Graphene edges can be tailor-made Theoretical physicists at Rice university are living on the edge as they study the astounding properties of graphene.
Current passes through metallic graphene unhindered but semiconductors allow a measure of control over those electrons.
semiconducting graphene (and semiconducting two-dimensional materials in general) are of great interest to scientists and industry working to shrink electronics for applications.
and get graphene with either pristine zigzag edges or what are called reconstructed zigzags. Perfect graphene looks like chicken wire,
with each six-atom unit forming a hexagon. The edges of pristine zigzags look like this://Turning the hexagons 30 degrees makes the edges"armchairs"
which atoms in graphene are enticed to shift around to form connected rings of five and seven atoms.
"Making graphene-based nano devices by mechanical fracture sounds attractive, but it wouldn't make sense until we know how to get the right types of edgesnd now we do said
Their study revealed that heating graphene to 1, 000 kelvins and applying a low but steady force along one axis will crack it in such a way that fully reconstructed 5-7 rings will form
fracturing graphene with low heat and high force is more likely to lead to pristine zigzags z
#A new step towards using graphene in electronic applications A team of the University of Berkeley
or have raised so many hopes with a view to their potential deployment in new applications as graphene has.
That is why ribbons or rows of graphene with nanometric widths are emerging as tremendously interesting electronic components.
therefore constitutes a significant success towards the desired deployment of graphene in commercial electronic applications.
However it will provide an environmentally friendly low-cost way to make nanoporous graphene for use in supercapacitors-devices that can store energy and release it rapidly.
In the chemical reaction that was developed the end result is nanoporous graphene a form of carbon that's ordered in its atomic and crystalline structure.
There are other ways to fabricate nanoporous graphene but this approach is faster has little environmental impact
and nanoporous graphene a pure form of carbon that's remarkably strong and can efficiently conduct heat and electricity.
By comparison other methods to make nanoporous graphene often use corrosive and toxic chemicals in systems that would be challenging to use at large commercial levels.
and for that purpose the more conductive nanoporous graphene will work much better. This solves a major problem in creating more powerful supercapacitors.
#Protons fuel graphene prospects Graphene impermeable to all gases and liquids can easily allow protons to pass through it,
One-atom thick material graphene first isolated and explored in 2004 by a team at The University of Manchester is renowned for its barrier properties
whether protons are repelled also by graphene. They fully expected that protons would be blocked as existing theory predicted as little proton permeation as for hydrogen.
The discovery makes monolayers of graphene and its sister material boron nitride attractive for possible uses as proton-conducting membranes
The University of Manchester research suggests that the use of graphene or monolayer boron nitride can allow the existing membranes to become thinner and more efficient with less fuel crossover and poisoning.
Because graphene can be produced these days in square metre sheets we hope that it will find its way to commercial fuel cells sooner rather than later r
High quality three-dimensional nanoporous graphene More information: Advanced Materials Interfaces onlinelibrary. wiley. com/store/#et/admi201400084. pd
#Graphene/nanotube hybrid benefits flexible solar cells Rice university scientists have invented a novel cathode that may make cheap, flexible dye-sensitized solar cells practical.
from nanotubes that are bonded seamlessly to graphene and replaces the expensive and brittle platinum-based materials often used in earlier versions.
The graphene/nanotube hybrid came along two years ago. Dubbed"James'bond"in honor of its inventor, Rice chemist James Tour, the hybrid features a seamless transition from graphene to nanotube.
The graphene base is grown via chemical vapor deposition and a catalyst is arranged in a pattern on top.
When heated again carbon atoms in an aerosol feedstock attach themselves to the graphene at the catalyst,
which lifts off and allows the new nanotubes to grow. When the nanotubes stop growing,
First, the graphene and nanotubes are grown directly onto the nickel substrate that serves as an electrode,
With no interruption in the atomic bonds between nanotubes and graphene, the material's entire area, inside and out, becomes one large surface.
or even graphene said Chang Ren Gogotsi's doctoral student at Drexel. When mixing MXENE with PVA containing some electrolyte salt the polymer plays the role of electrolyte
Crumpled graphene could provide an unconventional energy storag g
#Microtubes create cozy space for neurons to grow and grow fast Tiny, thin microtubes could provide a scaffold for neuron cultures to grow
one-step process for producing these nanopores in a graphene membrane using the photothermal properties of gold nanorods."
which a hot spot on a graphene membrane formed a nanopore with a self-integrated optical antenna.
