Graphene – Properties, Applications and Uses


By Michael Berger. Copyright © Nanowerk

2x2-logo-sm.jpg(Nanowerk Spotlight) Carbon comes in many different forms, from the graphite found in pencils to the world’s most expensive diamonds. In 1980, we knew of only three basic forms of carbon, namely diamond, graphite, and amorphous carbon. Then, fullerenes and carbon nanotubes were discovered and, in 2004, graphene joined the club. Graphene is an atomic-scale honeycomb lattice made of carbon atoms. Existing forms of carbon basically consist of sheets of graphene, either bonded on top of each other to form a solid material like the graphite in your pencil, or rolled up into carbon nanotubes (think of a single-walled carbon nanotube as a graphene cylinder) or folded into fullerenes.

Graphene

Mother of all graphitic forms. Graphene is a 2D building material for carbon materials of all other dimensionalities. It can be wrapped up into 0D buckyballs, rolled into 1D nanotubes or stacked into 3D graphite. (Artistic impression of a corrugated graphene sheet: Jannik Meyer) The reason nanotechnology researchers are so excited is that graphene and other two-dimensional crystals – it’s called 2D because it extends in only two dimensions: length and width; as the material is only one atom thick, the third dimension, height, is considered to be zero – open up a whole new class of materials with novel electronic, optical and mechanical properties. Early experiments with graphene have revealed some fascinating phenomena that excite researchers working towards molecular electronics. For instance, it was found that graphene remains capable of conducting electricity even at the limit of nominally zero carrier concentration because the electrons don’t seem to slow down or localize. The electrons moving around carbon atoms interact with the periodic potential of graphene’s honeycomb lattice, which gives rise to new quasiparticles that have lost their mass, or ‘rest mass’ (so-called massless Dirac fermions). That means that graphene never stops conducting. It was also found that they travel far faster than electrons in other semiconductors. Graphene is undoubtedly emerging as one of the most promising nanomaterials because of its unique combination of superb properties, which opens a way for its exploitation in a wide spectrum of applications ranging from electronics to optics, sensors, and biodevices. Watch a great introductory video on graphene:

Graphene production The quality of graphene plays a crucial role as the presence of defects, impurities, grain boundaries, multiple domains, structural disorders, wrinkles in the graphene sheet can have an adverse effect on its electronic and optical properties. In electronic applications, the major bottleneck is the requirement of large size samples, which is possible only in the case of CVD process, but it is difficult to produce high quality and single crystalline graphene thin films possessing very high electrical and thermal conductivities along with excellent optical transparency. Another issue of concern in the synthesis of graphene by conventional methods involves the use of toxic chemicals and these methods usually result in the generation hazardous waste and poisonous gases. Therefore, there is a need to develop green methods to produce graphene by following environmentally friendly approaches. The preparation methods for graphene should also allow for in-situ fabrication and integration of graphene-based devices with complex architecture that would enable eliminating the multi step and laborious fabrication methods at a lower production cost (read more: “Mass production of high quality graphene: An analysis of worldwide patents”). Currently, the most common techniques available for the production of graphene are shown schematically below, which includes micromechanical cleavage, chemical vapor deposition, epitaxial growth on SiC substrates, chemical reduction of exfoliated graphene oxide, liquid phase exfoliation of graphite and unzipping of carbon nanotubes. However, each of these methods can have its own advantages as well as limitations depending on its target application(s). In order to surmount these barriers in commercializing graphene, concerted efforts are being made by researchers at various R&D institutes, universities and companies from all over the globe to develop new methods for large scale production of low-cost and high quality graphene via simple and eco-friendly approaches.

       A shematic showing the conventional methods commonly used for the synthesis of graphene along with their key features, and the current and  future applicationsA schematic showing the conventional methods commonly used for the synthesis of graphene along with their key features, and the current and future applications. (Image: CKMNT) (click image to enlarge)

Here on Nanowerk we keep an updated list of graphene manufacturers and suppliers. Graphene-based nanomaterials have many promising applications in numerous areas:

Energy Graphene-based nanomaterials have many promising applications in energy-related areas. Just some recent examples: Graphene improves both energy capacity and charge rate in rechargeable batteries; activated graphene makes superior supercapacitors for energy storage; graphene electrodes may lead to a promising approach for making solar cells that are inexpensive, lightweight and flexible; and multifunctional graphene mats are promising substrates for catalytic systems.

These examples highlight the four major energy-related areas where graphene will have an impact: solar cells, supercapacitors, lithium-ion batteries, and catalysis for fuel cells. An excellent review paper (“Chemical Approaches toward Graphene-Based Nanomaterials and their Applications in Energy-Related Areas”) gives a brief overview of the recent research concerning chemical and thermal approaches toward the production of well-defined graphene-based nanomaterials and their applications in energy-related areas. The authors note, however, that before graphene-based nanomaterials and devices find widespread commercial use, two important problems have to be solved: one is the preparation of graphene-based nanomaterials with well-defined structures, and the other is the controllable fabrication of these materials into functional devices. Read more about graphene nanotechnology in energy applications.

