Graphene nanoribbons survive gamma radiation, revealing potential sensors for fusion reactors

A breakthrough in materials science has emerged from the University of Arizona, where researchers have discovered that graphene nanoribbons (GNRs) can endure exposure to gamma radiation while maintaining their structural integrity and responding electrically. This finding opens the door to using these nanomaterials as potential sensors in high-radiation environments such as fusion reactors and deep space missions. The research was detailed in a recent publication in ACS Applied Materials & Interfaces. The study, led by Zafer Mutlu, an assistant professor of materials science and engineering at the University of Arizona College of Engineering, involved integrating GNRs into semiconductor devices and subjecting them to gamma radiation. According to the findings, the nanoribbons survived the exposure and continued to respond electrically, although their performance changed significantly. Mutlu explained that this change in performance is precisely the kind of reaction desired from a sensor. The ability of GNRs to maintain their atomic structure while exhibiting a detectable electrical response suggests their potential utility in real-time monitoring within harsh conditions. Fusion energy, often hailed as a nearly limitless and clean power source, faces several technological hurdles, including the need for reliable methods to monitor the condition of a reactor’s first wall. This component, which separates the superheated plasma from the reactor structure, deteriorates over time due to intense radiation. Current silicon-based sensors cannot survive inside this environment, necessitating external placement and relying on indirect measurements or post-shutdown inspections. The use of GNR-based sensors could allow for more direct and continuous monitoring, potentially reducing the frequency of costly shutdowns and extending operational periods for fusion power plants. The research team fabricated the GNRs from the molecular level using advanced techniques developed by Mutlu. These ribbons were engineered to be exactly nine atoms wide, one atom thick, and approximately 45 nanometers long, far thinner than a human hair. Due to their microscopic dimensions, the ribbons exhibit behavior governed by quantum mechanics rather than classical physics. Without radiation, current flows through the GNRs in a predictable manner. However, when exposed to gamma radiation, reactive molecules generated in the surrounding air interact with the edges of the ribbons, altering their properties slightly without affecting their overall structure. These subtle alterations at the quantum level lead to a phenomenon known as Anderson localization, where charge-carrying electrons become trapped, resulting in a sharp reduction in electrical conductivity. The researchers believe this effect could be harnessed to create highly sensitive sensors capable of detecting even minor changes in radiation levels. Such sensors would provide valuable data on the health of reactor components, enabling proactive maintenance strategies. Beyond their potential applications in fusion energy, GNRs are being explored for their role in advancing electronic technologies. Their unique properties, including exceptional strength and thermal stability, position them as viable alternatives to traditional semiconductors like silicon. As chip technology approaches its physical limits, materials like GNRs could enable faster and more efficient computing devices, ranging from smartphones to artificial intelligence systems. The implications of this research extend beyond laboratory settings. If successfully implemented, GNR-based sensors could revolutionize how industries manage and monitor equipment in high-radiation environments. This includes not only nuclear reactors but also spacecraft navigating the cosmos, where radiation poses a constant threat to onboard electronics. The ability to deploy durable, responsive sensors in such conditions could enhance safety and reliability across multiple sectors. Further studies are needed to refine the integration of GNRs into practical sensor designs and to evaluate their long-term performance under sustained radiation exposure. Researchers are optimistic that continued exploration of these nanomaterials will yield innovations that address some of the most pressing challenges in both energy production and space exploration.