#Wonder-ink could soon let you 3d print objects out of stretchy graphene A new 3d printing ink being developed at Northwestern University could soon make it possible to build objects
which are made of graphene for 60 percent of their volume and 75 percent of their weight.
This unprecedentedly high graphene composition means that the oft-praised electric and mechanical properties of graphene might soon find their way into all kinds of macroscopic 3d printed creations, with important consequences for the electronics and biomedical fields (among many others.
the ability to print objects made mainly out of graphene could raise the bar even higher for material scientists and hobbyists alike.
Previous graphene-based inks could only print objects in two dimensions and, with a graphene content below 20 percent,
were unable to preserve the useful properties of the material. More recently, researchers have laid the foundations for building three-dimensional objects out of graphene,
though this did not extend to 3d printing. Now, however, researcher Ramille Shah and team have built a 3d printing ink that is composed of graphene for 60 percent of volume and 75 percent of weight.
What's more the secondary component of the ink (used as a binder) is a biocompatible, biodegradable and hyperelastic polyester (PLG) that,
According to Shah and colleagues, the secret to packing such a high percentage of graphene into their ink was embed to it in the form of microscopic flakes.
creating a single filament that maintains the much-celebrated properties of graphene even as it's being expelled from tips as small as 100 micrometers
a formulation with 20 percent graphene can stretch longitudinally by as much as 210 percent (at some cost in terms of electromechanical properties).
The 3-D printed graphene scaffolds could also play a role in tissue engineering and regenerative medicine when the scientists populated one of the graphene ink scaffolds with stem cells,
they found that the cells didn't just survive, but also divided, proliferated, and morphed into neuron-like cells.
But the applications of a highly-conductive graphene ink could be just as exciting in building high-performance electronics.
and graphene to create a new material combination that demonstrates so-called superlubricity. Led by nanoscientist Ani Sumant of Argonne Center for Nanoscale Materials (CNM) and Argonne Distinguished Fellow Ali Erdemir of Argonne Energy systems Division, the Argonne team combined diamond
nanoparticles, small patches of graphene, and a diamond-like carbon material to create superlubricity, a highly-desirable property in
as the graphene patches and diamond particles rub up against a large diamond-like carbon surface, the graphene rolls itself around the diamond particle, creating something that looks like a ball bearing on the nanoscopic level. he interaction between the graphene
and the diamond-like carbon is essential for creating the uperlubricityeffect, he said in a statement. he two materials depend on each other.
By creating the graphene-encapsulated diamond ball bearings, or scrolls, the team found a way to translate the nanoscale superlubricity into a macroscale phenomenon.
enough diamond particles and graphene patches prevent the two surfaces from becoming locked in state.
and rotated much more easily than a simple sheet of graphene or graphite, Berman said.
#World thinnest lightbulb developed using graphene A postdoctoral research scientist, Young Duck Kim, has led a team of scientists from Columbia, Seoul National University (SNU),
and Korea Research Institute of Standards and Science (KRISS) that have demonstrated for the first time ever an on-chip visible light source using graphene, an atomically thin and perfectly crystalline form of carbon,
They attached small strips of graphene to metal electrodes, suspended the strips above the substrate,
The study, right visible light emission from graphene is published in the Advance Online Publication on Nature Nanotechnology website on June 15. ee created
and graphene-based on-chip optical communications. Creating light in small structures on the surface of a chip is crucial for developing fully integrated hotoniccircuits that do with light
By measuring the spectrum of the light emitted from the graphene, the team was able to show that the graphene was reaching temperatures of above 2500 degrees Celsius,
hot enough to glow brightly. he visible light from atomically thin graphene is so intense that it is visible even to the naked eye,
without any additional magnification, explains Young Duck Kim, first and co-lead author on the paper and postdoctoral research scientist who works in Hone group at Columbia Engineering.
which the team discovered was due to interference between the light emitted directly from the graphene
and light reflecting off the silicon substrate and passing back through the graphene. Kim notes, his is only possible
because graphene is transparent, unlike any conventional filament, and allows us to tune the emission spectrum by changing the distance to the substrate.
The ability of graphene to achieve such high temperatures without melting the substrate or the metal electrodes is due to another interesting property:
graphene becomes a much poorer conductor of heat. This means that the high temperatures stay confined to a small ot spotin the center. t the highest temperatures,
the electron temperature is much higher than that of acoustic vibrational modes of the graphene lattice,
observes. hese unique thermal properties allow us to heat the suspended graphene up to half of temperature of the sun,
as compared to graphene on a solid substrate. The team also demonstrated the scalability of their technique by realizing large-scale of arrays of chemical-vapor-deposited (CVD) graphene light emitters.
