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Applied Graphene Materials presents to automotive and aerospace engineers

Posted By Graphene Council, Tuesday, June 23, 2020
SAE International, the global community of 200,000 automotive and aerospace engineers, hosted a virtual conference, WCX Digital Summit, on 16-18 June 2020.

As a guest speaker with The Graphene Council, Adrian Potts CEO, of Applied Graphene Materials gave a presentation titled ‘Graphene for Automotive Applications - Lighter, Stronger, Better

Dr. Potts talks about how to turn the remarkable performance of graphene into reality. Having the application technology to formulate a graphene-based dispersion correctly can make great use of the material’s advantages. The combination of a deep engagement with the end customer, understanding of their objectives, and AGM’s customized graphene dispersion solutions is delivering unique materials performance gains in a number of relevant areas to the automotive industry.

AGM are also leading the way in regulatory matters for use in nano-materials and have an impressive collection of data to support the end user, with practical ‘how-to’ knowledge that enables easy use of graphene.

This session highlighted the different ways graphene can be used to enhance performance in automotive applications.

•   Lighter & Tougher     Graphene in Composites
•   Lighter & Better        Graphene in Thermal applications
•   Better & Longer Life Graphene in Coatings

Tags:  Adrian Potts  Applied Graphene Materials  Graphene  SAE International 

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Vapor fix lifts up perovskite crystal performance

Posted By Graphene Council, Saturday, June 20, 2020
A simple and noninvasive treatment could become a prime post-crystallization process to optimize the optoelectronic properties of hybrid perovskite solar cell materials.

In this treatment devised by KAUST, bromine vapors penetrate the surface of as-synthesized perovskite crystals to reach their deep-lying layers, removing surface and bulk defects generated during crystal growth.

Lead-containing hybrid perovskites, such as methylammonium lead tribromide (MAPbBr3), present unique charge transport properties and easy processability in solution. These make them attractive as potential low-cost alternatives to traditional silicon-based light-harvesting solar cell materials. However, approaches that use solution processing to crystalize them tend to leave contaminants, such as oxygen and amorphous carbon. These approaches also produce halide vacancies that create lead cations, which can trap electrons to form metallic lead and restrict charge transport.

Various chemical treatments can reduce these defects, but most tinker with the composition of the precursor solution to optimize thin film and crystal formation. However, the researchers from the KAUST Solar Center sought something simpler.

"We were interested in developing a facile recipe that could be applied once crystal formation was complete," says Ahmad Kirmani, now a postdoc at the National Renewable Energy Laboratory, U.S., who conducted the study under the supervision of Aram Amassian and Omar Mohammed.

Co-author Ahmed Mansour, now a postdoc at Helmholtz-Zentrum Berlin, Germany, describes how the researchers chose a bromine vapor treatment because they had previously observed the improved conductivity of graphene when exposed to bromine. "Bromine is a volatile liquid at room temperature and readily evaporates without the need for any external source of energy," Mansour says.

The researchers suspended MAPbBr3 crystals in a bromine-vapor-saturated environment and monitored the effects of bromine exposure on material properties.

They were pleasantly surprised to find that bromine vapors suppressed metallic lead on the surface as well as in the bulk of the crystals, Mohammed says. "This meant that we could access the bulk properties of these crystals, such as their electrical conductivity," he adds. Prolonged bromine exposure produced a dramatic 10,000-fold enhancement in bulk electrical conductivity and a 50-fold increase in carrier mobility. Further assessment revealed that perovskite crystallization leaves behind voids and imperfections, which allows bromine to diffuse and permeate through the crystals.

Each of the former team members is currently exploring more applications for their treatment, such as for improving the power conversion efficiency of solar cells containing perovskite thin films as absorbers or for single-crystal devices--such as transistors, photodetectors and radiation detectors--that require excellent carrier mobility and intrinsic optoelectronic properties.

