Category Archives: electronics

Stress makes quantum dots ‘breathe’

A March 19, 2015 news item on ScienceDaily describes some new research on quantum dots,

Researchers at the Department of Energy’s SLAC National Accelerator Laboratory watched nanoscale semiconductor crystals expand and shrink in response to powerful pulses of laser light. This ultrafast “breathing” provides new insight about how such tiny structures change shape as they start to melt — information that can help guide researchers in tailoring their use for a range of applications.

In the experiment using SLAC’s Linac Coherent Light Source (LCLS) X-ray laser, a DOE Office of Science User Facility, researchers first exposed the nanocrystals to a burst of laser light, followed closely by an ultrabright X-ray pulse that recorded the resulting structural changes in atomic-scale detail at the onset of melting.

“This is the first time we could measure the details of how these ultrasmall materials react when strained to their limits,” said Aaron Lindenberg, an assistant professor at SLAC and Stanford who led the experiment. The results were published March 12 [2015] in Nature Communications.

A March 18, 2015 SLAC news release, which originated the news item, provides a general description of quantum dots,

The crystals studied at SLAC are known as “quantum dots” because they display unique traits at the nanoscale that defy the classical physics governing their properties at larger scales. The crystals can be tuned by changing their size and shape to emit specific colors of light, for example.

So scientists have worked to incorporate them in solar panels to make them more efficient and in computer displays to improve resolution while consuming less battery power. These materials have also been studied for potential use in batteries and fuel cells and for targeted drug delivery.

Scientists have also discovered that these and other nanomaterials, which may contain just tens or hundreds of atoms, can be far more damage-resistant than larger bits of the same materials because they exhibit a more perfect crystal structure at the tiniest scales. This property could prove useful in battery components, for example, as smaller particles may be able to withstand more charging cycles than larger ones before degrading.

The news release then goes on to describe the latest research showing the dots ‘breathe’ (Note: A link has been removed),

In the LCLS experiment, researchers studied spheres and nanowires made of cadmium sulfide and cadmium selenide that were just 3 to 5 nanometers, or billionths of a meter, across. The nanowires were up to 25 nanometers long. By comparison, amino acids – the building blocks of proteins – are about 1 nanometer in length, and individual atoms are measured in tenths of nanometers.

By examining the nanocrystals from many different angles with X-ray pulses, researchers reconstructed how they change shape when hit with an optical laser pulse. They were surprised to see the spheres and nanowires expand in width by about 1 percent and then quickly contract within femtoseconds, or quadrillionths of a second. They also found that the nanowires don’t expand in length, and showed that the way the crystals respond to strain was coupled to how their structure melts.

In an earlier, separate study, another team of researchers had used LCLS to explore the response of larger gold particles on longer timescales.

“In the future, we want to extend these experiments to more complex and technologically relevant nanostructures, and also to enable X-ray exploration of nanoscale devices while they are operating,” Lindenberg said. “Knowing how materials change under strain can be used together with simulations to design new materials with novel properties.”

Participating researchers were from SLAC, Stanford and two of their joint institutes, the Stanford Institute for Materials and Energy Sciences (SIMES) and Stanford PULSE Institute; University of California, Berkeley; University of Duisburg-Essen in Germany; and Argonne National Laboratory. The work was supported by the DOE Office of Science and the German Research Council.

Here’s a link to and a citation for the paper,

Visualization of nanocrystal breathing modes at extreme strains by Erzsi Szilagyi, Joshua S. Wittenberg, Timothy A. Miller, Katie Lutker, Florian Quirin, Henrik Lemke, Diling Zhu, Matthieu Chollet, Joseph Robinson, Haidan Wen, Klaus Sokolowski-Tinten, & Aaron M. Lindenberg. Nature Communications 6, Article number: 6577 doi:10.1038/ncomms7577 Published 12 March 2015

This paper is behind a paywall but there is a free preview available through ReadCube Access.

Cells as capacitors and resistors concept is key to smart bandages

Bandages that can detect bedsores as they are forming are a distinct possibility with advances in flexible electronics and miniaturization according to researchers at the University of California at Berkeley and the University of California at San Francisco. From a March 17, 2015 University of California at Berkeley news release by Sarah Yang (also on EurekAlert),

Engineers at the University of California, Berkeley, are developing a new type of bandage that does far more than stanch the bleeding from a paper cut or scraped knee. Thanks to advances in flexible electronics, the researchers, in collaboration with colleagues at UC San Francisco, have created a new “smart bandage” that uses electrical currents to detect early tissue damage from pressure ulcers, or bedsores, before they can be seen by human eyes – and while recovery is still possible.

“We set out to create a type of bandage that could detect bedsores as they are forming, before the damage reaches the surface of the skin,” said Michel Maharbiz, a UC Berkeley associate professor of electrical engineering and computer sciences and head of the smart-bandage project. “We can imagine this being carried by a nurse for spot-checking target areas on a patient, or it could be incorporated into a wound dressing to regularly monitor how it’s healing.”

The researchers exploited the electrical changes that occur when a healthy cell starts dying. They tested the thin, non-invasive bandage on the skin of rats and found that the device was able to detect varying degrees of tissue damage consistently across multiple animals.

