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

Scientists from the U.S. Department of Energy's (DOE) Argonne National Laboratory, SLAC National Accelerator Laboratory, and Lawrence Berkeley National Laboratory; the University of California, Berkeley; Pennsylvania State University; Stanford University; Rice University; the Indian Institute of Science in Bangalore, India; the Japan Synchrotron Radiation Research Institute in Sayo, Japan; RIKEN SPring-8 Center in Sayo, Japan; and the University of Tokyo in Japan are investigating a material with a highly unusual structure – one that changes dramatically when exposed to an ultrafast pulse of light from a laser. At the Center for Nanoscale Materials, a DOE Office of Science user facility at Argonne, the scientists used a technique called transient absorption spectroscopy to detect photocarrier activity within the material. This approach helped them determine how much charge gets released and how quickly the charge decays. 

Most optical sensors record data from light and then transmit all of the raw data to a computer for processing. This typically consumes more energy than necessary, because in most applications, only a small amount of information relative to the raw data is needed. So, scientists from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory and Sandia National Laboratories; the University of California, Berkeley; the University of California, Davis; and the University of Texas at Arlington are developing a less power-hungry approach, in which some data processing is conducted in the sensor itself, before the data is sent to a computer or processed by edge computing devices. The new sensor, called a “nanoscale hybrid,” stitches together nanostructures, such as nanotubes and nanowires. It is highly sensitive in part because the sensor’s nanoscale components are smaller than the wavelength of light. 

Engineers from Purdue University and GRIMM Aerosol Technik Ainring GmbH & Co. in Germany have found that chemical products from air fresheners, wax melts, floor cleaners, and deodorants can rapidly fill the air with nanoparticles that are small enough to get deep into our lungs. These nanoparticles form when fragrances interact with ozone, which enters buildings through ventilation systems. "Our research shows that fragranced products are not just passive sources of pleasant scents—they actively alter indoor air chemistry, leading to the formation of nanoparticles at concentrations that could have significant health implications," said Nusrat Jung, one of the engineers involved in this study.

Researchers from the U.S. Department of Energy’s Argonne National Laboratory and Fermi National Accelerator Laboratory, as well as Northern Illinois University have discovered that superconducting nanowire photon detectors, which are used for detecting photons (the fundamental particles of light) could potentially also function as highly accurate particle detectors, specifically for high-energy protons used as projectiles in particle accelerators. The ability to detect high-energy protons with superconducting nanowire photon detectors has never been reported before, and this discovery widens the scope of particle detection applications.

Researchers from Rutgers University, the New Jersey Institute of Technology, the Connecticut Agricultural Experiment Station in New Haven, CT, and the Environmental and Occupational Health Sciences Institute in Piscataway, NJ, have shown that microplastic and nanosplastic particles in soil and water can significantly increase how much toxic chemicals plants and human intestinal cells absorb. Using a cellular model of the human small intestine, the researchers found that nano-size plastic particles increased the absorption of arsenic by nearly six-fold compared with arsenic exposure alone. The same effect was seen with boscalid, a commonly used pesticide. Also, the researchers exposed lettuce plants to two sizes of polystyrene particles – 20 nanometers and 1,000 nanometers – along with arsenic and boscalid. They found the smaller particles had the biggest impact, increasing arsenic uptake into edible plant tissues nearly threefold compared to plants exposed to arsenic alone.

Researchers from Rice University, the University of California Berkeley, the University of Pennsylvania, and the Massachusetts Institute of Technology have shed light on how the extreme miniaturization of thin films affects the behavior of relaxor ferroelectrics — materials with noteworthy energy-conversion properties used in sensors, actuators, and nanoelectronics. The findings reveal that as the films shrink to dimensions comparable to internal polarization structures within the films, their fundamental properties can shift in unexpected ways. More specifically, when the films are shrunk down to a precise range of 25–30 nanometers, their ability to maintain their structure and functionality under varying conditions is significantly enhanced.

A major challenge in self-powered wearable sensors for health care monitoring is distinguishing different signals when they occur at the same time. Now, researchers from Penn State and Hebei University of Technology in China have addressed this issue by developing a new type of flexible sensor that can accurately measure both temperature and physical strain simultaneously but separately, potentially enabling better wound healing monitoring. The sensor is made with laser-induced graphene, which forms when a laser heats certain carbon-rich materials in a way that converts their surface into a graphene structure. 

Physicists from the Massachusetts Institute of Technology, Harvard University, and the National Institute for Materials Science in Tsukuba, Japan, have directly measured superfluid stiffness for the first time in "magic-angle" graphene – materials that are made from two or more atomically thin sheets of graphene twisted with respect to each other at just the right angle. The twisted structure exhibits superconductivity, in which electrons pair up, rather than repelling each other as they do in everyday materials. These so-called Cooper pairs can form a superfluid, with the potential to move through a material as an effortless, friction-free current. "But even though Cooper pairs have no resistance, you have to apply some push, in the form of an electric field, to get the current to move," says Joel Wang, one of the scientists involved in this study. "Superfluid stiffness refers to how easy it is to get these particles to move, in order to drive superconductivity." 

Researchers from Northwestern University have defined a method to tailor a sponge that is coated with nanoparticles to specific Chicago pollutants and then to selectively release them. In its first iteration, the sponge platform was made of polyurethane and coated with a substance that attracted oil and repelled water. The newest version is a highly hydrophilic (water-loving) cellulose sponge coated with nanoparticles tailored to other pollutants. The scientists found that by lowering the pH, metals flush out of the sponge. Once copper and zinc are removed, the pH is then raised, at which point phosphate comes off the sponge. Even after five cycles of collecting and removing minerals, the sponge worked just as well, and the resulting water had untraceable amounts of pollutants.

Researchers from the University of California, Berkeley; the U.S. Department of Energy’s Lawrence Berkeley National Laboratory; and the University of Cambridge have developed a practical way to make hydrocarbons – molecules made of carbon and hydrogen – powered solely by the sun. The device combines a light absorbing “leaf” made from a high-efficiency solar cell material called perovskite, with a flower-shaped copper nanocatalyst, to convert carbon dioxide into useful molecules. Unlike most metal catalysts, which can only convert carbon dioxide into single-carbon molecules, the copper flowers enable the formation of more complex hydrocarbons with two carbon atoms, such as ethane and ethylene, which are key building blocks for liquid fuels, chemicals, and plastics.