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

Scientists from Rice University, George Mason University, Johns Hopkins University, and Princeton University have discovered that tiny gold "seed" particles, a key ingredient in one of the most common nanoparticle recipes, are the same as gold buckyballs – 32-atom spherical molecules that are cousins of 60-carbon-atom molecules called buckyballs. Confirming that the widely used seeds were 32-gold-atom molecules rather than nanoparticles took years of effort, including state-of-the-art imaging and detailed theoretical analyses by the scientists.

Researchers from North Carolina State University, Iowa State University, and the University of British Columbia have developed a technique that uses a molecule-thin protective layer to control how the heat of a flame interacts with a material. "Our technique … employs a nanoscale thin film over a targeted material,” said Martin Thuo, one of the scientists involved in this study. “The thin film changes in response to the heat of the fire and regulates the amount of oxygen that can access the material. That means we can control the rate at which the material heats up." This work was performed in part at the Analytical Instrumentation Facility (AIF) at North Carolina State University, which is a member of the North Carolina Research Triangle Nanotechnology Network (RTNN), a site in the National Nanotechnology Coordinated Infrastructure (NNCI). 

Researchers at the University of Central Florida have developed new ways to produce energy and materials from methane, a greenhouse gas. The scientists invented a method to produce hydrogen from methane without releasing contaminants, such as higher polyaromatic compounds, carbon dioxide. or carbon monoxide. By using visible light and defect-engineered boron-rich photocatalysts, the innovation highlights a new functionality of nanomaterials for visible light-assisted capture and conversion of methane. Defect engineering refers to creating irregularly structured materials.

Researchers at Columbia University, the Technical University of Denmark, Aarhus University in Denmark, Université Paris-Saclay, and the National Institute for Materials Science in Tsukuba, Japan, have developed a simple new fabrication technique that may help physicists probe the fundamental properties of twisted layers of graphene and other 2D materials in a more systematic and reproducible way. They used long "ribbons" of graphene, rather than square flakes, to create devices that offer a new level of predictability and control over both twist angle and strain. The researchers showed that with just a little push from the tip of an atomic force microscope, they can bend a graphene ribbon into a stable arc that can then be placed flat on top of a second, uncurved, graphene layer.

Researchers at the University of Chicago have found that a sheet of glass crystal just a few atoms thick could trap and carry light. This discovery demonstrates what are essentially 2D photonic circuits. Photonic circuits already exist, but they are larger and three-dimensional, and particles of light, or photons, travel enclosed inside the waveguides used in these circuits. (Waveguides act like the wires that are used to carry electrical signals, but they carry photons instead.) With this system, the glass crystal is thinner than a photon – so, part of a photon actually sticks out of the crystal, as it travels. This work made use of the fabrication facilities of the Pritzker Nanofabrication Facility at the University of Chicago, which receives support from SHyNE Resource, a node of the National Nanotechnology Coordinated Infrastructure.

In rooms where smoking has taken place regularly, tobacco's imprint lingers on indoor surfaces, even long after regular smoking has stopped. The leftover residues, known as thirdhand smoke, can be a long-term source of indoor pollutants. Now, researchers from the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab), the University of California Berkeley, the University of California Riverside, and San Diego State University, have examined smoke-contaminated aged carpets and new carpets exposed to fresh smoke in the lab and found that carpets can be an important reservoir and source of contaminants from thirdhand smoke. The work was carried out at Berkeley Lab’s Air Quality Testing Laboratory and the Molecular Foundry, a user facility at Berkeley Lab. 

Researchers from the University of Missouri have developed a new method using nanopores – nanometer-sized holes – to help scientists advance their discoveries in neuroscience. "Potential applications include studying the structures of DNA- and RNA-based diseases and disorders,” said Li-Qun "Andrew" Gu, one of the scientists involved in this study. “Or we could potentially discover new small-molecule drug compounds that can be used in future drug discoveries."

Scientists from Rice University, Cornell University, the Army Research Laboratory, the Naval Research Laboratory, and the Indian Institute of Technology Kanpur mixed hexagonal boron nitride – a soft variety also known as "white graphite" – with cubic boron nitride – a material second to diamond in hardness – and found that the resulting nanocomposite interacted with light and heat in unexpected ways that could be useful in next-generation microchips and quantum devices. "What is fascinating about this study is that it opens up possibilities to tailor boron nitride materials with the right amounts of hexagonal and cubic structures, thus enabling a broad range of tailored mechanical, thermal, electrical, and optical properties in this material," said Pulickel Ajayan, one of the scientists involved in this study.

Engineers at Johns Hopkins University have developed nanoscale tattoos – dots and wires that stick to live cells, while flexing and conforming to the cells' wet and fluid outer structure. "If you imagine where this is all going in the future, we would like to have sensors to remotely monitor and control the state of individual cells and the environment surrounding those cells in real time," said David Gracias, the engineer who led the development of this technology. "If we had technologies to track the health of isolated cells, we could maybe diagnose and treat diseases much earlier and not wait until the entire organ is damaged."

Researchers from Penn State, Western Michigan University, and the U.S. Department of Energy’s Oak Ridge National Laboratory have found that atomic-scale steps on sapphire substrates enable crystal alignment of 2D materials during semiconductor fabrication. They also discovered that manipulation of these materials during synthesis may reduce defects and improve electronic device performance.