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First Graphene's Strong Advances in VFD Development

Posted By Graphene Council, Tuesday, January 28, 2020

First Graphene Limited  is pleased to provide an update of the work conducted in conjunction with 2D Fluidics Pty Ltd on the Vortex Fluidic Device (VFD) at the Company’s facilities at the Graphene Engineering and Innovation Centre (GEIC) in Manchester, UK and Flinders University

Background Summary on Graphene Oxide
Graphene oxide (GO) is the chemically modified derivative of graphene, whereby the basal planes and edges have been functionalised with oxygen containing functional groups such as hydroxyl, epoxy and carboxyl groups. These oxygen functionalities make GO hydrophilic and therefore dispersible, forming homogenous colloidal suspensions in water and most organic solvents. This makes it ideal for use in a range of applications.

To date, the most widely used process for the synthesis of graphene oxide is Hummer’s method. This typically  requires strong acids and oxidants, such as potassium chlorate (KClO3), nitric acid (HNO3), concentrated sulfuric acid (H2SO4) and potassium permanganate (KMnO4). Much work has been done to improve the synthesis methods while maintaining high surface oxidation, however these all required strong acids and oxidants.

Through its subsidiary 2D Fluidics Pty Ltd, FGR is developing a more benign processing route for oxidised graphene. The objective is to provide controlled levels of surface oxygen functionality to give better easier compatibility in aqueous and organic systems. This will not incur the higher oxygen (and other defect) levels which result from Hummer’s method and its subsequent reduction steps. It will also provide the ability to “tune or optimise” the surface oxidation level to suit respective applications.

FGR’s method synthesises GO directly from bulk graphite using aqueous H2O2 as the green oxidant. Different energy sources have been used for the conversion of H2O2 molecules into more active peroxidic species, such as a combination of a pulsed Nd:YAG laser and/or other light sources. The irradiation promotes the dissociation of H2O2 into hydroxyl radicals which then leads to surface oxidation.

The technology has been successfully transferred to the FGR laboratories at the Graphene Engineering and Innovation Centre (GEIC) in Manchester where it has undergone further development and optimisation to identify, understand and resolve future upscaling issues.

XPS analysis showed that the use of pre-treatment step in combination with the near infrared laser gave oxidised graphene sheets with an average surface oxidation of ~30- 35%: this will enhance compatibility with aqueous systems.

Further trials have already demonstrated that the two-step process is reproducible and versatile, with the ability to process different starting materials of graphite. The multi- disciplinary team has identified that control of the feed rate and energy input will allow us to control the surface oxidation, providing a consistent material that can be tailored as required for a range of applications.

Figure 5 shows that increase in surface oxygen content for two starting materials: graphite ore (top) and PureGRAPH® graphene (bottom). As we go through the two-  stage process, in both cases the surface oxygen functionality increases. The end- product has a range of functional groups, including C-O, C=O and COOH.

Next Steps
Operating parameters will now be established to provide yield data for future use in scaling the system for commercial production. It will also commence examining the end applications including, but not limited to the use in electronic devices, testing levels of toxicity for biological applications, for water filtration membranes and incorporation in membranes for studying anti-fouling properties.

Craig McGuckin, Managing Director of FGR, said, “The complementary characterisation techniques used to confirm the synthesis of oxidised graphene gives us confidence we are on the right route towards fabricating a material which is comparable to  the historical GO fabricated using the conventional Hummers method. We are  now  reviewing end applications and thus exploring a number of avenues which include but are not limited to the use in devices, testing levels of toxicity for biological applications, for water filtration membranes and incorporation in membranes for studying anti-fouling properties.”

Tags:  2D Fluidics Pty Ltd  2D materials  Craig McGuckin  First Graphene  Flinders University  Graphene  Graphene Engineering and Innovation Centre  graphene oxide 

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Tuning of optical absorbance of graphene quantum dots by high magnetic fields

Posted By Graphene Council, Monday, January 27, 2020

Recently, a Chinese research team reported (Biomaterials, "Magnetic-induced graphene quantum dots for imaging-guided photothermal therapy in the second near-infrared window") the synthesis of graphene quantum dots (GQDs) under an external high magnetic field (HMF) and their applications in photothermal therapy (PTT).

