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Nanoscale Chip Design Enables Future 'Internet of Things'

With each passing day we are becoming more intertwined into the Internet of Things, where each and every object in the world—your clothes closet and every article of clothing in it, your dishwasher and every dish in it, and so on—has its own IP address. Obviously, they will communicate wirelessly. That takes power and, in many cases, frequent battery changes.

Now Peter Kinget, a professor or electrical engineering at Columbia University, and his colleagues have developed a nanoscale chip that requires so little energy in transmitting wireless signals that the batteries may never need to be replaced.

The chip will be presented at the at the IEEE International Solid-State Circuits Conference (ISSCC) meeting  in two weeks by Kinget's Ph.D. student Baradwaj Vigraham under the user-friendly title "A Self-Duty-Cycled and Synchronized UWB Receiver SoC Consuming 375pJ/bit for -76.5dBm Sensitivity at 2Mbps."

The research is part of a larger, award-winning research program called EnHANTs. “The goal of Enhants is to make thin, flexible, energy self-reliant tags that can be attached to common objects (clothes, furniture, toys, books, walls, windows, shelves, etc.) in our environment for applications such as the Internet of Things, logistics, tracking and search, or disaster recovery,” explains Kinget.

To this end the credit-card-size tags Kinget and his collaborators (Gil Zussman and John Kymissis) have developed will collect energy with photovoltaic cells. The photovoltaics will draw energy from artificial light in addition to sunlight since indoor applications are of key interest.

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Nano-antenna Arrays May Yield Ultra-Efficient Solar Devices

Technological development is all about finding engineering solutions to scientific theories, and this is especially true in the field of nanotechnology. The work of Gerd Binnig and Heinrich Rohrer in inventing the Scanning Tunneling Microscope comes to mind as an example of trying to engineer something of substance out of little more than an idea based on some sound physics.

Now Brian Willis, associate professor of chemical, materials, and biomolecular engineering at the University of Connecticut, is applying his atomic layer deposition (ALD) fabrication process, which he developed in 2011 while at the University of Delaware, to create nano-antenna arrays for highly efficient solar power devices.

The theory is straightforward: If you could build nano-antenna arrays so that the core electrodes were no more than 1 or 2 nanometers apart, they would serve to both absorb and rectify solar energy—thus the name “rectennas.” These rectennas should be able to collect as much as 70 percent of the sun’s electromagnetic radiation and simultaneously convert that light into direct current electrical power.

With those kinds of potential yields (no pun intended), research into nano-antenna arrays has been growing of late, with some of the more recent research out of MIT looking at ways of using them for holographic TVs. However, for the specific use in photovoltaics the problem has been getting the core electrodes close enough. The best that could be previously achieved, using electron guns, was somewhere in the neighborhood of a 10 to 20 nanometers gap between the core electrodes.

This is where Willis comes in. After the core electrodes have been cut with an electron gun so that one of the pair of electrodes has been shaped into a sharp tip, Willis is able to coat the surfaces of both electrodes with copper atoms using his ALD process, reducing the gap to 1.5 nanometers.

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Nanoparticles of Silicon and Water Makes Hydrogen Gas in an Instant

The history of nanotechnology-based solutions for making fuel cells less expensive or more efficient has not really been what you would call a huge success. But a decade ago it seemed the focus on applying nanomaterials to areas such as improved catalysts for fuel cells was driven more by exploiting what the nanomaterials were good at rather than by what fuel cells needed to be more commercially viable.

Lately that dynamic has changed and nanotechnology has been finding itself more useful when it comes to cheap ways to isolate hydrogen—the high cost of which has been a key obstacle in reaching the so-called “hydrogen economy” where we can drive around in hydrogen-powered automobiles and power our mobile devices with fuel cells.

Three years ago, Angela Belcher at MIT mimicked the process of photosynthesis by developing a man-made virus that could effectively split water molecules into hydrogen and oxygen. Another team, at the University of California, also duplicated photosynthesis, but instead of exotic man-made viruses used a simpler nanowire-based material to cut the water molecules into its constituent parts.

The current state of the art for the artificial photosynthesis approach to isolating hydrogen may have been marked by HyperSolar Inc.’s announcement last year to commercialize a zero-carbon process for hydrogen gas production.

But now researchers at the University of Buffalo—in research published in the journal Nano Letters—have developed a new nanomaterial-based method for producing hydrogen that doesn’t require any light to activate the process. They have reduced silicon down to 10-nanometer particles so that when water is added the reaction produces hydrogen gas quickly and abundantly.

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Graphene and Boron Nitride Combined With Precision

The struggle for which material will be the de facto choice for two-dimensional (2-D) devices in future electronics has been ratcheting up over the last couple of years. In July of last year, IEEE Spectrum covered the development of the long-predicted single-layer thick structure of silicon, known as silicene.  2-D silicon is expected to have some of the same remarkable characteristics as graphene, but deliver them in a material that the semiconductor industry has been working with for decades.

