Graphene is a one-atom thick wonder material that is stronger than steel, and since its discovery it has seemingly led to one breakthrough after another. Here's the latest: the world's thinnest light bulb, reports Phys.org.
A team of scientists from Columbia, Seoul National University, and Korea Research Institute of Standards and Science are responsible for the invention, which could soon herald the further development of atomically thin, flexible, transparent displays. It could also make on-chip optical communications possible.
To create the super-slim light bulb, researchers used graphene as a filament. They attached small strips of graphene to metal electrodes and suspended the strips above the substrate, then passed a current through the filaments to cause them to heat up. The technique heated the graphene to temperatures in excess of 2,500 degrees Celsius, which was enough to cause it to glow brightly with visible light.
"The visible light from atomically thin graphene is so intense that it is visible even to the naked eye, without any additional magnification," explained Young Duck Kim, co-lead author on the study.
Scientists have tried to make such small light sources before, but micro-scale metal wires made from other materials cannot withstand the extremely hot temperatures required to make them glow in the visible range. Graphene, however, has a remarkable property: as it heats up, it becomes a much poorer conductor of heat. Essentially, this means that the highest temperatures are confined to a small spot in the center of the material, conveniently contained. This also means that less energy is needed to attain the high temperatures.
Interestingly, the invention represents a return to history of sorts. When Thomas Edison originally invented the light bulb, he first used carbon — which is the same stuff graphene is made of — as a filament too. But Edison never had the luxury of using carbon in so pure a form as graphene, at only one atom thick.
"We are just starting to dream about other uses for these structures — for example, as micro-hotplates that can be heated to thousands of degrees in a fraction of a second to study high-temperature chemical reactions or catalysis," suggested James Hone, one of the researchers on the study.
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