GQDs plays an increasingly important role in medical areas due to tunable optical behavior, good chemical stability, excellent biocompatibility and easy removal by the kidney.

However, the optical absorption of reported GQDs is mainly concentrated in the NIR-I region, which limits their PTT application in the longer wavelength region ( >1000 nm) because of the absorption and scattering of skin and tissue.

At present, methods to adjust the absorbance of GQDs mainly include surface passivation, heteroatom doping and size correction, which cannot achieve NIR-II absorbance of GQDs.

By introducing HMF during the preparation of GQDs, the joint team used phenol molecules as single precursors and hydrogen peroxide as oxidant, and the resulting 9T-GQDs were expected to possess strong absorbance in NIR-II region for improvement of their applications in PTT.

Compared with the GQDs obtained without HMF (named as 0T-GQDs), 9T-GQDs showed obvious absorbance in NIR-II region (∼1070 nm).

At the same time, 9T-GQDs had a fluorescence quantum yield of 16.67% and a photothermal conversion efficiency of 33.45%. In vivo experiments showed that 9T-GQDs had a significant inhibitory effect on tumor growth in mice in the treatment of photothermal cancer guided by NIR-II region imaging.

The joint research team was led by Prof. WANG Hui with High Magnetic Field Laboratory of the Chinese Academy of Sciences, Prof. CHEN Qianwang with University of Science and Technology of China and Prof. NIE Rongrong from Medical School of Nanjing University

Tags:  CHEN Qianwang  Chinese Academy of Sciences  Graphene  Healthcare  NIE Rongrong  WANG Hui 

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INST Mohali moving towards a globally competitive institution in Nano Science & Technology

Posted By Graphene Council, Monday, January 27, 2020
A cost-efficient and scalable method for graphene-based integrated on-chip micro supercapacitor, which is a miniaturized electrochemical storage device. A 'Nano-Spray Gel' that could be administered on-site for treatment of frostbite injuries and heal the wound; a novel low cost topical hemostatic device to address uncontrolled bleeding, purification devices for water and air respectively.

These are only some of the technologies rolled out by the Institute of Nanoscience and Technology (INST), one of the youngest autonomous institutions of the Department of Science and Technology. INST encourages all aspects of nanoscience and nanotechnology with major thrust in the areas of healthcare, agriculture, medical environment and energy with the ultimate goal to make a difference to society through nanoscience and technology.

INST brings together biologists, chemists, physicists, materials scientists, and engineers having an interest in nanoscience and technology. The scientists, having strengths in basic science together with more application-oriented minds from different backgrounds, work together by joining hands as a cohesive unit, under a congenial work environment, on a common platform apart from carrying out their individual research.

INST offers Ph.D. and Postdoctoral fellowships to students as part of its human resource development objective. Through its various activities, INST is committed to contribute significantly to the National Societal Programs like Swachh Bharat Abhiyan, Swasth Bharat, Smart Cities, Smart Villages, supporting the Strategic Sector, Make in India and Clean & Renewable Energy through scientific means and by generating processes, technologies and devices.

The institute encourages its scientists to publish their research in peer-reviewed international high impact journals which is reflected in their recent publication record in reputed journals like Energy and Environment, Nature Communication, JACS etc.INST supports industry’s through joint collaborations to address some of their needs like effluent management.

In addition, the institute imparts advanced training courses and laboratory techniques in the area of nanoscience, organizes important national and international level seminars and conferences, and supports the industry through joint industrial projects.INST is also promoting science amongst the young generation of the nation through its outreach program, especially for rural, remote and under-served schools by delivering talks to motivate the students to explore the world of science.

INST Mohali aims to emerge as India’s foremost research institution in Nano Science and Technology, which is globally competitive and contributes to the society through the application of nanoscience and nanotechnology in the field of healthcare, agriculture, energy and environment.

