The organic light-emitting diode (OLED) technology behind flexible cell phones, curved monitors, and televisions could one day be used to make on-skin sensors that show changes in temperature, blood flow, and pressure in real time. An international collaboration, led by researchers from Seoul National University in the Republic of Korea and Drexel University, has developed a flexible and stretchable OLED that could put the technology on track for this use and a range of new applications.

A study published in Nature Physics Jan. 14, co-led by Rice University’s Qimiao Si, brings together quantum criticality, where electrons fluctuate between different phases, and electronic topology, which describes a form of quantum organization based on the wave behavior of electrons. The researchers found that strong interactions among electrons can produce topological behavior, paving the way for new technologies that could use this quantum state in real-world applications.

Researchers have created a self-healing composite that is tougher than materials currently used in aircraft wings, turbine blades and other applications – and can repair itself more than 1,000 times. The researchers estimate their self-healing strategy can extend the lifetime of conventional fiber-reinforced composite materials by centuries compared to the current decades-long design-life.

Researchers at Princeton University and the University of Arizona have quantified U.S. groundwater in unprecedented breadth and detail. Combining direct measurements with artificial intelligence methods, their new map estimates groundwater depth across the continental United States at a resolution of around 30 meters (98 feet). The work provides a foundation for further research as well as local and regional decision-making around irrigation, conservation and water infrastructure.

A team of New York University scientists has created a gear mechanism that relies on fluids to generate rotation. The invention holds potential for a new generation of mechanical devices that offer greater flexibility and durability than do existing gears—whose origins date back to ancient China.