Another material that has been pushing graphene for the throne of the 2-D material of the future has been molybdenum disulfide (MoS2).  Two years ago it seemed that at best MoS2 could achieve would to be simply a complimentary material to graphene in applications that required transparent semiconductors.  Over the last six months, it’s no longer clear that MoS2 shouldn't have it's own starring role.  

So it would seem that graphene needs to step up its game if it’s to stake its claim to the 2-D material of the future for electronics applications. Researchers at Rice University have taken up the challenge and developed a process that can be duplicated with lithography techniques to weave graphene (the conductor) with hexagonal boron nitride (h-BN) (the insulator) to create patterns at nanoscale dimensions.

The research, which was published in the journal Nature Nanotechnology (“In-plane heterostructures of graphene and hexagonal boron nitride with controlled domain sizes”), is the latest evolution of a technique that was developed at Rice nearly three years ago. What distinguishes this new version is that the researchers were able to shrink the 2-D devices to even smaller dimensions.

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UK Attempts to Take a Leadership Role in the Commercialization of Graphene

Those associated with the UK government’s nanotechnology efforts have often pointed out that the country's first national nanotechnology initiative the UK Department of Trade and Industry’s National Initiative on Nanotechnology (NION) came into existence in 1986—a decade and a half before the United States formed its own National Nanotechnology Initiative in 2001. This historical reminder is seldom told as a matter of pride, but as a cautionary tale. After starting off as a world leader in the field, the UK has fallen farther behind the U.S., Germany, and Japan with each passing year.

Because of this belief that it let a treasure escape out of the front door, the UK government has been determined to not let history repeat itself with its handling of graphene research and commercialization. The British feel a kind of ownership of graphene ever since two Russian émigrés, Andre Geim and Konstantin Novoselov, created single-atom-thick sheets of carbon back in 2004 while at the University of Manchester. The UK government is determined to stake its claim in nanotechnology, with graphene as its quarry. To ensure that it gets the most commercialization bang for its development buck, the government began revealing plans last year aimed at making the UK a “graphene hub." And this time they were going to put their money where their mouth was, investing around US $71 million in a single research facility at the University of Manchester. In the past, the UK has been reluctant to invest in nanotechnology even if it meant some of their homegrown companies would move abroad.

Despite bold plans and investments, it was reported earlier this month that the UK had already fallen dramatically behind in graphene-related patents.

Nationality

Number of Graphene Patent Publications

Chinese entities

2,204

US entities

1,754

South Korea entities

1,160

United Kingdom entities

54

SOURCE: Q TANNOCK, CAMBRIDGEIP, 2013

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Solid Electrolyte Leads to Safer Energy-Dense Li-ion Batteries

The Boeing Dreamliner's problematic choice of a lithium-ion (Li-ion) battery designed around a cobalt oxide (CoO2) chemistry is making everyone a little nervous about Li-ion batteries in general. It harkens back to the mid-2000s when electronics giants apologetically had to recall the Li-ion batteries used in their laptop computers.

The CoO2 chemistry used in Li-Co-O2 batteries offers more power for its weight than the Li-Ti-O variety, but is less stable. However, if a better electrolyte solvent could be developed, much of that instability could be mitigated. (A commenter astutely discussed this topic in a response to a recent blog post.)

Along these lines, researchers at Oak Ridge National Laboratory (ORNL) have developed a nanostructured solid electrolyte for more energy-dense Li-ion batteries. They expect that replacing liquid electrolytes in Li-ion batteries with solid ones should lead to safer batteries.

"To make a safer, lightweight battery, we need the design at the beginning to have safety in mind," said ORNL's leader researcher, Chengdu Liang, in a press release. "We started with a conventional material that is highly stable in a battery system—in particular one that is compatible with a lithium metal anode."

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Gold Nanoparticles Might Make a Non-Toxic Treatment for Lymphoma

Gold in nanoparticle form is perhaps more precious than the macroscale variety when it comes to treating diseases. While the usual application areas for nanotechnology, such as electronics, are finding uses for gold nanoparticles, it is perhaps in the area of drug delivery and the detection and treatments of diseases such as cancer where they are destined to have their biggest impact.

Along these lines, researchers at Northwestern University have used gold nanoparticles to treat a common form of cancer, known as B-cell lymphoma—the most common type of non-Hodgkin lymphoma.

In research to be published in the journal Proceedings of the National Academy of Sciences, C. Shad Thaxton, M.D., and Leo I. Gordon, M.D. showed that they could trick B-cell lymphoma, which prefers to eat HDL (high-density lipoprotein) cholesterol—otherwise known as the “good cholesterol”—into eating gold nanoparticles instead of the HDL. Once the B-cell lymphoma cells start eating the gold nanoparticles (or artificial HDL particles), they get plugged up and can no longer feed on any more cholesterol. Deprived of their favorite food, the lymphoma cells essentially starve to death.