Bed sores are a big problem now and I imagine that as the population ages and more people find themselves in ill health, the problem will increase (from the news release),

Tackling a growing health problem

The findings, to be published Tuesday, March 17, in the journal Nature Communications, could provide a major boost to efforts to stem a health problem that affects an estimated 2.5 million U.S. residents at an annual cost of $11 billion.

Pressure ulcers, or bedsores, are injuries that can result after prolonged pressure cuts off adequate blood supply to the skin. Areas that cover bony parts of the body, such as the heels, hips and tailbone, are common sites for bedsores. Patients who are bedridden or otherwise lack mobility are most at risk.

“By the time you see signs of a bedsore on the surface of the skin, it’s usually too late,” said Dr. Michael Harrison, a professor of surgery at UCSF and a co-investigator of the study. “This bandage could provide an easy early-warning system that would allow intervention before the injury is permanent. If you can detect bedsores early on, the solution is easy. Just take the pressure off.”

Bedsores are associated with deadly septic infections, and recent research has shown that odds of a hospital patient dying are 2.8 times higher when they have pressure ulcers. The growing prevalence of diabetes and obesity has increased the risk factors for bedsores.

“The genius of this device is that it’s looking at the electrical properties of the tissue to assess damage. We currently have no other way to do that in clinical practice,” said Harrison. “It’s tackling a big problem that many people have been trying to solve in the last 50 years. As a clinician and someone who has struggled with this clinical problem, this bandage is great.”

The electrical components and their role in detecting bed sores is fascinating (from the news release),

Cells as capacitors and resistors

The researchers printed an array of dozens of electrodes onto a thin, flexible film. They discharged a very small current between the electrodes to create a spatial map of the underlying tissue based upon the flow of electricity at different frequencies, a technique called impedance spectroscopy.

The researchers pointed out that a cell’s membrane is relatively impermeable when functioning properly, thus acting like an insulator to the cell’s conductive contents and drawing the comparison to a capacitor. As a cell starts to die, the integrity of the cell wall starts to break down, allowing electrical signals to leak through, much like a resistor.

“Our device is a comprehensive demonstration that tissue health in a living organism can be locally mapped using impedance spectroscopy,” said study lead author Sarah Swisher, a Ph.D. candidate in electrical engineering and computer sciences at UC Berkeley.

To mimic a pressure wound, the researchers gently squeezed the bare skin of rats between two magnets. They left the magnets in place for one or three hours while the rats resumed normal activity. The resumption of blood flow after the magnets were removed caused inflammation and oxidative damage that accelerated cell death. The smart bandage was used to collect data once a day for at least three days to track the progress of the wounds.

The smart bandage was able to detect changes in electrical resistance consistent with increased membrane permeability, a mark of a dying cell. Not surprisingly, one hour of pressure produced mild, reversible tissue damage while three hours of pressure produced more serious, permanent injury.

Promising future

“One of the things that makes this work novel is that we took a comprehensive approach to understanding how the technique could be used to observe developing wounds in complex tissue,” said Swisher. “In the past, people have used impedance spectroscopy for cell cultures or relatively simple measurements in tissue. What makes this unique is extending that to detect and extract useful information from wounds developing in the body. That’s a big leap.”

Maharbiz said the outlook for this and other smart bandage research is bright.

“As technology gets more and more miniaturized, and as we learn more and more about the responses the body has to disease and injury, we’re able to build bandages that are very intelligent,” he said. “You can imagine a future where the bandage you or a physician puts on could actually report a lot of interesting information that could be used to improve patient care.”

Here’s a link to and a citation for the paper,

Impedance sensing device enables early detection of pressure ulcers in vivo by Sarah L. Swisher, Monica C. Lin, Amy Liao, Elisabeth J. Leeflang, Yasser Khan, Felippe J. Pavinatto, Kaylee Mann, Agne Naujokas, David Young, Shuvo Roy, Michael R. Harrison, Ana Claudia Arias, Vivek Subramanian, & Michel M. Maharbiz. Nature Communications 6, Article number: 6575 doi:10.1038/ncomms7575 Published 17 March 2015

This paper is behind a paywall but there is a free preview available via ReadCube Access.

Finally, one of the researchers describes the work in this 1 min. 31 secs. video,

Two Irelands-US research initiative: UNITE

Happy St. Patrick’s Day on March 17, 2015! Researchers, building on an earlier collaborative effort (FOCUS), have announced a new US-Ireland initiative, from a March 9, 2015 news item on Nanowerk,

A three-year US-Ireland collaborative scientific project aims to reduce power consumption and increase battery life in mobile devices. Researchers will explore new semiconducting materials in the miniaturisation of transistors which are essential to all portable devices.

Leading researchers from the Republic of Ireland (Tyndall National Institute & Dublin City University), Northern Ireland (Queens University Belfast) and the US (University of Texas at Dallas) – each funded by their respective government agencies – are collaborating to develop ultra-efficient electronic materials through the UNITE project: Understanding the Nature of Interfaces in Two-Dimensional Electronic Devices.

A March 9, 2015 (?) Tyndall National Institute press release, which originated the news item, details the project, the researchers, and the hoped for applications,

UNITE will create and test the properties of atomically-thin, 2-dimensional layers of semiconductors called, Transition Metal Dichalcogenides or TMD’s for short. These layers are 100,000 times smaller than the smallest thing the human eye can see. The properties these materials have displayed to date suggest that they could facilitate extremely efficient power usage and high performance computing.