Tags:  Graphene  Institute of Nanoscience and Technology  nanotechnology  supercapacitor  water purification 

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First Graphene Announces Steel Blue Signs Supply Agreement

Posted By Graphene Council, Monday, January 27, 2020

First Graphene is pleased to announce the execution of a supply agreement with Footwear Industries Pty Ltd (trading as “Steel Blue”) for the exclusive supply of PureGRAPH®10 for a twenty-four month term (“Supply Agreement”).

In August 2019, FGR announced that it was able to successfully incorporate PureGRAPH® into a thermoplastic polyurethane (“TPU”). Previously, the ability to successfully disperse graphene into a TPU masterbatch had been a major limitation for the graphene industry. Extensive research by FGR has resulted in a manufacturing method which has overcome this.

While existing TPU’s already possess high abrasion resistance and tensile strength, the incorporation of PureGRAPH® has improved mechanical properties while providing additional benefits in thermal heat transfer and chemical resistance whilst also reducing permeability.

Steel Blue will look to release future work boots with graphene components, including a TPU sole. This will potentially provide new design solutions and improvements in manufacturing processes and the comfort of the boot.

As announced on 15 November 2019, tests on prototype boots were conducted at Viclab Pty Ltd, one of Australia’s leading NATA accredited and independent mechanical testing services. The prototype boots complied with the following test procedures:

Impact resistance
Upper to outsole bond
Interlayer bond strength
Slip resistance on ceramic tile floor with NaLS and on steel floor with glycerine
Sole crack resistance
Tear strength
Abrasion (TPU)
Tensile
Hydrolysis
Fuel oil resistance
Chemical exposure (NaOH)

By including PureGRAPH® additives into the sole, improvements in key properties such as tear strength and abrasion resistance have been measured. Steel Blue have continued to test different applications and processes, with ongoing measuring of outcomes by Viclab Pty Ltd.

Upon successful testing, Steel Blue will look to incorporate PureGRAPH into existing and future models of boots, including the mid-sole and Metguard.

Other Key Terms of Supply Agreement
Pursuant to the Supply Agreement, Steel Blue will exclusively source graphene and any other graphite or graphene products from FGR.

FGR’s supply of its graphene products to Steel Blue will initially be exclusive for application in the production of safety footwear for sale in Australia and New Zealand. Following the initial term, exclusivity will only be available to Steel Blue if Steel Blue has achieved (and continues to maintain) a minimum order quantity. The initial minimum order quantity to be achieved in the second year of the Supply Agreement is two (2) tonnes of PureGRAPH®. Based on the currently agreed ordering schedule, product supply to Steel Blue in year one is anticipated to progress to an annualised basis of one (1) tonne as adoption commences across the Steel Blue footwear range and product lines.

Each party has the right to early termination if there is a material breach of the obligations of the other party. Additionally, Steel Blue has the option to extend the initial 24-month term for an additional 48 months.
 
Craig McGuckin, Managing Director for First Graphene Ltd., said, “The execution of this Supply Agreement represents the first of several anticipated for 2020. We are pleased to have worked with Steel Blue to develop a unique range of safety boots for local and export markets. Graphene is helping our customers to develop new products not previously seen with non-graphene technologies. PureGRAPH® additives are a key enabler in taking elastomers, composites, coatings and concrete materials to a new level and we will continue to seek out further new applications and markets where graphene can add value.”

Garry Johnson, Chief Executive Officer of Steel Blue said “Steel Blue is committed to developing innovative solutions for our customers. We’re excited by the product we have developed with First Graphene. These are two innovative, Western Australian founded companies who are taking new technologies to a world market.’’

Tags:  Craig McGuckin  First Graphene  Garry Johnson  Graphene  Steel Blue 

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Well-designed substrates make large single crystal bi-/tri-layer graphene possible

Posted By Graphene Council, Sunday, January 26, 2020
Researchers of the Center for Multidimensional Carbon Materials (CMCM) within the Institute for Basic Science (IBS, South Korea) have reported in Nature Nanotechnology the fabrication and use of single crystal copper-nickel alloy foil substrates for the growth of large-area, single crystal bilayer and trilayer graphene films.

