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Modified 'white graphene' for eco-friendly energy

Posted By Graphene Council, The Graphene Council, Wednesday, April 24, 2019
Updated: Tuesday, April 23, 2019
Scientists from TPU, Germany, and the United States have found a new way to functionalize a dielectric, otherwise known as 'white graphene', i.e. hexagonal boron nitride (hBN), without destroying it or changing its properties. Thanks to the new method, the researchers synthesized a 'polymer nano carpet' with strong covalent bond on the samples.

Prof Raul Rodriguez from the TPU Research School of Chemistry & Applied Biomedical Sciences explains:

'For the first time, we have managed to covalently functionalize hexagonal boron nitride without strong chemical compositions and the introduction of new defects into the material. In fact, earlier approaches had resulted in a different material with altered properties, i.e. hydrolyzed boron nitride. In our turn, we used nanodefects existing in the material without increasing their number, and eco-friendly photopolymerization.'

One of the promising options for using the new material, according to researchers, is catalysts for splitting water in hydrogen and oxygen. With this in view, 'polymer carpets' functioned as carriers of active substances, i.e. matrices. Nickel nanoparticles were integrated into the matrix. Catalysts obtained were used for electrocatalysis. Studies showed that they could be successfully used as an alternative to expensive platinum or gold.

'One of the important challenges in catalysis is forcing the starting material to reach active centers of the catalyst. 'Polymer carpets' form a 3D structure that helps to increase the area of contact of the active centers of the catalyst with water and makes hydrogen acquisition more efficient. It is very promising for the production of environmentally friendly hydrogen fuel,' - says the scientist.

Boron nitride is a binary compound of boron and nitrogen. While, hexagonal boron nitride or 'white graphene' is a white talc-like powder with hexagonal, graphene-like lattice. It is resistant to high temperatures and chemical substances, nontoxic, has a very low coefficient of friction, and functions both as a perfect dielectric and as a good heat conductor. Boron-nitride materials are widely used in the reactions of industrial organic synthesis, in the cracking of oil, for the manufacturing of products of high-temperature technology, the production of semiconductors, means for extinguishing fires, and so on.

Previously, a number of studies were devoted to functionalization of hexagonal boron nitride. Typically, this process uses strong chemical oxidants that not only destroy the material but also significantly change its properties. The method, which TPU scientists and their foreign colleagues use, allows them to avoid this.

'Studies have shown that we obtained homogenous and durable 'polymer carpets' which can be removed from the supporting substrate and used separately. What is more, this is a fairly universal technology since for functionalization we used different monomers which allow obtaining materials with properties optimal for use in various devices,' - says Prof Raul Rodriguez.

Tags:  2D materials  Graphene  Hexagonal Boron Nitride  Raul Rodriguez  TPU Germany 

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Building a Printing Press for New Quantum Materials

Posted By Graphene Council, The Graphene Council, Wednesday, April 24, 2019
Updated: Tuesday, April 23, 2019
Checking out a stack of books from the library is as simple as searching the library’s catalog and using unique call numbers to pull each book from their shelf locations. Using a similar principle, scientists at the Center for Functional Nanomaterials (CFN)—a U.S. Department of Energy (DOE) Office of Science User Facility at Brookhaven National Laboratory—are teaming with Harvard University and the Massachusetts Institute of Technology (MIT) to create a first-of-its-kind automated system to catalog atomically thin two-dimensional (2-D) materials and stack them into layered structures. Called the Quantum Material Press, or QPress, this system will accelerate the discovery of next-generation materials for the emerging field of quantum information science (QIS).

Structures obtained by stacking single atomic layers (“flakes”) peeled from different parent bulk crystals are of interest because of the exotic electronic, magnetic, and optical properties that emerge at such small (quantum) size scales. However, flake exfoliation is currently a manual process that yields a variety of flake sizes, shapes, orientations, and number of layers. Scientists use optical microscopes at high magnification to manually hunt through thousands of flakes to find the desired ones, and this search can sometimes take days or even a week, and is prone to human error.