Tyndall’s lead researcher Dr. Paul Hurley explains that, “materials that we are currently reliant on, such as silicon, are soon expected to reach the limit of their performance. If we want to continue to increase performance, while maintaining or even reducing power consumption, it is important to explore these new TMD materials.”

The application of these materials in transistors could prolong the battery charge life of portable devices and phones, as well as having applications in larger more power intensive operations like data storage and server centres. This will have obvious environmental benefits through the reduction of electrical energy consumed by information and communication technologies as well as benefitting consumers.

UNITE builds on a previous highly successful US-Ireland collaborative project between these academic research partners called FOCUS. The success of this project played a role in demonstrating why funders should back the new project, including training for five graduate students in the USA and Ireland, as well as student exchanges between the Institutes, which will provide a broader scientific and cultural experience for the graduates involved.

The press release goes on to describe FOCUS, the researchers’ prior collaborative project,

UNITE builds on a previous highly successful US-Ireland collaborative project between these academic research partners called FOCUS. The success of this project played a role in demonstrating why funders should back the new project, including training for five graduate students in the USA and Ireland, as well as student exchanges between the Institutes, which will provide a broader scientific and cultural experience for the graduates involved.

A March 13, 2015 (?) Tyndall National Institute press release describes both an event to celebrate the success enjoyed by FOCUS and gives specifics about the achievements,

FOCUS, a US-Ireland collaborative project will be presented as a research success highlight to An Taoiseach Enda Kenny on St. Patrick’s Day along with industry and academic leaders, at a Science Foundation Ireland (SFI) event in Washington DC. The event is to celebrate the SFI St. Patrick’s Day Science Medal Award and is an important occasion on the St. Patrick’s Day schedule in the USA.

Funded under the US-Ireland R&D Partnership Programme, FOCUS (Future Oxides and Channel Materials for Ultimate Scaling) linked researchers in Tyndall National Institute (Dr Paul Hurley), Dublin City University (Prof. Greg Hughes), Queen’s University Belfast (Dr David McNeill) and the University of Texas at Dallas (Prof. Robert Wallace).

Billions of silicon-based transistors are crammed onto a single chip and used in billions of electronic devices around the world such as computers, laptops and mobile phones. The FOCUS project group investigated if it was possible to use alternative materials to silicon in the active channels of transistors to improve their energy efficiency and battery life.

The consortium explored using Germanium and Indium-Gallium-Arsenide in combination with high dielectric constant oxides as a viable alternative to silicon. Their research was able to improve the electronic properties of these alternative semiconductor/oxide interfaces to the level needed for practical device applications and the outcomes of their research have now moved to industry for practical application.

The key achievements from the project include:

  • Strong collaboration with Intel USA and Intel Ireland resulting in Paul Hurley receiving the Intel Outstanding Researcher Award in 2012
  • Presentation of the project findings at the annual Intel European Research and Innovation Conference
  • 3 Postdocs trained and 5 PhDs awarded in areas of strong interest to semiconductor manufacturers
  • 35 journal papers published
  • 2011 article on InGaAs surface treatment optimisation listed as one of the top 10 most cited articles in the Journal of Applied Physics in 2012
  • 10 invited presentations at key scientific conferences
  • University research partnership established between Tyndall National Institute and University of Texas at Dallas
  • Project highlighted in Irish press, The Times of India and The Irish Voice
  • Visit by the Consul General of Ireland to University of Texas at Dallas
  • Numerous students and staff exchanges between all partner institutions

Good luck to the UNITE project!

Brain-like computing with optical fibres

Researchers from Singapore and the United Kingdom are exploring an optical fibre approach to brain-like computing (aka neuromorphic computing) as opposed to approaches featuring a memristor or other devices such as a nanoionic device that I’ve written about previously. A March 10, 2015 news item on Nanowerk describes this new approach,

Computers that function like the human brain could soon become a reality thanks to new research using optical fibres made of speciality glass.

Researchers from the Optoelectronics Research Centre (ORC) at the University of Southampton, UK, and Centre for Disruptive Photonic Technologies (CDPT) at the Nanyang Technological University (NTU), Singapore, have demonstrated how neural networks and synapses in the brain can be reproduced, with optical pulses as information carriers, using special fibres made from glasses that are sensitive to light, known as chalcogenides.

“The project, funded under Singapore’s Agency for Science, Technology and Research (A*STAR) Advanced Optics in Engineering programme, was conducted within The Photonics Institute (TPI), a recently established dual institute between NTU and the ORC.”

A March 10, 2015 University of Southampton press release (also on EurekAlert), which originated the news item, describes the nature of the problem that the scientists are trying address (Note: A link has been removed),

Co-author Professor Dan Hewak from the ORC, says: “Since the dawn of the computer age, scientists have sought ways to mimic the behaviour of the human brain, replacing neurons and our nervous system with electronic switches and memory. Now instead of electrons, light and optical fibres also show promise in achieving a brain-like computer. The cognitive functionality of central neurons underlies the adaptable nature and information processing capability of our brains.”

In the last decade, neuromorphic computing research has advanced software and electronic hardware that mimic brain functions and signal protocols, aimed at improving the efficiency and adaptability of conventional computers.