Yun Daniel Park, professor in the department of physics and astronomy at Seoul National University and co-lead author,
#3d printed Graphene Nanoflakes May Play Role in Regenerative medicine and Tissue Engineering (3d printing Industry) A research team at Northwestern University has begun printing three-dimensional structures with graphene nanoflakes.
The team, led by Ramille Shah, assistant professor of Materials science and engineering at the Mccormick School of engineering and Surgery at the Feinberg School of medicine, has developed a new kind of graphene ink that can be used to print large 3d structures.
Shah ink uses 60 to 70 percent graphene, preserving the integrity of the material, including its electrical conductivity.
The secret ingredient in Shah ink is a mix of biocompatible elastomer and fast-evaporating solvents.
This particular graphene-based ink is just one of 30 printable bio inks that Shah has formulated with her graduate team.
#World's Thinnest Light bulb Created from Graphene Graphene, a form of carbon famous for being stronger than steel
Researchers have developed a light-emitting graphene transistor that works in the same way as the filament in a light bulb."
This new graphene device, however, is so efficient and tiny, the resulting technology could offer new ways to make displays or study high-temperature phenomena at small scales,
In the new study, the scientists used strips of graphene a few microns across and from 6. 5 to 14 microns in length, each spanning a trench of silicon like a bridge.
An electrode was attached to the ends of each graphene strip. Just like tungsten, run a current through graphene
and the material will light up. But there is an added twist, as graphene conducts heat less efficiently as temperature increases,
which means the heat stays in a spot in the center, rather than being distributed relatively evenly as in a tungsten filament.
"The temperature of hot electrons at the center of the graphene is about 3, 000 K 4, 940 F,
while the graphene lattice temperature is still about 2, 000 K 3, 140 F, "he said."
"It results in a hotspot at the center and the light emission region is focused at the center of the graphene,
"It's also the reason the electrodes at either end of the graphene don't melt.
As for why this is the first time light has been made from graphene, study co-leader Yun Daniel Park,
a professor of physics at Seoul National University, noted that graphene is embedded usually in or in contact with a substrate."
"Physically suspending graphene essentially eliminates pathways in which heat can escape, "Park said.""If the graphene is on a substrate,
much of the heat will be dissipated to the substrate. Before us, other groups had reported only inefficient radiation emission in the infrared from graphene."
"The light emitted from the graphene also reflected off the silicon that each piece was suspended in front of.
The reflected light interferes with the emitted light, producing a pattern of emission with peaks at different wavelengths.
The principle of the graphene is said simple, Park, but it took a long time to discover."
#Charting quantum signatures of electronic transport in graphene Over the last seven years, Javier Sanchez-Yamagishi has built several hundred nanoscale stacked graphene systems to study their electronic properties."
"What interests me a lot is that the properties of this combined system depend sensitively on the relative alignment between them,
He assembles sandwiches of graphene and boron nitride with various horizontal orientations.""The tricks we would use were making cleaner devices,
Sanchez-Yamagishi was a lead co-author of a 2014 paper in Nature("Tunable symmetry breaking and helical edge transport in a graphene quantum spin Hall state)
"which showed that having a component of the applied magnetic field in the graphene plane forced electrons at the edge of graphene to move in opposite directions based on their spins.
"We were trying to realize some interesting quantum states in the graphene. It's called a Quantum Spin Hall State,
and collaborators demonstrated that a certain alignment of layered graphene and hexagonal boron nitride created a unique bandgap in graphene,
which could be a precursor to developing the material for functional transistors. Sanchez-Yamagishi's co-authors again included Young
Hofstadter butterfly Graphene and boron nitride layers each have arranged atoms in a hexagonal, or six-sided, pattern.
When the lattice arrangement of graphene and hexagonal boron nitride layers are aligned closely, and the samples are exposed to a large out-of-plane magnetic field,
In addition to the Hofstadter butterfly result, the same devices were also the first to show a bandgap in graphene.
"What was unexpected very was showed we that graphene, which usually conducts very well, under the conditions of that experiment with a very low angle of rotation between the graphene
and the HBN, became an insulator. It didn't conduct at all. That was a behavior
"Fortunate discovery The peculiar electronic behavior of graphene comes from its molecular structure, which is like a honeycomb or chicken-wire-shaped lattice of carbon atoms.
the graphene has to be aligned very closely to hexagonal boron nitride. When it's closely aligned,
when layers of graphene just one to few atoms thick are separated from the graphite.""Graphene conducts electricity better than graphite.