Tags:  Ahmad Kirmani  Graphene  KAUST  Omar Mohammed  optoelectronics 

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Manchester launches spin-out to bring innovative water-filtration technology to market

Posted By Graphene Council, Saturday, June 20, 2020
Scientists and innovation experts from The University of Manchester have worked together to successfully develop a new, market-ready technology using 2D materials that could be a game-changer for the water filtration sector.
ollowing an 18-month technical development and business planning programme - funded by the University - the team of innovators has launched a spin-out company called Molymem Limited to help take the new membrane product into the marketplace. The technology has applications in the pharmaceutical, wastewater management and food and beverage sectors.

The breakthrough development of a high-performing membrane coating is based around a new class of 2D materials, pioneered by Manchester researchers Professor Rob Dryfe and Dr Mark Bissett (pictured right), working with Clive Rowland, team leader for the Molymem project and the University’s Associate Vice-President for Intellectual Property.

Clive explained that membranes are used globally for separation applications in a wide range of valuable markets. “But all of these applications can be expensive,” he added. “They consume high energy and are prone to fouling - and, as a result, require frequent deep cleaning with corrosive chemicals. This causes lost production time and, due to the harsh nature of chemicals being used, it also leads to a deterioration in membrane quality over time.”

Using chemically modified molybdenum disulphide (MoS2), which is widely available at low cost and easily processed, Molymem has developed an energy-efficient and highly versatile membrane coating.

Fast-track innovation
Much of the lab-to-market work was carried out at the Graphene Engineering Innovation Centre (GEIC), which is dedicated to the fast-tracking of pilot innovation around graphene and other 2D materials. Graphene is the world’s first man-made 2D material and offers a range of disruptive capabilities.

Molymem is now ideally placed to raise investment capital to embark on its commercial journey – and interest has already been shown by industrial partners.

James Baker, CEO Graphene@Manchester, said: “The Molymem project demonstrates how the Graphene Engineering Innovation Centre can help to accelerate a breakthrough development in materials science into a brand-new, market-ready product.

“Molymem will now be mentored within the Graphene@Manchester innovation ecosystem as part our portfolio of graphene-based spin-outs. This includes bespoke support such as fundraising for future business development and rapid market development.”

Clive Rowland added: “Over the summer, I will hand-over the team leadership to Ray Gibbs, who is managing the University's graphene and 2D materials spin-out portfolio. Ray will look to fundraise and help take Molymem to the next stage of its exciting innovation journey.”

Tags:  2D materials  Clive Rowland  Graphene  Graphene Engineering Innovation Centre  James Baker  Mark Bissett  Rob Dryfe  University of Manchester  water purification 

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Graphene smart textiles developed for heat adaptive clothing

Posted By Graphene Council, Thursday, June 18, 2020
New research on the two-dimensional (2D) material graphene has allowed researchers to create smart adaptive clothing which can lower the body temperature of the wearer in hot climates.

A team of scientists from The University of Manchester’s National Graphene Institute have created a prototype garment to demonstrate dynamic thermal radiation control within a piece of clothing by utilising the remarkable thermal properties and flexibility of graphene. The development also opens the door to new applications such as, interactive infrared displays and covert infrared communication on textiles.

The human body radiates energy in the form of electromagnetic waves in the infrared spectrum (known as blackbody radiation). In a hot climate it is desirable to make use the full extent of the infrared radiation to lower the body temperature which can be achieved by using infrared-transparent textiles. As for the opposite case, infrared-blocking covers are ideal to minimise the energy loss from the body. Emergency blankets are a common example used to deal with treating extreme cases of body temperature fluctuation.

The collaborative team of scientists demonstrated the dynamic transition between two opposite states by electrically tuning the infrared emissivity (the ability to radiate energy) of graphene layers integrated onto textiles.

One-atom thick graphene was first isolated and explored in 2004 at The University of Manchester. Its potential uses are vast and research has already led to leaps forward in commercial products including; batteries, mobile phones, sporting goods and automotive.

The new research published today in journal Nano Letters, demonstrates that the smart optical textile technology can change its thermal visibility. The technology uses graphene layers to control of thermal radiation from textile surfaces.

