Solar Cells Info

Nanowerk News, May 7, 2007
http://www.nanowerk.com/news/newsid=1894.php

During the remarkable cascade of events in photosynthesis, plants approach the pinnacle of stinginess by scavenging nearly every photon of available light energy to produce food.Yet after many years of careful research into the exact mechanisms, some key questions remain about this fundamental biological process that supports almost all life on Earth.  Now a research team led by Neal Woodbury, a scientist at the Arizona State University (ASU) Biodesign Institute, has come up with a new insight into the mechanism of photosynthesis.

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News from LexisNexis
Zep Hu — Central News Agency – Taiwan , May 8, 2007
http://www.reed-electronics.com/semiconductor/articleXml/LN609939724.html??industryid=3028

Only 18 percent to 20 percent of the production equipment used by Taiwanese solar cell manufacturers is “made-in-Taiwan”, but the government has vowed to raise that to 50 percent by 2009, a senior officials at the Ministry of Economic Affairs announced Tuesday during a review of Taiwan solar energy industry.  Meanwhile, according to the ministry, the government has provided incentives bringing NT$2.84 billion (about US$85 million) of foreign and domestic investments to the industry so far, as well as patent and technology transfers worth NT$ 47.3 million.
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by Ann Steffora Mutschler, Senior Editor
Source:
Electronic News, May 9, 2007
http://www.edn.com/index.asp?layout=article&articleid=CA6440595

Littleton, Colo.-based thin-film photovoltaic module maker Ascent Solar Technologies Inc. said today it has been selected by the U.S. Air Force to develop a flexible thin film tandem solar cell with the goal of demonstrating thin film photovoltaic efficiencies of 20 percent, which is higher than other technologies manufactured so far.  According to the company, tandem solar cells are a combination of two cells stacked atop one another, with the top and bottom cells gathering energy from separate parts of the solar spectrum.
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On the surface of a new photovoltaic prototype, microscopic nanotube towers perform best when they catch light on their sides.

By David Talbot, April 17, 2007
source: MIT Technology Review
http://www.technologyreview.com/Energy/18539/

Solar cells generally crank out the most power at noon, when the sun is at its highest point and can strike the cell at a 90-degree angle. Before and after noon, efficiencies drop off. But researchers Georgia Tech Research Institute have come up with a prototype that does the opposite. Their solar cell, whose surface consists of hundreds of thousands of 100-micrometer-high towers, catches light at many angles and actually works best in the morning and afternoon.

“It may be intuitive: when the light goes straight down, the only interaction is with the tops of towers and the ‘streets’ below,” says Jud Ready, senior research engineer at the institute’s Electro-Optical Systems Laboratory. “But at an angle, the light has an opportunity to reflect off the sides of the towers.” When the sun is at a 90-degree angle, the prototype delivers only 3.5 percent efficiency. But it delivers better efficiencies at many other angles and is actually at its peak efficiency–7 percent–when light comes in at a 45-degree angle. That means the device operates at relatively high efficiencies during much of the day and has two efficiency peaks: one before noon, and one after noon.
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SUNY-Buffalo News Release /19 April 2007
Source:
http://www.buffalo.edu/news/8574

BUFFALO, N.Y. — Novel, self-assembly techniques for fabricating inorganic nanomaterials that could pave the way for more efficient and powerful solar cells, chemical sensors and detectors currently are being developed by a University at Buffalo chemist.

David F. Watson, Ph.D., an assistant professor in the Department of Chemistry in the University at Buffalo’s College of Arts and Sciences, has been awarded a prestigious National Science Foundation CAREER Award to conduct the research.  According to the NSF, the CAREER program recognizes and supports the early career-development activities of teacher-scholars “who are most likely to become the academic leaders of the 21st century.”

The research component of the grant involves a new approach to photochemistry, chemical reactions involving light, while the educational component will introduce students in the Buffalo Public Schools from underrepresented groups, including Native Americans, to principles of materials chemistry and scientific research through hands-on science activities.  The grant, which provides $576,100 over five years, will allow Watson and colleagues to conduct research aimed at better controlling the electron transfer reactivity of self-assembled inorganic nanomaterials.

In particular, Watson’s group is studying and characterizing photo-induced surface electron transfer reactions occurring within self-assembled inorganic nanomaterials, the reactions that drive solar cells and photocatalysts. The scientists will continue work on a self-assembly technique Watson developed for attaching quantum dots, tiny light-absorbing particles, to metal oxide films.  Using time-resolved spectroscopy, the researchers are able to probe systematically how composition, morphology and physical properties of the materials affect the kinetics and efficiency of electron transfer processes.

The researchers also will study how to improve the targeted patterning of nanoparticles onto metal oxide surfaces.  “This photochemical patterning strategy addresses one of the significant challenges in nanofabrication, to control both short-range and long-range order in nanostructured materials,” said Watson.  Short-range order refers to the organization of molecules and materials on the nanometer scale, while long-range order involves pattern formation on larger, even macroscopic, dimensions.  Watson’s approach combines the “top-down” and “bottom-up” methods of fabricating nanomaterials into a hybrid technique, in which photochemical reactions are used to organize nanoparticles on surfaces.