Sensors Functionalized graphene holds exceptional promise for biological and chemical sensors. Already, researchers have shown that the distinctive 2D structure of graphene oxide (GO), combined with its superpermeability to water molecules, leads to sensing devices with an unprecedented speed (“Ultrafast graphene sensor monitors your breath while you speak”). Scientists have now found that chemical vapors change the noise spectra of graphene transistors, allowing them to perform selective gas sensing for many vapors with a single device made of pristine graphene – no functionalization of the graphene surface required (“Selective gas sensing with pristine graphene”). Quite a cool approach is to interface passive, wireless graphene nanosensors onto biomaterials via silk bioresorption as demonstrated by a graphene nanosensor tattoo on teeth monitors bacteria in your mouth.

     graphene wireless sensor biotransferred onto the surface of a tooth

Optical image of the graphene wireless sensor biotransferred onto the surface of a tooth. (Image: McAlpine Group, Princeton University)

Researchers also have begun to work with graphene foams – three-dimensional structures of interconnected graphene sheets with extremely high conductivity. These structures are very promising as gas sensors (“Graphene foam detects explosives, emissions better than today’s gas sensors”) and as biosensors to detect diseases (see for instance: “Nanotechnology biosensor to detect biomarkers for Parkinson’s disease”).

Flexible, stretchable and foldable electronics Graphene has a unique combination of properties that is ideal for next-generation electronics, including mechanical flexibility, high electrical conductivity, and chemical stability. Combine this with inkjet printing and you get an inexpensive and scalable path for exploiting these properties in real-world technologies (“Inkjet printing of graphene for flexible electronics”). In contrast to flexible electronics, which rely on bendable substrates, truly foldable electronics require a foldable substrate with a very stable conductor that can withstand folding, i.e. an edge in the substrate at the point of the fold, which develops creases, and the deformation remains even after unfolding. That means that, in addition to a foldable substrate like paper, the conductor that is deposited on this substrate also needs to be foldable. To that end, researchers have demonstrated a fabrication process for foldable graphene circuits based on paper substrates.

         graphene on paperPhotographs of applications. a,b,c) Operation of a LED chip with graphene circuits on a paper substrate under -180° folding and 180° folding. d) Array of LED chips on a three-dimensional circuit board including negative and positive angle folding. e,f,g) Operation of a LED chip on the paper-based circuit board before and after crumpling. (Reprinted with permission from Wiley-VCH Verlag)

Graphene’s remarkable conductivity, strength and elasticity has made it a promising choice for stretchable electronics — a technology that aims to produce circuits on flexible plastic substrates for applications like bendable solar cells or robotic-like artificial skin. Scientists have devised a chemical vapor deposition (CVD) method for turning graphene sheets into porous three-dimensional foams with extremely high conductivity. By permeating this foam with a siloxane-based polymer, the researchers have produced a composite that can be twisted, stretched and bent without harming its electrical or mechanical properties (“Graphene: Foaming for stretchable electronics”).

Nanoelectronics Some of the most promising applications of graphene are in electronics (as transistors and interconnects), detectors (as sensor elements) and thermal management (as lateral heat spreaders). The first graphene field-effect transistors (FETs) – with both bottom and top gates – have already been demonstrated. At the same time, for any transistor to be useful for analog communication or digital applications, the level of the electronic low-frequency noise has to be decreased to an acceptable level (“Graphene transistors can work without much noise”). Transistors on the basis of graphene are considered to be potential successors for the some silicon components currently in use. Due to the fact that an electron can move faster through graphene than through silicon, the material shows potential to enable terahertz computing. In the ultimate nanoscale transistor – dubbed a ballistic transistor – the electrons avoid collisions, i.e. there is a virtually unimpeded flow of current. Ballistic conduction would enable incredibly fast switching devices. Graphene has the potential to enable ballistic transistors at room temperature. While graphene has the potential to revolutionize electronics and replace the currently used silicon materials  (“High-performance graphene transistor with high room-temperature mobility”), it does have an Achilles heel: pristine graphene is semi-metallic and lacks the necessary band gap to serve as a transistor. Therefore it is necessary to engineer band gaps in graphene. Experiments have demonstrated the benefits of graphene as a platform for flash memory which show the potential to exceed the performance of current flash memory technology by utilizing the intrinsic properties of graphene.

Photodetectors Researchers have demonstrated that graphene can be used for telecommunications applications and that its weak and universal optical response might be turned into advantages for ultrafast photonics applications. They also found that graphene could be potentially exploited as a saturable absorber with wide optical response ranging from ultra-violet, visible, infrared to terahertz (“The rise of graphene in ultra-fast photonics”). There is a very strong research interest in using graphene for applications in optoelectronics. Graphene-based photodetectors have been realized before and graphene’s suitability for high bandwidth photodetection has been demonstrated in a 10 GBit/s optical data link (“Graphene photodetectors for high-speed optical communications”). One novel approach is based on the integration of graphene into an optical microcavity. The increased electric field amplitude inside the cavity causes more energy to be absorbed, leading to a significant increase of the photoresponse (“Microcavity vastly enhances photoresponse of graphene photodetectors”).