It conducts better than silver or gold, "Sanchez-Yamagishi says. Sanchez-Yamagishi built a machine in the lab that stacks extremely thin layers of graphene and similar materials.
When two layers of graphene are misaligned, they are called twisted bilayer graphene.""In graphite, normally all the layers are aligned with each other;
electrons get slowed down, "he explains. It turns out that if two layers of graphene are stacked in alignment,
electrons traveling within a layer are slowed down in the same way. But with graphene, if the layers stacked on top of each other are misaligned,
they act as if one layer doesn't really feel the other layer.""You can put it right on top of each other,
they actually remain decoupled from each other, and it can still conduct electricity basically as well as if it was still a single sheet of graphene,
"he says.""If they are misaligned, then the electron in one layer does not get affected by the other layers and zips along quickly."
Sanchez-Yamagishi, 28, says he has grown from initially spending months to make good quality graphene to now making very intricate graphene devices and combining then with other materials.
Gold contacts send current through the graphene to measure its electrical properties. Often, graphene shapes used in test devices are shaped irregularly
since that is how they come off the natural graphite material. The graphite is rubbed on a sheet of silicon
and lifted off with special tape to create thin layers of graphene. Maximizing the amount of graphene that can be used for a device takes priority over making it look nice
Sanchez-Yamagishi says.""We're trying to push the technology to the highest level, so we're kind of relying on the tail end of the distribution here.
including those that are made with graphene electrodes.""It's amazing to be able to design a molecular circuit,
#Graphene gets bright: World's thinnest lightbulb developed Led by Young Duck Kim, a postdoctoral research scientist in James Hone's group at Columbia Engineering, a team of scientists from Columbia, Seoul National University (SNU),
and Korea Research Institute of Standards and Science (KRISS) reported today that they have demonstrated-for the first time-an on-chip visible light source using graphene, an atomically thin and perfectly crystalline form of carbon,
They attached small strips of graphene to metal electrodes, suspended the strips above the substrate,
right Visible light Emission from Graphene, is published in the Advance Online Publication (AOP) on Nature Nanotechnology's website on June 15."
and graphene-based on-chip optical communications.""Creating light in small structures on the surface of a chip is crucial for developing fully integrated'photonic'circuits that do with light
By measuring the spectrum of the light emitted from the graphene, the team was able to show that the graphene was reaching temperatures of above 2500 degrees Celsius,
hot enough to glow brightly. he visible light from atomically thin graphene is so intense that it is visible even to the naked eye,
without any additional magnification, explains Kim, first and co-lead author on the paper. Interestingly, the spectrum of the emitted light showed peaks at specific wavelengths,
which the team discovered was due to interference between the light emitted directly from the graphene
and light reflecting off the silicon substrate and passing back through the graphene. Kim notes
because graphene is transparent, unlike any conventional filament, and allows us to tune the emission spectrum by changing the distance to the substrate. he ability of graphene to achieve such high temperatures without melting the substrate
or the metal electrodes is due to another interesting property: as it heats up, graphene becomes a much poorer conductor of heat.
This means that the high temperatures stay confined to a small ot spotin the center. t the highest temperatures,
the electron temperature is much higher than that of acoustic vibrational modes of the graphene lattice,
observes. hese unique thermal properties allow us to heat the suspended graphene up to half of the temperature of the sun,
as compared to graphene on a solid substrate. he team also demonstrated the scalability of their technique by realizing large-scale of arrays of chemical-vapor-deposited (CVD) graphene light emitters.
The demand for a silicon material aided the discovery of graphene, a single layer of graphite
#Graphene-based film can be used for efficient cooling of electronics Researchers have developed a method for efficiently cooling electronics using graphene-based film.
Moreover, the graphene film is attachable to electronic components made of silicon, which favours the film's performance compared to typical graphene characteristics shown in previous, similar experiments.
Electronic systems available today accumulate a great deal of heat, mostly due to the ever-increasing demand on functionality.
professor at Chalmers University of Technology, were the first to show that graphene can have a cooling effect on silicon-based electronics.
That was the starting point for researchers conducting research on the cooling of silicon-based electronics using graphene. ut the methods that have been in place so far have presented the researchers with problems Johan Liu says. t has become evident that those methods cannot be used to rid electronic devices
When you try to add more layers of graphene, another problem arises, a problem with adhesiveness.
the graphene no longer will adhere to the surface, since the adhesion is held together only by weak Van der waals bonds."