The growth of large area graphene films with a precisely controlled numbers of layers and stacking orders can open new possibilities in electronics and photonics but remains a challenge. This study showed the first example of the synthesis of bi- and trilayer graphene sheets larger than a centimeter, with layers piled up in a specific manner, namely AB- and ABA-stacking.

“This work provides materials for the fabrication of graphene devices with novel functions that have not yet been realized and might afford new photonic and optoelectronic and other properties,” explains Rodney S. Ruoff, CMCM Director, Distinguished Professor at the Ulsan National Institute of Science and Technology (UNIST) and leading author of this study. Coauthor and Professor Won Jong Yoo of Sungkyunkwan University notes that “this paves the way for the study of novel electrical transport properties of bilayer and trilayer graphene.”

For example, the same IBS research group and collaborators recently published another paper in Nature Nanotechnology showing the conversion of AB-stacked bilayer graphene film, grown on copper/nickel (111) alloy foils (Cu/Ni(111) foils), to a diamond-like sheet, known as diamane. Coauthor Pavel V. Bakharev notes that: “Less than one year ago, we produced fluorinated diamond monolayer, F-diamane, by fluorination of exactly the AB-stacked bilayer graphene films described in this new paper. Now the possibility of producing bilayer graphene of a larger size brings renewed excitement and shows how fast this field is developing.”

The right choice of substrate is essential for the correct growth of graphene. Foils made only of copper limit the growth of bilayer graphene and favor uniform monolayer growth. It is possible to obtain multilayer graphene sheets on nickel film, but these are not uniform, and tend to have small “patches” with different thicknesses. Finally, the commercially available foils that contain both nickel and copper are not ideal. Therefore, IBS researchers prepared ‘home-made’ single crystal Cu/Ni(111) foils with desired features, building further on a technique reported by the group in Science in 2018. Nickel films are electroplated onto copper(111)-foils so that the nickel and copper interdiffuse when heated and yield a new single crystal foil that contains both elements at adjustable ratios. Ruoff suggested this method and supervised Ming Huang’s evaluations of the best concentrations of nickel to obtain uniform graphene sheets with the desired number of layers.

IBS researchers grew bi- and tri-layer graphene sheets on Cu/Ni(111) foils by chemical vapor deposition (CVD). Huang achieved AB-stacked bilayer graphene films of several square centimeters, covering 95% of the substrate area, and ABA-stacked trilayer graphene with more than 60% areal coverage. This represents the first growth of high coverage ABA-stacked trilayer graphene over a large area and the best quality obtained for AB-stacked bilayer graphene so far.

In addition to extensive spectroscopic and microscopic characterizations, the researchers also measured the electrical transport (carrier mobility and band gap tunability) and thermal conductivity of the newly synthesized graphene. The centimeter-scale bilayer graphene films showed a good thermal conductivity, as high as ~2300 W/mK (comparable with exfoliated bilayer graphene flakes), and mechanical performance (stiffness of 478 gigapascals for the Young’s modulus, and 3.31 gigapascals for the fracture strength).

The team then investigated the growth stacking mechanism and discovered it follows the so-called “inverted wedding cake” sequence as the bottom layers are positioned after the top one. “We showed with three independent methods that the 2nd layer for bilayer graphene, and the 2nd and 3rd layers of the trilayer sheet grow beneath a continuous top layer. These methods can be further used to study the structure and stacking sequence of other 2D thin film materials,” notes Huang.

Ruoff notes that these techniques for synthesizing and testing large-scale ultrathin films could stimulate worldwide interest in further experimenting with single crystal Cu/Ni alloy foils, and even in exploring fabrication and use of other single crystal alloy foils. This research was performed in collaboration with UNIST and Sungkyunkwan University.

