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

Transitioning from fossil fuels to a clean hydrogen economy will require cheaper and more efficient ways to use renewable sources of electricity to break water into hydrogen and oxygen. But a key step in that process, known as the oxygen evolution reaction, has proven to be a bottleneck. Now, an international team led by scientists at Stanford University, the U.S. Department of Energy's SLAC National Accelerator Laboratory, the U.S. Department of Energy's Lawrence Berkeley National Laboratory, and the University of Warwick in the United Kingdom has developed a suite of advanced tools to break through this bottleneck. The scientists were able to zoom in on individual catalyst nanoparticles and watch them accelerate the generation of oxygen inside custom-made electrochemical cells. 

Researchers at MIT and colleagues have turned magic-angle twisted bilayer graphene, which is composed of atomically thin layers of carbon, into three useful electronic devices. Normally, such devices, all key to the quantum electronics industry, are created using a variety of materials that require multiple fabrication steps. The MIT approach automatically solves a variety of problems associated with those more complicated processes. As a result, the work could usher in a new generation of quantum electronic devices for applications including quantum computing. Further, the devices can be superconducting, or conduct electricity without resistance.

Researchers at the U.S. Department of Energy's National Renewable Energy Laboratory have combined perovskite nanocrystals with a network of single-walled carbon nanotubes to create a material combination they think might have interesting properties for photovoltaics or detectors. When they shined a laser at it, they found a surprising electrical response. Normally, after absorbing the light, an electrical current would briefly flow for a short period of time. But in this case, the current continued to flow and did not stop for several minutes. Such behavior is referred to as "persistent photoconductivity" and is a form of "optical memory," where the light energy hitting a device can be stored in "memory" as an electrical current. 

Modern medicine relies on an extensive arsenal of drugs to combat deadly diseases. But getting those drugs into disease-ridden cells has remained a major challenge. To tackle this difficulty, scientists from the University of California Merced, the U.S. Department of Energy’s Lawrence Livermore National Laboratory, and collaborators from the Max Planck Institute of Biophysics in Germany have used carbon nanotubes to enable direct drug delivery from liposomes through the plasma membrane into the cell’s interior by facilitating fusion of the carrier membrane with the cell.

Silicon-based fiber optics are currently the best structures for high-speed, long-distance transmissions, but graphene — an all-carbon, ultra-thin and adaptable material — could improve performance even more. Researchers at the University of Wisconsin-Madison have now fabricated graphene into the smallest ribbon structures to date using a method that makes scaling up simple. In tests with these tiny ribbons, the scientists discovered that they were closing in on the properties they needed to move graphene toward usefulness in telecommunications equipment.

Researchers at Georgia State University have developed an intranasal influenza vaccine that is made of nanoparticles and that enhances the body's immune response to infection by the influenza virus. The vaccine uses recombinant hemagglutinin, a protein found on the surface of influenza viruses, as the antigen component of the vaccine. Hemagglutinin is integral to the ability of influenza virus to cause infection.

Scientists at the University of Connecticut and Ohio University have described the results of a study that looked at how nanoparticles of various sizes and shapes – including long and thin structures called nanoworms – move in blood vessels of different geometries, mimicking the constricted microvasculature. The scientists determined that nanoworms can travel more efficiently through the bloodstream, passing through blockages where spherical or flat shapes get stuck.

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.