Coatings Coating objects with graphene can serve different purposed. For instance, researchers have now shown that it is possible to use graphene sheets to create a superhydrophobic coating material that shows stable superhydrophobicity under both static as well as dynamic (droplet impact) conditions, thereby forming extremely water repelling structures.

       doped germanium surfaceSnapshots of a water droplet impacting the surface of the Teflon coated graphene foam. The impact velocity just prior to the droplet striking the surface was ∼76 cm/sec. The sequence of snapshots shows the deformation time history of the droplet upon impact. The droplet spreads, then retracts and successfully rebounds off the surface. The coefficient of restitution (i.e. ratio of droplet impacting velocity to ejecting velocity) is ∼0.37 for the Teflon coated foam. (Reprinted with permission from Wiley-VCH Verlag)

Research findings also have established graphene as the world’s thinnest known coating for protecting metals against corrosion. It was found that graphene, whether made directly on copper or nickel or transferred onto another metal, provides protection against corrosion. Another novel coating application is the the fabrication of polymeric AFM probes covered by monolayer graphene to improving AFM probe performance.

Other uses Researchers have exploited the extraordinary electrical and mechanical properties of graphene to create a very efficient electrical/sound transducer. This experimental graphene loudspeaker, without any optimized acoustic design, is simple to make and already performs comparably to or better than similar sized commercial counterparts, and with much lower power consumption. Recent research also points to an opportunity to replacing antibiotics with graphene-based photothermal agents to trap and kill bacteria. Graphene appears to be a most effective material for electromagnetic interference (EMI) shielding. Experiments suggests the feasibility of manufacturing an ultrathin, transparent, weightless, and flexible EMI shield by a single or a few atomic layers of graphene. Due to rapidly increasing power densities in electronics, managing the resulting heat has become one of the most critical issues in computer and semiconductor design. As a matter of fact, heat dissipation has become a fundamental problem of electronic transport at the nanoscale. This is where graphene comes in – it conducts heat better than any other known material (“‘Cool’ graphene might be ideal for thermal management in nanoelectronics”). Thermal interface materials (TIMs) are essential ingredients of thermal management and researchers  have achieved a record enhancement of the thermal conductivity of TIMs by addition of an optimized mixture of graphene and multilayer graphene (“Graphene sets new record as the most efficient filler for thermal interface materials”).

The concept of plasmonic cloaking is based on the use of a thin metamaterial cover to suppress the scattering from a passive object. Research shows that even a single layer of atoms, with the exciting conductivity properties of graphene, may achieve this functionality in planar and cylindrical geometries. This makes a single layer of graphene the thinnest possible invisibility cloak. Over the last decade, various solid lubricant materials, micro/nano patterns, and surface treatment processes have been developed for efficient operation and extended lifetime in MEMS/NEMS applications, and for various fabrication processes such as nanoimprint lithography and transfer printing. One of the important considerations in applying a solid lubricant at the micro- and nanoscale is the thickness of the lubricant and the compatibility of the lubricant deposition process with the target product. Graphene, with its atomically thin and strong structural with low surface energy, is a good candidate for these applications (“Graphene – the thinnest solid lubricant”).

In the decades-old quest to build artificial muscles, many materials have been investigated with regard to their suitability for actuator application (actuation is the ability of a material to reversibly change dimensions under the influence of various stimuli). Besides artificial muscles, potential applications include microelectro-mechanical systems (MEMS), biomimetic micro-and nanorobots, and micro fluidic devices. In experiments, scientists have shown that graphene nanoribbons can provide actuation. A relatively new method of purifying brackish water is capacitive deionization (CDI) technology. The advantages of CDI are that it has no secondary pollution, is cost-effective and energy efficient. Researchers have developed a CDI application that uses graphene-like nanoflakes as electrodes for capacitive deionization. They found that the graphene electrodes resulted in a better CDI performance than the conventionally used activated carbon materials (“Water desalination with graphene”). Researchers demonstrated the use of graphene as a transparent conductive coating for photonic devices and show that its high transparency and low resistivity make this two-dimensional crystal ideally suitable for electrodes in liquid crystal devices (LCDs).

Read more: Nanotechnology primer: graphene – properties, uses and applications http://www.nanowerk.com/spotlight/spotid=34184.php#ixzz2sFoRBTiU Follow us: @nanowerk on Twitter

The world’s largest graphene production plant is now operational in China


nanotechnology-solar-cells-1In July we reported that China’s Ningbo Morsh Technology is establishing a new graphene production line that will have an annual capacity of 300 tons (or tens of millions of graphene films). The line was supposed to be operational by August 2013, and now there are reports from china that finally production began.

 

The report further says that China plans to build a state-level graphene industrialization base in China’s Chongqing Municipality. Within 5 years, they hope to reach revenues of 100 billion yuan ($16.35 billion). If the capacity is indeed 300 tons per year, than China is now the world’s leading graphene producer by far.

Investment in Ningo Morsh’s production line exceeded 100 million yuan ($16 million). Ningbo Morsh Technology are supplying graphene to Chongqing Morsh Technology, who’s building a production line in Chongqing that will be used to produce 15″ single-layer graphene films that will be used to produce graphene transparent touch panel conductive films. Chongqing Morsh original plan was to start production by March 2014 and they already signed an agreement with Guangdong Zhengyang, an OGS maker to produce 10 million graphene based transparent conducting films (TCFs) in a year for the next five years.

