GrapheneA quantum probe based on an atomic-sized “color center” in diamonds has let researchers observe the flow of electric currents in graphene.

Made up of a lattice of carbon atoms only one atom thick, graphene is a key material for the electronics of the future. The thin carbon material is stronger than steel and due to its flexibility, transparency, and ability to conduct electricity, holds great promise for use in solar cells, touch panels, and flexible electronics.

No one has been able to see what is happening with electronic currents in graphene, says Lloyd Hollenberg, professor at the University of Melbourne and deputy director of the Centre for Quantum Computation and Communication Technology.

According to Hollenberg, this new technique overcomes significant limitations with existing methods for understanding electric currents in devices based on ultra-thin materials.

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GrapheneA team of researchers at the University of Manchester – where graphene was first discovered and won the Nobel Prize – created a graphene-oxide membrane for desalination. The newly developed sieve can turn seawater into drinking water, demonstrating graphene’s ability to filter common salts from water, leading to affordable desalination technology.

Prior to this research, graphene-oxide molecules have garnered significant attention from the scientific community, demonstrating their potential to filter our small nanoparticles, organic molecules, and even large salts. However, researchers have not been able to use a graphene-oxide membrane in desalination technologies, which require very small sieves, until this development.

This from the University of Manchester:

Previous research at The University of Manchester found that if immersed in water, graphene-oxide membranes become slightly swollen and smaller salts flow through the membrane along with water, but larger ions or molecules are blocked.

The Manchester-based group have now further developed these graphene membranes and found a strategy to avoid the swelling of the membrane when exposed to water. The pore size in the membrane can be precisely controlled which can sieve common salts out of salty water and make it safe to drink.

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GrapheneGraphene could offer a new way to cool tiny chips in phones, computers, and other gadgets.

“You can fit graphene, a very thin, two-dimensional material that can be miniaturized, to cool a hot spot that creates heating problems in your chip,” says Eva Y. Andrei, a physics professor at Rutgers University. “This solution doesn’t have moving parts and it’s quite efficient for cooling.”

As electronics get smaller and more powerful, there’s an increasing need to for chip-cooling solutions. Researcher show in a paper published in the Proceedings of the National Academy of Sciences that using graphene combined with a boron nitride crystal substrate creates a very efficient cooling mechanism.

“We’ve achieved a power factor that is about two times higher than in previous thermoelectric coolers,” says Andrei.

The power factor refers to the effectiveness of active cooling. That’s when an electrical current carries heat away, as shown in this study, while passive cooling is when heat diffuses naturally.

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By: Mike Williams, Rice University

Graphene

Rice University researchers have modeled a nanoscale sandwich, the first in what they hope will become a molecular deli for materials scientists.

Their recipe puts two slices of atom-thick graphene around nanoclusters of magnesium oxide that give the super-strong, conductive material expanded optoelectronic properties.

Rice materials scientist Rouzbeh Shahsavari and his colleagues built computer simulations of the compound and found it would offer features suitable for sensitive molecular sensing, catalysis and bio-imaging. Their work could help researchers design a range of customizable hybrids of two- and three-dimensional structures with encapsulated molecules, Shahsavari said.

The research appears this month in the Royal Society of Chemistry journal Nanoscale.

The scientists were inspired by experiments elsewhere in which various molecules were encapsulated using van der Waals forces to draw components together. The Rice-led study was the first to take a theoretical approach to defining the electronic and optical properties of one of those “made” samples, two-dimensional magnesium oxide in bilayer graphene, Shahsavari said.

“We knew if there was an experiment already performed, we would have a great reference point that would make it easier to verify our computations, thus allowing more reliable expansion of our computational results to identify performance trends beyond the reach of experiments,” Shahsavari said.

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By: Mike Williams, Rice University

GrapheneA new type of conductive graphene foam is incredibly tough and can be formed into just about any shape and size.

A chunk of the foam, which is reinforced by carbon nanotubes, can support more than 3,000 times its own weight and easily bounce back to its original height.

The Rice University lab of chemist James Tour tested this new “rebar graphene” as a highly porous, conductive electrode in lithium ion capacitors and found it to be mechanically and chemically stable. The results appear in the journal ACS Applied Materials and Interfaces.

