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

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.

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.