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Applying 'magic angle' twistronics to manipulate the flow of light

Posted By Graphene Council, Friday, June 12, 2020
Monash researchers are part of an international collaboration applying 'twistronics' concepts (the science of layering and twisting 2D materials to control their electrical properties) to manipulate the flow of light in extreme ways.

The findings, published today in the journal Nature, hold the promise for leapfrog advances in a variety of light-driven technologies, including nano-imaging devices; high-speed, low-energy optical computers; and biosensors.

This is the first application of Moire physics and twistronics to the light-based technologies, photonics and polaritonics, opening unique opportunities for extreme photonic dispersion engineering and robust control of polaritons on 2D materials.

APPLYING TWISTRONICS TO PHOTONS

The team took inspiration from the recent discovery of superconductivity in a pair of stacked graphene layers that were rotated to the 'magic twist angle' of 1.1 degrees.

In this stacked, misaligned configuration, electrons flow with no resistance, while separately, each of the two graphene layers shows no special electrical properties.

The discovery has shown how the careful control of rotational symmetries can unveil unexpected material responses.

The research team was led by Andrea Alù at the Advanced Science Research Center at the Graduate Center, CUNY, Cheng-Wei Qiu at National University of Singapore and Qiaoliang Bao formerly at Monash University.

The team discovered that an analogous principle can be applied to manipulate light in highly unusual ways. At a specific rotation angle between two ultrathin layers of molybdenum-trioxide, the researchers were able to prevent optical diffraction and enable robust light propagation in a tightly focused beam at desired wavelengths.

Typically, light radiated from a small emitter placed over a flat surface expands away in circles very much like the waves excited by a stone that falls into a pond. In their experiments, the researchers stacked two thin sheets of molybdenum-trioxide and rotated one of the layers with respect to the other. When the materials were excited by a tiny optical emitter, they observed widely controllable light waves over the surface as the rotation angle was varied. In particular, they showed that at the photonic 'magical twist angle' the configured bilayer supports robust, diffraction-free light propagation in tightly focused channel beams over a wide range of wavelengths.

"While photons - the quanta of light - have very different physical properties than electrons, we have been intrigued by the emerging discovery of twistronics, and have been wondering if twisted two-dimensional materials may also provide unusual transport properties for light, to benefit photon-based technologies," said Andrea Alù.

"To unveil this phenomenon, we used thin layers of molybdenum trioxide. By stacking two of such layers on top of each other and controlling their relative rotation, we have observed dramatic control of the light guiding properties. At the photonic magic angle, light does not diffract, and it propagates very confined along straight lines. This is an ideal feature for nanoscience and photonic technologies."

"Our experiments were far beyond our expectations," said Dr Qingdong Ou, who led the experimental component of the study at Monash University. "By stacking 'with a twist' two thin slabs of a natural 2D material, we can manipulate infrared light propagation, most intriguingly, in a highly collimated style."

"Our study shows that twistronics for photons can open truly exciting opportunities for light-based technologies, and we are excited to continue exploring these opportunities," said National University of Singapore graduate student Guangwei Hu, who led the theoretical component.

"Following our previous discovery published in Nature in 2018, we found that biaxial van der Waals semiconductors like α-MoO3 and V2O5 represent an emerging family of material supporting exotic polaritonic behaviors," said A/Prof Qiaoliang Bao, "These natural-born hyperbolic materials offer an unprecedented platform for controlling the flow of energy at the nanoscale."

DEVELOPMENT OF TWISTRONICS AND MAGIC ANGLES IN GRAPHENE

Novel electronic properties in 'misaligned' graphene sheets was first predicted by National University of Singapore Professor (and FLEET Partner Investigator) Antonio Castro Neto in 2007, and the 'magic angle' of 1.1 degrees was theorised by FLEET PI (University of Texas in Austin) in 2011.

Superconductivity in twisted graphene was experimentally demonstrated by Pablo Jarillo-Herrero (MIT) in 2018.

THE STUDY

Topological polaritons and photonic magic angles in twisted α-MoO3 bi-layers was published in Nature today, 11 June 2020 (DOI 10.1038/s41586-020-2359-9 ).

As well as support from the Australian Research Council, support was also provided by the US Air Force Office of Scientific Research, >Vannevar Bush Fellowship, Office of Naval Research, and National Science Foundation, as well as Singapore's Agency for Science Technology and Research (A*STAR), and China's National Natural Science Foundation.

Layering and twisting of 2D materials was performed at Monash University (Department of Materials Science and Engineering), while the topological polaritons was observed and characterised at the Melbourne Centre for Nanofabrication (MCN), the Victorian Node of the Australian National Fabrication Facility (ANFF).

PHOTONICS AT FLEET

Experimental physicist Dr Qingdong Ou is a research fellow now working with Prof Michael Fuhrer at Monash University to study nano-device fabrication based on 2D materials, within FLEET's Enabling technology B.

Qingdong seeks to minimise energy losses in light-matter interactions, aiming to realise ultra-low energy consumption in 2D-material-based photonic and optoelectronic devices. He also studies highly-confined low-loss polaritons in 2D materials using near-field optical nano-imaging within FLEET's Research theme 2.

FLEET is an Australian Research Council Centre of Excellence developing a new generation of ultra-low energy electronics.