Once high-quality 2-D flakes from different crystals have been located and their properties characterized, they can be assembled in the desired order to create the layered structures. Stacking is very time-intensive, often taking longer than a month to assemble a single layered structure. To determine whether the generated structures are optimal for QIS applications—ranging from computing and encryption to sensing and communications—scientists then need to characterize the structures’ properties.

“In talking to our university collaborators at Harvard and MIT who synthesize and study these layered heterostructures, we learned that while bits of automation exist—such as software to locate the flakes and joysticks to manipulate the flakes—there is no fully automated solution,” said CFN Director Charles Black, the administrative lead on the QPress project.

The idea for the QPress was conceived in early 2018 by Professor Amir Yacoby of the Department of Physics at Harvard. The concept was then refined through a collaboration between Yacoby; Black and Kevin Yager, leader of the CFN Electronic Nanomaterials Group; Philip Kim, also of Harvard’s Department of Physics; and Pablo Jarillo-Herrero and Joseph Checkelsky, both of the Department of Physics at MIT. 

According to Black, the unique CFN role was clear: “We realized that building a robot that can enable the design, synthesis, and testing of quantum materials is extremely well-matched to the skills and expertise of scientists at the CFN. As a user facility, CFN is meant to be a resource for the scientific community, and QIS is one of our growth areas for which we’re expanding our capabilities, scientific programs, and staff.”

Graphene sparks 2-D materials research
The interest in 2-D materials dates back to 2004, when scientists at the University of Manchester isolated the world’s first 2-D material, graphene—a single layer of carbon atoms. They used a surprisingly basic technique in which they placed a piece of graphite (the core material of pencils) on Scotch tape, repeatedly folding the tape in half and peeling it apart to extract ever-thinner flakes. Then, they rubbed the tape on a flat surface to transfer the flakes. Under an optical microscope, the one-atom-thick flakes can be located by their reflectivity, appearing as very faint spots. Recognized with a Nobel Prize in 2010, the discovery of graphene and its unusual properties—including its remarkable mechanical strength and electrical and thermal conductivity—has prompted scientists to explore other 2-D materials.

Many labs continue to use this laborious approach to make and find 2-D flakes. While the approach has enabled scientists to perform various measurements on graphene, hundreds of other crystals—including magnets, superconductors, and semiconductors—can be exfoliated in the same way as graphite. Moreover, different 2-D flakes can be stacked to build materials that have never existed before. Scientists have very recently discovered that the properties of these stacked structures depend not only on the order of the layers but also on the relative angle between the atoms in the layers. For example, a material can be tuned from a metallic to an insulating state simply by controlling this angle. Given the wide variety of samples that scientists would like to explore and the error-prone and time-consuming nature of manual synthesis methods, automated approaches are greatly needed.

“Ultimately, we would like to develop a robot that delivers a stacked structure based on the 2-D flake sequences and crystal orientations that scientists select through a web interface to the machine,” said Black. “If successful, the QPress would enable scientists to spend their time and energy studying materials, rather than making them.”

A modular approach
In September 2018, further development of the QPress was awarded funding by the DOE, with a two-part approach. One award was for QPress hardware development at Brookhaven, led by Black; Yager; CFN scientists Gregory Doerk, Aaron Stein, and Jerzy Sadowski; and CFN scientific associate Young Jae Shin. The other award was for a coordinated research project led by Yacoby, Kim, Jarillo-Herrero, and Checkelsky. The Harvard and MIT physicists will use the QPress to study exotic forms of superconductivity—the ability of certain materials to conduct electricity without energy loss at very low temperatures—that exist at the interface between a superconductor and magnet. Some scientists believe that such exotic states of matter are key to advancing quantum computing, which is expected to surpass the capabilities of even today’s most powerful supercomputing.