Source: EastDay.com

Origami Form and Nanotechnology combine to advance batteries


Nanotubes images(Nanowerk News) A combination of nanotechnology and the  traditional art of paper folding, known as origami, could be a key to a  significant step toward improved battery technologies.
Arizona State University engineers have constructed a  lithium-ion battery using paper coated with carbon nanotubes that provide  electrical conductivity.
Using an origami-folding pattern similar to how maps are folded,  they folded the paper into a stack of 25 layers, producing a compact, flexible  battery that provides significant energy density – or the amount of energy  stored in a given system or space per unit of volume of mass.
foldable battery
The  above image illustrates the architecture of a foldable lithium-ion battery ASU  engineers have constructed using paper coated with carbon nanotubes. They began  with a porous, lint-free paper towel, coated it with polyvinylidene difluoride  to improve adhesion of carbon nanotubes and then immersed the paper into a  solution of carbon nanotubes. Powders of lithium titanate oxide and lithium  cobalt oxide – standard lithium battery electrodes – are sandwiched between two  sheets of the paper. Thin foils of copper and aluminum are placed above and  below the sheets of paper to complete the battery.
Their research paper in the journal Nano Letters (“Folding Paper-Based Lithium-Ion Batteries for  Higher Areal Energy Densities”) has drawn attention from websites that focus  on news of technological breakthroughs.
The researchers have also developed a new process to incorporate  a polymer binder onto the carbon nanotube-coated paper. The polymer binder  improves adhesion of the structure’s active materials.
The achievements open up possibilities of using the origami  technique to create new forms of paper-based energy storage devices, including  batteries, light-emitting diodes, circuits and transistors, says Candace Chan,  who led the research team.
Chan is an assistant professor of materials science and  engineering in the School for Engineering of Matter, Energy and Transport, one  of ASU’s Ira A. Fulton Schools of Engineering.
Fellow ASU engineering faculty members, associate professor  Hanqing Jiang and assistant professor Hongyu Yu, have played leading roles in  the work.
We have also covered this work in our Nanowerk Spotlight series  here: Nanotechnology  researchers fabricate foldable Li-ion batteries.
Source: Arizona State University

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RMIT University, Australia:The Formation of Nanofins from Magnetic Nanoparticles: Video


Printing Graphene ChipsPublished on Oct  2, 2013

Heat has become one of the most critical issues in computer and semiconductor design: The ever increasing number of transistors in computer chips requires more efficient cooling approaches for the hot spots which are generated as a result of the operation of the transistors. Researchers at RMIT University in Australia have demonstrated a microfluidic technique of using thermally conductive and magnetic chromium oxide nanoparticles that can form low-dimensional fins in the vicinity of hot spots.

Read more at http://www.nanowerk.com/spotlight/spo…

Watch the Video Here:

With carbon nanotubes, a path to flexible, low-cost sensors


Nano Particles for Steel 324x182(Nanowerk News) Researchers at the Technische  Universitaet Muenchen (TUM) are showing the way toward low-cost,  industrial-scale manufacturing of a new family of electronic devices. A leading  example is a gas sensor that could be integrated into food packaging to gauge  freshness, or into compact wireless air-quality monitors. New types of solar  cells and flexible transistors are also in the works, as well as pressure and  temperature sensors that could be built into electronic skin for robotic or  bionic applications. All can be made with carbon nanotubes, sprayed like ink  onto flexible plastic sheets or other substrates.
Carbon nanotube-based gas sensors created at TUM offer a unique  combination of characteristics that can’t be matched by any of the alternative  technologies. They rapidly detect and continuously respond to extremely small  changes in the concentrations of gases including ammonia, carbon dioxide, and  nitrogen oxide. They operate at room temperature and consume very little power.  Furthermore, as the TUM researchers report in their latest papers, such devices  can be fabricated on flexible backing materials through large-area, low-cost  processes.
Flexible carbon nanotube Gas Sensors
Flexible, high-performance gas sensors (left) were made by spraying  a solution of carbon nanotubes (right) onto a plastic backing.
Thus it becomes realistic to envision plastic food wrap that  incorporates flexible, disposable gas sensors, providing a more meaningful  indicator of food freshness than the sell-by date. Measuring carbon dioxide, for  example, can help predict the shelf life of meat. “Smart packaging” – assuming  consumers find it acceptable and the devices’ non-toxic nature can be  demonstrated – could enhance food safety and might also vastly reduce the amount  of food that is wasted. Used in a different setting, the same sort of gas sensor  could make it less expensive and more practical to monitor indoor air quality in  real time.
Not so easy – but “really simple”
Postdoctoral researcher Alaa Abdellah and colleagues at the TUM  Institute for Nanoelectronics have demonstrated that high-performance gas  sensors can be, in effect, sprayed onto flexible plastic substrates. With that,  they may have opened the way to commercial viability for carbon nanotube-based  sensors and their applications. “This really is simple, once you know how to do  it,” says Prof. Paolo Lugli, director of the institute.
The most basic building block for this technology is a single  cylindrical molecule, a rolled-up sheet of carbon atoms that are linked in a  honeycomb pattern. This so-called carbon nanotube could be likened to an  unimaginably long garden hose: a hollow tube just a nanometer or so in diameter  but perhaps millions of times as long as it is wide. Individual carbon nanotubes  exhibit amazing and useful properties, but in this case the researchers are more  interested in what can be done with them en masse.
Laid down in thin films, randomly oriented carbon nanotubes form  conductive networks that can serve as electrodes; patterned and layered films  can function as sensors or transistors. “In fact,” Prof. Lugli explains, “the  electrical resistivity of such films can be modulated by either an applied  voltage (to provide a transistor action) or by the adsorption of gas molecules,  which in turn is a signature of the gas concentration for sensor applications.”
And as a basis for gas sensors in particular, carbon nanotubes  combine advantages (and avoid shortcomings) of more established materials, such  as polymer-based organic electronics and solid-state metal-oxide semiconductors.  What has been lacking until now is a reliable, reproducible, low-cost  fabrication method.
Spray deposition, supplemented if necessary by transfer  printing, meets that need. An aqueous solution of carbon nanotubes looks like a  bottle of black ink and can be handled in similar ways. Thus devices can be  sprayed – from a computer-controlled robotic nozzle – onto virtually any kind of  substrate, including large-area sheets of flexible plastic. There is no need for  expensive clean-room facilities.
“To us it was important to develop an easily scalable technology  platform for manufacturing large-area printed and flexible electronics based on  organic semiconductors and nanomaterials,” Dr. Abdellah says. “To that end,  spray deposition forms the core of our processing technology.”
Remaining technical challenges arise largely from  application-specific requirements, such as the need for gas sensors to be  selective as well as sensitive.
Publications
Fabrication of carbon nanotube thin films on  flexible substrates by spray deposition and transfer printing. Ahmed  Abdelhalim, Alaa Abdellah, Giuseppe Scarpa, Paolo Lugli. Carbon, Vol.  61, September 2013, 72-79.
Flexible carbon nanotube-based gas sensors  fabricated by large-scale spray deposition. Alaa Abdellah, Zubair Ahmad,  Philipp Köhler, Florin Loghin, Alexander Weise, Giuseppe Scarpa, Paolo Lugli.  IEEE Sensors Journal, Vol. 13 Issue 10, October 2013, 4014-4021.
Scalable spray deposition process for high  performance carbon nanotube gas sensors. Alaa Abdellah, Ahmed Abdelhalim,  Markus Horn, Giuseppe Scarpa, and Paolo Lugli. IEEE Transactions on  Nanotechnology 12, 174-181, 2013.
Source: Technische Universität München 