The successful demonstration of the modulation of optical properties on different forms of textile can leverage the ubiquitous use of fibrous architectures and enable new technologies operating in the infrared and other regions of the electromagnetic spectrum for applications including textile displays, communication, adaptive space suits, and fashion. Professor Coskun Kocabas

Professor Coskun Kocabas, who led the research, said: “Ability to control the thermal radiation is a key necessity for several critical applications such as temperature management of the body in excessive temperature climates. Thermal blankets are a common example used for this purpose. However, maintaining these functionalities as the surroundings heats up or cools down has been an outstanding challenge.”

Prof Kocabas added: “The successful demonstration of the modulation of optical properties on different forms of textile can leverage the ubiquitous use of fibrous architectures and enable new technologies operating in the infrared and other regions of the electromagnetic spectrum for applications including textile displays, communication, adaptive space suits, and fashion.”

This study built on the same group’s previous research using graphene to create thermal camouflage which was able to fool infrared cameras. The new research can also be integrated into existing mass-manufacture textile materials such as cotton. To demonstrate, the team developed a prototype product within a t-shirt allowing the wearer to project coded messages invisible to the naked eye but readable by infrared cameras.

“We believe that our results are timely showing the possibility of turning the exceptional optical properties of graphene into novel enabling technologies. The demonstrated capabilities cannot be achieved with conventional materials.

“The next step for this area of research is to address the need for dynamic thermal management of earth-orbiting satellites. Satellites in orbit experience excesses of temperature, when they face the sun and they freeze in the earth’s shadow. Our technology could enable dynamic thermal management of satellites by controlling the thermal radiation and regulate the satellite temperature on demand.” said Kocabas.

Professor Sir Kostya Novoselov was also involved in the research: “This is a beautiful effect, intrinsically routed in the unique band structure of graphene. It is really exciting to see that such effects give rise to these high-tech applications.” he said.

Tags:  2D material  Coskun Kocabas  Graphene  nanoparticles  textile  University of Manchester 

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Risk analyses for nanoparticles Nanosafety research without animal experiments

Posted By Graphene Council, Thursday, June 18, 2020
They are already in use in, say, cosmetics and the textile industry: Nanoparticles in sun blockers protect us from sunburn, and clothing with silver nanoparticles slows down bacterial growth. But the use of these tiny ingredients is also linked to the responsibility of being able to exclude negative effects for health and the environment. Nanoparticles belong to the still poorly characterized class of nanomaterials, which are between one and 100 nanometers in size and have a wide range of applications, for example in exhaust gas catalytic converters, wall paints, plastics and in nanomedicine. As new and unusual as nanomaterials are, it is still not clear whether or not they pose any risks to humans or the environment.

This is where risk analyses and life cycle assessments (LCA) come into play, which used to rely strongly on animal experiments when it came to determining the harmful effects of a new substance, including toxicity. Today, research is required to reduce and replace animal experiments wherever possible. Over the past 30 years, this approach has led to a substantial drop in animal testing, particularly in toxicological tests. The experience gained with conventional chemicals cannot simply be transferred to novel substances such as nanoparticles, however. Empa scientists are now developing new approaches, which should allow another substantial reduction in animal testing while at the same time enabling the safe use of nanomaterials.

"We are currently developing a new, integrative approach to analyze the risks of nanoparticles and to perform life cycle assessments," says Beatrice Salieri from Empa's Technology and Society lab in St. Gallen. One new feature, and one which differs from conventional analyses, is that, in addition to the mode of action of the substance under investigation, further data is included, such as the exposure and fate of a particle in the human body, so that a more holistic view is incorporated into the risk assessment.

These risk analyses are based on the nanoparticles' biochemical properties in order to develop suitable laboratory experiments, for example with cell cultures. To make sure the results from the test tube ("in vitro") also apply to the conditions in the human body ("in vivo"), the researchers use mathematical models ("in silico"), which, for instance, rely on the harmfulness of a reference substance. "If two substances, such as silver nanoparticles and silver ions, act in the very same way, the potential hazard of the nanoparticles can be calculated from that," says Salieri. 

