Researchers from France and Serbia reported that a graphene-based microphone was almost 32 more sensitive than normal nickel-based models. Their graphene-based microphones are almost 32 times more sensitive than standard nickel-based ones. A vibrating membrane was created from graphene by scientists from University of Belgrade. This vibrating membrane forms part of condenser microphones that convert sound into current. The vibrating membrane was able to display 15 higher sensitivity than a commercial standard microphone at frequencies of 11kHz. Marko Spasenovic (Assistant Professor at Belgrade University’s Institute of Physics) and his colleagues from France’s Laboratoire de Photonique et de Nanostructures (Laboratory for Photonics and Nanostructures), published their findings in 2D Materials. The potential of graphene is enormously promising in many areas, including Acoustics. Image: generic microphone – ioppublishing.org. Graphene – great potential for real-world applications Professor Spasenovic stated: “We wanted graphene to be shown that even though it is a new material, there are real-world applications.” Because of its lightweight, mechanical strength, and flexibility graphene is a great material for acoustic membranes. The graphene membrane was made on a nickel foil by chemical vapour deposition to ensure consistency across the different samples. To make it easy to compare, the graphene membrane and commercial microphone were etched off while the membrane was being made. The 15dB sensitivity was significantly higher than that of a commercial standard microphone. Professor Spasenovic’s team also created a 300-layer thickgraphene membrane that could be used to simulate ultrasonic performance. Ultrasonic is a sound wave with a frequency higher than the human hearing limit. Professor Spasenovic said that the microphone worked as expected. The possibility of making thicker graphene membranes, which would enable ultrasonic performance, is theoretically possible, but we aren’t quite there yet experimentally. Therefore, our microphone should only be considered a proof-of-concept. The graphene industry continues to work hard on improving graphene production. This should eventually lead to better microphones with lower costs. Graphene is a layer of carbon atoms in a hexagonal (6-sided) lattice structure. It’s the strongest known material, 207 stronger than steel. It’s also the lightest and thinnest material in existence. Graphene, the strongest and lightest material that we have ever seen, is also one of our thinnest. Graphene can be considered a 2-D object because it’s so thin. It was first produced in 2004, and is now being isolated by scientists. This material has great potential to be used in industry, high-tech medical devices, and many other industries. Graphene has remarkable thermal and electrical conductivity. It’s unique in the fact that graphene is extremely strong and thin, but also very flexible. There are many potential uses for it, including electric circuits and solar cells. It can also be used in a variety of chemical, industrial, and medical processes. Citation: “Multilayer graphene condenser microphone,” Dejan Todorovic, Aleksandar Matkovic, Marijana Milicevic, Djordje Jovanovic, Rados Gajic, Iva Salom and Marko Spasenovic. 2D Materials. 26 November, 2015. DOI: 10.1088/2053-1583/2/4/045013. Video – Graphene