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Graphene Mass Production, Roll to Roll


Nano Particles for Steel 324x182Graphene, the lightest and thinnest compound known to man at one atom thick, has several amazing and unique properties that make it a very interesting candidate for many futuristic applications. However, its use is presently limited due to a bottleneck in its synthesis and mass production, which are still at an infant stage and expensive.

The project, which is being funded with 10.5 million euros over four years, aims to develop the first roll-based chemical vapour deposition (CVD) machine for the mass production of few-layer graphene for transparent electrodes for LED and display applications, and adapts the process conditions of a wafer-scale carbon nanotube growth system to provide a low-cost batch process for graphene growth on silicon. The project focuses on applications such as transparent electrodes for OLEDs and GaN LEDs, optical switches, plasmonic waveguides, VLSI interconnects, and RF NEMs.

Due to its high carrier mobility,  long ballistic mean free path, a high frequency photoconductivity, and a large thermal conductivity, graphene is being considered as a component in  next-generation electronic, optoelectronics and microsystems. Production of graphene is possible by four main methods, and prototype devices based on graphene (eg. field effect transistors, photo-transistors and detectors, and transparent electrodes for touch screens,) have been demonstrated with very promising results. GRAFOL aims to turn an emerging technology, the on-substrate synthesis of graphene, into a large-scale production technology available to industry as shown conceptually in the figure.

 

The project aims to develop the first roll-based chemical vapour deposition (CVD) machine for the mass production of few-layer graphene for transparent electrodes for LED and display applications, and

(Photo : GRAFOL) The project aims to develop the first roll-based chemical vapour deposition (CVD) machine for the mass production of few-layer graphene for transparent electrodes for LED and display applications, and adapts the process conditions of a wafer-scale carbon nanotube growth system to provide a low-cost batch process for graphene growth on silicon.

It is important to realize that the advancement of microelectronics today is not only due to the shrinking of device dimensions, which nano-materials allow, but also to the enlargement of wafer size (the unit of measure for production).  The increase of wafer diameter from 50mm in 1970’s to 300mm in early 2000’s, corresponding to a  36 fold increase in area, has made it much more cost effective to manufacture  microelectronics, quite simply because more chips are made simultaneously. It is quoted by  semiconductor companies, that for graphene to be seriously considered for microelectronics, it must be  on at least the 300mm wafer scale, on Si and attain a life cycle production cost (taking into  account source materials, running costs, equipment depreciation) of $1 per square inch of  deposited area on a substrate. Such a competitive cost can only be achieved if the area of graphene  deposited is increased per run, that is, scaling the production to at  least a 300mm wafer scale (another wafer size transition to 450mm is expected towards the end of this decade).

Taking it one step further, for certain applications such as transparent electrodes graphene should be produced in even larger scale than that required for microelectronics. This  truly large-scale production of graphene would become possible with a successful development of roll-based technology.