The atomically thin nature of the graphene membrane makes it ideal for high resolution, high throughput,
"In addition, either the gold nanoplasmonic optical antenna or the graphene can be functionalized to be responsive to different base-pair combinations,
Molybdenum disulfide isn't quite as flat as graphene the atom-thick form of pure carbon
When viewed from above it looks like graphene with rows of ordered hexagons. But seen from the side three distinct layers are revealed with sulfur atoms in their own planes above and below the molybdenum.
Conversely graphene is an excellent conductor of heat (in the 2000-5000 W/mk range)
In this new effort the researchers sought to improve heat conduction in a plastic by applying graphene to its surface.
Graphene for the experiment was grown in sheets just a few microns thick and then applied to a thin sheet of PET.
The researchers suggest the graphene coated PET could be used in thermal management applications or thermal lighting
Researchers combine graphene and copper in hopes of shrinking electronics More information: Thermal conductivity of Graphene Laminate Nano Lett. 2014 14 (9) pp 5155-5161.
DOI: 10.1021/nl501996v. On Arxiv: http://arxiv. org/ftp/arxiv/papers/1407/1407.1359. pdfabstractwe have investigated thermal conductivity of graphene laminate films deposited on polyethylene terephthalate substrates.
Two types of graphene laminate were studied as deposited and compressed in order to determine the physical parameters affecting the heat conduction the most.
The measurements were performed using the optothermal Raman technique and a set of suspended samples with the graphene laminate thickness from 9 to 44 m. The thermal conductivity of graphene laminate was found to be in the range from 40 to 90 W/mk at room temperature.
It was found unexpectedly that the average size and the alignment of graphene flakes are more important parameters defining the heat conduction than the mass density of the graphene laminate.
The thermal conductivity scales up linearly with the average graphene flake size in both uncompressed and compressed laminates.
The compressed laminates have higher thermal conductivity for the same average flake size owing to better flake alignment.
Coating plastic materials with thin graphene laminate films that have up to 600 higher thermal conductivity than plastics may have important practical implications s
because it suggested that graphene might have potential applications in catalysing chemical reactions of industrial importance.
Graphene was one of the most exciting materials to work with in nanotechnology because its two-dimensional structure and unique chemical properties made it a promising candidate for new applications such as energy storage material composites as well as computing
Ever since the discovery of graphene in 2004 scientists have been looking for potential applications in nanochemistry he said.
Using powerful supercomputers researchers at UWA discovered that graphene nanoflakes can significantly enhance the rates of a range of chemical reactions.
Graphene is remarkably strong for its low weight-about 100 times stronger than steel -and it conducts heat and electricity with great efficiency.
The global market for graphene is reported to have reached US$9 million this year with most sales concentrated in the semiconductor electronics battery energy and composites.
Assistant professor Karton said the current investigation showed that graphene nonoflakes could efficiently catalyse a range of chemical reactions.
and extend the scope of the study to'infinite'graphene sheets rather than graphene nanoflakes he said d
The new device uses graphene a recently discovered form of carbon on a flexible plastic backing that conforms to the shape of tissue.
Moreover graphene is nontoxic to biological systems an improvement over previous research into transparent electrical contacts that are much thicker rigid difficult to manufacture and reliant on potentially toxic metal alloys.
graphene which earned researchers the 2010 Nobel prize in Physics; super-resolved fluorescent microscopy which earned researchers the 2014 Nobel prize in Chemistry;
Graphene-based carbon-layered electrode array technology for neural imaging and optogenetic applications. Nature Communications 5 Article number:
The National Science Foundation (NSF)- funded scientist theorized correctly that he could adapt it to separate carbon nanotubes rolled sheets of graphene (a single atomic layer of hexagonally bonded carbon atoms) long recognized for their potential applications in computers
#See-through one-atom-thick carbon electrodes powerful tool to study brain disorders Researchers from the Perelman School of medicine and School of engineering at the University of Pennsylvania and The Children's Hospital of Philadelphia have used graphene
The Center for Neuroengineering and Therapeutics (CNT) under the leadership of senior author Brian Litt Phd has solved this problem with the development of a completely transparent graphene microelectrode that allows for simultaneous optical imaging
and their colleagues Kuzum notes that the team developed a neuroelectrode technology based on graphene to achieve high spatial and temporal resolution simultaneously.