Tags:  2D materials  Andrea Alù  CUNY  Electronics  Graphene  Monash University  photonics  Qingdong Ou 

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UT Projects Win $23.6M in R&D Funds as Part of Portuguese Government Technology Program

Posted By Graphene Council, Wednesday, June 10, 2020
The UT Austin Portugal program, a 13-year-old innovation partnership between the university and the Portuguese government, received $23.6 million in funding to pursue 11 R&D projects as part of a major technology initiative from Portugal’s Ministry of Science, Technology and Higher Education.

The projects fall under four major categories: nanomaterials, earth-space interactions, medical physics and advanced computing. The teams will spend the next three years developing their projects, which could transform industries like automotive, space, health care and data science.

“Ranging from electromagnetic interference shielding nanomaterials, to in-beam time-of-flight positron emission tomography for proton radiation therapy, all the way to an ocean and climate change monitoring constellation based on radar altimeter data combined with gravity and ocean temperature and salinity measurements, the spread, number, and quality of the UT Austin Portugal joint strategic projects selected for funding within the recent competitive solicitation set forth by the Foundation for Science and Technology and National Innovation Agency are truly outstanding,” said Manuel Heitor, Portugal’s Minister of Science, Technology and Higher Education. “I look forward to witnessing the results of such collaborative research between Portuguese and UT researchers.”

The call for proposals included just three universities: The University of Texas at Austin, Carnegie Mellon University and the Massachusetts Institute of Technology. UT won the majority of the investment dollars, about 40% of the funding, and saw the most projects funded among the three engineering powerhouses.

“We had anticipated four to five projects would be selected for strategic grant awards and were astounded when we learned 11 had been selected by the evaluation panel in Portugal,” said John Ekerdt, Cockrell School associate dean for research and principal investigator for UT Austin Portugal. “This is a testament to the outstanding faculty and quality projects they proposed with collaborators in Portugal and to the close ties that have been forged between UT researchers and faculty and counterparts in Portugal.”

“The performance of the UT Austin Portugal program in the 2019 call for strategic projects has been remarkable,” said Marco Bravo, executive director of the UT Austin Portugal program. “Eleven of 14 project proposals submitted by the UT Austin Portugal research consortia were approved for funding through an independent assessment process. Overall, UT Austin Portugal saw 11 of its groundbreaking, industry-led proposals approved out of a total of 25 projects approved at this solicitation that included proposals from two other international partnerships, corresponding to nearly $24 million over three years. That’s 40% of total funding to UT Austin Portugal projects, the largest share of research dollars available. UT Austin researchers are to be congratulated on this effort.”

The UT Austin Portugal program dates back to 2007, and it is one of several partnerships between the Portuguese government and research institutions. The goal is to elevate science and technology in Portugal while fostering strong partnerships to help universities continue to innovate. The partnership with UT was extended in 2018, continuing the alliance until at least 2030.

“Of the three international partnerships with American universities sponsored by the Portuguese Foundation for Science and Technology in Portugal, the partnership with UT Austin had the best performance in this call, which was designed and launched on the Portuguese side,” said José Manuel Mendonça, national director of the program. “The 11 approved projects represent a proposal success rate of almost 80% for the UT Austin Portugal Program. The approved projects will, undoubtedly, contribute to promoting and strengthening collaborations with UT Austin in high-level R&D matters with immediate transposition to various sectors of economic activity, several of which are critical to Portugal's competitive position at an international level.”

About a third of the funds for UT’s projects come from the university, with the rest coming from a combination of public and private Portuguese entities. Each project team in Portugal is led by a Portuguese company. The UT side includes 21 faculty members and one from the MD Anderson Cancer Center.

Here is a look at the UT projects:

Shielding electronic devices from electromagnetic interference
This project proposes to use the “wonder material” graphene to improve on methods to combat electromagnetic interference, which can disrupt circuits and cause devices to fail. The team plans to create two composites with electromagnetic interference shielding capabilities and fabricate a solution to protect electric wires used in the automotive industry.

UT Austin Faculty: Deji Akinwande, Cockrell School of Engineering, Department of Electrical and Computer Engineering; Brian Korgel, Cockrell School of Engineering, McKetta Department of Chemical Engineering

New lasers for next-generation biomedical imaging
The use of multiphoton microscopy to examine cell behavior in live tissue over time has become an important research tool for learning more about brains and tumors. This project aims to increase the speed and depth of this form of imaging and diagnostics through the development and application of ultrashort laser pulses.

UT Austin Faculty: Andrew Dunn, Cockrell School of Engineering, Department of Biomedical Engineering; Adela Ben-Yakar, Cockrell School of Engineering, Walker Department of Mechanical Engineering

Nano-satellites for gravitational field assessment
Researchers propose to develop a nano-satellite prototype for studying gravitational fields. The project will also develop a platform for future nano-satellite capabilities, including Earth observation, communications and exploration missions.

UT Austin Faculty: Byron Tapley, Cockrell School of Engineering, Department of Aerospace Engineering and Engineering Mechanics, and the Center for Space Research; Brandon Jones, Cockrell School of Engineering, Department of Aerospace Engineering and Engineering Mechanics, and the Texas Spacecraft Laboratory

Software to match big data with high-performance computing
The advancement of technology has generated huge troves of data, which requires stronger computing power to process and analyze all that information. This project aims to create a software bundle to help companies pair their big data operations with high-performance computing, which includes tools for managing challenges such as computing and research storage.

