if the nanoparticles provide Trojan horse piggyback rides to other harmful molecules. The results appear online in the journal Environmental science:
The nanoparticle-pollutant package could then be eaten by sediment-dwelling organisms in a sort of'Trojan horse'effect allowing the adsorbed contaminants to accumulate up the food chain.
and packing at electrode surfaces the team combined knowledge about graphene and organic crystals. Though it was difficult Briseno says they managed to get the necessary compounds to stack like coins.
We had exploited essentially every substrate possible until we finally succeeded with graphene he adds which happened by accident
and transport electrical charges generated from solar energy. Earlier this year, Dr. David Barbero and his research team at Umeå University,
Oleshko points out that the young rapidly emerging field of additive manufacturing which creates devices by building up component materials layer by layer often needs to analyze its creations in a noninvasive way.
#How to make a perfect solar absorber The key to creating a material that would be ideal for converting solar energy to heat is tuning the material's spectrum of absorption just right:
When harnessing solar energy you want to trap it and keep it there Chou says; getting just the right spectrum of both absorption and emission is essential to efficient STPV performance.
Most of the sun's energy reaches us within a specific band of wavelengths Chou explains ranging from the ultraviolet through visible light and into the near-infrared.
which would add greatly to the complexity and expense of a solar power system. This is the first device that is able to do all these things at the same time Chou says.
and materials science to advance solar energy harvesting says Paul Braun a professor of materials science and engineering at the University of Illinois at Urbana-Champaign who was involved not in this research.
#New research points to graphene as a flexible low-cost touchscreen solution New research published today in the journal Advanced Functional Materials suggests that graphene-treated nanowires could soon replace current touchscreen technology
Researchers from the University of Surrey and AMBER the materials science centre based at Trinity college Dublin have demonstrated now how graphene-treated nanowires can be used to produce flexible touchscreens at a fraction of the current cost.
Using a simple scalable and inexpensive method the researchers produced hybrid electrodes the building blocks of touchscreen technology from silver nanowires and graphene.
Dr Alan Dalton from the University of Surrey said The growing market in devices such as wearable technology
We achieved this using graphene a material that can conduct electricity and interpret touch commands
Novel applications of'quantum dots'including lasers biological markers qubits for quantum computing and photovoltaic devices arise from the unique optoelectronic properties of the QDS
Resonant energy transfer from quantum dots to graphene More information: Edes Saputra Jun Ohta Naoki Kakuda and Koichi Yamaguchi Self-Formation of In-Plane Ultrahigh-Density Inas Quantum dots on Gaassb/Gaas (001) Appl.
and nuclear fuels and for storing nuclear waste generating a great deal of scientific interest on the structure properties and applications of these blended materials.
Composites have also been created to store the by-products of the nuclear energy cycle nuclear waste where the different components of the composite can each store a different part of the waste.
Gallium nitride micro-rods grown on graphene substrates Bendy light-emitting diode (LED) displays and solar cells crafted with inorganic compound semiconductor micro-rods are moving one step closer to reality thanks to graphene and the work of a team of researchers in Korea.
Currently most flexible electronics and optoelectronics devices are fabricated using organic materials. But inorganic compound semiconductors such as gallium nitride (Gan) can provide plenty of advantages over organic materials for use in these devices#including superior optical electrical and mechanical properties.
on graphene to create transferrable LEDS and enable the fabrication of bendable and stretchable devices.
When combined with graphene substrates these microstructures also show excellent tolerance for mechanical deformation. Why choose graphene for substrates?
Ultrathin graphene films consist of weakly bonded layers of hexagonally arranged carbon atoms held together by strong covalent bonds.
This makes graphene an ideal substrate because it provides the desired flexibility with excellent mechanical strength
#and it's also chemically and physically stable at temperatures in excess of 1000#C said Yi.
