDOI
TL;DR: In this article, photoinduced electron injection from eosin Y into the conduction band of titanium dioxide was further scrutinized, as previous studies on the charge injection from xanthene dyes have led to diverging conclusions.
Abstract: Photoinduced electron injection from eosin Y into the conduction band of titanium dioxide was further scrutinized, as previous studies on the charge injection from xanthene dyes have led to diverging conclusions. Eosin-sensitized TiO2 constitutes in many aspects a model system for studying the dynamics of charge injection: Adsorption of the sensitizer onto the oxide surface through electrostatic interaction and hydrogen bonding make this system exemplary of the weak electronic coupling case. The formation of dimeric eosin on the surface of metal oxide nanoparticles in an aqueous suspension was inferred from the study of the deactivation of the dye's singlet excited state on insulating particles, such as ZrO2 and Al2O3, and of the formation of the resulting radical ion pair, using femtosecond stimulated emission and transient absorption. It was found that dimers undergo ultrafast dismutation with a time constant of 500 fs. The same process occurs also on TiO2 particles and results in a competition between...

96 citations


Cited by
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[...]

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