 A fully integrated automated machine consisting of an exfoliator, a cataloger, a library, a stacker, and a characterizer is expected in three years. However, these modules will come online in stages to enable the use of QPress early on.   

The team has already made some progress. They built a prototype exfoliator that mimics the action of a human peeling flakes from a graphite crystal. The exfoliator presses a polymer stamp into a bulk parent crystal and transfers the exfoliated flakes by pressing them onto a substrate. In their first set of experiments, the team investigated how changing various parameters—stamping pressure, pressing time, number of repeated presses, angle of pressing, and lateral force applied during transfer—impact the process.

“One of the advantages of using a robot is that, unlike a human, it reproduces the same motions every time, and we can optimize these motions to generate lots of very thin large flakes,” explained Yager. “Thus, the exfoliator will improve both the quality and quantity of 2-D flakes peeled from parent crystals by refining the speed, precision, and repeatability of the process.”

In collaboration with Stony Brook University assistant professor Minh Hoai Nguyen of the Department of Computer Science and PhD student Boyu Wang of the Computer Vision Lab, the scientists are also building a flake cataloger. Through image-analysis software, the cataloger scans a substrate and records the locations of exfoliated flakes and their properties.

“The flakes that scientists are interested in are thin and thus faint, so manual visual inspection is a laborious and error-prone process,” said Nguyen. “We are using state-of-the-art computer vision and deep learning techniques to develop software that can automate this process with higher accuracy.”

“Our collaborators have said that a system capable of mapping their sample of flakes and showing them where the “good” flakes are located—as determined by parameters they define—would be immensely helpful for them,” said Yager. “We now have this capability and would like to put it to use.”

Eventually, the team plans to store a large set of different catalogued flakes on shelves, similar to books in a library. Scientists could then access this materials library to select the flakes they want to use, and the QPress would retrieve them.

According to Black, the biggest challenge will be the construction of the stacker—the module that retrieves samples from the library, “drives” to the locations where the selected flakes reside, and picks the flakes up and places them in a repetitive process to build stacks according to the assembly instructions that scientists program into the machine. Ultimately, the scientists would like the stacker to assemble the layered structures not only faster but also more accurately than manual methods.

The final module of the robot will be a material characterizer, which will provide real-time feedback throughout the entire synthesis process. For example, the characterizer will identify the crystal structure and orientation of exfoliated flakes and layered structures through low-energy electron diffraction (LEED)—a technique in which a beam of low-energy electrons is directed toward the surface of a sample to produce a diffraction pattern characteristic of the surface geometry.

“There are many steps to delivering a fully automated solution,” said Black. “We intend to implement QPress capabilities as they become available to maximize benefit to the QIS community.”

Tags:  2D materials  Amir Yacoby  Center for Functional Nanomaterials  Charles Black  Graphene  Kevin Yager 

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From 2D to 1D: Atomically quasi '1D' wires using a carbon nanotube template

Posted By Graphene Council, The Graphene Council, Wednesday, April 24, 2019
Updated: Tuesday, April 23, 2019
Researchers from Tokyo Metropolitan University have used carbon nanotube templates to produce nanowires of transition metal monochalcogenide (TMM), which are only 3 atoms wide in diameter. These are 50 times longer than previous attempts and can be studied in isolation, preserving the properties of atomically quasi "1D" objects. The team saw that single wires twist when perturbed, suggesting that isolated nanowires have unique mechanical properties which might be applied to switching in nanoelectronics.

Two-dimensional materials have gone from theoretical curiosity to real-life application in the span of less than two decades; the most well-known example of these, graphene, consists of well-ordered sheets of carbon atoms. Though we are far from leveraging the full potential of graphene, its remarkable electrical and thermal conductivity, optical properties and mechanical resilience have already led to a wide range of industrial applications. Examples include energy storage solutions, biosensing, and even substrates for artificial tissue.

