#Using lasers to tailor the properties of graphene Carbon nanomaterials display extraordinary physical properties, outstanding among any other substance available,
and Graphene has grown as the most promising material for brand-new electronic circuitry, sensors and optical communications devices.
Graphene is a single atomic-thick sheet of honeycomb carbon lattice, with unique electronic and optical properties,
But two problems hinder graphene's uptake in real world electronics. There is no large-scale technology to control the properties,
and the traditional technology used for silicon-based processors (solid state) is not suitable for graphene processing (molecular material).
The researchers from Technological Center AIMEN explore the use of ultrafast lasers as tool for graphene processing.
used to tailor the properties of graphene films in finely defined areas, to produce distinct behaviors useful for producing devices.
For this timescale, researches demonstrated that they can pattern graphene lattice by cutting adding external molecules or binding compounds (functional groups like oxygen or hydroxyl.
direct writing of devices on graphene can be done with high precision, producing nanodevices with minimal footprint and maximum efficiency.
As recently published in AIP Applied Physics Letters("Patterned graphene ablation and two-photon functionalization by picosecond laser pulses in ambient conditions),
"the work of AIMEN researches demonstrated laser based large scale patterning of graphene at high speed and resolution, opening new possibilities for device making.
and atmosphere molecules, resulting in new optical properties in graphene. The potential of the altered optical properties (like spectral transmission) of functionalized graphene are just starting to be recognized,
and the full industrial potential of this technology needs to be tackled. This research work lays a foundation for deep understanding of the chemical and physical processes for industrially feasible graphene patterning,
as well as tests in real device application for future electronics. About AIMEN Located in Northwestern Spain
Applying voltage to a 250-nanometer-thick sandwich of graphene, tantalum, nanoporous tantalum oxide and platinum creates addressable bits where the layers meet.
A schematic shows the layered structure of tantalum oxide, multilayer graphene and platinum used for a new type of memory developed at Rice university.
"The layered structure consists of tantalum, nanoporous tantalum oxide and multilayer graphene between two platinum electrodes.
The voltage-controlled movement of oxygen vacancies shifts the boundary from the tantalum/tantalum oxide interface to the tantalum oxide/graphene interface."
The graphene does double duty as a barrier that keeps platinum from migrating into the tantalum oxide and causing a short circuit.
#Black phosphorus surges ahead of graphene A Korean team of scientists tune BP's band gap to form a superior conductor,
a layered form of carbon atoms constructed to resemble honeycomb, called graphene. Graphene was heralded globally as a wonder-material thanks to the work of two British scientists who won the Nobel prize for Physics for their research on it.
Graphene is extremely thin and has remarkable attributes. It is stronger than steel yet many times lighter
more conductive than copper and more flexible than rubber. All these properties combined make it a tremendous conductor of heat and electricity.
graphene has no band gap. Stepping stones to a Unique State A material's band gap is fundamental to determining its electrical conductivity.
Graphene has a band gap of zero in its natural state, however, and so acts like a conductor;
Like graphene, BP is a semiconductor and also cheap to mass produce. The one big difference between the two is BP's natural band gap
"Graphene is a Dirac semimetal. It's more efficient in its natural state than black phosphorus
therefore we tuned BP's band gap to resemble the natural state of graphene, a unique state of matter that is different from conventional semiconductors."
Mastering Materials Combining two-dimensional sheets of elements in an organized way to produce new materials has been the goal of Drexel nanomaterials researchers for more than a decade.
That order was imposed by Michel W. Barsoum, Phd and Yury Gogotsi, Phd, Distinguished University and Trustee Chair professor in the College of Engineering and head of the Drexel Nanomaterials Group
Prior to their discovery, graphene, which is a single sheet of carbon atoms, was the first two-dimensional material to be touted for its potential energy storage capabilities.
graphene was difficult to modify in form and therefore had limited energy storage capabilities. The new MXENES have surfaces that can store more energy.