Aside from the obvious benefits of its transparency graphene offers other advantages: It can act as an anti-corrosive for metal surfaces to eliminate all corrosive electrochemical reactions in tissues Kuzum says.
Another advantage of graphene is that it's flexible so we can make very thin flexible electrodes that can hug the neural tissue Kuzum notes.
The graphene microelectrodes developed could have wider application. They can be used in any application that we need to record electrical signals such as cardiac pacemakers
Because of graphene's nonmagnetic and anti-corrosive properties these probes can also be a very promising technology to increase the longevity of neural implants.
Graphene's nonmagnetic characteristics also allow for safe artifact-free MRI reading unlike metallic implants. Kuzum emphasizes that the transparent graphene microelectrode technology was achieved through an interdisciplinary effort of CNT and the departments of Neuroscience Pediatrics and Materials science at Penn and the division of Neurology at CHOP.
Ertugrul Cubukcu's lab at Materials science and engineering Department helped with the graphene processing technology used in fabricating flexible transparent neural electrodes as well as performing optical and materials characterization in collaboration with Euijae Shim and Jason Reed.
The simultaneous imaging and recording experiments involving calcium imaging with confocal and two photon microscopy was performed at Douglas Coulter's Lab at CHOP with Hajime Takano.
which is also favorable for graphene, CNT-graphene, CNTMETAL oxide based flexible electrodes, "Qiang said."
#New self-assembly method for fabricating graphene nanoribbons First characterized in 2004 graphene is a two-dimensional material with extraordinary properties.
The thickness of just one carbon atom and hundreds of times faster at conducting heat and charge than silicon graphene is expected to revolutionize high-speed transistors in the near future.
Graphene's exotic electronic and magnetic properties can be tailored by cutting large sheets of the material down to ribbons of specific lengths
This new method of graphene fabrication by self-assembly is a stepping stone toward the production of self-assembled graphene devices that will vastly improve the performance of data storage circuits batteries and electronics.
To make devices out of graphene we need to control its geometric and electronic structures Weiss said.
Other bottom-up methods of fabricating graphene have been attempted but they have produced bundles of ribbons that need to be isolated subsequently
#A simple and versatile way to build 3-dimensional materials of the future Researchers in Japan have developed a novel yet simple technique called diffusion driven layer-by-layer assembly to construct graphene into porous
Graphene is essentially an ultra-thin sheet of carbon and possesses exciting properties such as high mechanical stability and remarkable electrical conductivity.
However the thin structure of graphene also acts as a major obstacle for practical uses. When piecing together these tiny sheets into larger structures the sheets easily stack with one another resulting in a significant loss of unique material properties.
and developed it into a technique to assemble graphene into porous 3d architectures while preventing stacking between the sheets.
By putting graphene oxide (an oxidized form of graphene) into contact with an oppositely charged polymer the two components could form a stable composite layer a process also known as interfacial complexation.
and induce additional reactions which allowed the graphene-based composite to develop into thick multilayered structures.
The resulting products display a foam-like porous structure ideal for maximizing the benefits of graphene with the porosity tunable from ultra-light to highly dense through simple changes in experimental conditions.
While we have demonstrated only the construction of graphene-based structures in this study we strongly believe that the new technique will be able to serve as a general method for the assembly of a much wider range of nanomaterials concluded Franklin Kim the principal investigator of the study y
and packing at electrode surfaces the team combined knowledge about graphene and organic crystals. Though it was difficult Briseno says they managed to get the necessary compounds to stack like coins.
We had exploited essentially every substrate possible until we finally succeeded with graphene he adds which happened by accident
#New research points to graphene as a flexible low-cost touchscreen solution New research published today in the journal Advanced Functional Materials suggests that graphene-treated nanowires could soon replace current touchscreen technology
Researchers from the University of Surrey and AMBER the materials science centre based at Trinity college Dublin have demonstrated now how graphene-treated nanowires can be used to produce flexible touchscreens at a fraction of the current cost.
