by Yury Gogotsi, Asia Sarycheva, and Babak Anasori
Spraying an antenna onto a flat surface. Drexel University Nanomaterials Lab, CC BY-ND
Hear the word “antenna” and you might think about rabbit ears on the top of an old TV or the wire that picks up radio signals for a car. But an antenna can be much smaller – even invisible. No matter its shape or size, an antenna is crucial for communication, transmitting and receiving radio signals between devices. As portable electronics become increasingly common, antennas must, too.
Wearable monitors, flexible smart clothes, industrial sensors and medical sensors will be much more effective if their antennas are lightweight and flexible – and possibly even transparent. We and our collaborators have developed a type of material that offers many more options for connecting antennas to devices – including spray-painting them on walls or clothes.
This crystal of silicon carbide (SiC) is almost as hard as diamond. In fact, moissanite, which is another name for SiC, is used as a less expensive alternative to diamonds in jewelry. Because of its hardness, SiC also is used in bulletproof vests and is added to products to provide a textured surface that won’t wear out, like the grip tape on skateboards. Scientists first discovered SiC in a meteorite in 1893—naturally occurring SiC is extremely rare on Earth. Since then, the vast majority of SiC has been made in the lab. Tokyo Institute of Technology’s Kouichi Yasuda made this 10-cm-tall crystal by applying a direct electric current to a mixture of silicon dioxide and carbon powders.
The work advances the possibility of applying quantum mechanical principles to existing optical fiber networks for secure communications and geographically distributed quantum computation. Prof. David Awschalom and his 13 co-authors announced their discovery in the June 23 issue of Physical Review X.
“Silicon carbide is currently used to build a wide variety of classical electronic devices today,” said Awschalom, the Liew Family Professor in Molecular Engineering at UChicago and a senior scientist at Argonne National Laboratory. “All of the processing protocols are in place to fabricate small quantum devices out of this material. These results offer a pathway for bringing quantum physics into the technological world.”
The findings are partly based on theoretical models of the materials performed by Awschalom’s co-authors at the Hungarian Academy of Sciences in Budapest. Another research group in Sweden’s Linköping University grew much of the silicon carbide material that Awschalom’s team tested in experiments at UChicago. And another team at the National Institutes for Quantum and Radiological Science and Technology in Japan helped the UChicago researchers make quantum defects in the materials by irradiating them with electron beams.
Scientists have developed a new low-temperature catalyst for producing high-purity hydrogen gas while simultaneously using up carbon monoxide (CO). The discovery-described in a paper set to publish online in the journal Science on Thursday, June 22, 2017-could improve the performance of fuel cells that run on hydrogen fuel but can be poisoned by CO.
“Thiscatalyst produces a purer form of hydrogen to feed into the fuel cell,” said José Rodriguez, a chemist at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory. Rodriguez and colleagues in Brookhaven’s Chemistry Division-Ping Liu and Wenqian Xu-were among the team of scientists who helped to characterize the structural and mechanistic details of the catalyst, which was synthesized and tested by collaborators at Peking University in an effort led by Chemistry Professor Ding Ma.
Because the catalyst operates at low temperature and low pressure to convert water (H2O) and carbon monoxide (CO) to hydrogen gas (H2) and carbon dioxide (CO2), it could also lower the cost of running this so-called “water gas shift” reaction.
“With low temperature and pressure, the energy consumption will be lower and the experimental setup will be less expensive and easier to use in small settings, like fuel cells for cars,” Rodriguez said.