#Pillared graphene gains strength Rice university researchers discovered that putting nanotube pillars between sheets of graphene could create hybrid structures with a unique balance of strength, toughness and ductility throughout all three dimensions.
Carbon nanomaterials are common now as flat sheets, nanotubes and spheres, and theye being eyed for use as building blocks in hybrid structures with unique properties for electronics,
particularly between carbon nanotubes and graphene, would affect the final hybrid properties in all directions. They found that introducing junctions would add extra flexibility
when compared with materials made of layered graphene. Their results appear this week in the journal Carbon("Junction configuration-induced mechanisms govern elastic and inelastic deformations in hybrid carbon nanomaterials".
"Carbon nanotubes are rolled-up arrays of perfect hexagons of atoms; graphene is a rolled out sheet of the same.
Both are super-strong and excel at transmitting electrons and heat. But when the two are joined,
the way the atoms are arranged can influence all those properties. ome labs are actively trying to make these materials or measure properties like the strength of single nanotubes and graphene sheets,
and quantitatively predict the properties of hybrid versions of graphene and nanotubes. These hybrid structures impart new properties
and functionality that are absent in their parent structures graphene and nanotubes. To that end the lab assembled three-dimensional computer models of illared graphene nanostructures, akin to the boron nitride structures modeled in a previous study to analyze heat transfer between layers. his time we were interested in a comprehensive understanding of the elastic and inelastic properties
of 3-D carbon materials to test their mechanical strength and deformation mechanisms, Shahsavari said. e compared our 3-D hybrid structures with the properties of 2-D stacked graphene sheets and 1-D carbon nanotubes.
Layered sheets of graphene keep their properties in-plane, but exhibit little stiffness or thermal conductance from sheet to sheet,
he said. But pillared graphene models showed far better strength and stiffness and a 42 percent improvement in out-of-plane ductility,
the ability to deform under stress without breaking. The latter allows pillared graphene to exhibit remarkable toughness along out-of-plane directions, a feature that is not possible in 2-D stacked graphene sheets or 1-D carbon nanotubes,
Shahsavari said. The researchers calculated how the atomsinherent energies force hexagons to take on or lose atoms to neighboring rings,
Turning the nanotubes in a way that forced wrinkles in the graphene sheets added further flexibility and shear compliance,
That leads to the notion the hybrids can be tuned to fail under particular circumstances. his is the first time anyone has created such a comprehensive atomistic ensto look at the junction-mediated properties of 3-D carbon nanomaterials
made of graphite with additional compounds bonded to the edges of two-dimensional sheets of graphene that make up the material.
#New graphene oxide biosensors may accelerate research of HIV and cancer drugs Longing to find a cure for cancer, HIV and other yet incurable diseases,
Researchers from the Laboratory of Nanooptics and Plasmonics, Moscow Institute of Physics and Technology-MIPT (Russia) have devised a novel type of graphene oxide (GO) based biosensor that could potentially significantly speed up the process of drug development.
& Interfaces("Highly sensitive and Selective Sensor Chips with Graphene oxide Linking Layer")."Valentyn Volkov is the co-lead author, a visiting professor from the University of Southern Denmark.
novel carbon materials like graphene have attracted much attention due to their large surface area, low-cost fabrication, and interaction with a wide range of biomolecules.
made of GO, a material with more attractive optical and chemical properties than pristine graphene. The GO"flakes"were deposited on the 35 nm gold layer.
the commercially available chip with carboxymethylated dextran (CMD) layer and the chip covered by monolayer graphene.
Experiments showed that the proposed GO chip has three times higher sensitivity than the CMD chip and 3. 7 times than the chip with pristine graphene.