However, compared to our biological systems, today’s computers are more than a million times less efficient. Simulating five seconds of brain activity takes 500 seconds and needs 1.4 MW of power, compared to the small number of calories burned by the human brain.

Using conventional fibre drawing techniques, microfibers can be produced from chalcogenide (glasses based on sulphur) that possess a variety of broadband photoinduced effects, which allow the fibres to be switched on and off. This optical switching or light switching light, can be exploited for a variety of next generation computing applications capable of processing vast amounts of data in a much more energy-efficient manner.

Co-author Dr Behrad Gholipour explains: “By going back to biological systems for inspiration and using mass-manufacturable photonic platforms, such as chalcogenide fibres, we can start to improve the speed and efficiency of conventional computing architectures, while introducing adaptability and learning into the next generation of devices.”

By exploiting the material properties of the chalcogenides fibres, the team led by Professor Cesare Soci at NTU have demonstrated a range of optical equivalents of brain functions. These include holding a neural resting state and simulating the changes in electrical activity in a nerve cell as it is stimulated. In the proposed optical version of this brain function, the changing properties of the glass act as the varying electrical activity in a nerve cell, and light provides the stimulus to change these properties. This enables switching of a light signal, which is the equivalent to a nerve cell firing.

The research paves the way for scalable brain-like computing systems that enable ‘photonic neurons’ with ultrafast signal transmission speeds, higher bandwidth and lower power consumption than their biological and electronic counterparts.

Professor Cesare Soci said: “This work implies that ‘cognitive’ photonic devices and networks can be effectively used to develop non-Boolean computing and decision-making paradigms that mimic brain functionalities and signal protocols, to overcome bandwidth and power bottlenecks of traditional data processing.”

Here’s a link to and a citation for the paper,

Amorphous Metal-Sulphide Microfibers Enable Photonic Synapses for Brain-Like Computing by Behrad Gholipour, Paul Bastock, Chris Craig, Khouler Khan, Dan Hewak. and Cesare Soci. Advanced Optical Materials DOI: 10.1002/adom.201400472
Article first published online: 15 JAN 2015

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This article is behind a paywall.

For anyone interested in memristors and nanoionic devices, here are a few posts (from this blog) to get you started:

Memristors, memcapacitors, and meminductors for faster computers (June 30, 2014)

This second one offers more details and links to previous pieces,

Memristor, memristor! What is happening? News from the University of Michigan and HP Laboratories (June 25, 2014)

This post is more of a survey including memristors, nanoionic devices, ‘brain jelly, and more,

Brain-on-a-chip 2014 survey/overview (April 7, 2014)

One comment, this brain-on-a-chip is not to be confused with ‘organs-on-a-chip’ projects which are attempting to simulate human organs (Including the brain) so chemicals and drugs can be tested.

Think of your skin as a smartphone

A March 5, 2015 news item on Azonano highlights work on flexible, transparent electronics designed to adhere to your skin,

Someone wearing a smartwatch can look at a calendar or receive e-mails without having to reach further than their wrist. However, the interaction area offered by the watch face is both fixed and small, making it difficult to actually hit individual buttons with adequate precision. A method currently being developed by a team of computer scientists from Saarbrücken in collaboration with researchers from Carnegie Mellon University in the USA may provide a solution to this problem. They have developed touch-sensitive stickers made from flexible silicone and electrically conducting sensors that can be worn on the skin.

Here’s what the sticker looks like,

Caption: The stickers are skin-friendly and are attached to the skin with a biocompatible, medical-grade adhesive. Credit: Oliver Dietze

Caption: The stickers are skin-friendly and are attached to the skin with a biocompatible, medical-grade adhesive. Credit: Oliver Dietze Courtesy: Saarland University

A March 4, 2015 University of Saarland press release on EurekAlert, which originated the news item, expands on the theme on connecting technology to the body,

… The stickers can act as an input space that receives and executes commands and thus controls mobile devices. Depending on the type of skin sticker used, applying pressure to the sticker could, for example, answer an incoming call or adjust the volume of a music player. ‘The stickers allow us to enlarge the input space accessible to the user as they can be attached practically anywhere on the body,’ explains Martin Weigel, a PhD student in the team led by Jürgen Steimle at the Cluster of Excellence at Saarland University. The ‘iSkin’ approach enables the human body to become more closely connected to technology. [emphasis mine]

Users can also design their iSkin patches on a computer beforehand to suit their individual tastes. ‘A simple graphics program is all you need,’ says Weigel. One sticker, for instance, is based on musical notation, another is circular in shape like an LP. The silicone used to fabricate the sensor patches makes them flexible and stretchable. ‘This makes them easier to use in an everyday environment. The music player can simply be rolled up and put in a pocket,’ explains Jürgen Steimle, who heads the ‘Embodied Interaction Group’ in which Weigel is doing his research. ‘They are also skin-friendly, as they are attached to the skin with a biocompatible, medical-grade adhesive. Users can therefore decide where they want to position the sensor patch and how long they want to wear it.’

In addition to controlling music or phone calls, the iSkin technology could be used for many other applications. For example, a keyboard sticker could be used to type and send messages. Currently the sensor stickers are connected via cable to a computer system. According to Steimle, in-built microchips may in future allow the skin-worn sensor patches to communicate wirelessly with other mobile devices.