Using a simple scalable and inexpensive method the researchers produced hybrid electrodes the building blocks of touchscreen technology from silver nanowires and graphene.
We achieved this using graphene a material that can conduct electricity and interpret touch commands
Resonant energy transfer from quantum dots to graphene More information: Edes Saputra Jun Ohta Naoki Kakuda and Koichi Yamaguchi Self-Formation of In-Plane Ultrahigh-Density Inas Quantum dots on Gaassb/Gaas (001) Appl.
Gallium nitride micro-rods grown on graphene substrates Bendy light-emitting diode (LED) displays and solar cells crafted with inorganic compound semiconductor micro-rods are moving one step closer to reality thanks to graphene and the work of a team of researchers in Korea.
Currently most flexible electronics and optoelectronics devices are fabricated using organic materials. But inorganic compound semiconductors such as gallium nitride (Gan) can provide plenty of advantages over organic materials for use in these devices#including superior optical electrical and mechanical properties.
on graphene to create transferrable LEDS and enable the fabrication of bendable and stretchable devices.
When combined with graphene substrates these microstructures also show excellent tolerance for mechanical deformation. Why choose graphene for substrates?
Ultrathin graphene films consist of weakly bonded layers of hexagonally arranged carbon atoms held together by strong covalent bonds.
This makes graphene an ideal substrate because it provides the desired flexibility with excellent mechanical strength
It's important to note that for the Gan micro-rod growth the very stable and inactive surface of graphene offers a small number of nucleation sites for Gan growth
which would enhance three-dimensional island growth of Gan micro-rods on graphene. To create the actual Gan microstructure LEDS on the graphene substrates the team uses a catalyst-free metal-organic chemical vapor deposition (MOCVD) process they developed back in 2002.
Among the technique's key criteria it's necessary to maintain high crystallinity control over doping formation of heterostructures
and reliability of Gan micro-rod LEDS fabricated on graphene to the test they found that the resulting flexible LEDS showed intense electroluminescence (EL)
Scientists grow a new challenger to graphene More information: Growth and characterizations of Gan micro-rods on graphene films for flexible light-emitting diodes by Kunook Chung Hyeonjun Beak Youngbin Tchoe Hongseok Oh Hyobin Yoo Miyoung Kim and Gyu
#Scientists grow a new challenger to graphene A team of researchers from the University of Southampton's Optoelectronics Research Centre (ORC) has developed a new way to fabricate a potential challenger to graphene.
Graphene a single layer of carbon atoms in a honeycomb lattice is increasingly being used in new electronic and mechanical applications such as transistors switches
Now ORC researchers have developed molybdenum di-sulphide (Mos2) a similar material to graphene that shares many of its properties including extraordinary electronic conduction
This new class of thin metal/sulphide materials known as transition metal di-chalcogenides (TMDCS) has become an exciting complimentary material to graphene.
However unlike graphene TMDCS can also emit light allowing applications such as photodetectors and light emitting devices to be manufactured.
The research also unveiled a previously unknown property of graphene. The two-dimensional chain of carbon atoms not only gives
in short, a material like graphene. Graphene is a super strong, super light, near totally transparent sheet of carbon atoms and one of the best conductors of electricity ever discovered.
Graphene owes its amazing properties to being two-dimensional.""Graphene not only has all these amazing properties,
but it is also ultra-thin and biologically inert,"said Rozhkova.""Its very presence allowed the other components to self-assemble around it,
which totally changes how the electrons move throughout our system.""Rozhkova's mini-hydrogen generator works like this:
both the br protein and the graphene platform absorb visible light. Electrons from this reaction are transmitted to the titanium dioxide on
Tests also revealed a new quirk of graphene behavior.""The majority of the research out there states that graphene principally conducts
and accepts electrons, "said Argonne postdoctoral researcher Peng Wang.""Our exploration using EPR allowed us to prove, experimentally,
that graphene also injects electrons into other materials.""Rozhkova's hydrogen generator proves that nanotechnology,
#Graphene sensor tracks down cancer biomarkers An ultrasensitive biosensor made from the wonder material graphene has been used to detect molecules that indicate an increased risk of developing cancer.
which was not possible using the traditional exfoliation technique where layers of graphene are stripped from graphite.