#Ultrathin graphene oxide lens could revolutionise next-gen devices Researchers at Swinburne University of Technology, collaborating with Monash University,
have developed an ultrathin, flat, ultra-lightweight graphene oxide optical lens with unprecedented flexibility. The ultrathin lens enables potential applications in on-chip nanophotonics
The researchers produced a film that is 300 times thinner than a sheet of paper by converting graphene oxide film to reduced graphene oxide through a photoreduction process. hese flexible graphene oxide lenses are mechanically robust
he newly demonstrated laser nano-patterning method in graphene oxides holds the key to fast processing and programming of high capacity information for big data sectors.
which provided the graphene oxide film for this research said this work opens up a new high-tech application for graphene oxide
The research is published in Nature Communications("Highly efficient and ultra-broadband graphene oxide ultrathin lenses with three-dimensional subwavelength focusing)
and uses non-corrosive, nontoxic 2d nanomaterial suspension in liquid form, such as graphene oxide, as the pressure sensing element to recognise force-induced changes.
Now, researchers report in Biomacromolecules("Biodegradable ph-Sensitive Poly (ethylene glycol) Nanocarriers for Allergen Encapsulation and Controlled Release")the development of a potentially better allergy shot that uses nanocarriers to address these unwanted issues.
The researchers designed a new type of nanocarrier based on the biocompatible molecule poly (ethylene glycol or PEG, that releases its cargo only in targeted immune cells.
The nanocarrier degrades when it encounters the acidic part of these cells, simultaneously releasing the allergen
"Exploiting the softness of nanomaterials gives us additional and unprecedented control mechanisms which may be employed when designing microscopic machines,
#Big range of behaviors for tiny graphene pores The surface of a single cell contains hundreds of tiny pores,
Now researchers at MIT have created tiny pores in single sheets of graphene that have an array of preferences and characteristics similar to those of ion channels in living cells.
Each graphene pore is less than 2 nanometers wide, making them among the smallest pores through
preferring to transport certain ions over others through the graphene layer. hat we see is that there is a lot of diversity in the transport properties of these pores,
Karnik says graphene nanopores could be useful as sensors for instance, detecting ions of mercury, potassium, or fluoride in solution.
In the future, it may be possible to make graphene nanopores capable of sifting out trace amounts of gold ions from other metal ions, like silver and aluminum.
and Sean Oern from MIT and Juan-carlos Idrobo from Oak ridge National Laboratory, publish their results today in the journal Nature Nanotechnology("Heterogeneous sub-continuum ionic transport in statistically isolated graphene nanopores").
Karnik reasoned that graphene would be a suitable material in which to create artificial ion channels:
A sheet of graphene is an ultrathin lattice of carbon atoms that is one atom thick, so pores in graphene are defined at the atomic scale.
To create pores in graphene, the group used chemical vapor deposition, a process typically used to produce thin films.
In graphene, the process naturally creates tiny defects. The researchers used the process to generate nanometer-sized pores in various sheets of graphene,
which bore a resemblance to ultrathin Swiss cheese. The researchers then isolated individual pores by placing each graphene sheet over a layer of silicon nitride that had been punctured by an ion beam
the diameter of which is slightly smaller than the spacing between graphene pores. The group reasoned that any ions flowing through the two-layer setup would have passed likely first through a single graphene pore,
and then through the larger silicon nitride hole. The group measured flows of five different salt ions through several graphene sheet setups by applying a voltage and measuring the current flowing through the pores.
The current-voltage measurements varied widely from pore to pore, and from ion to ion, with some pores remaining stable,
while others swung back and forth in conductance an indication that the pores were diverse in their preferences for allowing certain ions through. he picture that emerges is that each pore is different
and that the pores are dynamic, Karnik says. ach pore starts developing its own personality.
which given the single-atom thickness of graphene makes them among the smallest pores through
Meni Wanunu, an assistant professor of physics at Northeastern University, says the group work with graphene membranes may significantly improve on commercial membranes used for water purification,
which require large amounts of pressure to push water through. f these were replaced with graphene,
it is only through a fundamental understanding of ion transport that the overall anticipated behaviors of bulk graphene membranes can be drawn.
and will surely guide current and future graphene membrane design principles in years to come. e
next-generation health monitoring devices such as electronic stick-on tattoos (see for instance"wearing single-walled carbon nanotube electronics on your skin",a"temporary tattoo to monitor glucose levels"or"graphene nanosensor tattoo
#Graphene-coated'e textile'detects noxious gases Scientists in Korea have developed wearable, graphene-coated fabrics that can detect dangerous gases present in the air,
alerting the wearer by turning on an LED light("Ultrasensitive and Highly Selective Graphene-Based Single Yarn for Use in Wearable Gas Sensor").