The publication about ‘iSkin’ won the ‘Best Paper Award’ at the SIGCHI conference, which ranks among the most important conferences within the research area of human computer interaction. The researchers will present their project at the SIGCHI conference in April [2015] in Seoul, Korea, and beforehand at the computer expo Cebit, which takes place from the 16th until the 20th of March [2015] in Hannover (hall 9, booth E13).

Hopefully, you’ll have a chance to catch researchers’ presentation at the SIGCHI or Cebit events.

That quote about enabling “the human body to become more closely connected to technology” reminds me of a tag (machine/flesh) I created to categorize research of this nature. I explained the idea being explored in a May 9, 2012 posting titled: Everything becomes part machine,

Machine/flesh. That’s what I’ve taken to calling this process of integrating machinery into our and, as I newly realized, other animals’ flesh.

I think my latest previous post on this topic was a Jan. 10, 2014 post titled: Chemistry of Cyborgs: review of the state of the art by German researchers.

Europe’s search for raw materials and hopes for nanotechnology-enabled solutions

A Feb. 27, 2015 news item on Nanowerk highlights the concerns over the availability of raw materials and European efforts to address those concerns,

Critical raw materials’ are crucial to many European industries but they are vulnerable to scarcity and supply disruption. As such, it is vital that Europe develops strategies for meeting the demand for raw materials. One such strategy is finding methods or substances that can replace the raw materials that we currently use. With this in mind, four EU projects working on substitution in catalysis, electronics and photonics presented their work at the Third Innovation Network Workshop on substitution of Critical Raw Materials hosted by the CRM_INNONET project in Brussels earlier this month [February 2015].

A Feb. 26, 2015 CORDIS press release, which originated the news item, goes on to describe four European Union projects working on nanotechnology-enabled solutions,

NOVACAM

NOVACAM, a coordinated Japan-EU project, aims to develop catalysts using non-critical elements designed to unlock the potential of biomass into a viable energy and chemical feedstock source.

The project is using a ‘catalyst by design’ approach for the development of next generation catalysts (nanoscale inorganic catalysts), as NOVACAM project coordinator Prof. Emiel Hensen from Eindhoven University of Technology in the Netherlands explained. Launched in September 2013, the project is developing catalysts which incorporate non-critical metals to catalyse the conversion of lignocellulose into industrial chemical feedstocks and bio-fuels. The first part of the project has been to develop the principle chemistry while the second part is to demonstrate proof of process. Prof. Hensen predicts that perhaps only two of three concepts will survive to this phase.

The project has already made significant progress in glucose and ethanol conversion, according to Prof. Hensen, and has produced some important scientific publications. The consortium is working with and industrial advisory board comprising Shell in the EU and Nippon Shokubai in Japan.

FREECATS

The FREECATS project, presented by project coordinator Prof. Magnus Rønning from the Norwegian University of Science and Technology, has been working over the past three years to develop new metal-free catalysts. These would be either in the form of bulk nanomaterials or in hierarchically organised structures – both of which would be capable of replacing traditional noble metal-based catalysts in catalytic transformations of strategic importance.

Prof. Magnus Rønning explained that the application of the new materials could eliminate the need for the use for platinum group metals (PGM) and rare earth metals – in both cases Europe is very reliant on other countries for these materials. Over the course of its research, FREECATS targeted three areas in particular – fuel cells, the production of light olefins and water and wastewater purification.

By working to replace the platinum in fuel cells, the project is supporting the EU’s aim of replacing the internal combustion engine by 2050. However, as Prof. Rønning noted, while platinum has been optimized for use over several decades, the materials FREECATS are using are new and thus come with their new challenges which the project is addressing.

HARFIR

Prof. Atsufumi Hirohata of the University of York in the United Kingdom, project coordinator of HARFIR, described how the project aims to discover an antiferromagnetic alloy that does not contain the rare metal Iridium. Iridium is becoming more and more widely used in numerous spin electronic storage devices, including read heads in hard disk drives. The world supply depends on Platinum ore that comes mainly from South Africa. The situation is much worse than for other rare earth elements as the price has been shooting up over recent years, according to Prof. Hirohata.

The HARFIR team, divided between Europe and Japan, aims to replace Iridium alloys with Heusler alloys. The EU team, led by Prof. Hirohata, has been working on the preparation of polycrystalline and epitaxial thin films of Heusler Alloys, with the material design led by theoretical calculations. The Japanese team, led by Prof. Koki Takanashi at Tohoku University, is meanwhile working on the preparation of epitaxial thin films, measurements of fundamental properties and structural/magnetic characterisation by neutron and synchrotron x-ray beams.

One of the biggest challenges has been that Heusler alloys have a relatively complicated atomic structure. In terms of HARFIR’s work, if any atomic disordering at the edge of nanopillar devices, the magnetic properties that are needed are lost. The team is exploring solutions to this challenge.

IRENA

Prof. of Esko Kauppinen Aalto University in Finland closed off the first session of the morning with his presentation of the IRENA project. Launched in September 2013, the project will run until mid 2017 working towards the aim of developing high performance materials, specifically metallic and semiconducting single-walled carbon nanotube (SWCNT) thin films to completely eliminate the use of the critical metals in electron devices. The ultimate aim is to replace Indium in transparent conducting films, and Indium and Gallium as a semiconductor in thin film field effect transistors (TFTs).

