ADVANCED MATERIALS & PROCESSES | JULY/AUGUST 2024 1 1 PROCESS TECHNOLOGY STRONGER AND TOUGHER COMPOSITES Fiber-reinforced polymer composite materials have a lot going for them. They are strong and lightweight relative to their metallic counterparts. They’re also corrosion and fatigue resistant and can be tailored to meet specific industrial performance requirements. However, they are vulnerable to damage from strain because two diverse materials—rigid fibers and a soft matrix, or a binder substance—must be combined to make them. The interphase between the two materials needs improvement because of its influence on the overall mechanical properties of the composites. Now, scientists at the DOE’s Oak Ridge National Laboratory, Tenn., created a method that demonstrates how composite materials used in the automotive, aerospace, and renewable than silicon photovoltaics, which require high temperatures and a cleanroom environment. However, producing these cells involves high temperature annealing and tricky post-treatment steps, significantly slowing fabrication and making it hard to incorporate them into everyday items. These factors impede perovskite’s adoption in large-scale manufacturing and make it less environmentally sustainable. By fine-tuning the material’s chemical composition, the team developed a perovskite ink that created high-quality films much more effectively. The simpler fabrication technique also works better with standard manufacturing processes and reduces overall energy use, which lowers its carbon dioxide emissions. What’s more, the new material outperformed cells made using the high-temperature process. “We can now contemplate the development of high-efficiency solar cells with freeform designs capable of powering the ever-increasing array of wearable electronics, sensors, displays, security cameras, Internet of Things devices, et cetera,” says lead researcher Thuc-Quyen Nguyen. ucsb.edu. energy industries can be made stronger and tougher to better withstand mechanical or structural stresses over time. The research team deposited thermoplastic nanofibers like cobwebs to chemically create a supportive network that toughens the interphase. The team carefully selected the nanofibers and matrix material to create high-surface-area scaffolding or bridging as a load transfer pathway, a mechanism through which stress is passed between the reinforcing fibers and surrounding matrix material. The new process enables the material to withstand greater stress. Using this simple, scalable, and low-cost approach, the researchers were able to increase the strength of the composites by almost 60% and toughness by 100%. ornl.gov. HIGH PERFORMANCE CELLS FROM A LOW ENERGY PROCESS Researchers at UC Santa Barbara, Calif., developed a method to make high-quality perovskite films at room temperature. The new process simplifies the material’s production process for use in solar cells and increases its efficiency from under 20% to 24.4%. Solar cells made from perovskite boast many advantages compared to silicon-based solar cells. They’re lightweight, flexible, and can be applied as a spray or printed as ink. Perovskite solar cell production also has the potential for a smaller carbon footprint SME, Southfield, Mich., will partner with BlueForge Alliance, College Station, Texas, to support the U.S. Navy Submarine Industrial Base Program’s efforts to train more than 140,000 skilled workers in the next decade to build new submarines and sustain the current fleet. sme.org. Norman Noble Inc., Highland Heights, Ohio, won a Superior Safety Award from the National Tooling & Machining Association for exemplary performance in 2023. nnoble.com. BRIEFS A novel method makes composite materials stronger and tougher. Courtesy of Adam Malin/ORNL, U.S. Dept. of Energy. A thin perovskite film coats a leaf. Courtesy of Ahra Yi and Sangmin Chae et al.
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