ADVANCED MATERIALS & PROCESSES | JANUARY 2026 5 RESEARCH TRACKS ULTRA-THIN SODIUM FILMS SEE THE LIGHT Scientists from three universities— Yale, Oakland, and Cornell—collaborated to develop more cost-effective plasmonic materials, which are traditionally made of expensive metals like gold or silver. These materials are often used to manipulate light with extreme precision for applications ranging from solar panels to medical devices. The team’s new work brings together expertise in nanofabrication, ultrafast optics, and materials science. By developing a technique for structuring sodium into ultra-thin, precisely patterned films, the researchers found a way to stabilize the metal and make it perform exceptionally well in light- based applications. The new approach involved combining a thermally assisted spin coating with phase-shift photolithography, skillfully using heat and light to create nanoscopic surface patterns that trap and guide light in powerful ways. Further, the team used ultrafast laser spectroscopy to observe what happens when these sodium surfaces interact with light on time scales measured in trillionths of a second. The results were surprising, say researchers. Sodium’s electrons responded in ways that differ from traditional metals, suggesting it could offer new advantages for light-based technologies such as photocatalysis, sensing, and energy conversion. yale.edu. GRAPHENE-BASED SOLAR CELLS POWER TEMPERATURE SENSORS Researchers at the University of Arkansas and the University of Michigan report the first application of ultra-low power temperature sensors using graphene-based solar cells. They say the test is the first hurdle in developing autonomous sensor systems that draw power from multiple sources in the environment including solar, thermal, acoustic, kinetic, nonlinear, and ambient radiation. The goal is to develop multimodal sensors using the energy-harvesting capability of graphene that can last decades and help realize the Internet of Things in daily life. Success depended on overcoming two challenges: reducing sensor power demand to nanowatts as opposed to the current standard, which is measured in microwatts, and powering the sensor using energy harvested from the local environment. The Arkansas team was mostly responsible for completing the second challenge while the University of Michigan team was largely responsible for the first. The new study confirms it is possible to create an ultra-low power temperature sensor using graphenebased solar energy. By making them multimodal, intermittent shortages in solar power can be augmented with additional thermal or nonlinear power. Researcher Paul Thibado foresees the sensors being used in areas and fields where sensors would be useful but the need to replace batteries would make them labor and cost prohibitive. This could include things like tracking livestock, wearable fitness monitoring, building alarm systems, and predictive maintenance, among other applications. The next step is to perfect a kinetic energy harvester that collects energy from the vibrational qualities of graphene. This capability will then be joined with a solar sensor, creating a true multimodal sensor. uark.edu. Researchers from The University of Osaka and Daikin Industries Ltd., Japan, identified a new indicator for designing advanced lithium-ion batteries. They found that the electrolyte lithium-ion chemical potential, a measure of how “uncomfortable” a lithium ion is within a battery’s electrolyte, quantitatively determines whether a battery can be charged and discharged reversibly. www.osaka-u.ac.jp. BRIEF Researcher Conrad Kocoj works with ultrafast laser spectro- scopy equipment used to observe how sodium interacts with light. Testing of a graphene-based sensor. Courtesy of University of Arkansas.
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