But for laboratory studies on nanoparticles to be conclusive, a suitable model system must first be developed for each type of nanoparticle. "Substances that are inhaled are examined in experiments with human lung cells," explains Empa researcher Peter Wick who is heading the "Particles-Biology Interactions" lab in St. Gallen. On the other hand, intestinal or liver cells are used to simulate digestion in the body.

This not only determines the damaging dose of a nanoparticle in cell culture experiments, but also includes all biochemical properties in the risk analysis, such as shape, size, transport patterns and the binding – if any – to other molecules. For example, free silver nanoparticles in a cell culture medium are about 100 times more toxic than silver nanoparticles bound to proteins. Such comprehensive laboratory analyses are incorporated into so-called kinetic models, which, instead of a snapshot of a situation in the test tube, can depict the complete process of particle action.

Finally, with the aid of complex algorithms, the expected biological phenomena can be calculated from these data. "Instead of 'mixing in' an animal experiment every now and then, we can determine the potential risks of nanoparticles on the basis of parallelisms with well-known substances, new data from lab analyses and mathematical models," says Empa researcher Mathias Rösslein. In future, this might also enable us to realistically represent the interactions between different nanoparticles in the human body as well as the characteristics of certain patient groups, such as elderly people or patients with several diseases, the scientist adds.

As a result of these novel risk analyses for nanoparticles, the researchers also hope to accelerate the development and market approval of new nanomaterials. They are already being applied in the "Safegraph" project, one of the projects in the EU's "Graphene Flagship" initiative, in which Empa is involved as a partner. Risk analyses and LCA for the new "wonder material" graphene are still scarce. Empa researchers have recently been able to demonstrate initial safety analyses of graphene and graphene related materials in fundamental in vitro studies. In this way, projects such as Safegraph can now better identify potential health risks and environmental consequences of graphene, while at the same time reducing the number of animal experiments.

Tags:  Beatrice Salieri  Empa  Graphene  Medicine  nanomaterials  nanoparticles 

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CERN trials graphene for magnetic measurements

Posted By Graphene Council, Thursday, June 18, 2020
First isolated in 2004 by physicists at the University of Manchester using pieces of sticky tape and a graphite block, the one-atom-thick carbon allotrope graphene has been touted as a wonder material on account of its exceptional electrical, thermal and physical properties. Turning these properties into scalable commercial devices has proved challenging, however, which makes a recently agreed collaboration between CERN and UK firm Paragraf on graphene-based Hall-probe sensors especially novel.

There is probably no other facility in the world to be able to confirm this, so the project has been a big win on both sides, Ellie Galanis

With particle accelerators requiring large numbers of normal and superconducting magnets, high-precision and reliable magnetic measurements are essential. While the workhorse for these measurements is the rotating-coil magnetometer with a resolution limit of the order of 10–8 Vs, the most important tool for local field mapping is the Hall probe, which passes electrical current proportional to the field strength when the sensor is perpendicular to a magnetic field. 

However, measurement uncertainties in the 10–4 range required for determining field multipoles are difficult to obtain, even with the state-of-the-art devices. False signals caused by non-perpendicular field components in the three-dimensional sensing region of existing Hall probes can increase the measurement uncertainty, requiring complex and time-consuming calibration and processing to separate true signals from systematic errors. With an active sensing component made of atomically thin graphene, which is effectively two-dimensional, a graphene-based Hall probe in principle suffers negligible planar Hall effects and therefore could enable higher precision mapping of local magnetic fields.

Inspiration strikes
Stephan Russenschuck, head of the magnetic measurement section at CERN, spotted the potential of graphene-based Hall probes when he heard about a talk given by Paragraf – a recent spin-out from the department of materials science at the University of Cambridge – at a magnetic measurement conference in December 2018. This led to a collaboration, formalised between CERN and Paragraf in April, which has seen several graphene sensors installed and tested at CERN during the past year. 