Yet, despite the successful transition from 3D to 2D, the barrier separating 2D and 1D has been significantly more challenging to overcome. A class of materials known as transition metal monochalcogenides (TMMs, transition metal + group 16 element) have received particular interest as a potential nanowire in precision nanoelectronics. Theoretical studies have existed for over 30 years, and preliminary experimental studies have also succeeded in making small quantities of nanowire, but these were usually bundled, too short, mixed with bulk material or simply low yield, particularly when precision techniques were involved e.g. lithography. The bundling was particularly problematic; forces known as van der Waals forces would force the wires to aggregate, effectively masking all the unique properties of 1D wires that one might want to access and apply.

Now, a team led by Assistant Professor Yusuke Nakanishi from Tokyo Metropolitan University has succeeded in producing bulk quantities of well-isolated single nanowires of TMM. They used tiny, open-ended rolls of single-layered carbon, or carbon nanotubes (CNTs), to template the assembly and reaction of molybdenum and tellurium into wires from a vapor. They succeeded in producing single isolated wires of TMM, which were only 3-atoms thick and fifty times longer than those made using existing methods. These nanometer-sized CNT "test tubes" were also shown to be not chemically bound to the wires, effectively preserving the properties expected from isolated TMM wires. Importantly, they effectively "protected" the wires from each other, allowing for unprecedented access to how these 1D objects behave in isolation.

While imaging these objects using transmission electron microscopy (TEM), the team found that these wires exhibited a unique twisting effect when exposed to an electron beam. Such behavior has never been seen before and is expected to be unique to isolated wires. The transition from a straight to twisted structure may offer a novel switching mechanism when the material is incorporated into microscopic circuits. The team hope the ability to make well-isolated 1D nanowires might significantly expand our understanding of the properties and mechanisms behind the function of 1D materials.

Tags:  2D materials  Carbon Nanotubes  Graphene  nanoelectronics  Tokyo Metropolitan University  Yusuke Nakanishi 

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Graphene gives a tremendous boost to future terahertz cameras

Posted By Graphene Council, The Graphene Council, Tuesday, April 23, 2019
Updated: Saturday, April 20, 2019
Scientists have developed a novel graphene-enabled photodetector that operates at room temperature, is highly sensitive, very fast, has a wide dynamic range and covers a broad range of THz frequencies.

Detecting terahertz (THz) light is extremely useful for two main reasons:

First, THz technology is becoming a key element in applications regarding security (such as airport scanners), wireless data communication, and quality control, to mention just a few. However, current THz detectors have shown strong limitations in terms of simultaneously meeting the requirements for sensitivity, speed, spectral range, being able to operate at room temperature, etc.

Second, it is a very safe type of radiation due to its low-energy photons, with more than a hundred times less energy than that of photons in the visible light range.

Many graphene-based applications are expected to emerge from its use as material for detecting light. Graphene has the particularity of not having a bandgap, as compared to standard materials used for photodetection, such as silicon. The bandgap in silicon causes incident light with wavelengths longer than one micron to not be absorbed and thus not detected. In contrast, for graphene, even terahertz light with a wavelength of hundreds of microns can be absorbed and detected. Whereas THz detectors based on graphene have shown promising results so far, none of the detectors so far could beat commercially available detectors in terms of speed and sensitivity.

In a recent study, ICFO researchers Sebastian Castilla and Dr. Bernat Terres, led by ICREA Prof. at ICFO Frank Koppens and former ICFO scientist Dr. Klaas-Jan Tielrooij (now Junior Group Leader at ICN2), in collaboration with scientists from CIC NanoGUNE, NEST (CNR), Nanjing University, Donostia International Physics Center, University of Ioannina and the National Institute for Material Sciences, have been able to overcome these challenges. They have developed a novel graphene-enabled photodetector that operates at room temperature, and is highly sensitive, very fast, has a wide dynamic range and covers a broad range of THz frequencies.

