Gizmorama - June 17, 2015

Good Morning,

Are you ready for the world's thinnest light bulb? Well, it's more than just the thinnest light bulb. This new bulb may be more that just another bright idea.

Learn about this and more interesting stories from the scientific community in today's issue.

Until Next Time,
Erin

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*-- Engineers build world's thinnest light bulb using graphene --*
NEW YORK (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."


*-- Scientists create material that mimics adaptive squid skin --*
BRISTOL, England (UPI) - Scientists often try to take what they see in nature and recreate it or apply it to their work in the laboratory. That's what researchers at the University of Bristol did in designing a smart material inspired by the camouflaging skin of a squid.

The skin of squids and other cephalopods is characterized by chromatophores, small embedded pigmented cells which can expand and contract to manipulate the skin's color and texture. Recent research showed that squid skin can actually sense its surroundings -- without the assistance of the brain -- and respond by adopting a new appearance.

Material scientists at Bristol used this biological technology as a model to create camouflaging smart materials made of artificial chromatophores. The synthetic chromatophores are made of thin layers of dielectric elastomer, a soft, rubbery polymer that can be manipulated by pulses of electricity.

The new smart material enables scientists to recreate a patterning phenomenon used by real cephalopods called the "passing cloud" display. The pattern features bright bands of colors spreading out in waves across the skin; it's is employed as a way to distract and repel predators.

"Our ultimate goal is to create artificial skin that can mimic fast acting active camouflage and be used for smart clothing such as cloaking suits and dynamic illuminated clothing," lead researcher Aaron Fishman, a visiting fellow at Bristol, said in a press release.

"The cloaking suit could be used to blend into a variety of environments, such as in the wild," Fishman said. "It could also be used for signalling purposes, for example search and rescue operations when people who are in danger need to stand out."

The researchers hope to further develop their smart material so that is is more dynamic and able to respond to different stimuli and produce a diversity of patterns.

The smart skin's development was recently detailed in the Journal of the Royal Society Interface.

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