UT Austin Faculty: Vijay Chidambaram, College of Nature Sciences, Department of Computer Science; Todd Evans, Texas Advanced Computing Center

Sensors for monitoring cancer patients
This project will develop a biosensor that can be injected into prostate cancer patients after surgery. The minimally invasive sensor would allow medical personnel to monitor high-risk patients remotely and look for the development of early tumors, with the potential to increase the predictive value of cancer screenings.

UT Austin Faculty: Thomas Milner, Cockrell School of Engineering, Department of Biomedical Engineering; James Tunnell, Cockrell School of Engineering, Department of Biomedical Engineering

Wearable rehabilitation devices
Researchers will develop a series of nano-sensors embedded into clothing that administer electrostimulation to people suffering from a lack of mobility and motor deficiency. The sensors could be monitored remotely by health professionals, creating a mobile rehabilitation option for people who have trouble getting to a doctor’s office consistently or want greater freedom to complete treatment anywhere. The team envisions its project as a tool mostly for elderly people, but it has applications for training high-level athletes as well.

UT Austin Faculty: George Biros, Cockrell School of Engineering, Walker Department of Mechanical Engineering, and the Oden Institute for Computational Engineering and Sciences; Michael Cullinan, Cockrell School of Engineering, Walker Department of Mechanical Engineering

Software for gathering better data on manufacturing
Getting reliable data on manufacturing processes proves challenging due to issues with placing sensors in the right spots and retaining strong connectivity. Thin films loaded with small sensors that can be applied directly to the equipment represent a promising solution; however, installation has proved difficult. This project proposes a new set of software to make it easier to layer these films on top of equipment by providing necessary data to avoid mechanical problems during installation.

UT Austin Faculty: Rui Huang, Cockrell School of Engineering, Department of Aerospace Engineering and Engineering Mechanics, Center for Mechanics of Solids, Structures and Materials; Kenneth M. Liechti, Cockrell School of Engineering, Department of Aerospace Engineering and Engineering Mechanics, Center for Mechanics of Solids, Structures and Materials

A new way to measure next-generation cancer therapy
Proton radiation therapy, the use of protons rather than X-rays to treat cancer patients, is on the rise, but measuring the distance protons travel proves problematic. Typically, it takes a ring of detectors surrounding the patient to get accurate measurements, but that poses geometric challenges. This project proposes to develop a new type of Positron Emission Tomography scan, which shows how tissues and organs are functioning to better understand the range of protons and whether they are traveling to the right spots to attack the cancer.

UT Faculty: Karol Lang, College of Natural Sciences, Department of Physics; Narayan Sahoo, University of Texas MD Anderson Cancer Center, Department of Radiation Physics

Satellite constellations for monitoring climate change
This project aims to develop the next generation of radar altimeter instruments — which measure the distance between an aircraft and the terrain below it — and a series of small satellites that can understand long-term variability in local, regional and global climate created by changes in sea levels due to water temperature. The project also includes a data processing and visualization system using advanced modeling, estimation techniques, statistical and scientific machine learning methods and error analysis.

UT Austin Faculty: Byron Tapley, Cockrell School of Engineering, Department of Aerospace Engineering and Engineering Mechanics Department, and the Center for Space Research; Patrick Heimbach, Jackson School of Geosciences, Department of Geological Sciences, and the Oden Institute for Computational Engineering and Sciences

Improving cutting tools for airline and automotive components
Fabricating parts of cars and planes is hard on cutting tools and tends to ware them down. This project aims to develop coatings that better protect and extend the lifespan of these crucial pieces of equipment. The team also plans to develop simulation programs to improve cutting tools’ performance.

UT Austin Faculty: Gregory J. Rodin, Cockrell School of Engineering, Department of Aerospace Engineering and Engineering Mechanics, and the Oden Institute for Computational Engineering and Sciences; Filippo Mangolini, Cockrell School of Engineering, Walker Department of Mechanical Engineering

An alternative to traditional water treatment options
Traditional water treatment tech struggles to efficiently remove high amounts of pollutants from some types of surface and groundwater. This team is looking to use metallic nanoparticles to clean water by improving a process called catalytic hydrogenation, which involves adding hydrogen via a metallic catalyst.

UT Austin Faculty: Charles J. Werth, Cockrell School of Engineering, Department of Civil, Architectural, and Environmental Engineering; Simon M. Humphrey, College of Natural Sciences, Department of Chemistry

Tags:  Biomedical  Carnegie Mellon University  Electronics  Environment  Graphene  Healthcare  John Ekerdt  Marco Bravo  Massachusetts Institute of Technology  nanomaterials  Sensors  The University of Texas at Austin  Water Purification 

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Aerosol-printed graphene unveiled as low cost, faster food toxin sensor

Posted By Graphene Council, Wednesday, June 10, 2020
Researchers in the USA have developed a graphene-based electrochemical sensor capable of detecting histamines (allergens) and toxins in food much faster than standard laboratory tests.

The team used aerosol-jet printing to create the sensor. The ability to change the pattern geometry on demand through software control allowed rapid prototyping and efficient optimization of the sensor layout.

