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Charge Transport in Plastics Increased One Thousand Times

One of the factors that has kept conjugated semiconducting polymers from being even more effective in applications such as organic photovoltaics (OPVs) and organic light-emitting diodes (OLEDs) is the materials’ poor charge carrier mobility. Basically, charge doesn’t move through plastic—even the conjugated variety—as well as it does through silicon. The result is high losses and poor performance.

Nanomaterials such as graphene have been offered up as additives to increase carrier mobility in polymers

Now researchers at Umeå University in Sweden have developed a novel technique for improving the charge transport mobility of a polymer by more than a thousand times. The researchers were able to achieve this enormous increase without any doping of the polymer; instead, they controlled the orientation of the crystallite formations in the polymer.

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Flexible Pressure Sensors Stay Accurate Even When Bent

Research has shown that nanofibers can be fashioned into a pretty effective flexible pressure sensor. We have also seen carbon nanotubes structured into pyramid shapes  or just sprayed over silicone to produce flexible pressure sensors.

Now an international team at the University of Tokyo has produced nanofibers made from a mix of carbon nanotubes and graphene that overcomes a big problem facing flexible pressure sensors—that they lose their accuracy after being bent or deformed. The resulting pressure sensor could be used to better detect breast tumors, its inventors suggest.

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Detergent Triggers Self Assembly of Two-Dimensional Zinc Oxide

There is a fairly large number of materials that might have some pretty attractive properties if they could be made into monolayer, two-dimensional (2-D) sheets. Unfortunately, unlike graphene, which is fabricated by peeling away layers from bulk graphite, these other materials don’t have a multi-layered source. But now the fabrication of these materials has become a possibility through a novel “bottom-up” production technique whose development may have just changed the future of 2-D materials in electronics.

Researchers at the University of Wisconsin-Madison (UW-Madison) have developed a technique in which a zinc oxide monolayer self assembles in a liquid with the help of a surfactant.  After six years of trial-and-error testing with different surfacants, the UW-Madison researchers believe they have found the right mix.

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Nanoscale Thermal Interfaces Eliminate Overheating in Future Photonic Circuits

For years the prospects of photonic circuits—those that use photons instead of the electrons—were mired in a lack-of-space problem: A photonic system couldn’t get any smaller than a wavelength of light, about 1000 nanometers for infrared, while some dimensions of today’s transistors are one one-hundedth that size.

Enter plasmonics in which devices exploit the oscillating waves of electrons that are generated when photons hit a metal surface. Plasmonic-based approaches confine the size of the wavelength and makes it possible to fabricate smaller devices. But plasmonics for photonic circuits has some drawbacks too, namely surface-of-the-sun type heat.

Now researchers at Moscow Institute of Physics and Technology's (MIPT) Laboratory of Nanooptics and Plasmonics have found a solution to the problem of overheating of active plasmonic components using industry-standard heatsinks. If this solution proves successful, the prospects for photonic circuits will have brightened significantly.

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Graphene Offers Emission Tunability for Terahertz Lasers

Despite the myriad uses we have for lasers, once the wavelengths of light have been set for a laser, it’s usually fixed for that device.

Now researchers at the University of Manchester in the UK have demonstrated that they can tune a terahertz laser so that there is reversible control over its emission. They’ve done so by combining a graphene sheet with a terahertz quantum cascade laser. The key to this control over the laser’s emission is manipulating the doping of the graphene layer to change the concentration of charge carriers.

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Laser-Driven "Bubble Pen" Patterns Nanoparticles

Lasers have been used inside microscopes for many years to trap and move objects floating around in solution. 

Now Linhan Lin, a postdoctoral researcher in Yuebing Zheng’s group at the University of Texas in Austin and colleagues have developed a new strategy for drawing those particles down to the surface, where they can be arranged at will.

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Flexible Nanocomposite Film Could Yield Handheld Cancer Detector

This past September, we reported on research out of Vanderbilt University, in Nashville, in which nanowires were used to create the first integrated circularly polarized light (CPL) detector on a silicon chip that could ultimately lead to portable sensors for drug screening—or even enable quantum computers.

Now, researchers at the University of Michigan, in Ann Arbor, have continued this miniaturization of CPL detectors by developing a flexible nanocomposite circularly polarized-light detector that they claim could lead to the development of a cellphone-size cancer detector.

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Stable Superoxide Could Usher in New Class of Lithium-Air Batteries

Researchers at the U.S. Department of Energy’s (DOE’s) Argonne National Laboratory have added a twist to lithium-oxygen batteries (Li–O2) by successfully demonstrating for the first time the ability to stabilize crystalline lithium-superoxide (LiO2) which could usher in an entirely new class of batteries.

In research published in the journal Nature,  the Argonne researchers were able to produce the stable lithium-superoxide by using a graphene-based cathode. This approach avoids the presence of lithium peroxide (Li2O2), a solid precipitate that clogs the pores of the electrode in lithium-oxygen (aka lithium-air) batteries.

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Potential of Graphene Nanoribbons in Electronics Gets a Boost

If graphene is going to make a splash in electronics, it more than likely is going to be in the form of nanoribbons.  What makes them attractive is that their width determines their electronic properties: Narrow ones are semiconductors, while wider ones act as conductors. This essentially provides a simple way to engineer a band gap into graphene.

Last summer, this blog reported on news that a bottom-up approach to manufacturing graphene nanoribbons (GNRs) had been developed that is both compatible with current semiconductor manufacturing methods and can be scaled up.

Okay, so, GNRs have the properties you need for electronics and you can manufacture the material in bulk. But what can you do with it once you’ve made it? An international team of researchers at Tohoku University's Advanced Institute of Materials Research (AIMR) in Japan has demonstrated the ability to interconnect GNRs end to end using molecular assembly that forms elbow structures which are essentially interconnection points. The researchers believe that this development provides the key to unlocking GNRs’ potential in high-performance and low-power-consumption electronics.

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"Printing Press" Method Stamps Out Gold Nanoparticles With New Properties

Gold nanoparticles have become a de facto do-it-all substance, with applications including cancer treatment and a number of electronics applications. If gold nanoparticles have become the go-to nanomaterial for myriad applications, then DNA has to be considered a key tool for generating patterns upon which effective nanomaterial designs are based. 

Now researchers at McGill University, in Montreal, Canada, have brought gold nanoparticles and DNA together in a new process that serves as a kind of printing press that makes it easier to replicate such designs.

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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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