In their experiment, the scientists were able to optimize the photoresponse mechanism of a THz photodetector using the following approach. They integrated a dipole antenna into the detector to concentrate the incident THz light around the antenna gap region. By fabricating a very small (100 nm, about one thousand times smaller than the thickness of a hair) antenna gap, they were able to obtain a great intensity concentration of THz incident light in the photoactive region of the graphene channel. They observed that the light absorbed by the graphene creates hot carriers at a pn-junction in graphene; subsequently, the unequal Seebeck coefficients in the p- and n-regions produce a local voltage and a current through the device generating a very large photoresponse and, thus, leading to a very high sensitivity, high speed response detector, with a wide dynamic range and a broad spectral coverage.

The results of this study open a pathway towards the development a fully digital low-cost camera system. This could be as cheap as the camera inside the smartphone, since such a detector has proven to have a very low power consumption and is fully compatible with CMOS technology.

Tags:  Bernat Terres  CIC NanoGUNE  Donostia International Physics Center  Frank Koppens  Graphene  ICERA  ICFO  Klaas-Jan Tielrooij  Nanjing University  National Institute for Material Sciences  photodetectors  Sebastian Castilla  University of Ioannina 

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Light-driven artificial muscle made with nanomaterials

Posted By Graphene Council, The Graphene Council, Monday, April 22, 2019
Updated: Saturday, April 20, 2019

Reporting their findings in Advanced Materials ("Plasmonic-Assisted Graphene Oxide Artificial Muscles"), researchers in China have developed a plasmonic-assisted holistic artificial muscle that can independently act as a fully functional motor system without assembling or joints.

The artificial muscle's low-cost integrated design consists of a composite layer uniform bilayer configuration made of gold nanorods embedded in graphene oxide or reduced graphene oxide and a thermally expansive polymer layer (PMMA).

The gold nanorods of varying aspect ratios endow the graphene nanocomposites with tunable wavelength response. This enables the fabrication of a light-sensitive artificial muscle that can perform complex limb-like motions without joints.

Combining the synergistic effect of the gold nanorods' high plasmonic property and wavelength selectivity with graphene's good flexibility and thermal conductivity, the artificial muscle can implement full-function motility without further integration, which is reconfigurable through wavelength-sensitive light activation.

Upon photothermal heating, the mismatch between the deformations of two layers leads to significant bending, replicating the muscle-like contraction from one layer and expansion from the other.

To demonstrate the light-addressable manipulation of complicated multiped robot, the team developed a holistic spider robot.

They patterned each leg of the spider with three nodes (see figure g above). Despite that the spider has been patterned on 2D film, it can deform into 3D structures under light irradiation due to the bending of its legs.

When the laser beam irradiates the legs one by one, the legs bend one after another, which induced the displacement of the gravity center of the spider accordingly. In this way, the researchers could control the spider robot to lean forward and move toward the right direction at an average speed of 2.5 mm per second.

The authors conclude that their work bridges the gap between ideal request and realistic restrictions of biomimetic motor systems, and decreases the amount of discrete parts, the number of postprocessing steps, and the fabrication time, and thereby offers new opportunities for biological aid and for biomimetic mini robots to be remotely operated.

Tags:  artificial muscle  Graphene  graphene oxide  nanocomposites 

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Directa Plus Loss Unchanged In 2018 Despite More than Doubled Revenue

Posted By Graphene Council, The Graphene Council, Saturday, April 20, 2019
Directa Plus PLC reported its loss was flat in 2018 due to continued investments in business development, while revenue multiplied on the strong performance of its Textiles division.

The graphene-based product supplier reported a pretax loss of EUR4.0 million in 2018, broadly unchanged year-on-year, due to higher expenditure on raw materials, and changes in inventories and other expenses.

Meanwhile, revenue increased to EUR 2.3 million from EUR 952,199 in 2017, mainly from higher revenue in the company's Textiles segment, which grew to EUR 1.7 million from EUR 770,000.