Tags:  2D materials  Center for Multidimensional Carbon Materials  Graphene  Institute for Basic Science  nanomaterials  nanotechnology  Rodney S. Ruoff 

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Physicist obtain atomically thin molybdenum disulfide films on large-area substrates

Posted By Graphene Council, Thursday, January 23, 2020
Researchers from the Moscow Institute of Physics and Technology have managed to grow atomically thin films of molybdenum disulfide spanning up to several tens of square centimeters. It was demonstrated that the material's structure can be modified by varying the synthesis temperature. The films, which are of interest to electronics and optoelectronics, were obtained at 900-1,000 degrees Celsius. The findings were published in the journal ACS Applied Nano Materials.

Two-dimensional materials are attracting considerable interest due to their unique properties stemming from their structure and quantum mechanical restrictions. The family of 2D materials includes metals, semimetals, semiconductors, and insulators. Graphene, which is perhaps the most famous 2D material, is a monolayer of carbon atoms. It has the highest charge-carrier mobility recorded to date. However, graphene has no band gap under standard conditions, and that limits its applications.

Unlike graphene, the optimal width of the bandgap in molybdenum disulfide (MoS2) makes it suitable for use in electronic devices. Each MoS2 layer has a sandwich structure, with a layer of molybdenum squeezed between two layers of sulfur atoms. Two-dimensional van der Waals heterostructures, which combine different 2D materials, show great promise as well. In fact, they are already widely used in energy-related applications and catalysis. Wafer-scale (large-area) synthesis of 2D molybdenum disulfide shows the potential for breakthrough advances in the creation of transparent and flexible electronic devices, optical communication for next-generation computers, as well as in other fields of electronics and optoelectronics.

"The method we came up with to synthesize MoS2 involves two steps. First, a film of MoO3 is grown using the atomic layer deposition technique, which offers precise atomic layer thickness and allows conformal coating of all surfaces. And MoO3 can easily be obtained on wafers of up to 300 millimeters in diameter. Next, the film is heat-treated in sulfur vapor. As a result, the oxygen atoms in MoO3 are replaced by sulfur atoms, and MoS2 is formed. We have already learned to grow atomically thin MoS2 films on an area of up to several tens of square centimeters," explains Andrey Markeev, the head of MIPT's Atomic Layer Deposition Lab.

The researchers determined that the structure of the film depends on the sulfurization temperature. The films sulfurized at 500 ? contain crystalline grains, a few nanometers each, embedded in an amorphous matrix. At 700 ?, these crystallites are about 10-20 nm across and the S-Mo-S layers are oriented perpendicular to the surface. As a result, the surface has numerous dangling bonds. Such structure demonstrates high catalytic activity in many reactions, including the hydrogen evolution reaction. For MoS2 to be used in electronics, the S-Mo-S layers have to be parallel to the surface, which is achieved at sulfurization temperatures of 900-1,000 ?. The resulting films are as thin as 1.3 nm, or two molecular layers, and have a commercially significant (i.e., large enough) area.

The MoS2 films synthesized under optimal conditions were introduced into metal-dielectric-semiconductor prototype structures, which are based on ferroelectric hafnium oxide and model a field-effect transistor. The MoS2 film in these structures served as a semiconductor channel. Its conductivity was controlled by switching the polarization direction of the ferroelectric layer. When in contact with MoS2, the La:(HfO2-ZrO2) material, which was earlier developed in the MIPT lab, was found to have a residual polarization of approximately 18 microcoulombs per square centimeter. With a switching endurance of 5 million cycles, it topped the previous world record of 100,000 cycles for silicon channels.

Tags:  2D materials  ACS Applied Nano Materials  Andrey Markeev  Graphene  Moscow Institute of Physics and Technology  Optoelectronics  Semiconductors 

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Universities Minister celebrates Manchester’s materials reputation

Posted By Graphene Council, Wednesday, January 22, 2020
Advanced Materials were at the centre of the agenda for the Minister for Universities, Science, Research and Innovation, Chris Skidmore, last week during a thorough tour of The University of Manchester campus.

The Minister visited the University to discover more about the soon-to-open Henry Royce Institute, hear about the most recent graphene developments, discover more about how the AI and robotics are helping to solve challenges faced by the nuclear industry and finally tour the north campus and future home of IDManchester.