Commenting on the findings, which are published today in the IOP Publishing journal 2D Materials, senior author Professor Mark Hersam, from Northwestern University, said: "We developed an aerosol-jet printable graphene ink to enable efficient exploration of different device designs, which was critical to optimizing the sensor response."

As an additive manufacturing method that only deposits material where it is needed and therefore minimizes waste, aerosol-jet-printed sensors are low-cost, straightforward to make, and portable. This could potentially enable their use in places where continuous on-site monitoring of food samples is needed to determine and maintain the quality of products, as well as other applications.

Senior author Professor Carmen Gomes, from Iowa State University, said: "Aerosol-jet printing was fundamental to the development of this sensor. Carbon nanomaterials like graphene have unique material properties such as high electrical conductivity, surface area, and biocompatibility that can significantly improve the performance of electrochemical sensors.

"But, since in-field electrochemical sensors are typically disposable, they need materials that are amenable to low-cost, high-throughput, and scalable manufacturing. Aerosol-jet printing gave us this."

The team created high-resolution interdigitated electrodes (IDEs) on flexible substrates, which they converted into histamine sensors by covalently linking monoclonal antibodies to oxygen moieties created on the graphene surface by a CO2 thermal annealing process.

They then tested the sensors in both a buffering solution (PBS) and fish broth, to see how effective they were at detecting histamines.

Co-author Kshama Parate, from Iowa State University, said: "We found the graphene biosensor could detect histamine in PBS and fish broth over toxicologically-relevant ranges of 6.25 to 100 parts per million (ppm) and 6.25 to 200 ppm, respectively, with similar detection limits of 2.52 ppm and 3.41 ppm, respectively. These sensor results are significant, as histamine levels over 50 ppm in fish can cause adverse health effects including severe allergic reactions - for example, scombroid food poisoning.

"Notably, the sensors also showed a quick response time of 33 minutes, without the need for pre-labelling and pre-treatment of the fish sample. This is a good deal faster than the equivalent laboratory tests."

The researchers also found the biosensor's sensitivity was not significantly affected by the non-specific adsorption of large protein molecules commonly found in food samples and used as blocking agents.

Senior author Dr Jonathan Claussen, from Iowa State University, said: "This type of biosensor could be used in food processing facilities, import and export ports, and supermarkets where continuous on-site monitoring of food samples is needed. This on-site testing will eliminate the need to send food samples for laboratory testing, which requires additional handling steps, increases time and cost to histamine analysis, and consequently increases the risk of foodborne illnesses and food wastage.

"It could also likely be used in other biosensing applications where rapid monitoring of target molecules is needed, as the sample pre-treatment is eliminated using the developed immunosensing protocol. Apart from sensing small allergen molecules such as histamine, it could be used to detect various targets such as cells and protein biomarkers. By switching the antibody immobilized on the sensor platform to one that is specific towards the detection of suitable biological target species, the sensor can further cater to specific applications. Examples include food pathogens (Salmonella spp.), fatal human diseases (cancer, HIV) or animal or plant diseases (avian influenza, Citrus tristeza)."

Tags:  Biosensor  Carmen Gomes  Graphene  Iowa State University  Jonathan Claussen  Kshama Parate  Mark Hersam  Northwestern University  Sensors 

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Skoltech PhD students win the Haldor Topsoe scholarships

Posted By Graphene Council, Wednesday, June 10, 2020
Haldor Topsoe, a global leader in heterogeneous catalysis, has awarded scholarships to three Skoltech PhD students, Artem Grebenko, Natalia Katorova, and Filipp Obrezkov. Established by the company founder, Dr Haldor Topsoe, over 20 years ago, the Haldor Topsoe PhD Scholarship Program supports young scientists conducting research in heterogeneous catalysis and related fields that are part of Topsoe’s mainstream activity.

We caught up with the winners to find out about the focus and practical impact of their research and their feelings about the award.

Artem Grebenko, Physics PhD Program, Skoltech Center for Photonics and Quantum Materials (CPQM)

Within my study that deals with the heterostructures of metal-organic frameworks (MOF) and graphene, I have developed a new graphene synthesis method and a baseline MOF synthesis technique using a ligand called benzenehexathiol. During the next academic year, I expect to complete the study of the individual properties of graphene and MOF and assemble the first heterostructures by superimposing the MOF and graphene layers.

My study is the first systematic attempt at studying the properties of MOF with a fixed ligand and creating 2D heterostructures from organic materials and graphene. The big idea behind this research is finding the combinations that will uncover the applied potential of new structures. Conducting transparent 2D layers find application in microelectronics and various kinds of optical and gas sensors. At this stage, it is hard to tell exactly what properties those structures may have, but since the change of a ligand converts the MOF from the antiferromagnetic insulator (in the case of chromium) to the superconductor (in the case of copper), this line of research definitely holds a lot of promise.

I am convinced that new materials will transform our lives, as silicon did once. And so did graphene which is yet to make a hit. These are just two examples among a broad diversity of promising materials. Their practical application is still unclear, although MOFs have exhibited excellent catalytic performance in solar panels. I am very excited about the idea to use MOF and graphene structures in microelectronics, for example, transistor channels, sensors or bolometers. In fact, this has been my dream since 2014 when I was still a graduate student. I even attempted to launch a study but faced a lack of equipment and the fact that my project did not fit with the goals of the lab I worked for. It is only after I joined Skoltech that I could fulfil my dream.

