#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.
and a two-dimensional graphene platform to boost production of the hard-to-make element. The research also unveiled a previously unknown property of graphene.
The two-dimensional chain of carbon atoms not only gives and receives electrons, but can also transfer them into another substance.
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,
"This research,"Photoinduced Electron Transfer pathways in Hydrogen-Evolving Reduced graphene oxide-Boosted Hybrid Nano-Bio Catalyst,
#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.
To develop a viable bionsensor the researchers from the University of Swansea had to create patterned graphene devices using a large substrate area
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.
The researchers then patterned graphene devices using semiconductor processing techniques before attaching a number of bioreceptor molecules to the graphene devices.
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
Results showed that the graphene sensor was capable of detecting 8-OHDG concentrations as low as 0. 1 ng ml-1
The graphene biosensor was also considerably faster at detecting the target molecules completing the analysis in a matter of minutes.
and monitor a whole range of diseases as it is quite simple to substitute the specific receptor molecules on the graphene surface.
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 material is made of graphene nanoribbons atom-thick strips of carbon created by splitting nanotubes a process also invented by the Tour lab
The graphene-infused paint worked well Tour said but where it was thickest it would break down
but testing showed the graphene nanoribbons themselves formed an active network when applied directly to a surface.
#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.
Taro Hitosugi at the Advanced Institute of Materials Research (AIMR), Tohoku University discovered a new bottom-up fabrication method that produces defect-free graphene nanoribbons (GNRS) with periodic zigzag-edge regions.
and length distribution, is a stepping stone towards future graphene device fabrication by self-assembly. 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."
"Our method opens the possibility for self-assembling single graphene devices at desired locations, because of the length and of the direction control. t
#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.
This meant we were able to systematically vary the degree of fluorination in our graphene samples
The researchers were surprised to find that adding fluorine to graphene increased the material's friction
they also showed that the addition of fluorine increased the stiffness of the graphene samples and hypothesized this was increased responsible for the 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.
#Doped graphene nanoribbons with potential Graphene is a semiconductor when prepared as an ultra-narrow ribbon although the material is actually a conductive material.
Researchers from Empa and the Max Planck Institute for Polymer Research have developed now a new method to selectively dope graphene molecules with nitrogen atoms.
and undoped graphene pieces they were able to form heterojunctions in the nanoribbons thereby fulfilling a basic requirement for electronic current to flow in only one direction
when voltage is applied the first step towards a graphene transistor. Furthermore the team has managed successfully to remove graphene nanoribbons from the gold substrate on
which they were grown and to transfer them onto a nonconductive material. Graphene possesses many outstanding properties it conducts heat
and electricity it is transparent harder than diamond and extremely strong. But in order to use it to construct electronic switches a material must not only be an outstanding conductor it should also be switchable between on and off states.
The problem however is that the bandgap in graphene is extremely small. Empa researchers from the nanotech@surfaces laboratory thus developed a method some time ago to synthesise a form of graphene with larger bandgaps by allowing ultra-narrow graphene nanoribbons to grow via molecular self-assembly.
Graphene nanoribbons made of differently doped segmentsthe researchers led by Roman Fasel have achieved now a new milestone by allowing graphene nanoribbons consisting of differently doped subsegments to grow.
Instead of always using the same pure carbon molecules they used additionally doped molecules molecules provided with foreign atoms in precisely defined positions in this case nitrogen.
The researchers describe the corresponding heterojunctions in segmented graphene nanoribbons in the recently published issue of Nature Nanotechnology.
Transferring graphene nanoribbons onto other substratesin addition the scientists have solved another key issue for the integration of graphene nanotechnology into conventional semiconductor industry:
how to transfer the ultra-narrow graphene ribbons onto another surface? As long as the graphene nanoribbons remain on a metal substrate (such as gold used here) they cannot be used as electronic switches.
Gold conducts and thus creates a short-circuit that sabotages the appealing semiconducting properties of the graphene ribbon.
Fasel's team and colleagues at the Max-Planck-Institute for Polymer Research in Mainz have succeeded in showing that graphene nanoribbons can be transferred efficiently
and intact using a relatively simple etching and cleaning process onto (virtually) any substrate for example onto sapphire calcium fluoride or silicon oxide.
Graphene is thus increasingly emerging as an interesting semiconductor material and a welcome addition to the omnipresent silicon.
The semiconducting graphene nanoribbons are particularly attractive as they allow smaller and thus more energy efficient and faster electronic components than silicon.
