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A Top-10 Nanotechnology List Worth Reading

My aversion to top-5 or top-10 nanotechnology lists is powerful. However, Nature Nanotechnology has overcome my disgust with the top-10 idea and listed its top-10 most-downloaded articles in the last few weeks. I don’t know if this is a new or an established feature of the publication, but it is the first time I’ve seen it.

At the top of the list is the work done by Angela Belcher and her team at MIT in using viruses to self-assemble carbon nanotubes for use in dye-sensitized solar cells (DSSCs), about which the inventor of DSSCs, Michael Grätzel, remarked to me recently, “That’s a real breakthrough—we can learn a lot from her fascinating experiment.”

It’s an interesting list of research and opinion. On the opinion side, I was glad to see the publishers made available for everyone with or without a subscription a take on the toxicity of nanoparticles entitled The dose makes the poison“ that mirrors some of my own thoughts on the topic.

While some of the research I have covered, I have not reported a majority of the research listed on the pages of this blog. I have, however, recently highlighted some of the other work of the lead researchers, such as MIT researcher Michael Strano.

The most intriguing of the studies I have not covered are the Dutch-Swiss research into “Single-Molecule Transport Across an Individual Biomimetic Nuclear Pore Complex” (which in my defense was only published last week) and the South Korean and Japanese paper “Roll-to-Roll Production of 30-Inch Graphene Films for Transparent Electrodes.”

As I said, this is the first time I’ve seen this feature in Nature, so I will need to check back again and look to see if they offer it on some of their other journals, such as Nature Photonics and Nature Materials.

Harvesting Visible and Invisible Light in PVs with Colloidal Quantum Dots

The promise of multijunction solar cells made from colloidal quantum dots (CQDs) has been discussed as a hopeful prospect for collecting a broad spectrum of light from the sun. If achieved, it would make possible extremely high energy-conversion rates for photovoltaics (PVs).

One of the leading researchers in the field, Edward H. Sargent, and his research team at the University of Toronto have described a new device architecture that includes “a graded recombination layer to provide a progression of work functions from the hole-accepting electrode in the bottom cell to the electron-accepting electrode in the top cell, allowing matched electron and hole currents to meet and recombine,” as it's described in the most recent online edition of the journal Nature Photonics 

The solar power conversion efficiency for the device, according to the Nature abstract, is 4.2 percent—not quite staggering, since levels of 5 percent have been reported as the state of the art for CQD multijunction PVs.

The breakthrough appears to be in that "graded recombination layer," which serves as an interface between the visible and infrared junction passing electrons between the two layers.

When one considers that tandem CQD solar cells are believed to possess astronomical conversion efficiency rates of 42%, it would seem that the 4.2% achieved by the University of Toronto researchers means there is still room for improvement on the technology.

Nonetheless, Sargent has expressed hope that the technology described in the Nature Photonics paper will make it to market and be integrated into building materials, mobile devices, and automobile parts in the next five years.

In addition to the science, what I find interesting about the story is that this research was in part made possible by a US $10 million grant given to Sargent back in 2008 by King Abdullah University of Science and Technology (KAUST) in Thuwal, Saudi Arabia.

It seems Saudi Arabia is committed to developing solar energy alternatives despite sitting on one of the world’s largest oil reserves.

 

Russia's Nanotechnology Initiative Goes on a Spending Spree

I have been fascinated by the Russian government’s foray into nanotechnology; it contains intrigue,  hidden complexities, and more than its share of skepticism.

The list of skeptics even extends to the country's political leaders

"[Rusnano] is the kind of instrument that sometimes works and sometimes doesn't work at all," President Dmitry Medvedev said two years ago, calling the company a "large structure that has a lot of money and that still has to understand how to correctly spend it."

Well, it seems that Rusnano has overcome that learning curve and is spending…a lot. Over at TNT Log this week there is a pretty thorough recap of the deals that Rusnano has been involved in to date.

