Plastic analog–digital converter bring applications in the food and pharmaceuticals industries within reach, can greatly reduce food waste worldwide Less than one cent

Plastic analog–digital converter bring applications in the food and pharmaceuticals industries within reach, can greatly reduce food waste worldwide Less than one cent.

Invention opens the way to packaging that monitors food freshness - New plastic electronics can greatly reduce food waste worldwide

Millions of tons of food are thrown away each year because the 'best before' date has passed. But this date is always a cautious estimate, which means a lot of still-edible food is thrown away. Wouldn't it be handy if the packaging could 'test' whether the contents are still safe to eat? Researchers at Eindhoven University of Technology, Universitá di Catania, CEA-Liten and STMicroelectronics have invented a circuit that makes this possible: a plastic analog–digital converter. This development brings plastic sensor circuits costing less than one euro cent within reach. Beyond food, these ultra-low-cost plastic circuits have numerous potential uses, including, pharmaceuticals. The invention was presented last week at the ISSCC in San Francisco, the world's most important conference on solid-state circuits.

Consumers and businesses in developed countries throw away around 100 kilograms of food per person (*), mainly because the 'best before' date on the packaging has passed. That waste is bad for consumers' budgets and for the environment. Much of this wastage results from the difficulty in estimating how long food will stay usable. To minimize the risk of selling spoiled food to consumers, producers show a relatively short shelf life on their packaging.

Caption: This image shows the plastic analog-to-digital converter (ADC). The ADC shown is still relatively large, but in its final form it will be smaller. Credit: Eindhoven University of Technology/Bart van Overbeeke Usage Restrictions: None

Less than one cent To fight food waste, producers could include an electronic sensor circuit in their packaging to monitor the acidity level of the food, for example. The sensor circuit could be read with a scanner or with your mobile phone to show the freshness of your steak, or whether your frozen food was defrosted. Researcher Eugenio Cantatore of Eindhoven University of Technology (TU/e): "In principle that's all already possible, using standard silicon ICs. The only problem is they're too expensive. They easily cost ten cents. And that cost is too much for a one euro bag of crisps. We're now developing electronic devices that are made from plastic rather than silicon. The advantage is you can easily include these plastic sensors in plastic packaging." The plastic semiconductor can even be printed on all kinds of flexible surfaces, which makes it cheaper to use. And it makes sensor circuits costing less than one eurocent achievable. The very first printed ADC The researchers have succeeded in making two different plastic ADCs (analog-to-digital converters).

Each converts analog signals, such as the output value measured by a sensor, into digital form. One of these new devices is the very first printed ADC ever made. "This paves the way toward large area sensors on plastic films in a cost-effective way through printing manufacturing approaches", says Isabelle Chartier, Printed Electronics Business developer at CEA-Liten. The ISSCC rated the papers on these inventions as highlights of the conference.

Missing link

The new plastic ADCs bring applications in the food and pharmaceuticals industries within reach. A sensor circuit consists of four components: the sensor, an amplifier, an ADC to digitize the signal and a radio transmitter that sends the signal to a base station. The plastic ADC has been the missing link; the other three components already exist. "Now that we have all of the pieces, we need the integration," says Cantatore. He expects that it will still take at least five years before we can expect to see the new devices on supermarket shelves. Other potential applications are in pharmaceuticals, man-machine interfaces and in ambient intelligence systems in buildings or in transport.

Complex mathematics

Making this development was no easy task. The electrical characteristics of 'ordinary transistors' are highly predictable, while those of plastic transistors vary greatly. "All plastic transistors behave differently in the low-cost production processes at low temperatures," explains Cantatore. "That makes it much more difficult to use them in devices. You need complex mathematical models to be able to predict their behavior accurately."

The printed ADC circuit offers a resolution of four bits, and has a speed of two hertz. The circuits printed by CEA-Liten include more than 100 n- and p-type transistors and a resistance level on transparent plastic substrates. The carrier mobility of the printed transistors are above the amorphous silicon widely used in the display industry.

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This development falls under the Cosmic project supported by the EU and the ORICIS project supported by Dutch Technology Foundation STW and the Holst Centre/TNO.

(*) 'Global Food Losses and Food Waste', a study by the Food and Agriculture Organization of the United Nations (FAO), 2011


Contact: Eugenio Cantatore e.cantatore@tue.nl 31-613-478-250
Eindhoven University of Technology

Anisotropic Thermal Processing of Polymer Nanocomposites via the Photothermal Effect of Gold Nanorods

Researchers from North Carolina State University have developed a way to melt or “weld” specific portions of polymers by embedding aligned nanoparticles within the materials. Their technique, which melts fibers along a chosen direction within a material, may lead to stronger, more resilient nanofibers and materials.

