News from the NNI Community - Research Advances Funded by Agencies Participating in the NNI

Researchers at the University of Georgia have developed an inexpensive, spark-free, optical-based hydrogen sensor that is more sensitive – and faster – than previous models. The new optical device relies on the nanofabrication of a nanosphere template covered with a palladium cobalt alloy layer. Any hydrogen present is quickly absorbed, then detected by a light-emitting diode, and a silicon detector records the intensity of the light transmitted.

Researchers from the National Institute of Standards and Technology, Virginia Commonwealth University, and the University of Mississippi have built a biosensor by making an artificial version of the biological material that forms a cell membrane. Known as a lipid bilayer, it contains a tiny pore, about 2 nanometers wide in diameter, surrounded by fluid. Ions that are dissolved in the fluid pass through the nanopore, generating a small electric current. However, when a molecule of interest is driven into the membrane, it partially blocks the flow of current. The duration and magnitude of this blockade serve as a fingerprint, identifying the size and properties of a specific molecule.

Researchers at the University of California, Riverside, have used a nanoscale synthetic antiferromagnet to control the interaction between magnons. Magnons are quantum-mechanical units of electron spin fluctuations. When magnons interact with each other, they generate nonlinear features of the spin dynamics. Such nonlinearities play a central role in magnetic memory, spin torque oscillators, and other spintronic applications.

Researchers at the U.S. Department of Energy's Argonne National Laboratory have discovered a new way to generate 2D superconductivity at a material interface at a relatively high -- though still cold -- transition temperature (2.2 Kelvin instead of 0.2 Kelvin). This interfacial superconductor has novel properties that raise new fundamental questions and might be useful for quantum information processing or quantum sensing.

Researchers at Stanford University have designed and made single-wall carbon nanotube thermoelectric devices on flexible polyimide substrates as a basis for wearable energy converters. Carbon nanotubes are known for having good thermoelectric properties, which means it is possible to develop a voltage across them in a temperature gradient. But carbon nanotubes also have high thaermal conductivity, meaning it's difficult to maintain a thermal gradient across them, and they have been hard to assemble them into thermoelectric generators at low cost. The researchers used printed carbon nanotube networks to tackle both challenges.

Engineers at Duke University have developed the world's first fully recyclable printed electronics. The researchers created a completely recyclable, fully functional transistor with three carbon-based inks – based on carbon nanotubes, graphene, and nanocellulose – that can be easily printed onto paper or other flexible, environmentally friendly surfaces. Using the three inks in an aerosol jet printer at room temperature, the engineers showed that their all-carbon transistors performed well enough for use in a wide variety of applications, even six months after the initial printing.

A new real-time, 3D motion-tracking system developed at the University of Michigan combines transparent light detectors with advanced neural network methods to create a system that could one day replace LiDAR and cameras in autonomous technologies. While the technology is still in its infancy, future applications include automated manufacturing, biomedical imaging and autonomous driving. The imaging system exploits the advantages of transparent, nanoscale, highly sensitive graphene photodetectors.

Gold-silver alloys are useful catalysts that degrade environmental pollutants, facilitate the production of plastics and chemicals, and kill bacteria on surfaces. In nanoparticle form, these alloys could be useful as optical sensors or to catalyze hydrogen evolution reactions. But there's an issue: Silver doesn't always stay put. A new study by scientists at Rice University and the University of Duisburg-Essen in Germany has revealed a two-step mechanism behind silver's dissipation – a discovery that could help industry fine-tune nanoparticle alloys for specific uses.

Researchers at MIT have fabricated a hydrogel-based material that mimics the structure of the lobster's underbelly. The researchers ran the material through a battery of stretch and impact tests, and showed that, similar to the lobster underbelly, the synthetic material is remarkably "fatigue-resistant," able to withstand repeated stretches and strains without tearing. If the fabrication process could be significantly scaled up, materials made from nanofibrous hydrogels could be used to make straetchy and strong replacement tissues such as artificial tendons and ligaments.

Scientists at the U.S. Department of Energy’s Argonne National Laboratory have found a way to turn X-ray fluorescence into an ultra-high position-sensitive probe to measure tiny internal structures, called nanostructures, in thin films. In this technique, called X-ray waveguide fluorescence holography, the fluorescence emissions are enhanced and guided by the thin films themselves. The fluorescence reveals the evolution of nanostructures in real time with nearly atomic-level resolution, something no other technique has achieved.