But so fast and furious is the action at this point that there are already new deals here at the end of the week to add to the list. For instance, Rusnano and Toyota Tsusho have signed a memorandum of cooperation in the fields of electronics, organic chemistry, the environment, and automobile manufacturing.

A fair share of the announced deals really only involve MOUs, and the world of business is littered with MOUs that never actually turn into contracts. Nonetheless, is a picture developing from the deals we have seen thus far? 

It’s hard to say for sure, but at least TNT Log characterizes them as being on the riskier side of the investment scale. And well should they be, in my estimation. If you’re going after market segments that will be affected by the enabling technology of nanotech, then you're likely to find yourself in some pretty risky investments.

Carbon Nanotubes Fluoresce at Right Wave Length for Seeing Internal Organs

Researchers at Stanford University have discovered that fluorescent single-walled carbon nanotubes improve on the murky images provided by traditional dyes and deliver detailed and clear images of the internal organs of mice.

Interestingly, the idea of using fluorescent carbon nanotubes to illuminate the internal organs was partly inspired by the use of carbon nanotubes in drug delivery.

"We have already used similar carbon nanotubes to deliver drugs to treat cancer in laboratory testing in mice, but you would like to know where your delivery went, right?" says Hongjie Dai, a Stanford chemistry professor. "With the fluorescent nanotubes, we can do drug delivery and imaging simultaneously—in real time—to evaluate the accuracy of a drug in hitting its target."

The technique, described this month in the journal Proceedings of the National Academy of Sciences, is able to produce such clear images because of the wavelength at which the carbon nanotubes operate.

The problem has been that both the biocompatible dyes used today and biological tissue fluoresce at the same wavelength of below 900 nanometers. This creates a background fluorescence that results in murky images.

But the carbon nanotubes fluoresce at between 1000 and 1400 nm, where the biological tissue is hardly emitting any fluorescence so that there is minimal background noise.

"The nanotubes fluoresce naturally, but they emit in a very oddball region," Dai says. "There are not many things—living or inert—that emit in this region, which is why it has not been explored very much for biological imaging."

While computer tomography and magnetic resonance imaging still rule the roost when it comes to imaging deep tissue, this should push the capabilities and application of fluorescence imaging, which is used mainly in research and requires far simpler machinery.

Piezoelectrics and Thin Films Power Your Mobile With a Press of Your Finger

While the pedantic among us may quibble with phrases like “self-powering portable electronics” and start blathering about the second law of thermodynamics, new research from Australia is pushing the limits of piezoelectric materials for turning pressure into electrical energy for mobile devices.

The researchers have published their work in the journal Advanced Functional Materials after demonstrating a method for combining piezoelectric materials with thin-film technology to produce more easily integrated into mass-production techniques.

"The concept of energy harvesting using piezoelectric nanomaterials has been demonstrated, but the realization of these structures can be complex, and they are poorly suited to mass fabrication,” says Dr. Madhu Bhaskaran, lead coauthor of the research. "Our study focused on thin-film coatings because we believe they hold the only practical possibility of integrating piezoelectrics into existing electronic technology."

When more easily integrated piezoelectric materials are combined with groundbreaking work in reducing the amount of energy consumed by electronic devices like that done by Eric Pop and his team at the University of Illinois at Urbana-Champaign’s Beckman Institute for Advanced Science and Technology, it seems possible that we may be able to run our small electronic devices for longer than a few hours before we have to plug them into an outlet. 

Bad Videos Are Not the Way to Teach Nanotechnology

It’s that time of year again, when the daylight lasts longer, the temperatures begin to rise and the news cycle allows for whimsical pursuits.

This means that I have noticed a new round of videos being posted on the subject of nanotech.

The Nanoscale Informal Science Education (NISE), which is supposed to educate and engage the public on the subject of nanotechnology, has apparently circulated in its most recent newsletter a video that was a runner up in the American Chemical Society’s video contest back in 2009. 

