(Funded by the U.S. National Science Foundation)
Researchers at North Carolina State University have demonstrated a new technique that uses light to tune the optical properties of quantum dots. The researchers placed green-emitting perovskite quantum dots in a solution containing either chlorine or iodine. The solution was then run through a microfluidic system that incorporated a light source. The microfluidic environment enabled precise reaction control by ensuring uniform light exposure across small solution volumes, approximately 10 microliters per reaction droplet. The light triggered reactions that made the green-emitting perovskite quantum dots move closer to the blue end of the spectrum when chlorine was present in the solvent and closer to the red end of the spectrum when iodine was present in the solvent.

(Funded by the U.S. National Science Foundation)
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.

(Funded by the U.S. National Science Foundation)
Researchers at Washington University in St. Louis have developed ultra-thin materials, called metasurfaces, that can amplify and interact with light regardless of its polarization. The metasurfaces are made of tiny nanoantennas that can both amplify and control light in very precise ways and could replace conventional refractive surfaces in eyeglasses and smartphone lenses. The polarization-independent metasurfaces have what’s known as a high quality factor, which means they trap light over a narrow band of resonant frequencies for a long time, generating a strong response to external stimuli.

(Funded by the U.S. National Science Foundation)
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.

(Funded by the U.S. National Science Foundation, the U.S. Department of Defense, and the U.S. Department of Energy)
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.”