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

The Rice University laboratory of chemist James Tour has modified its flash Joule heating process to produce doped graphene that tailors its structures and electronic states to make them more suitable for optical and electronic nanodevices. The doping process adds other elements – a single element, pairs of elements, or trios of elements – to graphene’s 2D carbon matrix. The process takes about one second, is both catalyst- and solvent-free and is entirely dependent on “flashing” a powder that combines the dopant elements with carbon.

Researchers at the University of Illinois Urbana-Champaign have developed a new method to measure changes that occur in materials, such as glasses, at the nanoscale. The researchers extended an imaging technique used for scanning electron microscopes so it can also be used for transmission electron microscopes. The technique, called digital image correlation, takes a series of images and compares one image to the next in order to map what is happening in a material over time. 

Researchers from MIT, Columbia University, and the National Institute for Materials Science in Tsukuba, Japan, have engineered a new property into a well-known family of semiconductors, called transition metal dichalcogenides, by manipulating ultrathin sheets of the materials only a few atomic layers thick. The researchers showed that when two single sheets of a transition metal dichalcogenide are stacked parallel to each other, the material becomes ferroelectric. In a ferroelectric material, positive and negative charges spontaneously head to different sides. 

Researchers from the U.S. Department of Energy's Pacific Northwest National Laboratory and the University of Washington have successfully designed a bio-inspired molecule that can direct gold atoms to form perfect nanoscale stars. The work is a step toward understanding and controlling the shapes of metal nanoparticles and creating advanced materials with tunable properties

A team of U.S. researchers from various academic and research institutions has developed a new additive material that can make an inexpensive iron-nitrogen-carbon fuel cell catalyst more durable. In particular, the additive material, which is composed of tantalum-titanium oxide nanoparticles, scavenged and deactivated unstable atoms, molecules, or ions called free radicals. The researchers showed that when the nanoparticle material was added to the reactions of fuel cell systems, hydrogen peroxide yield was suppressed to less than 2% – a 51% reduction – and current density decay of fuel cells was reduced from 33% to 3%.

Researchers at Brown University have carried out a study investigating superconductivity in magic-angle trilayer graphene to better understand the unusual superconducting behavior observed in this material. The results from this study are similar to results from another study the researchers performed on magic-angle bilayer graphene, which suggests that superconducting phases in these two materials (magic-angle bilayer and magic-angle trilayer graphene) have a common origin. Both materials consist of sheets of graphene stacked together with a rotational misalignment of approximately 1.5 degrees.

With billions of transistors in a single computer chip, their manufacturing tools now operate at the molecular level.  Typically, these tools involve using stencils to selectively pattern or remove materials with high fidelity to form nanoscale electronic devices. As chips fit more and more components to keep up with the digital world's growing computational demands, these nanopatterning stencils are becoming smaller and more precise. Now, researchers from the University of Pennsylvania and the University of Konstanz in Germany have demonstrated how "multiblock" copolymers can produce exceptionally ordered patterns in thin films, achieving spacings smaller than three nanometers.

An international team of researchers has developed a wireless, biodegradable sensor that could offer doctors a way to monitor changes in brain chemistry without requiring a second operation to remove the implant. As a proof of concept, the researchers inserted the device into the deep brain region of a mouse, and the device collected data on levels of dopamine, an important neurotransmitter, as well as pH levels, temperature, and electrophysiology, before dissolving back into the body. The implant is composed of two-dimensional transition metal dichalcogenides, which are considered an emerging class of materials that are increasingly used in nanoelectronics and nanophotonics applications. 

Scientists at Rice University have put forth the idea that growing graphene on a surface that undulates like an egg crate would stress the graphene enough to create a very small electromagnetic field. This phenomenon, which is possible because graphene is pliable enough to adhere to a surface during chemical vapor deposition, could be useful for creating 2D electron optics.

Scientists at the University of Tennessee, Knoxville, have discovered that a form of cellulose obtained from plants can be added to ice cream to control the formation and growth of ice crystals in it – and the additive works better than currently used ice growth inhibitors when temperature fluctuates. The additive consists of cellulose nanocrystals, which are extracted from the plant cell walls of agricultural and forestry byproducts. In a model ice cream – a 25% sucrose solution – the cellulose nanocrystals initially had no effect, but after the model ice cream was stored for a few hours, the researchers found that the cellulose nanocrystals completely shut down the growth of ice crystals, while the crystals continued to enlarge in the untreated model ice cream.