However the generalized use of graphene nanoribbons in the electronics sector is anticipated not in the near future due in part to scaling issues
Fasel estimates that it may still take about 10 to 15 years before the first electronic switch made of graphene nanoribbons can be used in a product.
Graphene nanoribbons for photovoltaic componentsphotovoltaic components could also one day be based on graphene. In a second paper published in Nature Communications Pascal Ruffieux also from the Empa nanotech@surfaces laboratory
and his colleagues describe a possible use of graphene strips for instance in solar cells. Ruffieux and his team have noticed that particularly narrow graphene nanoribbons absorb visible light exceptionally well
and are therefore highly suitable for use as the absorber layer in organic solar cells. Compared to normal graphene
which absorbs light equally at all wavelengths the light absorption in graphene nanoribbons can be increased enormously in a controlled way
whereby researchers set the width of the graphene nanoribbons with atomic precision n
#Rethinking basic science of graphene synthesis shows route to industrial-scale production A new route to making graphene has been discovered that could make the 21st century's wonder material easier to ramp up to industrial scale.
Graphene tightly bound single layer of carbon atoms with super strength and the ability to conduct heat
and electricity better than any other known materialas potential industrial uses that include flexible electronic displays, high-speed computing, stronger wind turbine blades,
and more-efficient solar cells, to name just a few under development. In the decade since Nobel laureates Konstantin Novoselov and Andre Geim proved the remarkable electronic and mechanical properties of graphene
researchers have been hard at work to develop methods of producing pristine samples of the material on a scale with industrial potential.
Now, a team of Penn State scientists has discovered a route to making single-layer graphene that has been overlooked for more than 150 years."
"There are lots of layered materials similar to graphene with interesting properties, but until now we didn't know how to chemically pull the solids apart to make single sheets without damaging the layers,
and graphene could apply to many other layered materials of interest to researchers in the Penn State Center for Two-dimensional and Layered Materials who are investigating
what are referred to as"Materials Beyond Graphene.""The next step for Mallouk and colleagues will be to figure out how to speed the reaction up
Using the special properties of graphene a two-dimensional form of carbon that is only one atom thick a prototype detector is able to see an extraordinarily broad band of wavelengths.
and colleagues at the U s. Naval Research Lab and Monash University Australia gets around these problems by using graphene a single layer of interconnected carbon atoms.
By utilizing the special properties of graphene the research team has been able to increase the speed
Graphene a sheet of pure carbon only one atom thick is suited uniquely to use in a terahertz detector
because when light is absorbed by the electrons suspended in the honeycomb lattice of the graphene they do not lose their heat to the lattice
Light is absorbed by the electrons in graphene which heat up but don't lose their energy easily.
These heated electrons escape the graphene through electrical leads much like steam escaping a tea kettle.
Sensitive Room-temperature Terahertz Detection via Photothermoelectric Effect in Graphene Xinghan Cai et al. Nature Nanotechnology dx. doi. org/10.1038/nnano. 2014.18
#First graphene-based flexible display produced A flexible display incorporating graphene in its pixels'electronics has been demonstrated successfully by the Cambridge Graphene Centre and Plastic Logic,
the first time graphene has been used in a transistor-based flexible device. The partnership between the two organisations combines the graphene expertise of the Cambridge Graphene Centre (CGC),
with the transistor and display processing steps that Plastic Logic has developed already for flexible electronics.
This prototype is a first example of how the partnership will accelerate the commercial development of graphene,
and is a first step towards the wider implementation of graphene and graphene-like materials into flexible electronics.
Graphene is a two-dimensional material made up of sheets of carbon atoms. It is among the strongest most lightweight and flexible materials known,
or backplane, of this display includes a solution-processed graphene electrode, which replaces the sputtered metal electrode layer within Plastic Logic's conventional devices,
Graphene is more flexible than conventional ceramic alternatives like indium-tin oxide (ITO) and more transparent than metal films.
The ultra-flexible graphene layer may enable a wide range of products including foldable electronics. Graphene can also be processed from solution bringing inherent benefits of using more efficient printed
and roll-to-roll manufacturing approaches. The new 150 pixel per inch (150 ppi) backplane was made at low temperatures (less than 100°C) using Plastic Logic's Organic Thin Film Transistor (OTFT) technology.
The graphene electrode was deposited from solution and subsequently patterned with micron-scale features to complete the backplane.
"We are happy to see our collaboration with Plastic Logic resulting in the first graphene-based electrophoretic display exploiting graphene in its pixels'electronics,
"said Professor Andrea Ferrari, Director of the Cambridge Graphene Centre.""This is a significant step forward to enable fully wearable and flexible devices.