Instead they grew graphene onto a silicon carbide substrate under extremely high temperatures and low pressure to form the basis of the biosensor.
In their study the researchers used x-ray photoelectron spectroscopy and Raman spectroscopy to confirm that the bioreceptor molecules had attached to the graphene biosensor once fabricated
When 8-OHDG attached to the bioreceptor molecules on the sensor there was a notable difference in the graphene channel resistance
The graphene biosensor was also considerably faster at detecting the target molecules completing the analysis in a matter of minutes.
Graphene has superb electronic transport properties and has an intrinsically high surface-to-volume ratio
Now that we've created the first proof-of-concept biosensor using epitaxial graphene we will look to investigate a range of different biomarkers associated with different diseases and conditions as well as detecting a number of different biomarkers on the same chip.
On the edge of graphene More information: Generic epitaxial graphene biosensors of ultrasensitive detection of cancer risk biomarker Z Tehrani et al 2014 2d Mater. 1 025004. iopscience. iop. org/2053
-1583/1/2/025004/articl l
#Startup scales up graphene production develops biosensors and supercapacitors An official of a materials technology and manufacturing startup based on a Purdue University innovation says his company is addressing the challenge of scaling graphene production for commercial applications.
Glenn Johnson CEO of Bluevine Graphene Industries Inc. said many of the methodologies being utilized to produce graphene today are not easily scalable
and require numerous postprocessing steps to use it in functional applications. He said the company's product development team has developed a way to scale the production of graphene to meet commercial volumes and many different applications.
Our graphene electrodes are created using a roll-to-roll chemical vapor deposition process and then they are combined with other materials utilizing a different roll-to-roll process he said.
We can give the same foundational graphene electrodes entirely different properties utilizing standard or custom materials that we are developing for our own commercial products.
In essence what we've done is developed scalable graphene electrodes that are foundational pieces and can be customized easily to unique customer applications.
Timothy Fisher founder and Chief Technology Officer of Bluevine Graphene Industries developed the technology. He also is the James G. Dwyer Professor of Mechanical engineering at Purdue.
The patented technology has been licensed exclusively to Bluevine Graphene Industries through the Purdue Office of Technology Commercialization.
We're moving up to roll-to-roll large-scale manufacturing capabilities. These roll-to-roll systems allow us to increase output by a thousand-fold over the original research-scale processes Fisher said.
These state-of-the-art systems allow us to leverage the game-changing properties of graphene and in particular our graphene petal technology called Folium#at production scales that provide tremendous pricing advantages.
Bluevine Graphene Industries already is developing and testing two commercial applications for its Folium technology:
biosensors and supercapacitors. Johnson said the company's first-generation glucose monitoring technology could impact the use of traditional testing systems like lancets
which are made with gold and other precious metals. The second-generation technology could allow people to use noninvasive methods to test their glucose levels through saliva tears or urine.
Supercapacitors are Bluevine Graphene Industries'second application under development for its Folium graphene. Johnson said the company's graphene supercapacitors are reaching the energy density of lithium-ion batteries without a similar energy fade over time.
Our graphene-based supercapacitors charge in just a fraction of the time needed to charge lithium-ion batteries.
There are many consumer industrial and military applications he said. Wouldn't it be great if mobile phones could be recharged fully in only a matter of minutes
and quality assurance processes to produce commercial volumes of the Folium graphene. We also are focused on working with potential customers to continue to develop baseline products for both our biosensor
Graphene reinvents the futur t
#Nanoribbon film keeps glass ice-free: Team refines deicing film that allows radio frequencies to pass Rice university scientists who created a deicing film for radar domes have refined now the technology to work as a transparent coating for glass.
The graphene-infused paint worked well Tour said but where it was thickest it would break down
#Aligned carbon nanotube/graphene sandwiches By in situ nitrogen doping and structural hybridization of carbon nanotubes (CNTS) and graphene via a two-step chemical vapor deposition (CVD) scientists have fabricated nitrogen-doped aligned carbon nanotube/graphene (N-ACNT/G) sandwiches
with three-dimensional (3d) electron transfer pathways interconnected ion diffusion channels and enhanced interfacial affinity and activity.