Despite its attractive properties, graphene will not yet be used in mainstream electronic applications due to two technological obstacles, namely (1) mass production and (2) device integration. Device integration deals with aspects such as physical integration and process integration (material compatibility, thermal budget). Mass production must use the route of chemical vapour deposition (CVD) onto metal surfaces. To tackle mass production, equipment must be developed which addresses economical manufacturing (yield, throughput, equipment reliability and maintainability) as well as quality assurance (process qualification, material consistency /standard characteristics, monitoring). These obstacles are dealt with in this project.

The value-added / high tech applications developed here have been carefully selected to require graphene on surfaces, and to be those which truly benefit from not only the high specifications but also cost effective production of graphene when deposited on the wafer-scale or by a roll-based method.

GRAFOL  started in October 2011, and will run for 4 years. The coordinator is  the University of Cambridge, led by professor John Robertson. Professor  Robertson leads a team of 14 partners, consisting of both academic  research labs as well as businesses like ours. The project benefits from  expertise of the likes of Aixtron (one of the world’s largest  manufacturers of CVD machines, based in Aachen, Germany), Philips, Thales, and Intel. Financing  comes from the European Union’s FP7 research framework, under the  research theme “Nanosciences, nanotechnologies, materials  and new production technologies”, which focuses on projects with a  strong industrial impact. — Graphenea

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nanoparticle discovery could hail revolution in nanotube manufacturing


NANOSPHERES(Nanowerk News) A nanoparticle shaped like a spiky  ball, with magnetic properties, has been uncovered in a new method of  synthesising carbon nanotubes by physicists at Queen Mary University of London  and the University of Kent (“Boundary layer chemical vapor synthesis of  self-organized radial filled-carbon-nanotube structures”).

Sea Urchin nanoparticle

Sea Urchin Nanoparticle

Carbon nanotubes are  hollow, cylindrical molecules that can be manipulated to give them useful  properties. The nanoparticles were discovered accidentally on the rough surfaces  of a reactor designed to grow carbon nanotubes.

Described  as sea urchins because of their characteristic spiny appearance, the particles  consist of nanotubes filled with iron, with equal lengths pointing outwards in  all directions from a central particle.

The  presence of iron and the unusual nanoparticle shape could have potential for a  number of applications, such as batteries that can be charged from waste heat,  mixing with polymers to make permanent magnets, or as particles for cancer  therapies that use heat to kill cancerous cells.

The researchers  found that the rough surfaces of the reactor were covered in a thick powder of  the new nanoparticles and that intentional roughening of the surfaces produced  large quantities of the sea urchin nanoparticles.

“The surprising conclusion is that the sea urchin nanoparticles  grow in vapour by a mechanism that’s similar to snowflake formation. Just as  moist air flowing over a mountain range produces turbulence which results in a  snowfall, the rough surface disrupts a flow to produce a symmetrical and ordered  nanoparticle out of chaotic conditions,” said Dr Mark Baxendale from Queen  Mary’s School of Physics and Astronomy.
On analysis, the researchers found that a small fraction of the  iron inside the carbon nanotubes was a particular type usually only found in  high temperature and pressure conditions.
Dr Baxendale added: “We were surprised to see this rare kind of  iron inside the nanotubes. While we don’t know much about its behaviour, we can  see that the presence of this small fraction of iron greatly influences the  magnetic properties of the nanoparticle.”
Source: Queen Mary University of London

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Reducing Energy Costs with Better Batteries


3adb215 D BurrisA better battery—one that is cheap and safe, but packs a lot of power—could lead to an electric vehicle that performs better than today’s gasoline-powered cars, and costs about the same or less to consumers.  Such a vehicle would reduce the United States’ reliance on foreign oil and lower energy costs for the average American, so one of the Department of Energy’s (DOE’s) goals is to fund research that will revolutionize the performance of next-generation batteries.

In honor of DOE’s supercomputing month, we are highlighting some of the ways researchers are using supercomputers at the National Energy Research Scientific Computing Center (NERSC) are working to achieve this goal.

New Anode Boots Capacity of Lithium-Ion Batteries

Lithium-ion batteries are everywhere— in smart phones, laptops, an array of other consumer electronics, and electric vehicles. Good as they are, they could be much better, especially when it comes to lowering the cost and extending the range of electric cars. To do that, batteries need to store a lot more energy.

Using supercomputers at NERSC, Berkeley Lab researchers developed a new kind of anode—energy storing component—that is capable of absorbing eight times the lithium of current designs. The secret is a tailored polymer that conducts electricity and binds closely to lithium storing particles. The researchers achieved this result by running supercomputer calculations of different promising polymers until they found the perfect one. This research is an important step toward developing lithium-ion batteries with eight times their current capacity.

After more than a year of testing and many hundreds of charge-discharge cycles, Berkeley researchers found that their anode maintained its increased energy capacity.  This is a significant improvement from many lithium-ion batteries on the market today, which degrade as they recharge. Best of all, the anodes are made from low-cost materials that are also compatible with standard lithium battery manufacturing technologies.

Read More: https://www.nersc.gov/news-publications/news/science-news/2011/a-better-lithium-ion-battery-on-the-way/

Engineering Better Energy Storage

One of the biggest weaknesses of today’s electric vehicles is battery life—most cars can only go about 100-200 miles between charges. But researchers hope that a new type of battery, called the lithium-air battery, will one day lead to a cost-effective, long-range electric vehicles that could travel 300 miles or more between charges.