This cements the Cambridge graphene technology cluster and shows how an effective academic-industrial partnership is key to help move graphene from the lab to the factory floor.""
""The potential of graphene is well-known, but industrial process engineering is required now to transition graphene from laboratories to industry,
"said Indro Mukerjee, CEO of Plastic Logic.""This demonstration puts Plastic Logic at the forefront of this development,
which will soon enable a new generation of ultra-flexible and even foldable electronics"This joint effort between Plastic Logic
within the'realising the graphene revolution'initiative. This will target the realisation of an advanced, full colour, OELD based display within the next 12 months h
#Team develops ultra sensitive biosensor from molybdenite semiconductor Move over graphene. An atomically thin two-dimensional ultrasensitive semiconductor material for biosensing developed by researchers at UC Santa barbara promises to push the boundaries of biosensing technology in many fields from health care to environmental protection to forensic industries.
Based on molybdenum disulfide or molybdenite (Mos2) the biosensor materialsed commonly as a dry lubricanturpasses graphene's already high sensitivity offers better scalability
While graphene has attracted wide interest as a biosensor due to its two-dimensional nature that allows excellent electrostatic control of the transistor channel by the gate
and high surface-to-volume ratio the sensitivity of a graphene field-effect transistor (FET) biosensor is restricted fundamentally by the zero band gap of graphene that results in increased leakage current leading to reduced sensitivity explained Banerjee
Graphene has been used among other things to design FETSEVICES that regulate the flow of electrons through a channel via a vertical electric field directed into the channel by a terminal called a gate.
Graphene has received wide interest in the biosensing field and has been used to line the channel and act as a sensing element
despite graphene's excellent characteristics its performance is limited by its zero band gap. Electrons travel freely across a graphene FETENCE it cannot be switched offhich in this case results in current leakages and higher potential for inaccuracies.
Much research in the graphene community has been devoted to compensating for this deficiency either by patterning graphene to make nanoribbons
or by introducing defects in the graphene layerr using bilayer graphene stacked in a certain pattern that allows band gap opening upon application of a vertical electric fieldor better control and detection of current.
Enter Mos2 a material already making waves in the semiconductor world for the similarities it shares with graphene including its atomically thin hexagonal structure and planar nature as well as
what it can do that graphene can't: act like a semiconductor. Monolayer or few-layer Mos2 have a key advantage over graphene for designing an FET biosensor:
They have a relatively large and uniform band gap (1. 2-1. 8 ev depending on the number of layers) that significantly reduces the leakage current
and increases the abruptness of the turn-on behavior of the FETS thereby increasing the sensitivity of the biosensor said Banerjee.
Additionally according to Deblina Sarkar a Phd student in Banerjee's lab and the lead author of the article two-dimensional Mos2 is relatively simple to manufacture.
New rapid synthesis developed for bilayer graphene and high-performance transistors More information: ACS Nano pubs. acs. org/doi/abs/10.1021/nn500914 i
Ever since the discovery of graphene a single layer of carbon that can be extracted from graphite with adhesive tape scientists have been rapidly exploring the world of two-dimensional materials These materials have unique properties not seen in their bulk form.
Like graphene Mos2 is made up of layers that are bonded weakly to each other so they can be separated easily.
Graphene is inefficient at light emission because it has no band gap. Combining electronics and photonics on the same integrated circuits could drastically improve the performance and efficiency of mobile technology.
#Ultrafast graphene based photodetectors with data rates up to 50 GBIT/s In cooperation with Alcatel Lucent Bell labs researcher from AMO realized the worldwide fastest Graphene based photodetectors.
Graphene a two-dimensional layer of carbon atoms is currently one of the most promising materials for future ultrafast and compact telecommunication systems.
In the current work Graphene based photodetectors were integrated in a conventional silicon photonic platform designed for future on-chip applications in the area of ultrafast data communication.
In addition the specific features of Graphene-based photodetectors like dark current free and high speed operation
not only set a new benchmark for graphene based photodetectors but also demonstrate for the first time that Graphene based photodetectors surpass comparable detectors based on conventional materials concerning maximal data rates.
The work was supported by the European commission through the Flagship project Graphene and the integrated project Grafol as well as the DPG supported project Gratis.
The publication is published in the international renowned journal ACS Photonics and was chosen as Editor's Choice article.
Graphene and related materials promise cheap flexible printed cameras More information: 50 GBIT/s photodetectors based on wafer-scale graphene for integrated silicon photonic communication systems.
ACS Photonics Just Accepted Manuscript. DOI: 10.1021/ph500160 6
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