During the tour, the Minister, who was accompanied by President and Vice-Chancellor, Professor Dame Nancy Rothwell, met with leading academics and discussed breakthrough developments at the University since he last visited the campus just over a year ago.

Professor Phil Withers greeted the Minister to discuss and take-in the the new soon-to-open £150m Royce building, a new national hub for advanced materials research and commercialisation.

During the visit Chris Skidmore said: “The University of Manchester is doing amazing research in areas like x-ray imaging systems and the super material graphene. Outstanding university research like this will help build our reputation as a global science superpower while growing our economy, and it was a privilege to witness it first-hand.”

The University of Manchester is doing amazing research in areas like x-ray imaging systems and the super material graphene. Outstanding university research like this will help build our reputation as a global science superpower while growing our economy, and it was a privilege to witness it first-hand, Chris Skidmore, Minister of State for Universities, Science, Research and Innovation.

The delegation then visited state-of-the-art research facilities of the National Graphene Institute (NGI) with Professor Sir Andre Geim, who received a Nobel Prize for his work on initially isolating the two-dimensional (2D) material in 2004 and continues to explore and develop the untapped potential of related 2D materials in Manchester.

The NGI, along the with Graphene Engineering Innovation Centre (GEIC) forms the heart of Graphene City, an entire city-centre based end-to-end ecosystem to research, develop and commercialise unique graphene applications in tandem with industry.

A tour of the Manchester Institute of Biotechnology (MIB) was also on the agenda to visit the labs at the heart of the pioneering research led by Professor Nigel Scrutton and team which was recently honoured with the Queen's Anniversary Prize. The MIB was singled out as a beacon of excellence for being at the forefront of designing a sustainable future for the UK and communities across the world by developing disruptive bio-based technologies.

The visit concluded with the Minister heading to the RAIN project which uses robotic and AI technologies to solve challenges faced by the nuclear industry. It is led by Barry Lennox, Professor of Applied Control in the School of Electrical and Electronic Engineering,

Tags:  2D materials  Chris Skidmore  Dame Nancy Rothwell  Graphene  Graphene Engineering Innovation Centre  Phil Withers  University of Manchester 

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Talga Completes 2nd Commercial Scale Graphene Coating Trial

Posted By Graphene Council, Wednesday, January 22, 2020
Talga Resources Ltd announced the commencement of a new large scale commercial trial of its Talcoat graphene additive for maritime coatings.

At the core of the Talcoat product is Talga’s new patent-pending graphene functionalization technology in the form of an on-site dispersible powder that can successfully add graphene’s exceptional strength into paint and coatings.

Supported by the same shipowner, Talga has provided its next-generation graphene additive to enhance a primer coating successfully applied over a sizeable area of a second large container ship.

Unlike the first trial, the Talcoat product and the 2-part epoxy-based commercial coating system were supplied separately and mixed on-site by the paint applicators before spray application to the vessel during dry-docking.

The application of the coating was successful in meeting all conditions and standards required for ships of this size, confirming the potential of the Talcoat product as a ready-mix component for on-site incorporation by coating companies or paint applicators alike.

To further test the versatility and compatibility of the Talcoat additive, the trial used a commercial coating system from a world-leading coating supplier different from that used in the first trial.

The ocean-going cargo vessel, of similar size to the initial container ship being approximately 225m long and weighing 33,000 tons, has re-entered service at sea where over the next 12-18 months the test area will be evaluated on the performance boost delivered to the coating system.

“We continue taking graphene out of the lab and into the real world with these large scale coating trials underway on cargo ships," Talga Managing Director Mark Thompson said. "This application joins the other large scale clean technology product verticals we have been developing for several years such as graphene-enhanced concrete, plastics and packaging products.” 

Tags:  Coatings  Graphene  graphene additives  Mark Thompson  Talga Resources 

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New Chair in Materials Physics and Innovation Policy

Posted By Graphene Council, Tuesday, January 21, 2020
The University of Manchester has appointed Richard Jones as a new Chair in Materials Physics and Innovation Policy, joining Manchester from the University of Sheffield.

