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Molybdenum Disulfide Gets a Boost as a Li-ion Electrode Material

While the prospect of aluminum-ion batteries may have received a lift recently, the workhorse battery for both our handheld electronic devices and our electric vehicles remains the ubiquitous lithium-ion (Li-ion) battery.

And now, researchers at Kansas State University (KSU) have taken a fresh look at the venerable Li-ion battery: Using the two-dimensional material molybdenum disulfide (MoS2) on its electrodes, they say, may dramatically boost its storage capacity. What they have come up with is a hybrid material that combines MoS2 with silicon carbonitride (SiCN); it can store double the charge of electrodes using MoS2 on its own.

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Graphene Brings Photodetectors to the Brink of Terahertz Speeds

Researchers at the Institute of Photonic Sciences (ICFO) in Barcelona, Spain have been at the forefront of exploiting graphene’s optoelectronic capabilities.

The latest research out of ICFO has demonstrated a graphene-based ultrafast photodetector that can convert absorbed light into an electrical voltage at speeds of less than 50 femtoseconds. How fast is that? A femtosecond is a thousandth of a millionth of a millionth of a second. So fast—ultrafast.

In research published in the journal Nature Nanotechnology, the ICFO team addressed the niggling issue in graphene-based photothermoelectric devices, specifically charge carrier cooling times, which has limited their switching speeds.

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Perovskite Leads to 100-Percent Efficient Nanowire Lasers

Last year, perovskites established themselves as the “next big thing” in photovoltaic materials, with energy conversion efficiency numbers reaching as high as 20 percent.

Now researchers at the University of Wisconsin-Madison have demonstrated that perovskites can produce high-efficiency, ultra small lasers.

“While most researchers make these perovskite compounds into thin films for the fabrication of solar cells, we have developed an extremely simple method to grow them into elongated crystals that make extremely promising lasers,” said Song Jin, a professor at the University of Wisconsin-Madison, in a press release.

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Graphene Could Be Great for Spintronics

Graphene did not immediately impress anybody with its potential in the field of spintronics, the use of the spin of electrons to encode information rather than charge. If you laid graphene out flat, it didn’t appear to influence electron spin,  that property remained random rather than patterned. But that all changed when scientists saw what happens when you put a small bend in the graphene.

Since then, there’s been a steady stream of research looking at the capabilities of graphene in spintronic applications.  The latest, and perhaps most significant development, is news that researchers at Chalmers University of Technology in Sweden have been able to preserve electron spin for an extended distance using large area graphene.

"We believe that these results will attract a lot of attention in the research community and put graphene on the map for applications in spintronic components," said Saroj Dash, one of the Chalmers researchers, in a press release.

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Molybdenum Disulfide Could Help Memristors Mimic Neurons

The memristor seems to generate fairly polarized debate, especially here on this website in the comments on stories covering the technology. The controversy seems to fall along the lines that the device that HP Labs’ Stan Williams and Greg Snider developed back in 2008 doesn’t exactly line up with the original theory of the memristor proposed by Leon Chua back in 1971.

While this debate will not likely abate, research is continuing in developing two-terminal non-volatile memory devices based on resistance switching.

Along these lines, researchers at Northwestern University have pushed the envelope of the two-terminal device—which can only control one voltage channel—by creating a third terminal. The researchers believe that this will expand the capabilities of memristors into more complex electronics, paving the way for computers to more closely mimic the neurons of the human brain.

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Inexpensive 3-D Imaging Device Integrated Into a Smartphone

Last year we saw confirmation that 3-D printing had emerged into the mainstream. Six years ago, companies like MakerBot were the only ones showing their 3-D wares at CES. Last year, the Consumer Electronics Association dedicated an entire show floor at CES to 3-D printing, only to have it sell out and then sell out again after space was added.

While 3-D printing has been exploding, 3-D imaging of objects so they can be translated into 3-D-printed products has been lagging behind—keeping it an expensive option and outside the reach of most amateur 3-D printing enthusiasts.

Now researchers at CalTech have changed that by developing an inexpensive 3-D imaging device that can be integrated into a smartphone. The imager, they say, can send data to a 3-D printer that will allow it to reproduce a copy accurate to within micrometers of the original object’s dimensions.

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Graphene Finds Its Path in Supercapacitor Commercialization

Researchers at the California NanoSystems Institute (CNSI) at UCLA have been hotly pursuing the ability to apply graphene to the electrodes of supercapacitors. While their efforts have shown progress—improving energy density for a supercapacitor to almost 40 Watt-hours per kilogram from the industry average for a standard supercapacitor of 28 Wh/kg—it apparently hasn’t provided a big enough boost for supercapacitor manufacturers to walk away from the much cheaper activated carbon.

This has not deterred the team at CNSI from continuing to work with graphene and supercapacitors. In fact, they have recently employed the ubiquitous manganese dioxide used in alkaline batteries to create a hybrid material that they believe should boost the commercial prospects for 2-D materials in supercapacitors.

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Will Graphene-based Light Bulbs Be Graphene's Commercial Break Out?

The big story this week in graphene, after taking into account the discovery of “grapene,” has to be the furor that has surrounded news that a graphene-coated light bulb was to be the “first commercially viable consumer product” using graphene.

Since the product is not expected to be on store shelves until next year, “commercially viable” is both a good hedge and somewhat short on meaning. The list of companies with a commercially viable graphene-based product is substantial, graphene-based conductive inks and graphene-based lithium-ion anodes come immediately to mind. Even that list neglects products that are already commercially available, never mind “viable”, like Head’s graphene-based tennis racquets.

So, okay, the BBC got caught up in some PR language promoting what appears to be a UK-developed technology that’s been financed by a Canadian company. That’s nothing outside standard operating procedure. But there were still some issues in the piece that had me scratching my head.

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New 2-D Material Grapene Has Spectacular Properties

Today, 1 April, researchers at the Napa Valley Research Institute announced the discovery of a new two-dimensional material—grapene—that could one-day rival silicon in computers, steel in cars, and chocolate in candybars. (Yes. We know. That’s what they all say.) The new substance exists in flat sheets, connected by strong bonds composed of cellulose and lignin. In bulk form, its natural state, it’s found hanging in chaotically-arranged bunches.

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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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