The IRENA team is developing an alternative that is flexible, transparent and stretchable so that it can meet the demands of the electronics of the future – including the possibility to print electronics.

IRENA involves three partners from Europe and three from Japan. The team has expertise in nanotube synthesis, thin film manufacturing and flexible device manufacturing, modelling of nanotube growth and thin film charge transport processes, and the project has benefitted from exchanges of team members between institutions. One of the key achievements so far is that the project has succeeded in using a nanotube thin film for the first time as the both the electrode and hole blocking layer in an organic solar cell.

You’ll note that Japan is a partner in all of these projects. In all probability, these initiatives have something to do with rare earths which are used in much of today’s electronics technology and Japan is sorely lacking in those materials. China, by comparison, has dominated the rare earths export industry and here’s an excerpt from my Nov. 1, 2013 posting where I outline the situation (which I suspect hasn’t changed much since),

As for the short supply mentioned in the first line of the news item, the world’s largest exporter of rare earth elements at 90% of the market, China, recently announced a cap according to a Sept. 6, 2013 article by David Stanway for Reuters. The Chinese government appears to be curtailing exports as part of an ongoing, multi-year strategy. Here’s how Cientifica‘s (an emerging technologies consultancy, etc.) white paper (Simply No Substitute?) about critical materials published in 2012 (?), described the situation,

Despite their name, REE are not that rare in the Earth’s crust. What has happened in the past decade is that REE exports from China undercut prices elsewhere, leading to the closure of mines such as the Mountain Pass REE mine in California. Once China had acquired a dominant market position, prices began to rise. But this situation will likely ease. The US will probably begin REE production from the Mountain Pass mine later in 2012, and mines in other countries are expected to start operation soon as well.

Nevertheless, owing to their broad range of uses REE will continue to exert pressures on their supply – especially for countries without notable REE deposits. This highlights two aspects of importance for strategic materials: actual rarity and strategic supply issues such as these seen for REE. Although strategic and diplomatic supply issues may have easier solutions, their consideration for manufacturing industries will almost be the same – a shortage of crucial supply lines.

Furthermore, as the example of REE shows, the identification of long-term supply problems can often be difficult, and not every government has the same strategic foresight that the Chinese demonstrated. And as new technologies emerge, new elements may see an unexpected, sudden demand in supply. (pp. 16-17)

Meanwhile, in response to China’s decision to cap its 2013 REE exports, the Russian government announced a $1B investment to 2018 in rare earth production,, according to a Sept. 10, 2013 article by Polina Devitt for Reuters.

I’m not sure you’ll be able to access Tim Harper’s white paper as he is now an independent, serial entrepreneur. I most recently mentioned him in relation to his articles (on Azonano) about the nanotechnology scene in a Feb. 12, 2015 posting where you’ll also find contact details for him.

McGill University (Canada) researchers build DNA nanotubes block by block

McGill University (Montréal, Québec, Canada) researchers have found a new technique for creating DNA (deoxyribonucleic acid) nanotubes according to a Feb. 24, 2015 news item on Azonano,

Researchers at McGill University have developed a new, low-cost method to build DNA nanotubes block by block – a breakthrough that could help pave the way for scaffolds made from DNA strands to be used in applications such as optical and electronic devices or smart drug-delivery systems.

A Feb. 23, 2015 McGill University news release (also on EurekAlert), which originated the news item, describes current practice and the new technique,

Many researchers, including the McGill team, have previously constructed nanotubes using a method that relies on spontaneous assembly of DNA in solution. The new technique, reported today in Nature Chemistry, promises to yield fewer structural flaws than the spontaneous-assembly method. The building-block approach also makes it possible to better control the size and patterns of the DNA structures, the scientists report.

“Just like a Tetris game, where we manipulate the game pieces with the aim of creating a horizontal line of several blocks, we can now build long nanotubes block by block,” said Amani Hariri, a PhD student in McGill’s Department of Chemistry and lead author of the study. “By using a fluorescence microscope we can further visualize the formation of the tubes at each stage of assembly, as each block is tagged with a fluorescent compound that serves as a beacon. We can then count the number of blocks incorporated in each tube as it is constructed.”

This new technique was made possible by the development in recent years of single-molecule microscopy, which enables scientists to peer into the nano-world by turning the fluorescence of individual molecules on and off. (That groundbreaking work won three U.S.- and German-based scientists the 2014 Nobel Prize in Chemistry.)

Hariri’s research is jointly supervised by chemistry professors Gonzalo Cosa and Hanadi Sleiman, who co-authored the new study. Cosa’s research group specializes in single-molecule fluorescence techniques, while Sleiman’s uses DNA chemistry to design new materials for drug delivery and diagnostic tools.

The custom-built assembly technique developed through this collaboration “gives us the ability to monitor the nanotubes as we’re building them, and see their structure, robustness and morphology,” Cosa said.

“We wanted to control the nanotubes’ lengths and features one-by-one,” said Sleiman, who holds the Canada Research Chair in DNA Nanoscience. The resulting “designer nanotubes,” she adds, promise to be far cheaper to produce on a large scale than those created with so-called DNA origami, another innovative technique for using DNA as a nanoscale construction material.