It's important to note that for the Gan micro-rod growth the very stable and inactive surface of graphene offers a small number of nucleation sites for Gan growth
which would enhance three-dimensional island growth of Gan micro-rods on graphene. To create the actual Gan microstructure LEDS on the graphene substrates the team uses a catalyst-free metal-organic chemical vapor deposition (MOCVD) process they developed back in 2002.
Among the technique's key criteria it's necessary to maintain high crystallinity control over doping formation of heterostructures
and reliability of Gan micro-rod LEDS fabricated on graphene to the test they found that the resulting flexible LEDS showed intense electroluminescence (EL)
By taking advantage of larger-sized graphene films hybrid heterostructures can be used to fabricate various electronics
Scientists grow a new challenger to graphene More information: Growth and characterizations of Gan micro-rods on graphene films for flexible light-emitting diodes by Kunook Chung Hyeonjun Beak Youngbin Tchoe Hongseok Oh Hyobin Yoo Miyoung Kim and Gyu
-Chul Yi APL Materials September 23 2014: scitation. aip. org/content/aip/#/9/10.1063/1. 489478 1
#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.
Their optical biosensor for single unlabelled molecules could also be a breakthrough in the development of biochips:
and Biosensors at the Max Planck Institute for the Science of Light has succeeded now in amplifying the interaction of light with DNA molecules to the extent that their photonic biosensor can be used to observe single unlabelled molecules and their interactions.
"The researchers have tested their optical biosensor with a sample containing both an exactly matching DNA fragment
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.
The biosensor has been shown to be more than five times more sensitive than bioassay tests currently in use and was able to provide results in a matter of minutes opening up the possibility of a rapid point-of-care diagnostic tool for patients.
The biosensor has been presented today 19 september in IOP Publishing's journal 2d Materials. 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.
These receptors were able to bind to or target a specific molecule present in blood saliva or urine.
The molecule 8-hydroxydeoxyguanosine (8-OHDG) is produced when DNA is damaged and in elevated levels has been linked to an increased risk of developing several cancers.
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
and then exposed the biosensor to a range of concentrations of 8-OHDG. When 8-OHDG attached to the bioreceptor molecules on the sensor there was a notable difference in the graphene channel resistance
which the researchers were able to record. Results showed that the graphene sensor was capable of detecting 8-OHDG concentrations as low as 0. 1 ng ml-1
which is almost five times more sensitive compared with ELISAS. The graphene biosensor was also considerably faster at detecting the target molecules completing the analysis in a matter of minutes.
Moving forward the researchers highlight the potential of the biosensor to diagnose and monitor a whole range of diseases as it is quite simple to substitute the specific receptor molecules on the graphene surface.
Co-author of the study Dr Owen Guy said: Graphene has superb electronic transport properties and has an intrinsically high surface-to-volume ratio
which make it an ideal material for fabricating biosensors. 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.
Explore further: 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.
Patient noncompliance with doctor-recommended glucose testing frequency can be a problem. By making lancets more affordable and potentially noninvasive we are addressing a critical global need he said.
More frequent tests could lead to better control of the disease which could lead to an associated reduction in health risks.
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 if they kept working like new year after year? Johnson said the company will refine its production
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
and supercapacitor applications he said. Explore further: 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 new work by Rice chemist James Tour and his colleagues could keep glass surfaces from windshields to skyscrapers free of ice
and fog while retaining their transparency to radio frequencies (RF). The technology was introduced this month in the American Chemical Society journal Applied materials and Interfaces.
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.
It is expected highly that the N-ACNT/G sandwiches hold various potential applications in the area of nanocomposite energy storage environmental protection electronic device as well as healthcare because of their robust hierarchical structure 3d electron transfer
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.
Other potential military applications include electronics for remote sensors, unmanned aerial vehicles and high-capacity computing in remote operations.
#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 Biochemistry and Molecular biology at Penn State. In a paper first published online on Sept. 9 in the journal Nature Chemistry, Mallouk and colleagues at Penn State and the Research center for Exotic Nanocarbons at Shinshu University, Japan, describe a method called intercalation,
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
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