Carbon in the form of atom-thin graphene is among the strongest materials known and is highly conductive; multiwalled carbon nanotubes are widely used as conductive reinforcements in metals, polymers and carbon matrix composites. The Tour lab had already used nanotubes to reinforce two-dimensional sheets of graphene. Extending the concept to macroscale materials made sense, says Tour, a professor of computer science and of materials science and nanoengineering.

“We developed graphene foam, but it wasn’t tough enough for the kind of applications we had in mind, so using carbon nanotubes to reinforce it was a natural next step,” Tour adds.

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Nano-chimney to Cool Circuits

Overheating has emerged as a primary concern in the development of new electronic devices. A new study from Rice University looks to provide a solution to that, offering a strategy to vent heat away from nano-electronics through cone-like chimneys.

By putting these “chimneys” between the graphene and nanotube, the researchers effectively eliminate a barrier that typically blocks heat from escaping.

This from Rice University:

Researchers at Rice University discovered through computer simulations that removing atoms here and there from the two-dimensional graphene base would force a cone to form between the graphene and the nanotube. The geometric properties of the graphene-to-cone and cone-to-nanotube transitions require the same total number of heptagons, but they are more sparsely spaced and leave a clear path of hexagons available for heat to race up the chimney.

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Silly putty isn’t just for kids anymore.

Researchers in Ireland combined the classic kid’s toy with a special form of carbon to create a new material that has potential applications in medical devices such as heart monitors.


About 70 years ago, scientists came up with the recipe for silly putty as a substitute for rubber. The resulting formula yielded strange properties, but not many applications. However, by taking the strange silly putty formula and mixing it with graphene, the new mixture showed remarkable electrical, bouncy, liquid-like properties.

InSeNewly developed semiconductor materials are showing promising potential for the future of super-fast electronics.

A new study out of the University of Manchester details a new material called Indium Selenide (InSe). Like graphene, InSe if just a few atoms thick, but it differs from the “wonder material” in a few critical ways. While graphene has been hailed for its electronic properties, researchers state that it does not have an energy gap – making graphene behave more like a metal than a semiconductor.

Similarly, InSe can be nearly as thin as graphene while exhibiting electronic properties higher than that of silicon. Most importantly, InSe has a large energy gap, which could open the door to super-fast, next-gen electronic devices.

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GrapheneResearchers are shedding new light on cell biology with the development of a graphene sensor to monitor changes in the mitochondria.

The one-atom-thin layer of carbon sensor is giving researchers a new outlook into the process known as programmed cell death in mitochondria. The mitochondrion, which is found in most cells, has been known as the powerhouse of the cell due to its ability to metabolize and create energy for cells. However, the new researcher out of University of California, Irving shows that that convention wisdom on how cells create energy is only half right.

This from UC Irving:

[Peter] Burke and his colleagues tethered about 10,000 purified mitochondria, separated from their cells, to a graphene sensor via antibodies capable of recognizing a protein in their outer membranes. The graphene’s qualities allowed it to function as a dual-mode sensor; its exceptional electrical sensitivity let researchers gauge fluctuations in the acidity levels surrounding the mitochondria, while its optical transparency enabled the use of fluorescent dyes for the staining and visualization of voltage across the inner mitochondrial membranes.

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GrapheneOver the past few years, researchers have been exploring graphene’s amazing properties and vast potential applications. Now, a team from Iowa State University is looking to take those properties enabled by graphene and applied them to sensors and other technologies.

Many scientists have had a hard time moving graphene from the lab to the marketplace, but the research team from Iowa State University saw potential in using inkjet printers to create multi-layer graphene circuits and electrodes for the production of flexible, wearable electronics.

“Could we make graphene at scales large enough for glucose sensors?” ECS member and Iowa State University postdoctoral researcher, Suprem Das, wanted to know.

(MORE: Read more of Das’ work in the ECS Digital Library.)

The problem with the printing process is that the graphene would then have to be treated to improve its electrical conductivity, which could degrade the flexibility. Instead of using high temperatures and chemical to do this treatment, Das and other members of the team opted to use lasers.

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