#New 2d super-material could beat graphene to becoming the new silicon A purely theoretical mathematical study has inspired an experiment that could have serious real-world applications:
a crystalline material called titanium trisulfide could perform almost as well as graphene in many areas, while lacking one key weakness.
potentially making it a better candidate than graphene to allow truly next-generation electronics. The work here is very preliminary, but promising.
much like graphene but without being chemically pure. University of Nebraska-Lincoln chemist Xiao Cheng Zeng found that the computer model predicted the crystals were incredibly conductive,
and had one wonderful electronic property that graphene does not: just as in silicon, the electrons orbiting within titanium-trisulfide can be pushed easily up into the conduction band,
The approach was inspired by graphene itself: Nebraska-Lincoln Alexander Sinitskii created a macro-scale block of titanium trisulfide
The very earliest samples of graphene were made by repeatedly sticking and unsticking clear sticky tape over a powdered sample of pure carbon,
What this means is that purely scientific proofs of concept like current graphene computer chips might be made fully digital
Right now, graphene lack of a useful bandgap means that graphene computers are limited to analog computation only;
after graphene has saturated headline space for so long, is that there was only a few months needed to take this purely theoretical 2d substance from a computer simulation to practical, working transistors.
It possible that some of graphene newer, more efficient production processes might continue to work for titanium trisulfide and if so,
The pure transistor density already achieved with graphene, combined with the ability to create relatively ormaldigital architecture,
And combining graphene power efficiency with silicon current ability to soak up solar radiation could have an even bigger impact.
or exceed the current practicalities of graphene, for a price real people could ever actually afford
Researchers at Chalmers University of Technology, Sweden, have developed a method for efficiently cooling electronics using graphene-based film.
A team led by professor Johan Liu from Chalmers University had shown earlier that graphene can have a cooling effect on silicon-based electronics
but the challenge was to stick a thick layer of graphene to silicon chips. e have solved this problem by creating strong covalent bonds between the graphene film and the surface,
Moreover, functionalisation using this kind of bonding doubles the thermal conductivity of the graphene. ncreased thermal capacity could lead to several new applications for graphene.
One example is the integration of graphene-based film into microelectronic devices and systems, such as highly Efficient light Emitting Diode lasers and radio frequency components for cooling purposes, Liu said. raphene-based film could also pave the way for faster,
#Graphene used to create world's thinnest light bulb Researchers and engineers from Columbia University, Seoul National University (SNU),
and Korea Research Institute of Standards and Science (KRISS) created the device using tiny filaments of graphene attached to metal electrodes,
and graphene-based on-chip optical communications.""Interestingly, the ability of graphene to reach such elevated temperatures without melting
either the underlying substrate or the metal electrodes is because, as graphene is heated up, it is less able to conduct heat away from itself.
As a result, the concentration of heat is limited to the very center of the filaments
and light bouncing off the silicon substrate and back through the graphene filaments themselves.""This (phenomenon) 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."
"A graphene lattice is also a particularly efficient way to produce light, due to its inherent ability to maintain excitation levels that allow the freer flow of electrons.
That is, just as graphene is able to rapidly emit electrons when excited by lasers as the electrons remain at an elevated state,
"At the highest temperatures, the electron temperature is much higher than that of acoustic vibrational modes of the graphene lattice,
as compared to graphene on a solid substrate.""Not the first graphene light-bulb University of Manchester researchers lay claim to that but certainly the thinnest,
the new device also opens up many possibilities of alternative light generation at the microscale,
The short video below is an animation showing how the graphene filaments generate Light source: Columbia Universit U
#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,
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,
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.
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
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.
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,
"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 hexagonal boron nitride created a unique bandgap in graphene, which could be a precursor to developing the material for functional transistors.
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,
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,
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.
which favours the film's performance compared to typical graphene characteristics shown in previous, similar experiments.
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."
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.
a technique used for detecting and identifying graphene, he saw evidence that a graphene layer had formed indeed."
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,
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,
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,
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