Engineers build world's thinnest light bulb using graphene

"We are just starting to dream about other uses for these structures," mechanical engineer James Hone said.

By Brooks Hays

NEW YORK, June 15 (UPI) -- If you can dream it up, graphene can probably do it. Every scientist'' favorite 21st-century material can add another feather to its cap. The super strong, flexible and highly conductive material can now emit light, too.

Recently, engineers at the Columbia University used tiny strips of graphene to build a light bulb -- the world's thinnest light bulb. Their feat is detailed in a new study published in the journal Nature Nanotechnology.


The researchers -- in coordination with scientists from Seoul National University (SNU) and the Korea Research Institute of Standards and Science (KRISS) -- created a light bulb by attaching super thin strips of graphene to metal electrodes. When a current was passed through the suspended strips, the filament lit up.

"We've created what is essentially the world's thinnest light bulb," study co-author James Hone, a professor of mechanical engineering at Columbia, said in a press release. "This new type of 'broadband' light emitter can be integrated into chips and will pave the way towards the realization of atomically thin, flexible, and transparent displays, and graphene-based on-chip optical communications."


By finally integrating light onto a chip and ultimately into a so-called photonic circuit, researchers can finally replace electric currents with "photonic" circuits in semiconductor integrated circuits. Scientists have long tried to integrate the traditional incandescent filament into integrated circuits, but they burn too ho, putting at risk other circuit components.

The graphene filament, on the other hand, can be heated more efficiently and can be heated with limited heat transfer. The more it is heated up, the less efficiently it transfers heat. So the glowing filament keeps the high temperatures confined to the center of the graphene strips.

"At the highest temperatures, the electron temperature is much higher than that of acoustic vibrational modes of the graphene lattice, so that less energy is needed to attain temperatures needed for visible light emission," explained Myung-Ho Bae, a senior researcher at KRISS.

Bae is the study's co-lead author, along with Young Duck Kim, a postdoctoral researcher at Columbia.

"These unique thermal properties allow us to heat the suspended graphene up to half of the temperature of the sun, and improve efficiency 1000 times, as compared to graphene on a solid substrate," Bae added.

The researchers are now looking to perfect their discovery and develop novel applications for the light-emitting graphene.


"We are just starting to dream about other uses for these structures," Hone said, "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."

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