Treating cadmium-telluride (CdTe) solar cell materials with cadmium-chloride improves their efficiency, but researchers have not fully understood why. Now, an atomic-scale examination of the thin-film solar cells led by the Department of Energy’s Oak Ridge National Laboratory has answered this decades-long debate about the materials’ photovoltaic efficiency increase after treatment. A research team from ORNL, the University of Toledo and DOE’s National Renewable Energy Laboratory used electron microscopy and computational simulations to explore the physical origins of the unexplained treatment process. The results are published in Physical Review Letters (PRL). Thin-film CdTe solar cells are considered a potential rival to silicon-based photovoltaic systems because of their theoretically low cost per power output and ease of fabrication. Their comparatively low historical efficiency in converting sunlight into energy, however, has limited the technology’s widespread use, especially for home systems. Research in the 1980s showed that treating CdTe thin films with cadmium-chloride significantly raises the cell’s efficiency, but scientists have been unable to determine the underlying causes. ORNL’s Chen Li, first author on the PRL study, explains that the answer lay in investigating the material at an atomic level. “We knew that chlorine was responsible for this magical effect, but we needed to find
The post Atomic switcheroo explains origins of thin-film solar cell mystery has been published on Technology Org.
Like a hungry diner ripping open a dinner roll, a fuel cell catalyst that converts hydrogen into electricity must tear open a hydrogen molecule. Now researchers have captured a view of such a catalyst holding onto the two halves of its hydrogen feast. The view confirms previous hypotheses and provides insight into how to make the catalyst work better for alternative energy uses. This study is the first time scientists have shown precisely where the hydrogen halves end up in the structure of a molecular catalyst that breaks down hydrogen, the team reported online April 22 in Angewandte Chemie International Edition. The design of this catalyst was inspired by the innards of a natural protein called a hydrogenase enzyme. “The catalyst shows us what likely happens in the natural hydrogenase system,” said Morris Bullock of the Department of Energy’s Pacific Northwest National Laboratory. “The catalyst is where the action is, but the natural enzyme has a huge protein surrounding the catalytic site. It would be hard to see what we have seen with our catalyst because of the complexity of the protein.” Ironing Out Expense Hydrogen-powered fuel cells offer an alternative to burning fossil fuels, which generates greenhouse gases. Molecular hydrogen
The post First view of nature-inspired catalyst after ripping hydrogen apart provides insights for better, cheaper fuel cells has been published on Technology Org.
When researchers asked people to tell the stories of how they fell in love, what were the eleven most common factors?
Variables that influence falling in love:
1. Similarity in attitudes, background, personality traits
2. Geographic proximity
3. Desirable characteristics of personality and appearance
4. Reciprocal affection, the fact that the other likes us
5. Satisfying needs
6. Physical and emotional arousal
7. Social influences, norms, and the approval of people in our circle
8. Specific cues in the beloved's voice, eyes, posture, way of moving
9. Readiness for a romantic relationship...
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The city of Portland, OR will empty a 38-million gallon reservoir after a teenager allegedly urinated in it, according to the Associated Press. It's the second time in three years that Portland is flushing its Mount Tabor reservoir after a urine-related incident.
The reservoir is open-air and sits exposed to all of nature, leading many parties to question how necessary a draining would be, or how polluted 38 million gallons of water can really be by a single man's urine.
David Shaff, Portland's water bureau administrator, reserves a special disgust specifically for human urine. In 2011, when Shaff drained the reservoir following a urination, he reasoned to the Portland Mercury, "Do you want to be drinking someone's pee?… There's probably no regulation that says I have to be doing it but, again, who wants to be drinking pee?" This time around, Shaff wrote in a statement, "Our customers have an expectation that their water is not deliberately contaminated."
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Inexpensive computers, cell phones and other systems that substitute flexible plastic for silicon chips may be one step closer to reality, thanks to research published on April 16 in the journal Nature Communications. The paper describes a new proposal by University of Iowa researchers and their colleagues at New York University for overcoming a major obstacle to the development of such plastic devices—the large amount of energy required to read stored information. Although it is relatively cheap and easy to encode information in light for fiber optic transmission, storing information is most efficiently done using magnetism, which ensures information will survive for years without any additional power. “So a critical issue is how to convert information from one type to another,” says Michael Flatté, professor of physics and astronomy in the College of Liberal Arts and Sciences (CLAS) and director of the UI Optical Science and Technology Center. “Although it does not cost a lot of energy to convert one to the other in ordinary, silicon-chip-based computers, the energy cost is very high for flexible, plastic computing devices that are hoped to be used for inexpensive “throwaway” information processors. “Here we show an efficient means of converting information encoded in magnetic storage to
The post Information storage for the next generation of plastic computers has been published on Technology Org.
Yahia Makableh demonstrates how a small array of 9-millimeter, gallium-arsenide solar cells can provide energy for small devices. Engineering researchers at the University of Arkansas have achieved the highest efficiency ever in a 9 millimeter-squared solar cell made of gallium arsenide. After coating the cufflink-sized cells with a thin layer of zinc oxide, the research team reached a conversion efficiency of 14 percent. A small array of these cells – as few as nine to 12 – generate enough energy for small light-emitting diodes and other devices. But surface modification can be scaled up, and the cells can be packaged in large arrays of panels to power large devices such as homes, satellites, or even spacecraft. The research team, led by Omar Manasreh, professor of electrical engineering, published its findings in Applied Physics Letters and the April 2014 issue of Solar Energy Materials and Solar Cells. An alternative to silicon, gallium arsenide is a semiconductor used to manufacture integrated circuits, light-emitting diodes and solar cells. The surface modification, achieved through a chemical synthesis of thin films, nanostructures and nanoparticles, suppressed the sun’s reflection so the cell could absorb more light. But even without the surface coating, the researchers were able to achieve 9-percent efficiency
The post Researchers achieve higher solar-cell efficiency with zinc-oxide coating has been published on Technology Org.
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