The fact that my scholarship application was recognized as an “excellent proposal” by Haldor Topsoe means that I am doing something of value for the industry. While other winners focused on heterogeneous catalysis, Haldor Topsoe’s core research area, I concentrated on making the samples by synthesizing graphene based on heterogeneous catalysis. I derive great pleasure from contributing to science even though I have always thought my work should have a practical purpose. For me, the award is a source of confidence and inspiration for further work. 

Natalia Katorova, Materials Science PhD program, Skoltech Center for Energy Science and Technology (CEST)

My study of potassium-ion batteries has evolved into a startup, K-Plus, that my colleague and I have launched at Skoltech recently and which is strongly supported by the Institute, CEST, and our supervisors and main inspirers, professors Artem Abakumov and Keith Stevenson. Potassium-ion batteries can be a highly cost-effective alternative to modern lithium-ion batteries in stationary energy storage applications, such as solar or wind energy storage solutions. However, the electrochemical performance of a potassium-ion battery, like any other metal-ion battery, is driven by the passivating layer formed by the electrolyte decomposition products on the electrode surface, so in my thesis research, I examine the processes at the electrode/electrolyte interface and try to find ways of improving the properties of the passivating layer.

I have always wanted to work on tasks of high relevance for the global community, and metal-ion batteries are something that everyone in the modern world uses in one way or another. Also, I have always wanted to be part of a cool and inspiring team that would encourage my self-development. This is why I chose to work on this topic in our research team.

We have been actively implementing the results of my study to assemble prototypes of potassium-ion batteries in a prismatic cell. Although they are low-capacity prototypes suitable for LEDs or small electric motors only, they prove that the new technology does work and can be successfully used in the future. Now we plan to tackle a bigger challenge, which is scaling, and assemble larger prototypes with capacities of up to 10-50 Ah. I believe someday you will hear more about the achievements of our potassium-ion batteries!

Winning a competition like this one means a lot for a researcher whose scientific achievements have been recognized by the world scientific community. Also, it means you are going in the right research direction and your findings could have a high impact on our everyday life. I am delighted that the Topsoe Fellowship Program Committee singled out my project from many other applications. 

Filipp Obrezkov, Materials Science PhD program, Skoltech Center for Energy Science and Technology (CEST)

My PhD thesis is devoted to the development of novel organic cathode materials for lithium, sodium and potassium dual-ion batteries. The operational mechanism of such devices differs from working principles of classical metal-ion batteries. In particular, while the dual-ion battery charges, cations and anions are simultaneously transferred from the electrolyte solution to the anode and cathode surfaces, respectively, initiating the electrochemical transformations. As the battery discharges, the reverse process occurs.

This technology is especially interesting scientifically because it might allow to create ultrafast batteries that would take only a few seconds to charge. The design of suitable organic cathode material could potentially facilitate the development of dual-ion batteries with high energy density, which none of the existing solutions can do.

I started to work on this project 3 years ago, as I realized that new batteries with enhanced specific energy, power and stability are one of the most essential tasks of modern electrochemistry and materials science, in particular, due to the fact that organic dual-ion batteries are among the most promising technologies that could advance these research areas quite significantly.

One of the promising potential applications of dual-ion batteries is their utilization in stationary energy storage systems which can allow to enhance the operational efficiency of power plants during off-peak hours.

I am honored to be an awardee of Haldor Topsoe PhD scholarship program because it is a great recognition of high scientific quality of my project, as well as its prospects for the industry.

Tags:  Artem Grebenko  Filipp Obrezkov  Graphene  Natalia Katorova  Skoltech 

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First Graphene Joins Europe’s Flagship Programme

Posted By Graphene Council, Tuesday, June 9, 2020
First Graphene Ltd has been accepted as an Associate Member of the EU Graphene Flagship. The company joins the €1 billion EU funded programme at a crucial time as the Flagship transitions from R&D to commercialisation and requires graphene manufacturers with industrial supply capability.

The Graphene Flagship has a budget of €1 billion and coordinates nearly 170 academic and industrial research groups in 21 countries and has more than 90 associate members.  FGR through its UK subsidiary is the first Australian entity to be admitted to the consortium.

The Graphene Flagship is tasked with bringing together academic and industrial researchers to take graphene from the realm of academic laboratories into European society in the space of 10 years, thus generating economic growth, new jobs and new opportunities.

This follows the Company also joining the BSI and ISO/TC229 working groups for the development of graphene characterisation standards, thereby ensuring alignment of the Company’s quality processes with the emerging international standards.

First Graphene intends to stay at the leading edge in terms of controlling the quality of graphene related products.  The Company continues to invest in its processing capability through measurement and automation and is a Tier 1 Member of the Graphene Engineering Innovation Centre at the University of Manchester with direct access to world-class analytical equipment and techniques and supporting expertise.  The Company will continue to invest in analytical methods and process tools to ensure world leading PureGRAPH® product quality for our customers.

Craig McGuckin, Managing Director for First Graphene Ltd, said, “FGR joining the EU Graphene Flagship at this time is auspicious, as FGR continues to commercialise it PureGRAPH® range of graphene powders.  As the world leader in the production of large volume, high quality graphene powders membership of this organisation is at an appropriate time as various projects transition from R&D to commercialisation.”