I also saw this week a video produced in 2010 for another video contest this time for something called Time for Nano.

It all starts quite hopefully with the theme music from all the Warner Brothers cartoons, but it quickly becomes apparent that it is presenting a “camera pill” technology that is ingested to take images from inside your body and somehow it is being presented as nanotechnology.

Now I have taken some what I believe to be well-deserved swipes recently at EU attempts at public outreach, and this is a prime example of what I am concerned about.

So childish and poorly informed is the approach to educating the public about nanotechnology that no one seemed to care that one of the videos submitted for a nanotechnology video competition had nothing to do with nanotechnology.

I would like to suggest that if we want to circulate a video to introduce the public to nanotechnology, let’s just all agree to use the Stephen Fry video (despite his own personal misconceptions on the topic) and happily call it a day.

EU Embarks on Yet Another Public Outreach Project

Europe is once again trying to appease…umh…I mean inform the public about the subject of nanotechnology with another public outreach program entitled Nanochannels.

I say ‘again’ because there have been similar efforts in the past. There was Nanologue, which is a completed EU project that except for those directly engaged in it few have heard of.

Over at the blog Frogheart the reasonable question is asked why no one mentioned the work previously done by Nanologue in this field when announcing Nanochannels. Since I was in the meeting at EuroNanoForum in which the outreach program was discussed, I can confirm that a dreary recap was provided of the Nanologue project. The extent to which this data informed the new project was hard to discern from the near-comatose expression on the face of the audience.

But moving on, in addition to Nanologue there was ObservatoryNANO that was supposed to inform government, industry and finance decision makers about issues pertaining to nanotechnology and in doing so often provided unintended guffaws.

One of the groups behind ObservatoryNANO and now Nanochannels is the Institute of Nanotechnology, which certainly has background in this sort of thing as it also provided some of the background material for last year’s nearly universally lambasted UK nanotechnology strategy report.

That report too managed to forget all the other reports that had come before. While starting from scratch is sometimes necessary and even a good thing, managing to dispose of an entire body of knowledge in order to offer up odd suggestions seems to miss the spirit of starting fresh.

It would appear that Nanochannels (a somewhat unfortunate name in that nanochannels is a term that actually refers to a structure in nanotechnology) is somewhat similar to the UK project Nano&Me, except that Nano&Me was set up for £77k and Nanochannels has a budget of €894,940.

You would think with that kind of money they would have a website, but no, unless of course you count a Facebook page

You know the EU might take a page from the US government in its nanotechnology outreach strategy and just start getting serious about the subject. Just because some groups have decided that juvenile discourse is the way to address the topic of nanotechnology doesn’t mean that governments should embark on a children’s-book approach to the subject to get it all sorted.

IBM Takes Graphene One Step Further with the First IC Built from It

In poker parlance it would seem that IBM has gone “all in” with graphene replacing silicon in the chips of the future.

The latest news in the graphene story is that IBM has built an integrated circuit out of the wonder material. The research, which was published in the magazine Science last week, describes IBM’s success at building a “wafer-scale graphene circuit…in which all circuit components, including graphene field-effect transistor and inductors, were monolithically integrated on a single silicon carbide wafer.”

According to the Spectrum article cited above, it took researchers a year of engineering work to sort how to connect the graphene to the other metallic elements of the circuit and how to perform lithography on it without damaging it.

To overcome the latter challenge the Spectrum article intriguingly says, “One way the team addressed the damage problem was to grow the graphene on a silicon-carbide wafer, then coat it with a common polymer, PMMA, and a resist that was sensitive to jets of electrons used in electron beam lithography.”

I am assuming then that there were other ways tested but this turned out to be the best (I don’t have a Science subscription, so I don’t know if other methods were in fact tried.).

Like anyone who follows to any extent developments in material science around chips I have become somewhat mesmerized at the developments that have been coming fast and furious around graphene.

