Published on November 4th, 2013 | By: Jim Destefani0
Other materials stories that may be of interestPublished on November 4th, 2013 | By: Jim Destefani
University of the Basque Country researchers have developed and patented a new light emitting material based on boron nitride nanotubes and suitable for developing high-efficiency optoelectronic devices. The scientists say structural defects in the BN nanotubes and application of an electric field perpendicular to the structures allow the nanotubes to emit light across the spectrum from infrared to far ultraviolet and facilitates control of the emissions. The defects enabling controlled emission are gaps that appear in nanotube walls due to the absence of a boron atom, which is the most common defect in its manufacture. “All nanotubes are very similar, but the fact that you have these defects makes the system operational and efficient, and what is more, the more defects you have, the better it functions,” one researcher explains.
A research team led by Sandia National Laboratory scientists has created a tunable plasmonic crystal researchers say could increase the bandwidth of high-speed communication networks and generally enhance high-speed electronics. The material’s tunable plasmonic effect is achieved by adjusting a voltage applied to an electron plasma that forms naturally at the interface of semiconductors with different band gaps, making the crystal agile in transmitting terahertz light at varying frequencies. Scientists say the plasmonic crystal method could be used to shrink the size of photonic crystals, which are artificially built to allow transmission of specific wavelengths, and to develop tunable metamaterials, which require micron- or nano-sized bumps to tailor interactions between manmade structures and light. Results of the work were recently published in an online paper in Nature Photonics.
Scientists at the University of Twente (Netherlands) MESA+ Institute for Nanotechnology have designed a device that can store data for millions of years even in extreme temperatures. The information carrier is a tungsten wafer encapsulated by silicon nitride. A QR code is etched into the tungsten and is protected by the Si3N4. Each pixel of the large QR code contains a smaller QR code that in turn stores different information. The researchers performed an accelerated aging test by heating the storage device to 200°C for an hour. After the test there was no visible degradation of the tungsten, and the encoded information was still easily readable. The QR codes became more difficult to read after exposure to temperature of 440°C, even though the tungsten was not affected.
Scientists from Clemson University and the University of Virginia are working together to convert waste heat into high-quality electricity. The researchers are developing thermoelectric materials that provide direct conversion of heat into electricity. The materials and devices are currently being used in vehicles to convert waste heat from the exhaust system into electricity. The system effectively recovers more than 60% of waste heat that is lost relative to the input energy. The researchers have investigated several materials, including half Heusler alloys and silicon-germanium, to understand the effect of core shell thermoelectric materials. Moving forward, they plan to work on thermoelectric cooling materials that will provide zonal cooling for vehicles.
Researchers at Oregon State University and the University of Oregon have developed a platform to study the aqueous chemistry of aluminum that they say should open the door to significant advances in electronics, manufacturing, construction, agriculture, and drinking water treatment, among other applications. Aluminum in solution with water affects the biosphere, hydrosphere, geosphere, and astrosphere, the scientists say. But up to now there has been no effective way to explore the variety and complexity of compounds that aluminum forms in water. The researchers’ integrated platform to study aqueous aluminum allows them to synthesize aqueous aluminum clusters in a controlled way, analyze them with new techniques, and use computational chemistry to interpret the results. The discovery also may be applicable to research on other metal atoms, the scientists say.
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