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.

Nanocrystalline thin-film PV cells

Abstract: Reference LPI-ARTICLE-1993-015View record in Web of Science Record created on 2006-02-21, modified on 2017-05-12

A Blue Photosensitizer Realizing Efficient and Stable Green Solar Cells via Color Tuning by the Electrolyte

Abstract: Semitransparent dye-sensitized solar cells (DSCs) are appealing as aesthetically pleasing and colorful see-through photovoltaics. Green semitransparent DSCs have been presented, but the best ones rely on green zinc porphyrin photosensitizers and high volatile electrolytes. For potential outdoor applications, the zinc porphyrin DSCs employing ionic liquid electrolytes merely reached a power conversion efficiency (PCE) of 6.3% even with opaque mesoporous TiO2 films. Herein, the new green DSC is realized by using a blue organic photosensitizer in conjunction with an orange ionic-liquid-based electrolyte, presenting a simple and an effective path for color tuning of photovoltaics. The new approach allows for broadly modulating the color from spring green to cyan by tuning the contributions of the light absorption by the dye-sensitized TiO2 film and the electrolyte layer. The new semitransparent DSCs with spring green to cyan colors have PCEs ranging from 6.7% to 8.1% and show stability for 1000 h under accelerated ageing test at 80 °C, superior to the zinc porphyrin DSCs. The findings pave a new way to achieve efficient and stable colorful solar cells.

Investigation on the Interface Modification of TiO2 Surfaces by Functional Co-Adsorbents for High-Efficiency Dye-Sensitized Solar Cells

Abstract: The influence of interface modification of sensitized TiO2 surfaces by co-adsorbents on photovoltaic performance is detailed. We investigated different functional groups of co-adsorbents, such as carboxylic (4-guanidino butyric acid, chenodeoxycholic acid), phosphinic (dineohexyl phosphinic acid), and phosphonic (dodecyl phosphonic acid), to better highlight their influence on the device performance and accurately classify them into de-aggregating agents or agents with both de-aggregating and co-adsorbing properties. By optimizing the type of co-adsorbent and its concentration in the dye solution, we reached an efficiency of 11.0 % using 4-guanidino butyric acid or dineohexyl phosphinic acid, compared to 10.6 % when the benchmark chenodeoxycholic acid was used. The presence of co-adsorbents on the TiO2 surface was studied using ATR-FTIR spectroscopy. The role of these co-adsorbents on the band edge shift versus the recombination resistance is discussed.

Highly soluble energy relay dyes for dye-sensitized solar cells.

Abstract: High solubility is a requirement for energy relay dyes (ERDs) to absorb a large portion of incident light and significantly improve the efficiency of dye-sensitized solar cells (DSSCs). Two benzonitrile-soluble ERDs, BL302 and BL315, were synthesized, characterized, and resulted in a 65% increase in the efficiency of TT1-sensitized DSSCs. The high solubility (180 mM) of these ERDs allows for absorption of over 95% of incident light at their peak wavelength. The overall power conversion efficiency of DSSCs with BL302 and BL315 was found to be limited by their energy transfer efficiency of approximately 70%. Losses due to large pore size, dynamic collisional quenching of the ERD, energy transfer to desorbed sensitizing dyes and static quenching by complex formation were investigated and it was found that a majority of the losses are caused by the formation of statically quenched ERDs in solution.

I and i

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 …

Fast parallel algorithms for short-range molecular dynamics

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.

A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films

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.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

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。

Environmental Applications of Semiconductor Photocatalysis

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.