New double-pane quantum dot solar windows generate power with better efficiency

January 3, 2018 by  
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Researchers at an American national laboratory have now employed quantum dots for double-pane solar windows that offer shading, insulation, and, of course, generate energy – with greater efficiency. The Los Alamos National Laboratory team drew on a new window architecture utilizing two layers of low-priced quantum dots, tuned to take in distinct parts of the solar spectrum. The double-pane windows were equipped with manganese-doped quantum dots, absorbing blue and ultraviolet, on the surface of the front glass pane, and copper indium selenide quantum dots, absorbing the rest of the spectrum, on the back pane’s surface. Once light is absorbed, dots re-emit it at a longer wavelength. Total internal reflection guides the light to the edges, where it can be gathered and turned into power by solar cells in the window frame. Related: National laboratory scales up quantum-dot solar windows that can power entire buildings Solar-spectrum splitting – in which higher- and lower-energy solar photons can be processed separately – is key to the research, according to Los Alamos. And the dots in the front layer are essentially reabsorption free, which the laboratory said the team accomplished by incorporating into quantum dots manganese ions “that serve as highly emissive impurities. Light absorbed by the quantum dots activates these impurities. Following activation, the manganese ions emit light at energies below the quantum-dot absorption onset. This trick allows for almost complete elimination of losses due to self-absorption by the quantum dots.” The journal Nature Photonics published the research online on New Year’s Day. Per the article’s abstract, the researchers’ prototype “exhibits a high optical quantum efficiency of 6.4 percent for sunlight illumination and solar-to-electrical power conversion efficiency of 3.1 percent. The efficiency gains due to the tandem architecture over single-layer devices quickly increases with increasing LSC [luminescent solar concentrator] size and can reach more than 100 percent in structures with window sizes of more than 2,500 centimeters squared.” Double-pane quantum dot solar window research could lower the cost of solar power , according to lead researcher Victor Klimov, who said in a statement , “Because of the strong performance we can achieve with low-cost, solution processable materials, these quantum-dot-based double-pane windows and even more complex luminescent solar concentrators offer a new way to bring down the cost of solar electricity.” Via Los Alamos National Laboratory Images via Los Alamos National Laboratory Twitter and Depositphotos

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New double-pane quantum dot solar windows generate power with better efficiency

"Bomb cyclone" to slam East Coast with more bitterly cold weather

January 3, 2018 by  
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A massive winter storm known as a “bomb cyclone” will smash into the US East Coast this week. This powerful weather event will bring an even deeper freeze to a region that has suffered bitter cold weather for the past 10 days. The storm in question, which will impact coastal areas from Georgia to Maine, is given its extreme name because of the predicted rapid pressure drop, an indication of the storm’s strength. The bomb cyclone is described as being similar to a winter hurricane, with accompanying freezing rain, ice, snow, and powerful winds. Although the effects of the storm will be acutely felt by East Coast residents, the most extreme weather conditions are expected to remain offshore. The storm is expected to particularly impact New England , off the coast of which it is expected to be the strongest the region has seen in decades. Boston is expected to receive up to seven inches of snow, in addition to powerful winds capable of knocking down trees and power lines. The temperatures in Boston are expected to drop to 27 degrees below the average for this time of year. When the storm has ended, the entire coast is expected to be hit with another wave of frigid air. Related: Storm ‘unfreezes’ North Pole, causing temps 50 degrees higher than normal Further south, the storm’s impact will still be substantial. Coastal Georgia and even areas of North Florida are expected to receive some snow, as are coastal cities further north in the Southeast. In Charleston, South Carolina, one to three inches of snow and sleet are expected. By the time the storm reaches New England, its central pressure will have dropped 53 millibars in only 24 hours, an astonishing pressure drop unheard of outside of a hurricane -strength storm. After the weekend, the East Coast is expected to enjoy a respite from winter’s deep freeze when temperatures warm up. Via Washington Post Images via Depositphotos and Ryan Maue/weather.us

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"Bomb cyclone" to slam East Coast with more bitterly cold weather

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