Tags:  Craig McGuckin  First Graphene  Graphene  Graphene Flagship  University of Manchester 

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ZEN Graphene Solutions Announces Collaboration with UBC-O on Department of National Defence Project

Posted By Graphene Council, Tuesday, June 9, 2020
ZEN Graphene Solutions Ltd. is pleased to announce it will be commencing a new research collaboration with Prof. Mohammad Arjmand and his team at the University of British Columbia (UBC)‐Okanagan Campus, with a $200,000 Department of National Defence (DND) Innovation for Defence Excellence and Security (IDEaS) award. ZEN will be providing in-kind contributions of Albany PureTM materials and consultation with its technical team.

The goal of this collaborative research project is to develop electrically conductive, molded and 3D printed graphene/polymer nanocomposites as more versatile replacements for metallic electromagnetic shields that are currently in use. The new shields will be lightweight and corrosion resistant along with the additional benefits of low cost, ease of processing and improved design options compared to current metallic shields. In this collaboration, the developed conductive polymer shields will protect sensitive electronic equipment in satellites; however, the shields will also have use in a broad spectrum of applications in various industries, such as information technology, medical sciences, automotive, defence, and aerospace. The technology of developing 3D printing multifunctional polymer nanocomposite filaments will also allow for the rapid, low-cost fabrication of complex geometries of multifunctional polymer nanocomposites such as artificial electromagnetic shields. If DND elects to advance the project to Phase 2, it will support the research with a $1 million grant.

ZEN would also like to congratulate Prof. Arjmand and his Nanomaterials and Polymer Nanocomposites Laboratory (NPNL) for being awarded two additional grants. The Canada Foundation for Innovation (CFI) John R. Evans Leaders Fund and the British Columbia Knowledge Development Fund (BCKDF) awarded a grant of $320,000 that will allow him to acquire the necessary equipment for the synthesis and characterization of graphene and its polymer nanocomposites. Prof. Arjmand was also awarded an additional $101,224 from the NSERC Research Tools and Instruments (RTI) Grant Program with support from the UBC School of Engineering. These funds will be used to purchase a state-of-the-art extruder to develop polymer nanocomposite filaments and pellets. All this equipment will be used to synthesize and characterize graphene materials from ZEN’s Albany PureTM Graphite and develop novel graphene-based polymer composites.

Francis Dubé, ZEN CEO commented, “We are happy to see the Department of National Defence investing in graphene-based technologies with the UBCO team led by Prof. Arjmand and ZEN. We are also pleased that Prof. Arjmand and his NPNL center have been recognized with the additional funding from CFI, BCKDF and NSERC. These equipment purchases will help drive graphene innovation in polymers for ZEN.”

Prof. Arjmand stated, “Our expertise in the synthesis of graphene, polymer processing, 3D printing, and polymer nanocomposites allows us to develop the next generation of high-performance multifunctional polymer nanocomposites with unique properties and complex geometries. We look forward to continuing to work with ZEN Graphene to bring these next generation products to market.”

Tags:  3D Printing  Francis Dubé  Graphene  Mohammad Arjmand  nanocomposites  polymers  University of British Columbia  ZEN Graphene Solutions 

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Liquid metals break down organic fuels into ultra-thin graphitic sheets

Posted By Graphene Council, Tuesday, June 9, 2020
For the first time, researchers at the University of New South Wales (UNSW), Sydney, Australia, show the synthesis of ultra-thin graphitic materials at room temperature using organic fuels. These fuels can be as simple as basic alcohols such as ethanol.

Nanoscale graphitic materials, such as graphene, are ultra-thin sheets of carbon compounds that are sought after materials with great promises for battery storages, solar cells, touch panels and even more recently fillers for polymers.

These researchers were able to synthesize ultra-thin carbon-based materials on the surface of liquid metals at room temperature electrochemically. Before this report, others had shown electro-formation of such carbon-based materials only by transferring sheets onto the electrodes or electrode exfoliation of naturally-occurring carbon crystals from mines.

“Using gallium liquid metal, we could catalytically break down the fuels and form carbon-carbon bonds (the base of graphitic sheets) from organic fuels at room temperature. The ultra-smooth surface of liquid metals could then template atomically-thin carbon based sheets. Removal of these sheets was easy as they do not stick to the liquid metal surface.” suggested Prof Kalantar-Zadeh, the lead of this project and the Director of the Centre for Advanced Solid and Liquid based Electronics and Optics (CASLEO) at UNSW.

“It is simple. Why has room temperature electro-synthesis of two-dimensional graphitic materials not been achieved before? We cannot offer a definitive answer. Perhaps disregarding ultra-catalysts such as liquid metals and too much emphasis on solid electrodes which are inherently not smooth.” added Dr. Mohannad Mayyas the first author of the paper.

The paper was published in highly reputed journal of Advanced Materials ("Liquid-Metal-Templated Synthesis of 2D Graphitic Materials at Room Temperature").

Researchers from RMIT, Australia, University of California Los Angels (UCLA), USA, and the Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), Korea are the other collaborators of the research and authors of the manuscript.

