Mid-holidays edition:
For all their promise, solar cells have frustrated scientists in one crucial regard: Most are rigid. They must be deployed in stiff and often heavy fixed panels, limiting their applications. So researchers have been trying to get photovoltaics to loosen up. The ideal: flexible, decal-like solar panels that can be peeled off like band-aids and stuck to virtually any surface, from papers to window panes. Now the ideal is real. Stanford researchers have succeeded in developing the world’s first peel-and-stick thin-film solar cells. The advance is described in a paper in the December 20, 2012 issue of Scientific Reports. Unlike standard thin-film solar cells, peel-and-stick thin-film solar cells do not require any direct fabrication on the final carrier substrate. This is a far more dramatic development than it may initially seem. All the challenges associated with putting solar cells on unconventional materials are avoided with the new process, vastly expanding the potential applications of solar technology. Utilizing the process, researchers attached thin-film solar cells to paper, plastic and window glass, among other materials. “It’s significant that we didn’t lose any of the original cell efficiency,” explains Xiaolin Zheng, a Stanford assistant professor of mechanical engineering and senior author of the paper.
Searcy, former head of materials and molecular research division of Berkeley Lab, passes away
Alan Searcy, who served as associate director and head of the Berkeley Lab’s Materials and Molecular Research Division (predecessor of the Materials Sciences Division) from 1980 to 1984, passed away on Nov. 5 in Walnut Creek. Searcy joined the UC Berkeley engineering faculty in 1954 and remained a professor there for more than 50 years. Searcy achieved many accolades, including the Fulbright Lectureship (1960), the Guggenheim Fellowship (1967) and the Miller Research Professorship (1970-71). He was a charter member of the World Academy of Ceramics, an AAAS fellow and an American Ceramic Society Fellow. Searcy served the Berkeley campus in a number of capacities, including appointments as vice chancellor from 1964-67.
Paper waste used to make bricks
Researchers at the University of Jaen (Spain) have mixed waste from the paper industry with ceramic material used in the construction industry. The result is a brick that has low thermal conductivity, meaning it acts as a good insulator. However, its mechanical resistance still requires improvement. The scientists collected cellulous waste from a paper factory (recycled waste in this case) along with sludge from the purification of its waste water. In their laboratory they then mixed this material with clay used in construction and passed the mixture through a pressure and extrusion machine to obtain bricks. “Adding waste means that the end product has low thermal conductivity and is therefore a good insulator,” explains Carmen Martínez. Another of the advantages of adding waste to the brick prototypes is that they provide energy due to their organic material content. This could help to reduce fuel consumption and kiln time required for brick production.
A new tool for secret agents—and the rest of us: Caltech engineers make tiny, low-cost, terahertz imager chip
A secret agent is racing against time. He knows a bomb is nearby. He rounds a corner, spots a pile of suspicious boxes in the alleyway, and pulls out his cell phone. As he scans it over the packages, their contents appear onscreen. In the nick of time, his handy smartphone application reveals an explosive device, and the agent saves the day. Sound far-fetched? In fact it is a real possibility, thanks to tiny inexpensive silicon microchips developed by a pair of electrical engineers at the California Institute of Technology. The chips generate and radiate high-frequency electromagnetic waves, called terahertz waves, that fall into a largely untapped region of the electromagnetic spectrum—between microwaves and far-infrared radiation—and that can penetrate a host of materials without the ionizing damage of X-rays. When incorporated into handheld devices, the new microchips could enable a broad range of applications in fields ranging from homeland security to wireless communications to health care, and even touchless gaming.
Study reveals new factor that could limit the life of hybrid and electric car batteries
A new study of the batteries commonly used in hybrid and electric-only cars has revealed an unexpected factor that could limit the performance of batteries currently on the road. Researchers led by Ohio State University engineers examined used car batteries and discovered that over time lithium accumulates beyond the battery electrodes-in the “current collector,” a sheet of copper, which facilitates electron transfer between the electrodes and the car’s electrical system. Key to the discovery of lithium in the current collector was collaboration between the Ohio State team and Gregory Downing, a research chemist at the National Institute of Standards and Technology and an expert on a technique called neutron depth profiling, a tool for impurity analysis in materials.
Xiao-Gang Wen and the 500 phases of matter
Forget solid, liquid, and gas: There are in fact more than 500 phases of matter. In a major paper in a new issue of Science, Perimeter Institute (Waterloo, Canada) faculty member Xiao-Gang Wen reveals a modern reclassification of all of them. Using modern mathematics, Wen and collaborators reveal a new system, which can, at last, successfully classify symmetry-protected phases of matter. Their new classification system will provide insight about these quantum phases of matter, which may in turn increase our ability to design states of matter for use in superconductors or quantum computers. This paper, titled, “Symmetry-Protected Topological Orders in Interacting Bosonic Systems,” is a revealing look at the intricate and fascinating world of quantum entanglement, and an important step toward a modern reclassification of all phases of matter.
NIF report asks for more time to achieve ignition
(Science) When the National Ignition Facility (NIF) went into full operation in 2009, the facility’s managers confidently predicted achieving ignition-a self-sustaining fusion reaction that produces excess energy-before the end of fiscal year 2012. Now, NIF faces an uncertain future after its managers admitted to Congress that they need at least another 3 years to try to identify what has prevented the giant laser fusion lab in California from achieving ignition. NIF officials have not attempted to set a new goal, and supporters say that uncertainty shouldn’t count against NIF.
Next scientific fashion could be designer nanocrystals
Three University of Chicago chemistry professors hope that their separate research trajectories will converge to create a new way of assembling what they call “designer atoms” into materials with a broad array of potentially useful properties and functions. These “designer atoms” would be nanocrystals—crystalline arrays of atoms intended to be manipulated in ways that go beyond standard uses of atoms in the periodic table. Such arrays would be suited to address challenges in solar energy, quantum computing, and functional materials. The partners in the project are David Mazziotti, Greg Engel, and Dmitri Talapin. All three have made key advances that are critical for moving the project forward. Now, with $1 million in funding from the W. M. Keck Foundation, they can build on their separate advances in a concerted way toward a new goal.