Physicists Jason Bochinski and Laura Clarke, with materials scientist Joe Tracy, placed specifically aligned gold nanorods within a solid material. Gold nanorods absorb light at different wavelengths, depending upon the size and orientation of the nanorod, and then they convert that absorbed light directly into heat. In this case, the nanorods were designed to respond to light wavelengths of 520 nanometers (nm) in a horizontal alignment and 800 nm when vertically aligned. Human beings can see light at 520 nm (it looks green), while 808 nm is in the near infrared spectrum, invisible to our eyes.

When the different wavelengths of light were applied to the material, they melted the fibers along the chosen directions, while leaving surrounding fibers largely intact.

Polarized light selectively heats and melts nanofibers containing aligned gold nanorods within a cross-hatched mat when the polarization direction is parallel to the nanofiber direction.

“Being able to heat materials spatially in this way gives us the ability to manipulate very specific portions of these materials, because nanorods localize heat – that is, the heat they produce only affects the nanorod and its immediate surroundings,” Tracy says. According to Bochinski, the work also has implications for optimizing materials that have already been manufactured: “We can use heat at the nanoscale to change mechanical characteristics of objects postproduction without affecting their physical properties, which means more efficiency and less waste.” The researchers’ findings appear in Particle & Particle Systems Characterization. The work was funded by grants from the National Science Foundation and Sigma Xi. Graduate students Wei-Chen Wu and Somsubhra Maity and former undergraduate student Krystian Kozek contributed to the work. -peake- “Anisotropic Thermal Processing of Polymer Nanocomposites via the Photothermal Effect of Gold Nanorods”

Authors: Jason Bochinski, Laura Clarke, Joe Tracy, Somsubrha Maity, Krystian Kozek and Wei-Chen Wu, North Carolina State University

Published: Particle & Particle Systems Characterization

Abstract:

By embedding metal nanoparticles within polymeric materials, selective thermal polymer processing can be accomplished via irradiation with light resonant with the nanoparticle surface plasmon resonance due to the photothermal effect of the nanoparticles which efficiently transforms light into heat.

The wavelength and polarization sensitivity of photothermal heating from embedded gold nanorods is used to selectively process a collection of polymeric nanofibers, completely melting those fibers lying along a chosen direction while leaving the remaining material largely unheated and unaffected.

Fluorescence-based temperature and viscosity sensing was employed to confirm the presence of heating and melting in selected fibers and its absence in counter-aligned fibers. Such tunable specificity in processing a subset of a sample, while the remainder is unchanged, cannot easily be achieved through conventional heating techniques.

Contact: Tracey Peake tracey_peake@ncsu.edu 919-515-6142 North Carolina State University

Rainbow Trapping in Hyperbolic Metamaterial Waveguide

BUFFALO, N.Y. – University at Buffalo engineers have created a more efficient way to catch rainbows, an advancement in photonics that could lead to technological breakthroughs in solar energy, stealth technology and other areas of research.

Qiaoqiang Gan, PhD, an assistant professor of electrical engineering at UB, and a team of graduate students described their work in a paper called “Rainbow Trapping in Hyperbolic Metamaterial Waveguide,” published Feb. 13 in the online journal Scientific Reports.

They developed a “hyperbolic metamaterial waveguide,” which is essentially an advanced microchip made of alternate ultra-thin films of metal and semiconductors and/or insulators. The waveguide halts and ultimately absorbs each frequency of light, at slightly different places in a vertical direction (see the above figure), to catch a “rainbow” of wavelengths.

Gan is a researcher within UB’s new Center of Excellence in Materials Informatics.

“Electromagnetic absorbers have been studied for many years, especially for military radar systems,” Gan said. “Right now, researchers are developing compact light absorbers based on optically thick semiconductors or carbon nanotubes. However, it is still challenging to realize the perfect absorber in ultra-thin films with tunable absorption band.

An up-close look at the “hyperbolic metamaterial waveguide,” which catches and ultimately absorbs wavelengths (or color) in a vertical direction.

“We are developing ultra-thin films that will slow the light and therefore allow much more efficient absorption, which will address the long existing challenge.”