Richard is an experimental soft matter physicist. His first degree and PhD in Physics both come from Cambridge University. Following postdoctoral work at Cornell University, USA, he was a lecturer at the University of Cambridge’s Cavendish Laboratory, before moving to Sheffield in 1998. In 2006 he was elected a Fellow of the Royal Society, in recognition of his work in the field of polymers and biopolymers at surfaces and interfaces, and in 2009 he won the Tabor Medal of the UK’s Institute of Physics for his contributions to nanoscience.

He is the author of more than 190 research papers, and three books, Polymers at Surfaces and Interfaces (with Randal Richards, CUP 1999), Soft Condensed Matter, (OUP 2002), and Soft Machines: Nanotechnology and Life (OUP 2004).

He was Pro-Vice-Chancellor for Research and Innovation at Sheffield from 2009 to 2016, was a member of EPSRC Council from 2013 – 2018, and chaired Research England’s Technical Advisory Group for the Knowledge Exchange Framework. He has written extensively about science and innovation policy, and was a member of the Sheffield/Manchester Industrial Strategy Commission.

Richard will join the Faculty of Science and Engineering and contribute to the pioneering work in advanced materials that is currently being carried out at Manchester. The University is home to several major national materials research centres including the National Graphene Institute, the Graphene Engineering Innovation Centre and the soon-to-open Henry Royce Institute for advanced materials research and innovation.

Richard is a greatly respected materials physicist who has also made very significant contributions to major national and international activities and to the areas of regional economic growth, productivity and prosperity. I am delighted that he will be joining us, President and Vice-Chancellor, Professor Dame Nancy Rothwell.

Richard said: “Manchester is one of the world’s great universities, whose research in many fields, including advanced materials, has international reach. In addition to its national importance, it plays a central role in driving economic growth and prosperity in the city and across the North of England. This is an exciting time to join The University of Manchester and I’m looking forward to being part of this important work.”

Professor Dame Nancy Rothwell, President and Vice-Chancellor of The University of Manchester said: “Richard is a greatly respected materials physicist who has also made very significant contributions to major national and international activities and to the areas of regional economic growth, productivity and prosperity. I am delighted that he will be joining us.”

Professor Martin Schröder, Vice President and Dean of the University’s Faculty of Science and Engineering, added: “I am thrilled and delighted to welcome Professor Richard Jones to the University.

“Richard is a renowned experimental physicist with a focus on materials science, specialising in the properties at surfaces and interfaces. Richard has wider interests in the social and economic consequences of nanotechnology and has contributed significantly to innovation within the higher education sector. I very much look forward to working with Richard and developing and delivering new initiatives across science and engineering.”

Tags:  Dame Nancy Rothwell  Graphene  Martin Schröder  Richard Jones  University of Manchester 

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Adding graphene to amorphous carbon random-access memories could lead to smaller memory devices that consume less power

Posted By Graphene Council, Tuesday, January 21, 2020
Researchers at Graphene Flagship partner the Cambridge Graphene Centre, University of Cambridge, have developed a new type of resistive memory that can be scaled down beyond current limitations. They also collaborated with colleagues at Soochow University to discuss the state-of-the-art technology and evaluate the future of resistive memories based on graphene and related materials (GRMs). Furthermore, Graphene Flagship partners at CNRS, France, and CSIC and ICREA, Spain, along with SAC member Luigi Colombo, analysed the properties and device structures required for practical GRM-based memory devices to reach their potential.

Data storage in computers comes in two distinct flavours: volatile and non-volatile memory, and both are essential in modern electronic devices. Volatile memory is used in random access memory (RAM) and computer processors to store temporary data, whereas non-volatile memory is used in hard drives and flash drives for long-term data storage.