CNTS and graphene the most highlighted sp2-bonded carbon nanomaterials over the past decades have attracted enormous attention in the area of energy storage heterogeneous catalysis healthcare environmental protection as well as nanocomposites
The combination of CNTS and graphene into 3d hybrid composites can usually mitigate the self-aggregation
Up to now several strategies have been explored to fabricate such CNTS/graphene hybrids including post-organization methods and in situ growth while integration of high-quality CNTS and graphene without barrier layers is still difficult.
A team from Tsinghua University (China) led by Prof. Qiang Zhang and Fei Wei have fabricated now successfully sandwich-like N-ACNT/G hybrids via a two-step catalytic growth on bifunctional natural materials.
and graphene was deposited sequentially onto the surface of lamellar flakes at the bottom of aligned CNTS through a high-temperature (H-T) CVD.
After catalyst removal alternative aligned CNTS and graphene were connected vertically to each other in long-range periodicity thereby forming a sandwich-like structure.
and graphene were grown on the NPS and lamellar flakes at L -and H-T CVD respectively and conjointly. first-author Cheng Tang explained to Phys.
Org''Thereby the seamless connection of high-quality aligned CNTS and graphene provided 3d electron transfer pathways and interconnected ion diffusion channels.
and graphene provides rapid electron transfer and mechanical robustness. The 3d interconnected mesoporous space improves the penetration and diffusion of electrolytes.
Rational hybridization of N-doped graphene/carbon nanotubes for oxygen reduction and oxygen evolution reaction More information:
/Graphene Sandwiches: Facile Catalytic Growth on Bifunctional Natural Catalysts and Their Applications as Scaffolds for High-Rate Lithium-Sulfur Batteries.
#Molecular self-assembly controls graphene-edge configuration A research team headed by Prof. Patrick Han and Prof.
Graphene, with its low dimensionality, high stability, high strength, and high charge-carrier mobility, promises to be a revolutionary material for making next-generation high-speed transistors.
graphene's properties are predicted to be directly controllable by its structure. For example, recent works have demonstrated that the bandgap of armchair GNRS is controlled by the ribbon width.
These features could be exploited for making single graphene interconnections between prefabricated structures by self-assembly."
#Engineers advance understanding of graphene's friction properties (Phys. org) An interdisciplinary team of engineers from the University of Pennsylvania has made a discovery regarding the surface properties of graphene the Nobel-prize winning material that consists of an atomically thin sheet
However on the nanoscale adding fluorine to graphene had been reported to vastly increase the friction experienced
Besides its applications in circuitry and sensors graphene is of interest as a super-strong coating.
Because graphene is so strong thin and smooth one of its potential applications is to reduce friction and increase the lifespan of these devices.
We wanted to better understand the fundamental mechanisms of how the addition of other atoms influences the friction of graphene.
The addition of fluorine atoms to graphene's carbon lattice makes for an intriguing combination
so we thought fluorinated graphene might be like two-dimensional Teflon. To test the friction properties of this material the Penn researchers collaborated with Paul Sheehan and Jeremy Robinson of the Naval Research Laboratory.
Sheehan and Robinson were the first to discover fluorinated graphene and are experts in producing samples of the material to specification.
The researchers were surprised to find that adding fluorine to graphene increased the material's friction
whose expertise is in developing atomic scale simulations of mechanical action to help explain what the addition of the fluorine was doing to the graphene's surface.
It turns out that by adding fluorine Liu said we're changing the energy corrugation landscape of the graphene.
In fluorinated graphene the fluorine atoms do stick up out of the plane of carbon atoms but the physical changes in height paled in comparison to the changes of local energy each fluorine atom produced.
and deep valleys in between them compared to the smooth plane of regular graphene. You could say it's like trying slide over a smooth road versus a bumpy road.
Beyond the implication for graphene's coating applications the team's findings provide fundamental insight into graphene's surface properties.
Seeing that fluorine increases friction in graphene isn't necessarily a bad thing since it may give us a way to tailor that property to a given application.
On the edge of graphene More information: Fluorination of Graphene Enhances Friction Due to Increased Corrugation.
Qunyang Li Xin-Z. Liu Sang-Pil Kim Vivek B. Shenoy Paul E. Sheehan Jeremy T. Robinson and Robert W. Carpick.
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