Here’s a link to and a citation for the paper,

Stepwise growth of surface-grafted DNA nanotubes visualized at the single-molecule level by Amani A. Hariri, Graham D. Hamblin, Yasser Gidi, Hanadi F. Sleiman & Gonzalo Cosa. Nature Chemistry (2015) doi:10.1038/nchem.2184 Published online 23 February 2015

This article is behind a paywall.

Crumpling graphene to create a 3D structure and reflattening it afterwards

The reseaarchers at the University of Illinois College of Engineering are quite excited about a new technique for crumpling graphene as a Feb. 17, 2015 news item on ScienceDaily reports,

Researchers at the University of Illinois at Urbana-Champaign have developed a unique single-step process to achieve three-dimensional (3D) texturing of graphene and graphite. Using a commercially available thermally activated shape-memory polymer substrate, this 3D texturing, or “crumpling,” allows for increased surface area and opens the doors to expanded capabilities for electronics and biomaterials.

“Fundamentally, intrinsic strains on crumpled graphene could allow modulation of electrical and optical properties of graphene,” explained SungWoo Nam, an assistant professor of mechanical science and engineering at Illinois. “We believe that the crumpled graphene surfaces can be used as higher surface area electrodes for battery and supercapacitor applications. As a coating layer, 3D textured/crumpled nano-topographies could allow omniphobic/anti-bacterial surfaces for advanced coating applications.”

A Feb. 16, 2015 University of Illinois College of Engineering news release (also on EurekAlert), which originated the news item, describes the nature of graphene and what makes this technique so exciting,

Graphene—a single atomic layer of sp2-bonded carbon atoms—has been a material of intensive research and interest over recent years.  A combination of exceptional mechanical properties, high carrier mobility, thermal conductivity, and chemical inertness, make graphene a prime candidate material for next generation optoelectronic, electromechanical, and biomedical applications.

“In this study, we developed a novel method for controlled crumpling of graphene and graphite via heat-induced contractile deformation of the underlying substrate,” explained Michael Cai Wang, a graduate student and first author of the paper, “Heterogeneous, Three-Dimensional Texturing of Graphene,” which appeared in the journal Nano Letters. ”While graphene intrinsically exhibits tiny ripples in ambient conditions, we created large and tunable crumpled textures in a tailored and scalable fashion.”

“As a simpler, more scalable, and spatially selective method, this texturing of graphene and graphite exploits the thermally induced transformation of shape-memory thermoplastics, which has been previously applied to microfluidic device fabrication, metallic  film patterning, nanowire assembly, and robotic self-assembly applications,” added Nam, whose group has filed a patent for their novel strategy. “The thermoplastic nature of the polymeric substrate also allows for the crumpled graphene morphology to be arbitrarily re-flattened at the same elevated temperature for the crumpling process.”

“Due to the extremely low cost and ease of processing of our approach, we believe that this will be a new way to manufacture nanoscale topographies for graphene and many other 2D and thin-film materials.”

The researchers are also investigating the textured graphene surfaces for 3D sensor applications.

“Enhanced surface area will allow even more sensitive and intimate interactions with biological systems, leading to high sensitivity devices,” Nam said.

The funding agencies for this project were unexpectedly interesting (to me), from the news release,

Funding for this research was provided through the Air Force Office for Scientific Research, American Chemical Society and Brain Research Foundation. [emphasis mine] In addition to Wang, co-authors from Nam’s research group at Illinois include SungGyu Chun, Ryan Han, Ali Ashraf, and Pilgyu Kang.

Here’s a link to and a citation for the paper,

Heterogeneous, Three-Dimensional Texturing of Graphene by Michael Cai Wang, SungGyu Chun, Ryan Steven Han, Ali Ashraf, Pilgyu Kang, and SungWoo Nam. Nano Lett., Article ASAP
DOI: 10.1021/nl504612y Publication Date (Web): February 10, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

Dexter Johnson has written a Feb. 20, 2015 post highlighting this work on his Nanoclast blog (on the Institute of Electrical and Electronics Engineers [IEEE] website).

Sensing smoke with nanoscale sensors

A Feb. 17, 2015 news item on Nanowerk notes that current smoke sensors are ultra-violet light detectors in the context of research about developing better ones,

Researchers at the University of Surrey’s [UK] Advanced Technology Institute manipulated zinc oxide, producing nanowires from this readily available material to create a ultra-violet light detector which is 10,000 times more sensitive to UV light than a traditional zinc oxide detector.

A Feb. 17, 2015 University of Surrey press release (also on EurekAlert), which originated the news item, provides more detail about the work and the theory (Note: Links have been removed),

Currently, photoelectric smoke sensors detect larger smoke particles found in dense smoke, but are not as sensitive to small particles of smoke from rapidly burning fires.

Researchers believe that this new material could increase sensitivity and allow the sensor to detect distinct particles emitted at the early stages of fires, paving the way for specialist sensors that can be deployed in a number of applications.

“UV light detectors made from zinc oxide have been used widely for some time but we have taken the material a step further to massively increase its performance,” said Professor Ravi Silva, co-author of the study and head of the Advanced Technology Institute. “Essentially, we transformed zinc oxide from a flat film to a structure with bristle-like nanowires, increasing surface area and therefore increasing sensitivity and reaction speed.”

The team predict that the applications for this material could be far-reaching. From fire and gas detection to air pollution monitoring, they believe the sensor could also be incorporated into personal electronic devices – such as phones and tablets – to increase speed, with a response time 1,000 times faster than traditional zinc oxide detectors.