The firm sought to develop and test the device ahead of a full product launch by the end of this year, and the results so far, based on well-calibrated field measurements in CERN’s reference magnets, have been very promising. “The collaboration has proved that the sensor has no planar effect,” says Paragraf’s Ellie Galanis. “This was a learning step. There is probably no other facility in the world to be able to confirm this, so the project has been a big win on both sides.”

The graphene Hall sensor also operates over a wide temperature range, down to liquid-helium temperatures at which superconducting magnets in the LHC operate. “How these sensors behave at cryogenic temperatures is very interesting,” says Russenschuck. “Usually the operation of Hall sensors at cryogenic temperatures requires careful calibration and in situ cross-calibration with fluxmetric methods. Moreover, we are now exploring the sensors on a rotating shaft, which could be a breakthrough for extracting local, transversal field harmonics. Graphene sensors could get rid of the spurious modes that come from nonlinearities and planar effects.”

CERN and Paragraf, which has patented a scalable process for depositing two-dimensional materials directly onto semiconductor-compatible substrates, plan to release a joint white paper communicating the results so far and detailing the sensor’s performance across a range of magnetic fields.

Tags:  CERN  Ellie Galanis  Graphene  Paragraf  Sensors  Stephan Russenschuck 

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Khalifa University Researchers Develop Hybrid Graphene-Sand Material to Remove Pollutants from Industrial Wastewater

Posted By Graphene Council, Thursday, June 18, 2020
Khalifa University of Science and Technology today announced a team of researchers has developed a graphene-sand hybrid material capable of absorbing pollutants from industrial wastewater, using two natural resources of great abundance in the UAE – sand and dates.

Safely and affordably removing pollutants from industrial wastewater is a primary focus area for governments worldwide. Conventional methods that are used for removing different harmful pollutants from wastewater suffer from drawbacks such as cost-effectiveness, efficiency, range of applicability, and reusability. Comparatively, adsorption method is a relatively mature, globally-acclaimed, economically feasible, and efficient technology for arresting environmental pollutants.

The Khalifa University research team has developed the graphene-sand hybrid material capable of adsorbing pollutants, which involves attaching pollutants onto small particles that are then easily removed.

While synthesizing graphene-sand adsorbents can be prohibitively expensive, the Khalifa University researchers have turned to a previously unused resource – date syrup – to provide the carbon needed to produce the graphene. The adsorbent can be used as an environmentally benign and scalable option for decontaminating wastewater, with the adsorption capacity far surpassing that of similar reported graphene-based adsorbents.

Led by Dr. Fawzi Banat, Professor, Chemical Engineering, the team includes Anjali Edathil, former Research Engineer, and Shaihroz Khan, visiting Research Assistant. The in-situ strategy used to produce the graphene-sand hybrid with date syrup is described in a paper published in Scientific Reports.

Dr. Banat’s team used pyrolysis – the process of chemically decomposing organic materials at high temperatures in the absence of oxygen – to decompose the date syrup. This triggers a change of chemical composition and the synthesis of a large volume of graphene material, that subsequently attaches to desert sand without the use of any external chemical agents. Moreover, graphene’s high surface area, combined with its versatile chemistry and highly water-repellent surface physical property, makes it an ideal adsorbent for removing pollutants.

Dr. Banat’s graphene-sand hybrid adsorbent was tested in the laboratory and showed remarkable efficiency in simultaneously removing both dye and heavy metals from multicomponent systems. The researchers concluded that their adsorbent had great potential as an exceptional material resource of water purification.

“This will undoubtedly open new avenues for the practicability of graphene to curb the existing water shortage,” said Dr. Banat. “We hope our material will help in increasing water resources in the UAE, reducing energy consumption in wastewater treatment processes and be used to convert oily wastewaters from waste-to-commodity that can be used in applications such as industrial recycling and agriculture.”