"The researchers, from the Electronics and Telecommunications Research Institute and Konkuk University in the Republic of korea, coated cotton and polyester yarn with a nanoglue called bovine serum albumin (BSA.
The yarns were wrapped then in graphene oxide sheets. Graphene is an incredibly strong one-atom-thick layer of carbon,
and is known for its excellent conductive properties of heat and electricity. The graphene sheets stuck very well to the nanoglueo much
so that further testing showed the fabrics retained their electrical conducting properties after 1, 000 consecutive cycles of bending
Finally, the graphene oxide yarns were exposed to a chemical reduction process, which involves the gaining of electrons.
The reduced-graphene oxide-coated materials were found to be particularly sensitive to detecting nitrogen dioxide a pollutant gas commonly found in vehicle exhaust that also results from fossil fuel combustion.
Exposure of these specially-treated fabrics to nitrogen dioxide led to a change in the electrical resistance of the reduced graphene oxide.
The fabrics were three times as sensitive to nitrogen dioxide in air compared to another reduced graphene oxide sensor previously prepared on a flat material.
#Researchers grow nanocircuitry with semiconducting graphene nanoribbons In a development that could revolutionize electronic ciruitry, a research team from the University of Wisconsin at Madison (UW)
and the U s. Department of energy's Argonne National Laboratory has confirmed a new way to control the growth paths of graphene nanoribbons on the surface of a germainum crystal (Nature Communications,"Direct oriented growth of armchair graphene nanoribbons on germanium").
and this method provides a straightforward way to make semiconducting nanoscale circuits from graphene, a form of carbon only one atom thick.
"UW researchers used chemical vapor deposition to grow graphene nanoribbons on germanium crystals. This technique flows a mixture of methane, hydrogen and argon gases into a tube furnace.
At high temperatures, methane decomposes into carbon atoms that settle onto the germanium's surface to form a uniform graphene sheet.
when graphene grows on germanium, it naturally forms nanoribbons with these very smooth, armchair edges,"said Michael Arnold, an associate professor of materials science and engineering at UW-Madison."
so all the desirable features we want in graphene nanoribbons are happening automatically with this technique.""Graphene, a one-atom-thick, two-dimensional sheet of carbon atoms, is known for moving electrons at lightning speed across its surface without interference.
This high mobility makes the material an ideal candidate for faster, more energy-efficient electronics. However, the semiconductor industry wants to make circuits start
As a semimetal, graphene naturally has no band-gaps, making it a challenge for widespread industry adoption.
researchers confirmed the presence of graphene nanoribbons growing on the germanium. Data gathered from the electron signatures allowed the researchers to create images of the material's dimensions and orientation.
graphene and it shows some characteristic electronic properties, "said Kiraly.""What's even more interesting is that these nanoribbons can be made to grow in certain directions on one side of the germanium crystal,
0). Previous research shows that graphene sheets can grow on germanium crystal faces (1, 1, 1) and (1, 1,
0). However, this is the first time any study has recorded the growth of graphene nanoribbons on the (1,
researchers can now focus their efforts on exactly why self-directed graphene nanoribbons grow on the (1, 0,
and graphene that may play a role e
#Experimental treatment regimen effective against HIV PROTEASE inhibitors are a class of antiviral drugs that are used commonly to treat HIV, the virus that causes AIDS.
#Ultrasensitive sensors made from boron-doped graphene Ultrasensitive gas sensors based on the infusion of boron atoms into graphene--a tightly bound matrix of carbon atoms--may soon be possible, according to an international team of researchers
Graphene is known for its remarkable strength and ability to transport electrons at high speed, but it is also a highly sensitive gas sensor.