Using supercomputers at NERSC and powerful microscopes, a team of researchers from the Pacific Northwest National Laboratory (PNNL) and Princeton University built a novel graphene membrane that could produce a lithium-air battery with the highest-energy capacity to date. Because the material does not rely on platinum or other precious metals, its potential cost and environmental impact are significantly less than current technology.

Read More: https://www.nersc.gov/news-publications/news/science-news/2012/bubbles-help-break-energy-storage-record-for-lithium-air-batteries/

Promise for Onion-Like Carbons as Supercapacitors

The two most important electrical storage technologies on the market today are batteries and capacitors—both have their pluses and minuses. Batteries can store a lot of energy, but have slow charge and discharge rates. While capacitors generally store less energy but have very fast (nearly instant) charge and discharge rates, and last longer than rechargeable batteries. Developing technologies that combine the optimal characteristics of both will require a detailed understanding of how these devices work at the molecular level. That’s where supercomputers come in handy.

One promising electrical storage device is the supercapacitator, which combines the fast charging and discharging rates of conventional capacitators, as well as the high-power density, high-capacitance (ability to store electrical charge), and durability of a battery. Today supercapacitators power electric vehicles, portable electronic equipment and various other devices. Despite their use in the marketplace, researchers believe these energy storage devices could perform much better. One area that they are hoping to improve is the device’s electrode, or a conductor through which electricity enters or leaves.

Most supercapacitor electrodes are made of carbon-based materials, but one promising material yet to be explored is graphene. The strongest material known, graphene also has unique electrical, thermal, mechanical and chemical properties. Using supercomputers at NERSC, scientists ran simulations to understand how the shape of a graphene electrode affects its electrical properties. They hope that one-day this work will inspire the design of supercapacitators that can hold a much more stable electric charge.

Read More: http://www.nersc.gov/news-publications/news/science-news/2012/why-onion-like-carbons-make-high-energy-supercapacitors/

A Systematic Approach to Battery Design

New materials are crucial for building advanced batteries, but today the development cycle is too slow. It takes about 15 to 18 years to go from conception to commercialization. To speed up this process, a team of researchers from Lawrence Berkeley National Laboratory (Berkeley Lab) and the Massachusetts Institute of Technology (MIT) created a new computational tool called the Materials Project, which is hosted at NERSC.

The Materials Project uses supercomputers at NERSC, Berkeley Lab and the University of Kentucky to characterize the properties of inorganic compounds—such as stability, voltage, capacity and oxidation state—via computer simulations. The results are then organized into a database with a user-friendly web interface that allows users to easily access and search for the compound that they would like to use in their new material design. Knowing the properties of a compound beforehand allows researchers to quickly assess whether their idea will be successful, without spending money and time developing prototypes and experiments that will eventually lead to a dead-end.

In early 2013, DOE pledged $120 million over five years to establish the Joint Center for Energy Storage Research (JCESR). As part of this initiative, the Berkeley Lab and MIT researchers will run simulations at NERSC to predict the properties of electrolytes—a liquid. The results will be incorporated into a database similar to the Materials Project. Eventually researchers will be able to combine the JCESR database with the Materials Project to get a complete scope of battery components. Together, these resources allow scientists to employ a systematic and predictive approach to battery design.

Read More: https://www.nersc.gov/news-publications/news/science-news/2012/nersc-helps-develop-next-gen-batteries/

For more information about how Berkeley Lab is celebrating DOE supercomputing month, please visit: http://cs.lbl.gov/news-media/news/2013/supercomputing-sept-2013/


About Berkeley Lab Computing Sciences

The Lawrence Berkeley National Laboratory (Berkeley Lab) Computing  Sciences organization provides the computing and networking resources  and expertise critical to advancing the Department of Energy’s research  missions: developing new energy  sources, improving energy efficiency, developing new materials and  increasing our understanding of ourselves, our world and our universe. ESnet, the Energy Sciences Network, provides the high-bandwidth, reliable connections that link scientists at 40 DOE research sites to each other and to experimental facilities and supercomputing centers around the country. The National Energy Research  Scientific Computing Center (NERSC) powers the discoveries of 5,500 scientists at national laboratories and universities, including those at Berkeley Lab’s Computational Research Division (CRD). CRD  conducts research and development in mathematical modeling and  simulation, algorithm design, data storage, management and analysis,  computer system architecture and high-performance software  implementation.

Nanotechnology Today – Fuel Cells, Buckyballs and Carbon Nanotubes


Nanotubes images 

To celebrate the 25th anniversary of National Chemistry Week, we visited the Maryland Nanocenter at the University of Maryland (UMD) to check out the latest research in nanotechnology — this year’s theme for NCW.

Three UMD researchers explain how their work in the nano-scale could lead to better fuel cells, solar cells, cancer treatments and super strong materials made from carbon nanotubes. Check out the video for a first hand look at the exciting applications of nanotechnology available today, and those that are just around the corner.

Drs. Eichhorn and Reutt-Robey at the University of Maryland ‘illuminate’ for us some of the current nano-technology being developed for commercial applications.