Tags:  Fawzi Banat  Graphene  Khalifa University  Water Purification 

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Vittangi Project Supported by National Interest Demarcation

Posted By Graphene Council, Thursday, June 18, 2020
Battery anode and graphene additives company Talga Resources Ltd is pleased to advise of positive developments at its 100% owned Vittangi graphite project in northern Sweden (“Vittangi”).

A recent decision by the Swedish Geological Survey (“SGU”) completed the demarcation of Vittangi as a mineral deposit of national interest1. This designation adds support to consider the exploitation of Vittangi as a mineral deposit when government authorities review development plans and any potential competing land uses.

Under the Swedish Environmental Code, deposits of valuable substances or materials can be defined as being of national interest, meaning municipalities and central government agencies may not authorise activities that might prevent or significantly hinder exploitation of the mineral deposit. The national interest area covers the entirety of Talga’s currently defined Vittangi graphite resources (see Table 1 below), and undrilled extensional deposits, as detailed in Figure 1.

The SGU noted the Vittangi graphite deposit's significance to the country's supply capacity and its special material properties and concluded the deposit constitutes a unique natural asset of valuable substances or materials.

Further, they consider locally produced graphite could help strengthen the competitiveness of the Swedish battery manufacturing industry and that, as the known highest grade graphite deposit in the world, Vittangi could “meet a great need not only within Sweden but internationally”.
The decision2 takes note of the European Commission’s listing of graphite as a critical raw material and their warning that a lack of access to such critical commodities could slow the development of fossil-free energy sources.

Commenting on SGU’s decision, Talga Managing Director Mark Thompson said: "We welcome SGU’s decision as a positive and timely development following Talga’s recent lodgement of the Vittangi Graphite Project mining permit applications, towards becoming Europe’s first vertically integrated producer of Li-ion battery active anode material."

SGU Decision Background
In preparing the demarcation SGU obtained extensive information on the Vittangi Graphite Project including details relating to its geology and material properties. The demarcation defines the boundaries of the original declaration of Nunasvaara as a deposit of national interest which contained only a centre co-ordinate. Results from Talga’s extensive exploration work were made available during the investigation and SGU carried out their own detailed electromagnetic survey to assist in the demarcation, which covers approximately 20km strike of graphite mineralisation.

Competent Persons Statement
The Nunasvaara Mineral Resource estimate was first reported in the Company’s announcement dated 27 April 2017 titled ‘Talga Substantially Increases Flagship Graphite Resource Size, Grade and Status’. The Company confirms that it is not aware of any new information or data that materially affects the information included in the previous market announcement and that all material assumptions and technical parameters underpinning the Resource estimate in the previous market announcement continue to apply and have not materially changed.

The Niska Mineral Resource estimate was first reported in the Company’s announcement dated 15 October 2019 titled ‘Talga boosts Swedish graphite project with maiden Niska resource’. The Company confirms that it is not aware of any new information or data that materially affects the information included in the previous market announcement and that all material assumptions and technical parameters underpinning the Resource estimate in the previous market announcement continue to apply and have not materially changed.

Tags:  Graphene  Graphite  Mark Thompson  Talga Resources 

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ZEN Graphene Solutions Ltd. Reports on Expressions of Interest for Non-Brokered Private Placements of Units

Posted By Graphene Council, Thursday, June 18, 2020
ZEN Graphene Solutions Ltd. is pleased to announce it has received expression of interest from investors in an amount of $1,777,000 for the non-brokered private placement announced on June 15, 2020. These expressions of interest have far exceeded management’s expectation and, subject to TSX Venture Exchange approval, the Company is working diligently to complete the Offering. Management believes that this highlights the progress ZEN has made in becoming an advanced materials graphene company. Following completion of the Offering, ZEN’s cash balance will exceed any balance in recent years thereby ensuring the Company can continue executing its business plan during the COVID-19 pandemic. A subsequent news release will be issued concurrently with the closing of the Offering.