The remaining revenue came from Directa's Environmental division, which is focused on Grafysorber product for treating oil contaminated water.

Directa said it has continued to invest in new equipment and technology in 2018, with EUR120,000 related mainly to the purchase of industrial equipment to improve its manufacturing process.

Moreover, laboratory equipment to support the development of applications, particularly in Directa's textile and environmental markets, were also acquired during the period.

"2018 has seen accelerating commercial traction with agreements and collaborations signed, and orders received, for products to be delivered over the next twelve months," said Founder & Chief Executive Giulio Cesareo.

"There is every reason to look forward with great excitement to the coming year's activity at Directa Plus as we move forward on a number of extremely promising fronts," added Cesareo. Directa shares were trading 0.4% lower on Wednesday at 63.75 pence each.

Tags:  Directa Plus  Giulio Cesareo  Graphene 

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Light-induced active ion transport in graphene oxide membranes

Posted By Graphene Council, The Graphene Council, Wednesday, April 10, 2019
Updated: Thursday, March 21, 2019

Nanofluidic channels feature a unique unipolar ionic transport when properly designed and constructed. Recent research in nanofluidics has adopted reconstructed layered two-dimensional (2D) sheets – such as graphene oxide or clay – as a promising material platform for nanofluidics. These membranes contain a high volume fraction of interconnected 2D nanochannels.

Compared to other materials used for nanofluidic devices, such as anodized aluminum oxide membrane, block copolymer membrane and nanofluidic crystals, a unique feature of layered membranes is that the channels are horizontally aligned and the channel height (i.e., the spacing between the layers), which is responsible for confinement of the electrolyte, remains uniform throughout the entire thin film.

"However, mass and charge transport in existing membrane materials follows their concentration gradient," Wei Guo, a professor at the Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, tells Nanowerk. "Attaining anti-gradient transport as effective as natural counterparts remains a great challenge in fully abiotic nanosystems."

In new work led by Guo, reported in Nature Communications ("Photo-induced ultrafast active ion transport through graphene oxide (GO) membranes"), the researchers demonstrate a coupled photon-electron-ion transport phenomenon through graphene oxide membranes.

It shows a straightforward way on how to power the transport in 2D layered materials using the energy of light.
"Using the energy of light, cations are able to move thermodynamically uphill over a broad range of concentrations, at rates orders of magnitude faster than that via simple diffusion," Guo explains. "Based on this mechanism, we developed photonic ion switches, photonic ion diodes, and photonic ion transistors as the fundamental elements for active ion sieving and artificial photosynthesis on synthetic nanofluidic circuits."

This is the first discovery of photo-induced active (anti-gradient) ion transport in 2D layered materials with extraordinarily high pumping rates. It provides a completely new way for remote, non-invasive, and active control of the transport behaviors in synthetic membrane materials.

"Using light to control the mass and charge transportation in fully synthetic membranes is the dream of a materials scientist, like me," says Guo. "As far as I know, many research groups currently are engaged in this field. However, their findings are restricted to use the light as a gate, allowing or prohibiting the transport. In contrast, we use the light as a motive force to realize active transport."

Upon asymmetric light illumination, a net cationic flow through the layered graphene oxide membrane is generated from the non-illuminated region to the illuminated region. This phenomenon is reported for the first time.



Against a concentration gradient, the pumping rates for cations can be five orders of magnitude higher than that via simple diffusion.

The team established a theoretical model and performed molecular dynamics simulations to unveil the mechanism. Light irradiation reduces the local electric potential on the graphene oxide membrane following a carrier diffusion mechanism. When the illumination is applied to an off-center position, an electric potential difference is built across the GO strip that can drive the transport of ionic species.

Superior to existing molecular transport systems, the light-induced active ion transport reported in this work does not rely on lipid or liquid membranes, which significantly improves its robustness and compatibility. In addition, it does not hinge on specific ion-binding shuttle molecules to achieve the transmembrane ion transport. Thus, its transport range can be at the scale of centimeters.