Light is made of photons that, because they move extremely fast (i.e., at the speed of light), are difficult to tame. In their initial attempts to slow light, researchers relied upon cryogenic gases. But because cryogenic gases are very cold – roughly 240 degrees below zero Fahrenheit – they are difficult to work with outside a laboratory.

Before joining UB, Gan helped pioneer a way to slow light without cryogenic gases. He and other researchers at Lehigh University made nano-scale-sized grooves in metallic surfaces at different depths, a process that altered the optical properties of the metal. While the grooves worked, they had limitations. For example, the energy of the incident light cannot be transferred onto the metal surface efficiently, which hampered its use for practical applications, Gan said.

The hyperbolic metamaterial waveguide solves that problem because it is a large area of patterned film that can collect the incident light efficiently. It is referred to as an artificial medium with subwavelength features whose frequency surface is hyperboloid, which allows it to capture a wide range of wavelengths in different frequencies including visible, near-infrared, mid-infrared, terahertz and microwaves.

It could lead to advancements in an array of fields.

For example, in electronics there is a phenomenon known as crosstalk, in which a signal transmitted on one circuit or channel creates an undesired effect in another circuit or channel. The on-chip absorber could potentially prevent this.

The on-chip absorber may also be applied to solar panels and other energy-harvesting devices. It could be especially useful in mid-infrared spectral regions as thermal absorber for devices that recycle heat after sundown, Gan said.

Technology such as the Stealth bomber involves materials that make planes, ships and other devices invisible to radar, infrared, sonar and other detection methods. Because the on-chip absorber has the potential to absorb different wavelengths at a multitude of frequencies, it could be useful as a stealth coating material.

Additional authors of the paper include Haifeng Hu, Dengxin Ji, Xie Zeng and Kai Liu, all PhD candidates in UB’s Department of Electrical Engineering. The work was sponsored by the National Science Foundation and UB’s electrical engineering department.

Contact: Cory Nealon cmnealon@buffalo.edu 716-645-4614 University at Buffalo

Colorimetric Plasmon Resonance Imaging Using Nano Lycurgus Cup Arrays

Utilizing optical characteristics first demonstrated by the ancient Romans, researchers at the University of Illinois at Urbana-Champaign have created a novel, ultra-sensitive tool for chemical, DNA, and protein analysis.

"With this device, the nanoplasmonic spectroscopy sensing, for the first time, becomes colorimetric sensing, requiring only naked eyes or ordinary visible color photography," explained Logan Liu, an assistant professor of electrical and computer engineering and of bioengineering at Illinois. "It can be used for chemical imaging, biomolecular imaging, and integration to portable microfluidics devices for lab-on-chip-applications. His research team's results were featured in the cover article of the inaugural edition of Advanced Optical Materials (AOM, optical section of Advanced Materials).

The Lycurgus cup was created by the Romans in 400 A.D. Made of a dichroic glass, the famous cup exhibits different colors depending on whether or not light is passing through it; red when lit from behind and green when lit from in front. It is also the origin of inspiration for all contemporary nanoplasmonics research—the study of optical phenomena in the nanoscale vicinity of metal surfaces.

Caption: This image shows a model of nano cup arrays. Credit: University of Illinois at Urbana-Champaign. Usage Restrictions: None.

"This dichroic effect was achieved by including tiny proportions of minutely ground gold and silver dust in the glass," Liu added. "In our research, we have created a large-area high density array of a nanoscale Lycurgus cup using a transparent plastic substrate to achieve colorimetric sensing. The sensor consists of about one billion nano cups in an array with sub-wavelength opening and decorated with metal nanoparticles on side walls, having similar shape and properties as the Lycurgus cups displayed in a British museum. Liu and his team were particularly excited by the extraordinary characteristics of the material, yielding 100 times better sensitivity than any other reported nanoplasmonic device. Colorimetric techniques are mainly attractive because of their low cost, use of inexpensive equipment, requirement of fewer signal transduction hardware, and above all, providing simple-to-understand results. Colorimetric sensor can be used for both qualitative analytic identification as well as quantitative analysis. The current design will also enable new technology development in the field of DNA/protein microarray.

"Our label-free colorimetric sensor eliminates the need of problematic fluorescence tagging of DNA/ protein molecules, and the hybridization of probe and target molecule is detected from the color change of the sensor," stated Manas Gartia, first author of the article, "Colorimetrics: Colorimetric Plasmon Resonance Imaging Using Nano Lycurgus Cup Arrays." "Our current sensor requires just a light source and a camera to complete the DNA sensing process. This opens the possibility for developing affordable, simple and sensitive mobile phone-based DNA microarray detector in near future. Due to its low cost, simplicity in design, and high sensitivity, we envisage the extensive use of the device for DNA microarrays, therapeutic antibody screening for drug discovery, and pathogen detection in resource poor setting."