"e have solved now this problem by managing to create strong covalent bonds between the graphene film and the surface,
The stronger bonds result from so-called functionalisation of the graphene, i e. the addition of a property-altering molecule.
it creates so-called silane bonds between the graphene and the electronic component (see picture). Moreover, functionalisation using silane coupling doubles the thermal conductivity of the graphene.
The researchers have shown that the in-plane thermal conductivity of the graphene-based film, with 20 micrometer thickness, can reach a thermal conductivity value of 1600 W/mk,
which is four times that of copper. ncreased thermal capacity could lead to several new applications for graphene,
says Johan Liu.""One example is the integration of graphene-based film into microelectronic devices and systems,
such as highly Efficient light Emitting Diodes (LEDS), lasers and radio frequency components for cooling purposes. Graphene-based film could also pave the way for faster, smaller, more energy efficient, sustainable high power electronics."
"Image: Graphene-based film on an electronic component with high heat intensity. Credit: Johan Liu Source:
http://www. mynewsdesk. com/uk/chalmers/..
#Environmentally friendly lignin nanoparticle'greens'silver nanobullet to battle bacteria Researchers have developed an effective and environmentally benign method to combat bacteria by engineering nanoscale particles that add the antimicrobial potency of silver to a core of lignin,
Improve Lives of Millions March 5th, 2015anousheh Ansari Wins the National Space Society's Space Pioneer Award for"Service to the Space Community"March 5th, 2015enhanced Graphene Components for Next
2015quantum research past, present and future for discussion at AAAS February 16th, 2015discoveries Enhanced Graphene Components for Next Generation Racing yacht March 5th, 2015american Chemical Society Presidential Symposia:
Improve Lives of Millions March 5th, 2015anousheh Ansari Wins the National Space Society's Space Pioneer Award for"Service to the Space Community"March 5th, 2015enhanced Graphene Components for Next
Professor Cronin's research spans a broad range of topics including electrical and spectroscopic characterization of carbon nanotubes, graphene,
and other novel lower dimensional materials. 2d materials such as graphene and few-layer transition metal dichalcogenides (TMDCS) have been attracting a lot of research interest in recent years
While graphene has many advantages it is suited not to the field of optoelectronics where TMDCS such as molybdenum disulphide (Mos2) have a clear advantage thanks to exhibiting a finite band gap in the visible wavelength range.
#Caltech scientists develop cool process to make better graphene Abstract: A new technique invented at Caltech to produce graphene--a material made up of an atom-thick layer of carbon--at room temperature could help pave the way for commercially feasible graphene-based solar cells and light-emitting diodes, large-panel displays, and flexible electronics."
"With this new technique, we can grow large sheets of electronic-grade graphene in much less time
and at much lower temperatures,"says Caltech staff scientist David Boyd, who developed the method.
and the novel properties of the graphene it produces. Graphene could revolutionize a variety of engineering and scientific fields due to its unique properties,
which include a tensile strength 200 times stronger than steel and an electrical mobility that is two to three orders of magnitude better than silicon.
or 1, 000 degrees Celsius--for incorporating graphene fabrication with current electronic manufacturing. Additionally, high-temperature growth of graphene tends to induce large, uncontrollably distributed strain--deformation--in the material,
which severely compromises its intrinsic properties.""Previously, people were only able to grow a few square millimeters of high-mobility graphene at a time,
and it required very high temperatures, long periods of time, and many steps,"says Caltech physics professor Nai-Chang Yeh, the Fletcher Jones Foundation Co-Director of the Kavli Nanoscience Institute and the corresponding author of the new study."
"Our new method can consistently produce high-mobility and nearly strain-free graphene in a single step in just a few minutes without high temperature.
at that time a Caltech professor of mechanical engineering and applied physics, was trying to reproduce a graphene-manufacturing process he had read about in a scientific journal.
In this process, heated copper is used to catalyze graphene growth.""I was playing around with it on my lunch hour,
which provides the carbon atoms needed for graphene growth. When later Boyd examined the copper plate using Raman spectroscopy,
a technique used for detecting and identifying graphene, he saw evidence that a graphene layer had formed indeed."
"It was an'A-ha!''moment,"Boyd says.""I realized then that the trick to growth is to have a very clean surface, one without the copper oxide."
but that it simultaneously produced graphene as well. At first, Boyd could not figure out why the technique was so successful.
"The valves were letting in just the right amount of methane for graphene to grow,
The ability to produce graphene without the need for active heating not only reduces manufacturing costs,
and nine to ten different steps to make a batch of high-mobility graphene using high-temperature growth methods,
"Work by Yeh's group and international collaborators later revealed that graphene made using the new technique is of higher quality than graphene made using conventional methods:
and it has the highest electrical mobility yet measured for synthetic graphene. The team thinks one reason their technique is so efficient is that a chemical reaction between the hydrogen plasma
which to grow graphene. The scientists also discovered that their graphene grows in a special way.