The proceeds of the Offering will be used to fund ongoing work on the Albany Graphite Project including: Graphene research and scale up, COVID-19 initiatives and other graphene application development, and general corporate purposes. All securities issued to purchasers under the Offering will be subject to a four-month hold period from the closing date of the Offering, pursuant to applicable securities legislation and policies of the Exchange. Finders’ fees may be paid, as permitted by Exchange policies and applicable securities law.

Tags:  Graphene  Graphite  ZEN Graphene Solutions 

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Engineers advance insights on black phosphorus as a material for future ultra-low power flexible electronics

Posted By Graphene Council, Thursday, June 18, 2020
Black phosphorus is a crystalline material that is attracting growing research interest from semiconductor device engineers, chemists and material scientists to create high-quality atomically thin films.

From the perspective of a 2D layered material, black phosphorus shows promise for applications in next-generation flexible electronics that could enable advances in semiconductors, medical imaging, night vision and optical communication networks.

As a prospective graphene and silicon substitute, it has outstanding properties like tunable bandgap, which graphene lacks. A bandgap, an energy band in which no electron states can exist, is essential for creating the on/off flow of electrons that are needed in digital logic and for the generation of photons for LEDs and lasers.

Unfortunately, black phosphorus is hard to make and hard to keep. It degrades quickly when exposed to air. Why this happens and the exact mechanisms by which it happens—whether oxygen or moisture in the air degrade or both—remain a topic of active debate in the research community.

Vanderbilt engineering researchers have shown for the first time that the reaction of black phosphorus to oxygen can be observed at the atomic scale using in situ-transmission electron microscopy (TEM).  See YouTube videos.

The results are reported in their paper—Visualizing Oxidation Mechanisms in Few-Layered Black Phosphorus via In Situ Transmission Electron Microscopy—in the American Chemical Society’s Applied Materials & Interfaces journal.

“In research, a lot of times different and often contradictory hypothesis exist in the scientific community. However, the ability to observe a reaction at atomic resolution in real-time offers much needed clarity to propel advances. We are using the insights from our in-situ TEM experiments at atomic resolution in our lab to develop novel synthesis and preservation methods for black phosphorus,” said Piran Kidambi, assistant professor of chemical and biomolecular engineering.

“Current approaches have looked at encapsulating it with an oxide or polymer layer without really understanding why or how the oxidation proceeds,” said Andrew E. Naclerio, second year graduate student in the Department of Chemical and Biomolecular Engineering and the paper’s first author.

“Most understanding of black phosphorus oxidation has been based on results from spectroscopic probes,” said Kidambi, Naclerio’s adviser. In collaboration with Dmitri Zakharov, staff scientist at Brookhaven National Laboratory in Upton, New York, the team used environmental transmission electron microscopy (ETEM), which provides real time in-situ observation of structural  information on a sample and reaction at atomic resolution.

“This is one of the few microscopes in the United States and the world with the capability to perform atomic resolution imaging while introducing gases and heating,” Kidambi said. The collaboration grew from a peer-reviewed user proposal and is funded by Department of Energy (DOE).

“Some insights we obtained were that the reaction proceeds via the formation of an amorphous layer that subsequently evaporates. Different crystallographic edges lead to varying degrees of etching and this agrees well will with theoretical calculations,” Kidambi said.

The collaboration for theoretical calculations with two of the paper’s authors, researchers  Jeevesh Kumar and Mayank Shrivastava at the Indian Institute of Science in Bangalore, was formed at a conference where Kidambi was invited to give a talk.

The team aim to synthesize atomically thin films of black phosphorus using chemical vapor deposition, and insights on oxidation can be used to develop effective passivation techniques.

The Kidambi Research Group in the School of Engineering’s Department of Chemical and Biomolecular Engineering is affiliated with the Vanderbilt Institute of Nanoscale Science and Engineering (VINSE), the Interdisciplinary Materials Science Program and the Vanderbilt University Data Science Institute.

Tags:  Andrew E. Naclerio  Electronics  Graphene  photonics  Piran Kidambi  Vanderbilt Institute of Nanoscale Science and Engi 

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