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When You Keep Nanotubes Short, They’re Not Like Asbestos

For at least the past five years, NGOs committed to seeing nanotechnology research stopped dead in its tracks have trotted out Ken Donaldson’s research at the University of Edinburgh to support their aims. Donaldson’s research indicated that multi-walled nanotubes (MWNTs) that are longer than 20 μm have a similar pathogenic effect to asbestos.

The writing was on the wall right from the beginning for any concern this research might have generated. The common sense question was: What if you kept the MWNTs short?

Richard Jones essentially raised this question on his blog at the time of Donaldson publishing his research in Nature Nanotechnology: “Not all carbon nanotubes are equal when it comes to their toxicity. Long nanotubes produce an asbestos-like response, while short nanotubes, and particulate graphene-like materials don’t produce this response.”

Five years later and we have experimental confirmation that the way to reduce the pathogenic risk from MWNTs is to keep them short. In research published in the journal Angewandte Chemie (“Asbestos-like Pathogenicity of Long Carbon Nanotubes Alleviated by Chemical Functionalization”), Professor Kostas Kostarelos at the University College London’s School of Pharmacy found that if you chemically functionalized MWNTs so they become shorter, then they are a safe and risk-free material.

“The apparent structural similarity between carbon nanotubes and asbestos fibres has generated serious concerns about their safety profile and has resulted in many unreasonable proposals of a halt in the use of these materials even in well-controlled and strictly regulated applications, such as biomedical ones,” said Kostarelos in a university press release. “What we show for the first time is that in order to design risk-free carbon nanotubes both chemical treatment and shortening are needed.”

This certainly doesn’t put the issue to rest. Not for the reasons that NGOs will likely employ—which will  be to ignore this most recent research—but because how can we be assured that MWNTs used in a material matrix do not exceed 20 μm in length? Further, what about the safety of the workers who handle the MWNTs before they are chemically functionalized (shortened)?

Sound scientific research is still needed and it will in all likelihood be pursued. Whether this will satisfy those who are well-versed in how to leverage preliminary studies into scare screeds remains to be seen. When more in-depth research finds that those preliminary studies were not as well founded as they made others believe, the fear mongers typically remain defiant in part through dismissing the latest research.

Faster and Cheaper Process for Graphene in Li-ion Batteries

Over the last couple of years, research to improve lithium-ion (Li-ion) batteries have been turning to graphene, particularly after researchers at Northwestern University successfully sandwiched a layer of silicon between graphene sheets in the anodes of Li-ion batteries.

But most of the Li-ion battery work being done with graphene to date has depended on high-vacuum environments to create the layered material. Now Gurpreet Singh, a Kansas State University assistant professor of mechanical and nuclear engineering, is leading a team that's looking at faster and cheaper ways of synthesizing the material.

"We are exploring new methods for quick and cost-effective synthesis of two-dimensional materials for rechargeable battery applications," Singh said in a university press release.

The two-dimensional materials to which Singh refers includes not only graphene but also tungsten disulfide nanosheets. In his work with graphene, which was published in the journal Applied Materials & Interfaces (“Synthesis of Graphene Films by Rapid Heating and Quenching at Ambient Pressures and Their Electrochemical Characterization”),Singh’s team was able to create the graphene outside of a vacuum.

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Graphene Could Help Prevent Another Lance Armstrong

After a professional cycling career in which he claimed repeatedly to have never given a positive drug test, Lance Armstrong has reportedly confessed to using performance-enhancing drugs in achieving his Tour de France victories.

While his confession will likely raise a lot of questions, surely one has to be how could the drug tests have failed in detecting the illicit drugs? Great advances have been made in drug testing since Lance Armstrong won his first Tour de France in 1999. At that time, there was no test for EPO—the drug of choice of endurance athletes looking for an edge—but a test was developed in 2000. Nonetheless, Armstrong and many others who have recently confessed got away with it between 2000 and now despite the new tests.

Now drug testing may have a new ally in combating cheating in professional cycling and all professional sports. Researchers at the University of Manchester in the UK in cooperation with colleagues at Aix-Marseille University in France are reporting on an optical system—enabled by esoteric stuff such as metamaterials, plasmonics, and singular optics along with the wonder material graphene—to detect a single molecule of a drug in a few minutes.

The research, which is published in the journal Nature Materials (“Singular phase nano-optics in plasmonic metamaterials for label-free single-molecule detection”), is essentially a proof of concept for new sensing devices that exploit the field of singular optics, which operates on the phenomena of abrupt phase changes to light.

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Nanoclast

IEEE Spectrum’s nanotechnology blog, featuring news and analysis about the development, applications, and future of science and technology at the nanoscale.

 
Editor
Dexter Johnson
Madrid, Spain
 
Contributor
Rachel Courtland
Associate Editor, IEEE Spectrum
New York, NY
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