海角社区-Led Research Team Shows Alloys Could Excel at Detecting Infrared Light
May 11, 2020
BATON ROUGE, LA 鈥� A group of researchers from 海角社区, Argonne National Laboratory and Drexel University have discovered an alloy that has practical application in the ultrafast detection of near-infrared light, which is important to the military for missile defense systems and night vision goggles.
The research was published in the latest issue of Advanced Materials in a paper titled, 鈥淣oble-Transition Alloy Excels at Hot-Carrier Generation in the Near Infrared.鈥�
The project was led by 海角社区 Chemical Engineering Assistant Professor Kevin McPeak and his graduate student Sara Stofela in collaboration with 海角社区 Chemical Engineering Professor William Shelton, 海角社区 Chemical Engineering graduate students Tiago Leite and Daniel Willis, 海角社区 Physics Professor Phillip Sprunger, 海角社区 Center for Advanced Microstructures & Devices Professor Orhan Kizilkaya, Benjamin Diroll with Argonne National Laboratory鈥檚 Center for Nanoscale Materials, and Mohammad Taheri and Professor Jason Baxter with Drexel University鈥檚 Department of Chemical and Biological Engineering.
The group鈥檚 work, which took place over four years, focused on developing a material that excels at generating hot carriers when excited with near-infrared light.
Near-infrared light cannot be seen by the human eye, making it useful for the military in reconnaissance missions. Hot carriers are electrons and holes, which are above and below, respectively, the equilibrium energy of the system. Since these carriers are above the equilibrium energy of the system, they can be used to drive an electrical circuit.
The problem, however, is finding a material that will offer both hot-carrier generation and a sufficient carrier lifetime so that the electrons and holes can be collected from the metal. Single-element metals struggle to do this well. There is, however, as the team discovered, an alloy that fits the bill.
鈥淲e explored an alloy of gold and palladium in this paper,鈥� McPeak said. 鈥淎u (or gold) has been heavily studied for the generation of hot carriers by other groups, especially in under visible light. Pd (or palladium) can generate a lot of carriers in the near-infrared but they decay very rapidly because the carriers scatter off each other. The hot carriers decay so fast in Pd that they can鈥檛 be extracted quick enough to drive an electric circuit.
鈥淲e show that by alloying Au and Pd we can both extend the lifetime of the carriers in Pd and increase the number of carriers from Au. These alloy materials have practical applications in the ultrafast detection of near-infrared light, which is important to the military for intelligence, surveillance, and reconnaissance systems.鈥�
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