With the addition of boron atoms, the boron graphene sensors were able to detect noxious gas molecules at extremely low concentrations, parts per billion in the case of nitrogen oxides and parts per million for ammonia
and 10,000 times greater sensitivity to ammonia compared to pristine graphene. The researchers believe these results,
reported today in the Proceedings of the National Academy of Sciences("Ultrasensitive gas detection of large-area boron-doped graphene),
"We were previously able to dope graphene with atoms of nitrogen, but boron proved to be much more difficult.
Once we were able to synthesize what we believed to be boron graphene, we collaborated with experts in the United states
The result was large-area, high-quality boron-doped graphene sheets. Once fabricated, the researchers sent boron graphene samples to researchers at the Honda Research Institute USA Inc.,Columbus, Ohio, who tested the samples against their own highly sensitive gas sensors.
Konstantin Novoselov's lab at the University of Manchester UK, studied the transport mechanism of the sensors.
confirmed the presence of the boron atoms in the graphene lattice and their effect when interacting with ammonia or nitrogen oxide molecules.
chief scientist and project leader at Honda Research Institute USA Inc."Our approach combines novel nanomaterials with continuous ultraviolet light radiation in the sensor design that have been developed in our laboratory by lead researcher Dr
theoretical work indicates that boron-doped graphene could lead to improved lithium-ion batteries and field-effect transistors, the authors report t
#Novel'crumpling'of hybrid nanostructures increases SERS sensitivity By"crumpling"to increase the surface area of graphene-gold nanostructures,
an assistant professor of mechanical science and engineering at Illinois."This mechanical self-assembly strategy will enable a new class of 3d crumpled graphene-gold (Au) nanostructures.
"This work demonstrates the unique capability of micro-to-nanoscale topographies of the crumpled graphene-Au nanoparticles--higher density,
""We achieve a 3d crumpled graphene-Au hybrid structure by the delamination and buckling of graphene on a thermally activated, shrinking polymer substrate.
This process enables precise control and optimization of the size and spacing of integrated Au nanoparticles on crumpled graphene for higher SERS enhancement."
"According to Nam, the 3d crumpled graphene-Au nanostructure exhibits at least one order of magnitude higher SERS detection sensitivity than that of conventional, flat graphene-Au nanoparticles.
The hybrid structure is adapted further to arbitrary curvilinear structures for advanced, in situ, nonconventional, nanoplasmonic sensing applications."
An earlier study by Nam's research group was the first to demonstrate graphene integration onto a variety of different microstructured geometries,
and the 3d integration of gold nanoparticle/graphene hybrid structures r
#Facebook M Is trained and Monitored by Humans, Facebook Reveals Facebook has entered the virtual digital assistant space with a new service for its millions of Messenger users,
The Stanford team ended up using our old friend graphene to play the cathode to aluminum's anode.
#Researchers grow nanocircuitry with semiconducting graphene nanoribbons In a development that could revolutionize electronic circuitry, a research team from the Univ. of Wisconsin at Madison (UW)
and the U s. Dept of energy (DOE)' s Argonne National Laboratory has confirmed a new way to control the growth paths of graphene nanoribbons on the surface of a germainum crystal.
and this method provides a straightforward way to make semiconducting nanoscale circuits from graphene, a form of carbon only one atom thick.
"UW researchers used chemical vapor deposition to grow graphene nanoribbons on germanium crystals. This technique flows a mixture of methane, hydrogen,
At high temperatures, methane decomposes into carbon atoms that settle onto the germanium's surface to form a uniform graphene sheet.
when graphene grows on germanium, it naturally forms nanoribbons with these very smooth, armchair edges,"said Michael Arnold, an associate professor of materials science and engineering at UW-Madison."
so all the desirable features we want in graphene nanoribbons are happening automatically with this technique.""Graphene, a one-atom-thick, 2-D sheet of carbon atoms, is known for moving electrons at lightning speed across its surface without interference.
