The news item from David L. Chandler at the Massachusetts Institute of Technology (MIT) claims that researchers there have come close to realizing the “ideal” for solar absorption, trapping and containing all of light’s wavelengths that reach earth’s surface from the sun. This absorbed sunlight is converted to heat by a two-dimensional metallic dialectric photonic crystal, which can absorb sunlight from a wide range of angles and withstand extremely high temperatures. Even better, it can be made cheaply and in large quantities, according to MIT. One aspect of the design that might make it difficult to use on aircraft is its high operating temperature. A solar-thermophotovoltaic (STVP) device, the energy from the sunlight hitting the cells is “first converted to heat, which then causes the material to glow, emitting light that can, in turn, be converted to an electric current.” Having worked on an earlier version of STVPs, the researchers noted that the solar cells had many hollow cavities. Nature …
Lighter, Stronger, and Morphable
If you have a pre-teen roaming around the house, you more than likely know the shared delight of assembling the biggest possible thing you can make from Lego® blocks. There must be something of that delight in the Center for Bits and Atoms at the Massachusetts Institute of Technology (MIT). There, researchers have invented, “A new approach to assembling big structures — even airplanes and bridges — out of small interlocking composite components,” according to a story by David L. Chandler of the MIT News Office. Neil Gershenfeld, director of the Center, and post-doctoral student Kenneth Cheung recently co-authored a paper published in the journal Science, in which they describe assembling strong lightweight structures with “cubocts,” lattice structures that are the lightest and strongest in existence, as stated in the Center’s publications. The Center claims 12.3 megaPascals, or 1,784 pound per square inch strength for the 7.3 milligrams per cubic centimeter material (about 0.45 pounds per cubic foot). Balsa wood, …
Thinner than Kleenex®, as Powerful as the Sun
David L. Chandler of the Massachusetts Institute of Technology (MIT) News Office reports that an MIT research team headed by Jeffrey Grossman has found a way to make sheets that push “towards the ultimate power conversion from a material” for solar power. His team has managed to fabricate molecule-thick photovoltaic sheets which could pack hundreds of times more power per weight than conventional solar cells. Senior author of a new paper on the team’s study in Nano Letters, Grossman found that despite the interest in two-dimensional materials such as graphene – only an atom thick – few have studied their potential for solar applications. Grossman says, “They’re not only OK, but it’s amazing how well they do.” Stacking sheets of graphene and materials such as molybdenum disulfide would make solar cells with one to two percent efficiency in converting sunlight to electricity. That seems disappointingly low compared to the 15 to 20 percent efficiency of commercially available silicon solar cells. …
Cambridge Crude and Range Euphoria
Massachusetts Institute of Technology (MIT) scientists have announced what they claim is a “Significant advance in battery architecture [that] could be breakthrough for electric vehicles and grid storage.” According to a story by David L. Chandler from the MIT News Office, the new battery system is lightweight and inexpensive, and could make recharging “as quick and easy as pumping gas into a conventional car.” Seemingly requiring some active components within the battery, this “semi-solid flow cell” pumps solid particles suspended in a carrier liquid which form the cathodes and anodes through the system. According to the MIT news item, “These two different suspensions are pumped through systems separated by a filter, such as a thin porous membrane.” Mechanically more complex than today’s batteries, the system still has a claimed “10-fold improvement over present liquid-flow batteries” (not necessarily that much better than lithium ion, then), but lower manufacturing costs. The different fluids are contained in two different containers and not …