Gartia explained that light-matter interaction using sub-wavelength hole arrays gives rise to interesting optical phenomena such as surface plasmon polaritons (SPPs) mediated enhanced optical transmission (EOT). In case of EOT, more than expected amount of light can be transmitted through nanoholes on otherwise opaque metal thin films. Since the thin metal film has special optical property called surface plasmon resonance (SPR) which is affected by tiny amount surrounding materials, such device has been used as biosensing applications.

According to the researchers, most of the previous studies have mainly focused on manipulating in-plane two-dimensional (2D) EOT structures such as tuning the hole diameter, shape, or distance between the holes. In addition, most of the previous studies are concerned with straight holes only. Here, the EOT is mediated mainly by SPPs, which limits the sensitivity and figure of merits obtainable from such devices.

"Our current design employs 3D sub-wavelength tapered periodic hole array plasmonic structure. In contrast to the SPP mediated EOT, the proposed structure relies on Localized Surface Plasmon (LSP) mediated EOT," Gartia said. "The advantage of LSPs is that the enhanced transmission at different wavelengths and with different dispersion properties can be tuned by controlling the size, shape, and materials of the 3D holes. The tapered geometry will funnel and adiabatically focus the photons on to the sub-wavelength plasmonic structure at the bottom, leading to large local electric field and enhancement of EOT.

"Secondly the localized resonance supported by 3D plasmonic structure will enable broadband tuning of optical transmission through controlling the shape, size, and period of holes as well as the shape, size, and period of metallic particles decorated at the side walls. In other words, we will have more controllability over tuning the resonance wavelengths of the sensor."

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In addition to Gartia and Liu, the paper's co-authors included Austin Hsiao, Anusha Pokhriyal, Sujin Seo, Gulsim Kulsharova, and Brian T. Cunningham at Illinois, and Tiziana C. Bond, at the Meso, Micro and Nano Technologies Center at Lawrence Livermore National Laboratory, California.

Contact: Logan Liu loganliu@illinois.edu 217-244-4349 University of Illinois College of Engineering

Plasmonic Halos—Optical Surface Plasmon Drumhead Modes: Nanoscopic microcavities offer newfound control in light filtering.

Plasmonic Halos—Optical Surface Plasmon Drumhead Modes: Boston College researchers' unique nanostructure produces novel 'plasmonic halos' Nanoscopic microcavities offer newfound control in light filtering.

CHESTNUT HILL, MA (February 7, 2013) – Using the geometric and material properties of a unique nanostructure, Boston College researchers have uncovered a novel photonic effect where surface plasmons interact with light to form "plasmonic halos" of selectable output color. The findings appear in the journal Nano Letters.

The novel nanostructure proved capable of manipulating electron waves known as surface plasmon polaritons, or SPPs, which were discovered in the 1950s but of late have garnered the attention of scientists for their potential applications in fields that include waveguiding, lasing, color filtering and printing.

The team put a layer of a polymer film on a glass substrate and then dotted the surface with holes precisely defined by a process of electron beam lithography, using the BC Integrated Sciences Nanofabrication Clean Room facility. The team next applied a layer of silver, thick enough to be nontransparent to visible light. In addition to covering the thin film on top, the silver coated the contours of the holes in the film, as well as the exposed circles of the glass substrate below. The effect produced an array of silver microcavities.

Caption: Boston College researchers have constructed a unique nanostructure that exploits microcavity features to filter visible light into "plasmonic halos" of selected color output. The device could have applications in areas such as biomedical plasmonics or discrete optical filtering. Credit: Nano Letters. Usage Restrictions: None.

When the researchers directed light from below and through the glass substrate, light "leaking" through nanoscale gaps on the perimeters of the microcavities created SPP waves on their top surfaces. At particular wavelengths of the incident light, these waves formed modes or resonances analogous to acoustic waves on a drumhead, which in turn effectively filtered the light transmitted to the far side, accounting for the "halo" appearance, said Boston College Ferris Professor of Physics Michael Naughton, who co-authored the report with Senior Research Associate Michael J. Burns and doctoral student and lead author Fan Ye. The team's research was funded by the W. M. Keck Foundation. Central to this control effect are "step gaps" formed along the perimeter of each circle, which give the nanostructure the ability to modulate which waves of light pass through. It is within this geometry that the interaction of light upon the silver surface coating resulted in the excitation of plasmon waves, said Naughton. Examination of the SPPs by Mr. Ye using a near-field scanning optical microscope offered unique insights into the physics at work within the structure, Naughton said.