But meanwhile some interesting developments are occurring with other materials that come in two dimensions like graphene but have a natural band gap. While the molybdenite is not being positioned as a direct competitor with graphene in the post-silicon battlefield, one has to wonder whether there are other minerals out there in addition to molybdenite that could fit the bill and push graphene to the side.

Not that there is such a competitor out there mind you, but once upon a time not too long ago carbon nanotubes were the new wonder material that would someday replace silicon. If I were a betting man, I would be looking to hedge my wager somewhat.

Nanoscale Conductors Enable New Battery Architecture: The Semi-Solid Flow Cell

Researchers at MIT, led by W. Craig Carter and Yet-Ming Chiang, have developed a new architecture for batteries that combines the design of liquid-flow batteries with that of conventional lithium-ion batteries resulting in a 10-fold improvement in the energy density of liquid-flow batteries and reducing the size of a battery system such as found now in electric cars to about half their current size.

The research, which was originally published in the Wiley journal Advanced Energy Materials, was able to overcome the low energy density of liquid-flow batteries by creating a semi-solid material that “kind of oozes,” according to Chiang. The new material is able to store energy in “suspensions of solid storage compounds” and the “charge transfer is accomplished via dilute yet percolating networks of nanoscale conductors.”

The result is that the cathodes and anodes of the battery are particles that are suspended in the liquid electrolyte. And the two different suspensions are pumped through systems separated by a thin porous membrane.

The design also separates the storing and discharging of the battery into two different physical structures. According to Chiang, this separated architecture will enable batteries to be designed more efficiently.

Since the design is expected to reduce the size (and cost) of a battery system by as much as half, it is being touted as a way to make electric vehicles more competitive with internal combustion engines.

Chiang and his researchers have even gone so far as to dub the semi-solid liquid “Cambridge Crude”, no doubt a reference to their Cambridge, MA location. The researchers also posit the idea that the “Cambridge Crude” could be pumped like gas to recharge a car. However, I would make one small caveat on that notion: what are you supposed to do with the semi-solid liquid that you’re disposing of? I expect that one would run into all sorts of environmental concerns.

Nonetheless the researchers have developed what appears to be a new design architecture for batteries and have demonstrated that slurry-type active materials can be used for storing electrical energy.

If the research has the potential for commercial development, it seems the right research team developed it since Chiang’s earlier work on lithium-ion batteries led to the MIT spinoff A123 Systems and it has already been licensed by Chiang’s and Carter’s new company 24M Technologies (itself a spinoff from A123 systems).

Nanotech's Role in Clean Drinking Water Creeping Forward

While attending the EuroNanoForum 2011 conference this week in Budapest, Hungary, I was confronted with at least once considering how nanotechnology could be used in water purification and desalination. You really can’t get through one of these things without hearing how nanotechnology could save the world.

But the water issue is one that over the years I have taken some interest in, putting together a conference on the subject seven years ago, and even taking up the issue here on Spectrum’s pages here, here and here.

A couple of years back, the Meridian Institute published a good white paper entitled “Conventional and Nano-Based Water Technologies,” which did a nice job of cataloguing all the nanotech-based solutions for water desalination.

We have another one to add to that list possibly in a recent article published Physics World  written by Jason Reese, Weir Professor of Thermodynamics and Fluid Mechanics at the University of Strathclyde.

The article relates how CNTs are enabling a technique used by Reese that moves away from the high-energy-cost process of reverse osmosis. In this technique, Reese has shown that the CNTs can improve water permeability 20 times that of modern commercial reverse-osmosis membranes. A factor of 20 improvement in permeability should have a pretty significant impact on the energy requirements.

This is certainly a move in the right direction. However, I have to confess that when I put the NanoWater conference together seven years ago, I had somewhat greater expectations that we would be further along at this point. I am not entirely convinced it’s a lack of technological solutions, nanotech related or otherwise, that is the cause of the delay.

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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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