This work provides a new route for remote, non-invasive, and active control of the transport behaviors in synthetic membrane materials. It demonstrates a way to fabricate innovative membrane materials for active ionic sieving, artificial photosynthesis, and modular computation on integrated nanofluidic circuits.

Following the mechanism proposed in this work, as shown in the figure below, the researchers constructed photonic ion switches (PIS), photonic ion diodes (PID), and photonic ion transistors (PIT) as the fundamental elements for light-controlled nanofluidic circuits.



"So far in our lab, the photo-induced active ion transport systems has been developed to the third generation," notes Guo. "The photo-induced active ion transport phenomenon can be also found in almost the whole family of 2D semiconductors. There is tremendous room to further exploit their unique photo-responsiveness in liquid processable colloidal 2D materials. The present work opens up exciting new possibilities."

"Now, we are trying to amplify the generation of photocurrent and voltage, and scale up the membrane materials with, for example, printing techniques," he concludes. "Also, we intend to further extend the scope of the materials with which the active transport behaviors can take place."

Tags:  2D materials  Beijing  Chinese Academy of Sciences  Graphene  graphene oxide  photonics  Wei Guo 

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New research uses graphene sensors to detect ultralow concentrations of NO2

Posted By Graphene Council, The Graphene Council, Wednesday, April 10, 2019
Updated: Wednesday, April 10, 2019
The research, as published in ACS Sensors, was led by an international collaboration of scientists from Linköping University, Chalmers University of Technology, Royal Holloway, University of London and the University of Surrey.

The findings demonstrate why single-layer graphene should be used in sensing applications and opens doors to new technology for use in environmental pollution monitoring, new portable monitors and automotive and mobile sensors for a global real-time monitoring network.

As part of the research, graphene-based sensors were tested in conditions resembling the real environment we live in and monitored for their performance. The measurements included, combining NO2, synthetic air, water vapor and traces of other contaminants, all in variable temperatures, to fully replicate the environmental conditions of a working sensor.

Key findings from the research showed that, although the graphene-based sensors can be affected by co-adsorption of NO2 and water on the surface, at about room temperature, their sensitivity to NO2 increased significantly when operated at elevated temperatures, 150 °C. This shows graphene sensitivity to different gases can be tuned by performing measurements at different temperatures.

Testing also revealed a single-layer graphene exhibits two times higher carrier concentration response upon exposure to NO2 than bilayer graphene — demonstrating single-layer graphene as a desirable material for sensing applications.

Christos Melios, a lead scientist on the project from NPL, said: “Evaluating the sensor performance in conditions resembling the real environment is an essential step in the industrialisation process for this technology.

“We need to be able to clarify everything from cross-sensitivity, drift in analysis conditions and recovery times, to potential limitations and energy consumption, if we are to provide confidence and consider usability in industry.”

By developing these very small sensors and placing them in key pollution hotspots, there is a potential to create a next-generation pollution map – which will be able to pinpoint the source of pollution earlier, in unprecedented detail, outlining the chemical breakdown of data in high resolution in a wide variety of climates.

Christos continued: “The use of graphene into these types of gas sensors, when compared to the standard sensors used for air emissions monitoring, allows us to perform measurements of ultra-low sensitivity while employing low cost and low energy consumption sensors. This will be desirable for future technologies to be directly integrated into the Internet of Things.”

NO2 typically enters the environment through the burning of fuel, vehicle emissions, power plants, and off-road equipment. Extreme exposure to NO2 can increase the chances of respiratory infections and asthma. Long-term exposure can cause chronic lung disease and is linked to pollution related death across the world.  

Figures from the European Environment Agency also links NO2 pollution to premature deaths in the UK, with the UK being ranked as having the second highest number of annual deaths in Europe. In 2014, 14,050 deaths in the UK were recorded as being NO2 pollution related, 5,900 of which were recorded in London alone1.