“This is a great example of a bespoke, designer nanomaterial that is adaptable to personal needs, yet still affordable. Due to the way in which this material is manufactured, it is ideally suited for use in future flexible electronics – a hugely exciting area,” added Professor Silva.

Here’s a link to and a citation for the paper,

On-chip Fabrication of High Performance Nanostructured ZnO UV Detectors by Mohammad R. Alenezi, Simon J. Henley, & S. R. P. Silva. Scientific Reports 5, Article number: 8516 doi:10.1038/srep08516 Published 17 February 2015

This paper is open access.

NanoXplore: graphene and graphite in Québec (Canada)

For the second time this week I’m going to be mentioning the province of Québec (Canada) in relation to its ‘nanotechnology’ businesses (see: Cellulose nanocrystals (CNC), also known as nanocrystalline cellulose (NCC), and toxicity; some Celluforce news; anti-petroleum extremists posted on Feb. 19, 2015). A Feb. 20, 2015 news item on Azonano announces a graphene production facility in the Montréal area,

Group NanoXplore Inc., a Montreal-based company specialising in the production and application of graphene and its derivative materials, announced today that its graphene production facility is in full operation with a capacity of 3 metric tonnes per year. This is the largest graphene production capacity in Canada and, outside of China, one of the 5 largest in the world.

A Feb. 19, 2015 NanoXplore news release on MarketWire, which originated the news item, provides a bit more detail in amidst the promotional hype,

NanoXplore’s production process is unique and the core of the company’s competitive advantage. The proprietary process gently and efficiently creates pristine graphene from natural flake graphite without creating the crystalline defects that can limit performance. The process also functionalises the graphene material during production making subsequent mixing with a broad range of industrial materials simple and efficient. NanoXplore’s facility is routinely producing several standard grades of graphene as well as derivative products such as a unique graphite-graphene composite suitable for anodes in Li-ion batteries. [emphasis mine]

Another graphite connection in Québec

Interestingly, back in 2012 Hydro-Québec signed a deal with another Québec-based company, Focus Graphite (which owns a graphite deposit in the northeastern part of the province) to explore ways to produce more efficient lithium-ion batteries (my Nov 27, 2012 posting).

Getting back to the news release, it also provides a summary description of NanoXplore,

NanoXplore is a privately held advanced materials company focused on the large-scale production of high quality graphene and the integration of graphene into real world industrial products. NanoXplore achieves significant improvements in performance for its customers with very low levels of graphene because its material is of high quality (few defects, highly dispersible), because the production process can easily tune the dimensions of the graphene platelets, and because NanoXplore has specific expertise in dispersing graphene in a broad range of industrial materials. NanoXplore partners with its customers to integrate graphene into their products and processes, providing them with innovative products and a strong competitive advantage.

Graphite mines

NanoXplore, too, has some sort of relationship with a graphite mine or, in this case mining company, Mason Graphite (from the NanoXplore website’s Investors’ page),

FROM MINE TO PRODUCT

Partnered with Canadian mining company Mason Graphite, NanoXplore has access to lower quartile graphite/graphene production costs as well as a stable, long term, large flake source of raw material. Local government bodies have embraced the graphite-graphene cluster. With production and R&D centrally located in Montreal, NanoXplore offers world class innovation and true intellectual property safety for its formulation partners.

By the way, Benoit Gascon, NanoXplore’s board chair (scroll down to the bottom  of the team list) is also Mason Graphite’s Chief Executive Officer (CEO). The company has recently announced a detailed study on large-scale production of value-added graphite products (from a Feb. 11, 2015 Mason Graphite news release),

Mason Graphite Inc. (“Mason Graphite” or the “Company”) (TSX VENTURE:LLG)(OTCQX:MGPHF) announces that it has initiated a detailed study for large scale processing of value-added graphite products.

Value-added processing includes micronization, additional purification, spheronization and coating, resulting in graphite products that are suitable for a wide range of electrochemical applications (including alkaline batteries, lithium-ion batteries and fuel cells), technical applications (including carbon brushes, brake linings, plastics and lubricants), and other specialized uses.

The development and validation of the fabrication processes for these graphite products will be carried out by the National Research Council of Canada (“NRC”) along with Hatch, and is expected to conclude by the end of 2015. Following initial scoping work, equipment trials and product testing, the Company intends to provide preliminary results and an updated work program by mid-2015.

The NRC is the Government of Canada’s premier research and technology organization. Hatch is an engineering firm located in Montreal which is already working closely with Mason Graphite on the development of the Lac Gueret Graphite Project.

Other parts of Canada and the graphite/graphene enterprise

NanoXplore and Focus Graphite are not the only companies with connections to a graphite mine in Québec. There’s also Vancouver (Canada)-based Lomiko Metals (mentioned here in an April 17, 2013 posting [for the first time]. A. Paul Gill, Lomiko’s CEO, seems to be pursuing a similar business strategy in that Lomiko, too, has a number of business alliances, e.g., the mine, a research and development laboratory, etc. Moving out of Québec, there is also a graphite mine in Ontario owned by Northern Graphite (my Feb. 6, 2012 posting). It seems Canadians in eastern Canada have a valuable resource in graphite flakes.