By adjusting the type of metal used to coat the structure or varying the circumferences of the microcavities, Naughton said the step-gap structure is capable of manipulating the optical properties of the device in the visible light range, giving the researchers newfound control in light filtering.

This kind of control, the team reports, could have applications in areas such as biomedical plasmonics or discrete optical filtering.

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Contact: Ed Hayward ed.hayward@bc.edu 617-552-4826 Boston College

Model Based Iterative Reconstruction for Bright Field Electron Tomography

WEST LAFAYETTE, Ind. – Researchers are improving the performance of technologies ranging from medical CT scanners to digital cameras using a system of models to extract specific information from huge collections of data and then reconstructing images like a jigsaw puzzle.

The new approach is called model-based iterative reconstruction, or MBIR.

"It's more-or-less how humans solve problems by trial and error, assessing probability and discarding extraneous information," said Charles Bouman, Purdue University's Michael and Katherine Birck Professor of Electrical and Computer Engineering and a professor of biomedical engineering.

MBIR has been used in a new CT scanning technology that exposes patients to one-fourth the radiation of conventional CT scanners. In consumer electronics, a new camera has been introduced that allows the user to focus the picture after it has been taken.

Researchers are improving the performance of technologies ranging from medical CT scanners to digital cameras using a system of models to extract specific information from huge collections of data and then reconstructing images like a jigsaw puzzle. Here, the method is used to create a high-resolution 3-D electron microscopy reconstruction of aluminum nanoparticles, aiding efforts to design nanocomposites for applications ranging from fuel cells to transparent coatings. (Purdue University, U.S. Air Force Research Laboratory and Carnegie Mellon University)

"These innovations are the result of 20 years of research globally to develop iterative reconstruction," Bouman said. "We are just scratching the surface. As the research community builds more accurate models, we can extract more information to get better results." In medical CT scanners, the reduction of radiation exposure is due to increased efficiency achieved via the models and algorithms. MBIR reduces "noise" in the data, providing greater clarity that allows the radiologist or radiological technician to scan the patient at a lower dosage, Bouman said. "It's like having night-vision goggles," he said. "They enable you to see in very low light, just as MBIR allows you to take high-quality CT scans with a low-power X-ray source." Researchers also have used the approach to improve the quality of images taken with an electron microscope. New findings are detailed in a research paper being presented during the Electronic Imaging 2013 conference in San Francisco this week. Traditionally, imaging sensors and software are designed to detect and measure a particular property. The new approach does the inverse, collecting huge quantities of data and later culling specific information from this pool of information using specialized models and algorithms.

"We abandon the idea of purity – collecting precisely what we need," Bouman said. "Instead, let's take all the measurements we possibly can and then later extract what we want. This increases the envelope of what you can do enormously."

Purdue, the University of Notre Dame and GE Healthcare used MBIR to create Veo, a new CT scanning technology that enables physicians to diagnose patients with high-clarity images at previously unattainable low radiation dose levels. The technology has been shown to reduce radiation exposure by 78 percent.

"If you can get diagnostically usable scans at such low dosages this opens up the potential to do large-scale screening for things like lung cancer," Bouman said. "You open up entirely new clinical applications because the dosage is so low."

A CT scanner is far better at diagnosing disease than planar X-rays because it provides a three-dimensional picture of the tissue. However, conventional CT scanners emit too much radiation to merit wider diagnostic use.

"But as the dosage goes down, the risk-benefit tradeoff for screening will become much more favorable," Bouman said. "For electron microscopy, the principle advantage is higher resolutions, but there is also some advantage in reduction of electron dosage, which can damage the sample."

The research to develop Veo has been a team effort with Ken Sauer, an associate professor of electrical engineering at Notre Dame, in collaboration with Jean-Baptiste Thibault, Jiang Hsieh and Zhou Yu. Thibault and Yu worked on the technology as graduate assistants under Bouman and Sauer and both currently work for GE Healthcare.

"And, there are lots of other people doing similar and related research at other universities and research labs around the world," Bouman said. "Ultimately, 3-D X-ray CT images might require little more dosage than old-fashion planar chest X-rays. This would allow CT to be used for medical screening without significant adverse effects."