Tags:  Battery  Graphene  graphitic  Kalantar-Zadeh  Mohannad Mayyas  University of New South Wales 

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HKUST Research Team Successfully Discovers New Material Generation Mechanism for Chip Design, Quantum Computing and Noise Reduction

Posted By Graphene Council, Monday, June 8, 2020
The research team of the Hong Kong University of Science and Technology (HKUST) has recently made important progress in the field of new materials. Combining the characteristics of two-dimensional materials and topological materials, the team has for the first time discovered a universal generation mechanism of new materials with "type-II" Dirac cones. Many extraordinary properties of the material are realized in experiments, which addressed the key issue that the material could only be obtained sporadically under stringent limits. This mechanism can guide the preparation of new two-dimensional materials that have specific directional responses to external signals such as electric fields, magnetic fields, light waves, sound waves, etc., and will provide valuable applications for modern electronic communications, quantum computing, optical communications, and even sound insulation and noise reduction materials. 

As a typical representative of two-dimensional materials, since its discovery in 2004, graphene has been regarded as one of the greatest material discoveries in the 21st century. As the thinnest, strongest and most thermally conductive "super material" in the world today, graphene has been widely used in transistors, biosensors and batteries, and its discovery led to the 2010 Nobel Prize in Physics. On the other hand, topological materials, because of the existence of extraordinary properties such as zero-dissipative edge transport, are considered to be the cornerstones of the development of future electronic devices, and their discovery led to the 2016 Nobel Prize in Physics. In fact, graphene is also a topological material, and its extraordinary properties are mostly derived from its topological "Dirac cones". However, the "Dirac cones" in graphene belong to the "type-I" Dirac cones of the theoretical predictions. The more unique "type-II" Dirac cones in the theoretical predictions, because of their strongly directional responses to external signals that the type-I Dirac cones do not have, will bring many more possibilities to the development and applications of electronic devices. However, so far, the "Dirac cone of the second kind" can only be found sporadically in some materials, lacking a systematic generation mechanism.

To address this critical issue, the research team led by Prof. WEN Weijia and Dr. WU Xiaoxiao, from the Department of Physics, for the first time, discovered and successfully implemented the systematic generation mechanism of new two-dimensional materials with type-II Dirac cones based on the relevant theories of two-dimensional materials and topological materials, using the band-folding mechanism (a material-independent, universal principle for periodic lattices). Due to its unique topological bands, its response to external signals is extremely directional, so the two-dimensional materials with type-II Dirac cones have important academic and application values for the designs of high-precision detecting devices of external signals, such as electric fields, magnetic fields, light waves, and sound waves. The systematic design and material independence of this scheme also help to relax the precision requirements for circuit designs, making the design of corresponding electronic products easier and more flexible. The team used acoustic field scanning techniques to directly observe the type-II Dirac cone in acoustics, as well as many of its properties that were only proposed in theories previously.

The success of this experimental study has opened up a new field of researches and applications of two-dimensional materials and topological materials, and brought many more possibilities for the future applications of the new materials. The findings of this study have been published in the renowned journal Physical Review Letters.

The ventilated sound absorbers developed by Prof. Wen’s group based on acoustic metamaterials. The ventilated sound absorbers can simultaneously achieve high-performance sound absorption and air flow ventilation, which is important for noise reduction applications in the environment with free air flows, such as air conditioners, exhaust hoods, and ducts.

"Our findings of the deterministic scheme for type-II Dirac points could profoundly broaden application prospects on fronts such as 5G communications, optical computing such as quantum computing and noise reduction. Our team plans to apply the experimental results to electronic devices such as dedicated chips, new touch control materials, filter modules, wireless transmission and biosensors.” said Prof. Wen, “Also, type-II DPs observed in acoustic waves suggest viable new materials for sound barriers, providing potential solutions for high-efficiency soundproofing walls. While we improve the performance of acoustic metamaterials, we will seek to continuously expand their applications in aspects ranging from low-frequency sound absorption, noise reduction in ventilation systems, intelligent active noise cancelling, traffic noise abatement to architectural acoustics. We also hope that these materials can be truly industrialized.”

Long engaged in researching the field of advanced materials, Prof. Wen and his team have made a range of key achievements in the basic and applied research of new materials science. In 2014, he was awarded second-class 2014 State Natural Science Award (SNSA) for the project on "Structural and Physical Mechanism Investigation for Giant Electrorheological Fluid".

Tags:  Batteries  biosensors  Graphene  Hong Kong University of Science and Technology  transistor  WEN Weijia  WU Xiaoxiao 

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With a Twist, Researchers Make a Device Breakthrough

Posted By Graphene Council, Monday, June 8, 2020
In recent years, researchers have found that when certain materials are twisted at specific angles, they can bring out some remarkable properties.

Putting their own spin on this field of research, known as “twistronics,” a team of researchers has found that similar methods can elicit properties that could lead to new optoelectronic devices. The work is a collaboration between the laboratory of Fengnian Xia, the Barton L. Weller Associate Professor in Engineering and Science at Yale University; Professor Fan Zhang’s group in University of Texas at Dallas; Kenji Watanabe and Takashi Taniguchi of National Institute for Materials Science, Japan. Their results were published this week in Nature Photonics.