Video by Kirk Zamieroski Produced by the American Chemical Society

 

 

Nanosensors Could Aid Drug Manufacturing


nanomanufacturing-2 CAMBRIDGE, Mass. MIT News Office: Chemical engineers find that arrays of carbon nanotubes can detect flaws in drugs and help improve production.      — MIT chemical engineers have discovered that arrays of billions of nanoscale sensors have unique properties that could help pharmaceutical companies produce drugs — especially those based on antibodies — more safely and efficiently.
Using these sensors, the researchers were able to characterize variations in the binding strength of antibody drugs, which hold promise for treating cancer and other diseases. They also used the sensors to monitor the structure of antibody molecules, including whether they contain a chain of sugars that interferes with proper function.
“This could help pharmaceutical companies figure out why certain drug formulations work better than others, and may help improve their effectiveness,” says Michael Strano, an MIT professor of chemical engineering and senior author of a recent paper describing the sensors in the journal ACS Nano.
The team also demonstrated how nanosensor arrays could be used to determine which cells in a population of genetically engineered, drug-producing cells are the most productive or desirable, Strano says. Lead author of the paper is Nigel Reuel, a graduate student in Strano’s lab. The labs of MIT faculty members Krystyn Van Vliet, Christopher Love and Dane Wittrup also contributed, along with scientists from Novartis.
Testing drug strength
Strano and other scientists have previously shown that tiny, nanometer-sized sensors, such as carbon nanotubes, offer a powerful way to detect minute quantities of a substance. Carbon nanotubes are 50,000 times thinner than a human hair, and they can bind to proteins that recognize a specific target molecule. When the target is present, it alters the fluorescent signal produced by the nanotube in a way that scientists can detect.
Some researchers are trying to exploit large arrays of nanosensors, such as carbon nanotubes or semiconducting nanowires, each customized for a different target molecule, to detect many different targets at once. In the new study, Strano and his colleagues wanted to explore unique properties that emerge from large arrays of sensors that all detect the same thing.
The first feature they discovered, through mathematical modeling and experimentation, is that uniform arrays can measure the distribution in binding strength of complex proteins such as antibodies. Antibodies are naturally occurring molecules that play a key role in the body’s ability to recognize and defend against foreign invaders. In recent years, scientists have been developing antibodies to treat disease, particularly cancer. When those antibodies bind to proteins found on cancer cells, they stimulate the body’s own immune system to attack the tumor.
For antibody drugs to be effective, they must strongly bind their target. However, the manufacturing process, which relies on nonhuman, engineered cells, does not always generate consistent, uniformly binding batches of antibodies.

Currently, drug companies use time-consuming and expensive analytical processes to test each batch and make sure it meets the regulatory standards for effectiveness. However, the new MIT sensor could make this process much faster, allowing researchers to not only better monitor and control production, but also to fine-tune the manufacturing process to generate a more consistent product.
“You could use the technology to reject batches, but ideally you’d want to use it in your upstream process development to better define culture conditions, so then you wouldn’t produce spurious lots,” Reuel says.
Measuring weak interactions
Another useful trait of such sensors is their ability to measure very weak binding interactions, which could also help with antibody drug manufacturing.
Antibodies are usually coated with long sugar chains through a process called glycosylation. These sugar chains are necessary for the drugs to be effective, but they are extremely hard to detect because they interact so weakly with other molecules. Drug-manufacturing organisms that synthesize antibodies are also programmed to add sugar chains, but the process is difficult to control and is strongly influenced by the cells’ environmental conditions, including temperature and acidity.
Without the appropriate glycosylation, antibodies delivered to a patient may elicit an unwanted immune response or be destroyed by the body’s cells, making them useless.
“This has been a problem for pharmaceutical companies and researchers alike, trying to measure glycosylated proteins by recognizing the carbohydrate chain,” Strano says. “What a nanosensor array can do is greatly expand the number of opportunities to detect rare binding events. You can measure what you would otherwise not be able to quantify with a single, larger sensor with the same sensitivity.” This tool could help researchers determine the optimal conditions for the correct degree of glycosylation to occur, making it easier to consistently produce effective drugs.
Mapping production
The third property the researchers discovered is the ability to map the production of a molecule of interest. “One of the things you would like to do is find strains of particular organisms that produce the therapeutic that you want,” Strano says. “There are lots of ways of doing this, but none of them are easy.”
The MIT team found that by growing the cells on a surface coated with an array of nanometer-sized sensors, they could detect the location of the most productive cells. In this study, they looked for an antibody produced by engineered human embryonic kidney cells, but the system could also be tailored to other proteins and organisms.
Once the most productive cells are identified, scientists look for genes that distinguish those cells from the less productive ones and engineer a new strain that is highly productive, Strano says.
The researchers have built a briefcase-sized prototype of their sensor that they plan to test with Novartis, which funded the research along with the National Science Foundation.
“Carbon nanotubes coupled to protein-binding entities are interesting for several areas of bio-manufacturing as they offer great potential for online monitoring of product levels and quality. Our collaboration has shown that carbon nanotube-based fluorescent sensors are applicable for such purposes, and I am eager to follow the maturation of this technology,” says Ramon Wahl, an author of the paper and a principal scientist at Novartis.