Substrates with high surface areas, he explained, allow for optically dense patterns and more efficient light harvesting, thereby potentially increasing the efficiency of solar cells and other devices.  “Because our surface substrate is the photochemically active component, our approach also might enable more widely applicable patterning techiques,” he said.

Watson’s grant also will provide summer research internships to students at various high schools in Buffalo through collaborations with faculty in the departments of chemistry and physics in the UB College of Arts and Sciences and in the departments of chemical and biological engineering and electrical engineering in the UB School of Engineering and Applied Sciences.

The educational program builds on the extensive partnership that exists between UB’s Department of Chemistry and Buffalo Public School 19, a Native American magnet school for middle school students.

Also with the support of the CAREER award, Watson is designing a “writing-intensive” course for advanced undergraduates and graduate students in the Department of Chemistry that will address one of his key educational concerns.

“Chemistry majors typically don’t do a lot of writing during their undergraduate or graduate careers, but it’s a huge part of what we do as scientists,” he said. “The idea is to get the students used to doing a lot of writing and to write mock reviews and critique each others’ work.”

Watson lives in Williamsville.  The University at Buffalo is a premier research-intensive public university, the largest and most comprehensive campus in the State University of New York.

Tom Simonite, NewScientist.com news service /  20 April 2007
Source:
http://environment.newscientist.com/article/dn11676

Heating plastic solar cells can alter their structure in a way that boosts efficiency, new research shows. The US and Korean scientists behind the discovery say it could ultimately allow flexible, lightweight plastic cells to replace rigid traditional cells.  Solar cells are usually made from silicon, which is inflexible and relatively heavy. By contrast, plastic solar cells could be more easily supported and wrapped around surfaces (see Pliable solar cells are on a roll). It might even be possible to spray light-collecting plastic onto a surface.
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By engineering nano-size branches and trunks into plastic solar cells, researchers have improved their ability to harvest the energy in sunlight

By David Biello, April 21, 2007
Source: Scientific American.com
http://www.sciam.com/article.cfm?chanID=sa002&articleID=1496CAD6-E7F2-99DF-34B95C45D49BA57C

Solar cells made from cheap, plastic polymer barely capture the energy in sunlight. Photons reflect off the plastic and it is too thin to absorb much, giving the polymers color. “The very fact that it has color is telling you this thing is not working as well as it should,” says David Carroll, a physicist at Wake Forest University in Winston-Salem, N.C. But plastic solar cells offer flexibility, are lightweight and, theoretically, low cost, which means they could be incorporated into a range of products. “You can’t think of doing anything cheaper than making Saran wrap and that’s basically what these are,” says Lawrence Kazmerski, director of the Department of Energy’s (DOE) National Center for Photovoltaics in Golden, Colo.
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By David Talbot, MIT Technology Review
http://www.technologyreview.com/read_article.aspx?ch=specialsections&sc=emerging&id=18285
Arthur Nozik hopes quantum dots will enable the production of more efficient and less expensive solar cells, finally making solar power competitive with other sources of electricty.
No renewable power source has as much theoretical potential as solar energy. But the promise of cheap and abundant solar power remains unmet, largely because today’s solar cells are so costly to make.  Photovoltaic cells use semiconductors to convert light energy into electrical current. The workhorse photo­voltaic material, silicon, performs this conversion fairly efficiently, but silicon cells are relatively expensive to manufacture. Some other semiconductors, which can be deposited as thin films, have reached market, but although they’re cheaper, their efficiency doesn’t compare to that of silicon. A new solution may be in the offing: some chemists think that quantum dots–tiny crystals of semi­conductors just a few nanometers wide–could at last make solar power cost-competitive with electricity from fossil fuels.
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Robert Jaques, vnunet.com , 03 May 2007
soruce: http://www.vnunet.com/vnunet/news/2189078/boffins-join-quantum-dots

Scientists have published details of a “breakthrough” method for producing quantum dots – molecular specks of semiconductors – which they believe could pave the way for better and cheaper solar panels. The research at Rice University’s Center for Biological and Environmental Nanotechnology (CBEN) appears this week in the journal Small. The scientists describe a new chemical method for making four-legged cadmium selenide quantum dots, which previous research has shown to be particularly effective at converting sunlight into electrical energy. Quantum dots are “mega-molecules” of semiconducting materials that are smaller than living cells. They interact with light in unique ways to give off different-coloured light or to create electrons and holes, due partly to their tiny size, partly to their shape and partly to the material from which they are made.
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By: University of New South Wales, May 3, 2007
source:
http://www.yubanet.com/artman/publish/article_56150.shtml

Solar energy could become more affordable following a breakthrough by UNSW scientists, who have boosted the efficiency of solar cell technology.  The advance could see the price of an installed solar system for an average house fall from around $20,000 to $15,000. Up to 45 percent of the cost of solar cell technology is due to the high cost of the silicon used to convert sunlight to electricity.
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