By twisting two atomic layers, researchers have been exploring the various novel physical phenomena. A particularly interesting material system in the field is what’s known as small-twist-angle bilayer graphene. It consists of two layers of graphene - each the thickness of one atom - twisted at an angle of less than 2 degrees. This twist significantly modifies the electronic properties of monolayer graphene. Among the properties that researchers have discovered are superconductivity and certain topological properties.

However, little research has been done on how it affects a device’s response to infrared light. Taking this approach, the Xia group and collaborators found that the emergence of the moiré pattern in twisted bilayer graphene (TBG) leads to a device with a very strong, and tunable, photoresponse in mid-infrared wavelength range. Compared with regular bilayer graphene that hasn’t been twisted, the photoresponse is more than 20 times stronger. That's because this twist significantly enhances the light-matter interaction and induces a narrow bandgap. It’s a particularly interesting result, since almost all matters at room temperature emit light in this wavelength range.

Critical to achieving these results is the specific angle at which the layers are twisted. After fabricating and measuring several devices with various twist angles, the researchers found that a TBG device exhibits the best result when twisted at an angle of about 1.8 degrees. Such promising optical properties could provide an alternative material platform for tunable mid-infrared optoelectronics, such as efficient photodetection, light modulation and imaging. The researchers further investigated the origin of the photoresponse, and the bolometric effect was identified as the origin. In short, the incident energy in photons is absorbed by the twisted bilayer graphene, leading to its enhanced temperature. As the material conductance varies when temperature changes, the photocurrent emerges.

Bingchen Deng, the first author of the study, and co-author Chao Ma - both Ph.D. students in Xia’s lab - said the next step is applying similar methods to different materials to see what properties they can discover. In particular, this includes optical properties, since the lab has developed the full capability of conducting low-temperature infrared optoelectronic measurements over the years.

Tags:  Barton L. Weller  Fan Zhang  Graphene  Japan  Kenji Watanabe  laboratory of Fengnian Xia  Takashi Taniguchi of National Institute for Materi  University of Texas at Dallas  Yale University 

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Stable skyrmions in graphene-based epitaxial trilayers

Posted By Graphene Council, Monday, June 8, 2020
Recent advances on the stabilization and manipulation of chiral magnetization configurations in systems consisting in alternating atomic layers of ferromagnetic and non-magnetic materials hold promise of innovation in spintronics technology. The low dimensionality of the systems promotes spin orbit driven interfacial effects like antisymmetric Dzyaloshinskii-Moriya interactions (DMI) and surface magnetic anisotropy, whose relative strengths may be tuned to achieve stable nanometer sized magnetic objects with fixed chirality, which are proposed as carriers of information in future spin-orbitronics technology.

While in most of the cases this is obtained by engineering complex multilayers stacks in which interlayer dipolar fields become important, a research team guided by Dr. Paolo Perna at IMDEA Nanociencia and by Oksana Chubykalo-Fesenko at ICMM-CSIC, has considered a simple epitaxial trilayer in which a ferromagnet (namely Cobalt, Co), with variable thickness, is embedded between a heavy metal and graphene. The latter enhances the perpendicular magnetic anisotropy of the system, promotes a Rashba-type DMI, and can sustain very long spin diffusion length. The work, mostly performed by the PhD student they supervise Mr. Pablo Olleros-Rodriguez, consists in the development of a layer-resolved micromagnetic model capable to account for the low dimensionality nature of the interactions, which leads to macroscopic parameters that depend on the thickness of the ferromagnetic layer.

We demonstrate that our model correctly reproduces the experimental magnetization configurations and the spin reorientation transition. In particular, we are able to predict the experimental parameters that will lead to Néel, Bloch or mixed chiral skyrmions. Our results demonstrate that for samples with Co thickness larger than 3.6 nm intrinsic mixed (predominantly Bloch-type) skyrmions are stabilized in 256 nm wide dots.

This work is a collaboration between "SpinOrbitronics" group led by Paolo Perna (IMDEA Nanociencia) and Oksana Chubykalo-Fesenko (ICMM-CSIC) and has been partially funded by the FLAG ERA grant SOgraphMEM, NANOMAGCOST (Comunidad de Madrid), FUN-SOC-RTI2018, SKYTRON-FIS2016, and the Severo Ochoa Programme for Centres of Excellence in R&D awarded to IMDEA Nanociencia.

FLAG-ERA is an ERA-NET (European Research Area Network) initiative that aims to create synergies between new research projects and the Graphene Flagship and Human Brain Project. The goals and activities of FLAG-ERA are, in close connection with the Flagships, to set up mechanisms to facilitate and encourage integration of nationally/regionally funded research into the Flagship work plans. The project SOgraphMEM, recommended for funding to the national/regional research funding organisations of FLAG-ERA by the Joint Translational Call (JTC) 2019 Steering Committee, has recently been chosen as Partnering Project of the Graphene Flagship amongst other 16 newly-funded projects that will receive around €11 million in funding overall. SOgraphMEM is coordinated by Dr. Perna and will investigate the promising of graphene in spintronics, particularly it will test specific materials for a novel branch of spintronics called spin-orbitronics exploiting electron spin and momentum.

Tags:  FLAG-ERA  Graphene  Graphene Flagship  IMDEA Nanociencia  Instituto de Ciencia de Materiales de Madrid  Oksana Chubykalo-Fesenko  Pablo Olleros-Rodriguez  Paolo Perna 

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