Graphene produced using conventional thermal processes grows from a random patchwork of depositions. But graphene growth with the plasma technique is more orderly.
The graphene deposits form lines that then grow into a seamless sheet, which contributes to its mechanical and electrical integrity.
A scaled-up version of their plasma technique could open the door for new kinds of electronics manufacturing,
Yeh says. For example, graphene sheets with low concentrations of defects could be used to protect materials against degradation from exposure to the environment.
Another possibility would be to grow large sheets of graphene that can be used as a transparent conducting electrode for solar cells and display panels."
"In the future, you could have based graphene cellphone displays that generate their own power, "Yeh says. Another possibility, she says,
is to introduce intentionally imperfections into graphene's lattice structure to create specific mechanical and electronic attributes."
"If you can strain graphene by design at the nanoscale, you can artificially engineer its properties.
But for this to work, you need to start with a perfectly smooth, strain-free sheet of graphene,
"Yeh says.""You can't do this if you have a sheet of graphene that has uncontrollable defects in different places."#
"##Along with Yeh and Boyd, additional authors on the paper,"Single-Step Deposition Of high-Mobility Graphene at Reduced Temperatures,"include Caltech graduate students Wei Hsiang Lin, Chen Chih
Hsu and Chien-Chang Chen; Caltech staff scientist Marcus Teague; Yuan-Yen Lo, Tsung-Chih Cheng,
New cheap and efficient electrode for splitting water March 18th, 2015graphene Graphene'gateway'discovery opens possibilities for improved energy technologies March 18th,
2015imperfect graphene opens door to better fuel cells: Membrane could lead to fast-charging batteries for transportation March 18th,
New cheap and efficient electrode for splitting water March 18th, 2015energy Graphene'gateway'discovery opens possibilities for improved energy technologies March 18th, 2015clean energy future:
New cheap and efficient electrode for splitting water March 18th, 2015imperfect graphene opens door to better fuel cells:
and reduce damage on biomolecules and two-dimensional nanomaterials, such as graphene March 18th, 2015graphene'gateway'discovery opens possibilities for improved energy technologies March 18th,
2015drexel Univ. materials research could unlock potential of lithium-sulfur batteries March 17th, 2015symmetry matters in graphene growth:
Rice university scientists gain control of electronic, fluorescent properties of coal-based graphene Abstract: Graphene quantum dots made from coal,
introduced in 2013 by the Rice university lab of chemist James Tour, can be engineered for specific semiconducting properties in either of two single-step processes.
In a new study this week in the American Chemical Society journal Applied materials & Interfaces, Tour and colleagues demonstrated fine control over the graphene oxide dots'size-dependent band gap,
Tour said graphene quantum dots may prove highly efficient in applications ranging from medical imaging to additions to fabrics and upholstery for brighter and longer-lasting colors."
Graphene quantum dots are photoluminescent, which means they emit light of a particular wavelength in response to incoming light of a different wavelength.
and reduce damage on biomolecules and two-dimensional nanomaterials, such as graphene March 18th, 2015news and information 30 years after C60:
A long strived-for silicon dodecahedron synthesised at room temperature March 18th, 2015symmetry matters in graphene growth: Rice researchers find subtle interactions with substrate may lead to better control March 16th,
Rice researchers'theory combines strength, stiffness and toughness of composites into a single design map March 16th, 2015symmetry matters in graphene growth:
Controlling particles with light and microfibers March 18th, 2015imperfect graphene opens door to better fuel cells: Membrane could lead to fast-charging batteries for transportation March 18th, 2015news and information 30 years after C60:
Rice university scientists gain control of electronic, fluorescent properties of coal-based graphene March 18th, 2015graphene'gateway'discovery opens possibilities for improved energy technologies March 18th,
New cheap and efficient electrode for splitting water March 18th, 2015imperfect graphene opens door to better fuel cells:
New cheap and efficient electrode for splitting water March 18th, 2015imperfect graphene opens door to better fuel cells:
New cheap and efficient electrode for splitting water March 18th, 2015imperfect graphene opens door to better fuel cells:
and reduce damage on biomolecules and two-dimensional nanomaterials, such as graphene March 18th, 2015rice fine-tunes quantum dots from coal:
Rice university scientists gain control of electronic, fluorescent properties of coal-based graphene March 18th, 2015nano piano's lullaby could mean storage breakthrough March 16th, 2015nanoelectronics Quantum computing:
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