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

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.

A team led by the University of Illinois Urbana-Champaign has demonstrated a more efficient and environmentally friendly method to produce hydrogen peroxide. Currently, producing hydrogen peroxide requires a complicated, multi-step process and large facilities. The researchers found that a catalyst with a ratio of one palladium to 220 gold atoms generates almost 100% hydrogen peroxide. The scientists are now using these results to pursue the development of nanoparticle catalysts with new compositions and reactors to enable hybrid chemical-electrochemical methods for the production of hydrogen peroxide.

Researchers from Iowa State University, ETH Zurich in Switzerland, Paul Scherrer Institut in Switzerland, the Swiss Federal Laboratories for Materials Science and Technology, Graz University of Technology in Austria, and IBM Research Europe have developed new types of materials that combine two or three types of nanoparticles into structures that display fundamental new properties, such as superfluorescence. The researchers combined perovskite nanocubes – tiny crystals with useful electrical or optical properties – with spherical nanoparticles to form a regular, repeating structure called a superlattice. This is the first time such nanoparticles have been combined.

Physicists from across three continents – including MIT and the U.S. Department of Energy’s Brookhaven National Laboratory – have reported the first experimental evidence to explain the unusual electronic behavior behind the world's thinnest superconductor. The scientists used a new experimental technique, called resonant inelastic X-ray scattering, to study high-temperature superconductivity in a monolayer-thin film of iron selenide, providing a new route to investigate the mechanisms enabling high-temperature superconductivity. The resulting data could help guide the development of better superconductors, and, in turn, transform the fields of medical diagnostics, quantum computing, and energy transport, which all use superconductors.

Researchers at Washington State University have developed a new technique that uses chemically sensitive “soft” X-rays and offers a simpler, non-disruptive way of gaining insight into "nanocarriers" for highly targeted drug delivery and environmental clean-up. Currently researchers have to rely on attaching fluorescent dyes or heavy metals to label parts of organic nanocarrier structures for investigation, often changing them in the process. The new X-ray method has been demonstrated on a smart drug delivery nanoparticle and a polysoap nanostructure intended to capture crude oil spilled in the ocean.