This high mobility makes the material an ideal candidate for faster, more energy-efficient electronics. However, the semiconductor industry wants to make circuits start
As a semimetal, graphene naturally has no band-gaps, making it a challenge for widespread industry adoption.
researchers confirmed the presence of graphene nanoribbons growing on the germanium. Data gathered from the electron signatures allowed the researchers to create images of the material's dimensions and orientation.
graphene and it shows some characteristic electronic properties, "said Kiraly.""What's even more interesting is that these nanoribbons can be made to grow in certain directions on one side of the germanium crystal,
0). Previous research shows that graphene sheets can grow on germanium crystal faces (1, 1, 1) and (1, 1,
0). However, this is the first time any study has recorded the growth of graphene nanoribbons on the (1,
researchers can now focus their efforts on exactly why self-directed graphene nanoribbons grow on the (1, 0,
and graphene that may play a role. This research is detailed in a paper published in Nature Communications s
Usually, the thin filmssed by organic bulk heterojunction solar cellsre created by mixing conjugated polymers and fullerenes,
which the lab describes as occer ball-like carbon molecules known as buckyballs. After uniformity is achieved by spin casting the mixture on a rotating substrate
which aided in dissolving fullerenes and made the film structure more uniform. Lack of uniformity in a film mixture causes clusters to form,
#Cobalt atoms on graphene a powerful combo Graphene doped with nitrogen and augmented with cobalt atoms has proven to be an effective, durable catalyst for the production of hydrogen from water, according to scientists at Rice Univ. The Rice lab of chemist James Tour and colleagues at the Chinese Academy of Sciences,
The researchers discovered that heat-treating graphene oxide and small amounts of cobalt salts in a gaseous environment forced individual cobalt atoms to bind to the material.
They tested nitrogen-doped graphene on its own and found it lacked the ability to kick the catalytic process into gear.
Atom-thick graphene is the ideal substrate, Tour said, because of its high surface area, stability in harsh operating conditions and high conductivity.
#Nanoquakes probe new 2-D material In a step towards a post-graphene era of new materials for electronic applications,
'fluffy'carbon electrode made from graphene (comprising one-atom-thick sheets of carbon atoms), and additives that alter the chemical reactions at work in the battery,
changing it to a highly porous form of graphene, adding lithium iodide, and changing the chemical makeup of the electrolyte,
%The highly porous graphene electrode also greatly increases the capacity of the demonstrator, although only at certain rates of charge and discharge.
and smartphones, was reached by using a'fluffy'carbon electrode made from graphene. What's more, by changing the chemical mix from earlier versions of lithium-air batteries,
with many graphene edges that proved to be crucial to catalysis."This is a low-cost, one-step, scalable process,
#Graphene pushes the speed limit of light-to-electricity conversion ICFO researchers Klaas-Jan Tielrooij, Lukasz Piatkowski,
have demonstrated now that a graphene-based photodetector converts absorbed light into an electrical voltage at an extremely high speed.
The study, entitled"Generation of photovoltage in graphene on a femtosecond timescale through efficient carrier heating"
As Klaas-Jan Tielrooij comments,"the experiment uniquely combined the ultrafast pulse shaping expertise obtained from single molecule ultrafast photonics with the expertise in graphene electronics.
Facilitated by graphene's nonlinear photo-thermoelectric response, these elements enabled the observation of femtosecond photodetection response times."
"The ultrafast creation of a photovoltage in graphene is possible due to the extremely fast and efficient interaction between all conduction band carriers in graphene.
Next, the electron heat is converted into a voltage at the interface of two graphene regions with different doping.
"it is amazing how graphene allows direct nonlinear detecting of ultrafast femtosecond (fs) pulses.""The results obtained from the findings of this work,
which has been funded partially by the EC Graphene Flagship, open a new pathway towards ultra-fast optoelectronic conversion.
Koppens comments,"Graphene photodetectors keep showing fascinating performances addressing a wide range of applications
#Protein finding can pave way for improved treatment of malignant melanoma New research now demonstrates that the presence of the protein megalin in a malignant melanoma is an indicator of cancer cells that are particularly aggressive.
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