In the electron microscope research, MBIR was used to take images of tiny beads called aluminum nanoparticles.

"We are getting reconstruction quality that's dramatically better than was possible before, and we think we can improve it even further," Bouman said.

Improved resolution could help researchers design the next generation of nanocomposites for applications such as fuel cells and transparent coatings.

The paper was authored by Purdue doctoral student Singanallur Venkatakrishnan; U.S. Air Force Research Laboratory researchers Lawrence Drummy and Jeff Simmons; Michael Jackson, a researcher from BlueQuartz Software; Carnegie Mellon University researcher Marc De Graef; and Bouman. A tutorial article (pdf) also appeared in January in the journal Current Radiological Reports.

The models and algorithms in MBIR apply probability computations to extract the correct information, much as people use logical assumptions to draw conclusions.

"You search all possible data to find what you are looking for," Bouman said. "This is how people solve problems. You saw Bob yesterday at the store; you wonder where he was coming from. Well, you determine that he was probably coming from work because you have some probabilistic models in your mind. You know he probably wasn't coming from San Francisco because Bob doesn't go to San Francisco very often, etc."

MBIR also could bring more affordable CT scanners for airport screening. In conventional scanners, an X-ray source rotates at high speed around a chamber, capturing cross section images of luggage placed inside the chamber. However, MBIR could enable the machines to be simplified by eliminating the need for the rotating mechanism.

Future research includes work to use iterative reconstruction to study materials. Purdue is part of a new Multi-University Research Initiative funded by the U.S. Air Force and led by De Graef. Researchers will use the method to study the structure of materials, work that could lead to development of next-generation materials.

Contact: Emil Venere venere@purdue.edu 765-494-4709 Purdue University

Controlling the Orientation, Edge Geometry, and Thickness of Chemical Vapor Deposition Graphene'

A new way of growing graphene without the defects that weaken it and prevent electrons from flowing freely within it could open the way to large-scale manufacturing of graphene-based devices with applications in fields such as electronics, energy, and healthcare.

A team led by Oxford University scientists has overcome a key problem of growing graphene – a one atom-thick layer of carbon – when using an established technique called chemical vapour deposition, that the tiny flakes of graphene form with random orientations, leaving defects or 'seams' between flakes that grow together.

The discovery, reported in a paper to be published in ACS Nano, reveals how these graphene flakes, known as 'domains', can be lined up by manipulating the alignment of carbon atoms on a relatively cheap copper foil – the atomic structure of the copper surface acts as a 'guide' that controls the orientation of the carbon atoms growing on top of them.

Optical micrograph showing graphene domains formed across grain boundaries.

A combination of control of this copper guide and the pressure applied during growth makes it possible to control the thickness of these domains, the geometry of their edges and the grain boundaries where they meet – 'seams' that act as obstacles to the smooth progress of electrons necessary to create efficient graphene-based electrical and electronic devices.

'Current methods of growing flakes of graphene often suffer from graphene domains not lining up,' said Professor Nicole Grobert of Oxford University's Department of Materials who led the work. 'Our discovery shows that it is possible to produce large sheets of graphene where these flakes, called 'domains', are well-aligned, which will create a neater, stronger, and more 'electron-friendly' material.'

In principle the size of the sheet of graphene that can be created is only limited by the size of the copper base sheet.

The Oxford-led team, which includes researchers from Forschungszentrum Juelich Germany, the University of Ioannina Greece, and Renishaw plc, has shown that it is also possible using the new technique to selectively grow bilayer domains of graphene – a double layer of closely packed carbon atoms – which are of particular interest for their unusual electrical properties.

'People have used copper as a base material before, but this is the first time anyone has shown that the many different types of copper surfaces can indeed strongly control the structure of graphene,' said Professor Grobert. 'It's an important step towards finding a way of manufacturing graphene in a controlled fashion at an industrial scale, something that is essential if we are to bridge the gap between fundamental research and building useful graphene-based technologies.'
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A report of the research, entitled 'Controlling the Orientation, Edge Geometry, and Thickness of Chemical Vapor Deposition Graphene', is published online in the journal ACS Nano.

The team filed a UK patent application on the work in 2012 with the help of Isis Innovation, the University of Oxford’s technology transfer firm.

Contact: University of Oxford Press Office press.office@admin.ox.ac.uk 44-018-652-83877 University of Oxford