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

Researchers at the University of Southern California, Los Angeles, have shown that when water comes into contact with an electrode surface, all of its molecules do not respond in the same way. The researchers designed a unique electrode built from monolayer graphene, placed it on a cell of water, and ran a current through the electrode. The scientists observed that the top layer of water molecules closest to the electrode aligned in a completely different way than the rest of the water molecules. This discovery was unexpected and could enable more accurate simulations of how aqueous chemical reactions affect the materials they work with.

Researchers from Cornell University and Harvard University have developed a technology that uses nanoscale sensors and fiber optics to measure how much water is present inside a leaf’s surface. The engineering feat provides a minimally invasive research tool that will greatly advance the understanding of basic plant biology, and open the door for breeding more drought-resistant crops. The technology could eventually be adapted for use as an agronomic tool for measuring water status in crops in real time.

Researchers from Yale University, the U.S. Department of Energy’s Argonne National Laboratory, the National University of Singapore, and ETH Zurich have discovered a complex, three-dimensional crystal, called the single gyroid, within feathers of the blue-winged leafbird. By comparing the color-producing nanostructures present in close relatives, the researchers discovered that this species can make single gyroid photonic crystals, which have highly desirable optical and electronic properties that make them ideal for use in photovoltaic cells to generate solar energy.

Researchers from Yale University, the U.S. Department of Energy’s Argonne National Laboratory, the National University of Singapore, and ETH Zurich have discovered a complex, three-dimensional crystal, called the single gyroid, within feathers of the blue-winged leafbird. By comparing the color-producing nanostructures present in close relatives, the researchers discovered that this species can make single gyroid photonic crystals, which have highly desirable optical and electronic properties that make them ideal for use in photovoltaic cells to generate solar energy.

For some 30 years, scientists have used superconducting materials to record individual photons, or single particles of light. But these detectors, which consist of ultracold nanowires, were limited to recording single photons at visible-light and in the near infrared (IR). By altering the composition of these nanowires, researchers at the National Institute of Standards and Technology (NIST) and colleagues have now demonstrated that the devices can record single photons whose wavelengths are up to five times longer than single photons that were previously detected.

Researchers at Rice University have discovered that hexagonal boron nitride, an atomically thin insulating two-dimensional material, is so resistant to cracking that it defies a century-old theoretical description engineers still use to measure toughness. Hexagonal boron nitride is used in 2D electronics because of its heat resistance, chemical stability, and dielectric properties. Its surprising toughness could also make it an ideal option for adding tear resistance to flexible electronics made from 2D materials, which tend to be brittle.

Researchers at the University of South Florida have developed a novel approach to mitigating electromigration in nanoscale electronic interconnects that are ubiquitous in state-of-the-art integrated circuits. Electromigration is the phenomenon in which an electrical current passing through a conductor causes the atomic-scale erosion of the material, eventually resulting in device failure. The researchers mitigated electromigration by coating copper metal interconnects with hexagonal boron nitride, an atomically thin insulating two-dimensional material that shares a similar structure as graphene.

Electrical engineers at the University of California, San Diego, have developed a technology that improves the resolution of an ordinary light microscope so that it can be used to directly observe finer structures and details in living cells. The technology consists of a microscope slide coated with a light-shrinking material, called a hyperbolic metamaterial, that consists of nanometers-thin alternating layers of silver and silica glass. 

New research by scientists from Rice University, the Technion-Israel Institute of Technology, and Eindhoven University of Technology suggests the jiggling motion of carbon nanotubes suspended in liquid solutions could have implications for the structure, processing, and properties of nanotube fibers formed from those solutions. Carbon nanotubes can already be formed into fibers that are stronger than steel and as conductive as metals, and Rice University scientists are exploring ways to reduce greenhouse gas emissions by substituting carbon nanotube fibers for metals and other emission-intensive materials.

A Northwestern University-led research team has developed a water treatment membrane that repeatedly removes and reuses phosphate from polluted waters. The researchers liken this development to a "Swiss Army knife" for pollution remediation as they tailor their membrane to absorb and later release other pollutants. The membrane is a porous, flexible substrate that selectively sequesters up to 99% of phosphate ions from polluted water. Coated with nanostructures that bind to phosphate, the membrane can be tuned by controlling the pH to either absorb or release nutrients to allow for phosphate recovery and reuse of the membrane for many cycles.