When interacted with water and other chemicals, NO2 can also form into acid rain, which severely damages sensitive ecosystems, such as lakes and forests.

Existing legislation from the European Commission suggests hourly exposure to NO2 concentration should not be exceeded by more than 200 micrograms per cubic metre (µg/m3) or ~106 parts per billion (ppb), and no more than 18 times annually. This translates to an annual mean of 40 mg m3 (~21 ppb) NO2 concentration2

In central London, for example, the average NO2 concentration for 2017 showed concentration levels of NO2 ranged from 34.2 to 44.1 ppb per month, a huge leap from the yearly average.

These figures show there is an urgent need for a low-cost solution to mitigate the impact of NO2 in the air around us. This work could provide the answer to early detection and prevention of these types of pollutants, in line with the government’s Clean Air Strategy.

Further experimentation in this area could see the graphene-based sensors introduced into industry within the next 2–5 years, providing an unprecedented level of understanding of the presence of NO2 in our air.

Tags:  Chalmers University of Technology  Christos Melios  Graphene  Linköping University  National Physical Laboratory  Royal Holloway  Sensors  University of London  University of Surrey 

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Graphene and 2D Materials on Track to Innovative Applications

Posted By Graphene Council, The Graphene Council, Wednesday, April 10, 2019
Updated: Wednesday, April 10, 2019

The CORDIS Results Pack showcases 12 articles on 6 ambitious cutting-edge EU research projects funded under the EU’s FP7 and Horizon 2020 research programmes relevant to graphene and 2D materials. Of these, seven articles cover different aspects of the Graphene Flagship. 


The Graphene Flagship is the EU’s biggest research initiative and has a budget of EUR 1 billion, representing a new form of joint, coordinated research initiative on an unprecedented scale. Through a combined academic-industrial consortium, the research effort covers the entire value chain, from materials production to components and system integration, aiming to exploit the unique properties of graphene. 

An introduction to graphene outlines work conducted by the Flagship including collaboration with the European Space Agency over the use of graphene in space applications such as light propulsion and thermal management. Researchers also used optoelectronic communication systems to provide fast data for the future. The large-scale production of graphene for commercial market applications involved scaling up manufacturing to industrial scale whilst maintaining consistency high quality and cost efficiency.

Scientists investigated chemical processing and functional applications of graphene and graphene-related materials for engineering new molecular structures with unique properties. Graphene spintronics utilised both electron charge and spin at room temperature to create new possibilities for information processing and storage. Finally the Flagship has investigated the use of graphene for biomedical applications to develop innovative medical devices and sensors for detecting treating and managing nervous system diseases. 

European graphene research doesn’t all fall under the remit of the Flagship and researchers are using other EU funding mechanisms to undertake other projects. GRAPHEALTH produced the next generation of wearable sensors while GRASP applied interactions between graphene and light to quantum computing and biomedicine. GraTA developed tunneling accelerometers for use in machine vibration monitoring. HIGRAPHEN created dense polymer composites for use in optoelectronics and energy storage. PolyGraph (working closely with the Graphene Flagship) studied graphene-reinforced polymers for use in the aeronautics and automobiles sectors.

Tags:  2D materials  Cordis  Graphene  Medical  The Graphene Flagship 

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First Graphene receives R&D refund

Posted By Graphene Council, The Graphene Council, Wednesday, April 10, 2019
Updated: Tuesday, April 2, 2019
First Graphene is pleased to advise it has received a Research and Development refund of over $680,000.

The refund will supplement the Company’s working capital as it advances its graphene commercialisation strategies.

First Graphene is a leading supplier of high-quality, bulk graphene products and is a Tier 1 partner at the Graphene Engineering and Innovation Centre (GEIC), Manchester, UK.

Tags:  Bulk Graphene Pricing Report  First Graphene  Graphene  Graphene Engineering and Innovation Centre 

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