Over the past 25 years, this technology has advanced tremendously – with Moore's Law predicting a near-doubling in the number of transistors on a microchip every two years, while the cost of computers roughly halves. For most of the past few decades, this has resulted in exponential growth in computer storage space and a corresponding reduction in size. But Moore's Law is dying, and we are rapidly approaching the physical limits of data storage. One of the reasons for this is that when the size of memory devices approaches the nanometer scale, leakage currents in capacitors lead to severe data losses.

By integrating a layer of graphene into resistive RAM devices made with tetrahedral amorphous carbon, Graphene Flagship scientists have now developed a new type of memory that can be scaled down beyond previous size limitations. The new memory devices could lead to better-performing computers and personal electronics with much larger storage capacities. In the devices, tetrahedral amorphous carbon, which has high electrical resistance, is sandwiched between two electrodes. When an electric field is applied between the electrodes, a conductive path forms in the carbon layer, connecting the two electrodes and forming a low resistance state. The high- and low-resistance states can be used to encode data in the form of binary 1s and 0s.

In their paper, published in the journal 2D Materials, Graphene Flagship partner University of Cambridge showed that by adding a graphene layer between an amorphous carbon layer and one of the electrodes, they can significantly improve the performance of the memory and suppress the leakage current that leads to data loss. "Leakage currents become more dominant as device sizes get smaller, and it's important that the two memory states – the high- and low-resistance states, or the ones and zeroes – are not too close together," explains Anna Ott from the Cambridge Graphene Centre. "Adding a graphene layer improves this ratio by an order of magnitude and suppresses the leakage current, showing that amorphous carbon-based memories are suitable for achieving the smallest possible memory size."

In their Advanced Electronic Materials paper, the Graphene Flagship researchers conclude that the main challenges facing scientists developing new, state-of-the-art resistive RAM devices, are creating durable devices that can run for over 109 switching cycles and achieving data retention times of over 10 years. The researchers find that augmenting resistive RAM with GRMs results in highly stable devices with very promising performance. They show that GRMs are already fit for some non-volatile memory requirements, and that they can be a promising alternative to currently used technologies. 

In the Advanced Materials publication, the Graphene Flagship researchers state that for these technologies to be realized, scientists must focus on two main areas of progress: high-speed and high-capacity non-volatile memories and low-cost, flexible and transparent storage devices for wearable electronics. "You normally need one to two decades of intense research before an exciting proof-of-concept like this can turn into a game-changing technology and hit the market," comments Samorì from Graphene Flagship Partner University of Strasbourg. He emphasizes that this is feasible, but sustainable and continuous funding support will be needed before it can become a reality.

Indeed, Ott explains that graphene-enabled memory devices compare well to state-of-the-art: in terms of speed, they are faster than traditional flash memories, comparable to the dynamic RAM common in today's computer components, and slower than static RAM, which Ott says is expected. "Carbon-based resistive RAM provides much better scaling possibilities compared to static and dynamic RAM and flash memories. We can also add oxygen to get oxygen-amorphous carbon, which improves the endurance – how many times the device can be switched between the two resistance states – to be comparable to flash memories," she continues.

Daniel Neumaier, leader of the Graphene Flagship's Electronic Devices Work Package, comments: "These papers are highly valuable for scientists trying to create smaller and smaller resistive RAM technology. Data loss due to leakage currents is one of the main problems in nanoscale-sized memory devices, and the work demonstrates that incorporating tetrahedral amorphous carbon reduces this problem."

Further collaborations could lead to graphene-integrated memories hitting the market. However, the integration of GRMs into memory manufacturing processes may be a challenge. "This will be one of the main issues to overcome in order to bring graphene from laboratories to factories," concludes Ott.

Andrea C. Ferrari, Science and Technology Officer of the Graphene Flagship and Chair of its Management Panel, adds: "These publications show that graphene and related materials are finding their way into new applications of resistive memories. These are at the centre of an ever-increasing research effort and, yet again, the Graphene Flagship and its collaborators are at the forefront of not just novel research, but also of the outlining of future directions."

Tags:  2D materials  Andrea C. Ferrari  Anna Ott  Daniel Neumaier  Graphene  Graphene Flagship  University of Cambridge 

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