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Solar clothing from nanotextiles

"Back to the Future" Serves as Inspiration for Clothing With a Solar-Powered Battery

Jayan Thomas, an associate professor at the University of Central Florida’s (UCF’s) NanoScience Technology Center, has devoted a fair amount of his recent research to developing nanoprinting techniques to produce high-density supercapacitors. Thomas and his colleagues at UCF have been following that up with research in the area of supercapacitors aimed at creating nanowire-enabled cables that can both conduct and store energy.

Now Thomas has kept on this supercapacitor theme, but this time has taken some inspiration from the pop culture—namely the movie Back to the Future Part II—to create garments that can serve as solar-powered batteries that would never need to be plugged in.

“That movie was the motivation,” said Thomas in a press release. “If you can develop self-charging clothes or textiles, you can realize those cinematic fantasies—that’s the cool thing.”

In research published in the journal Nature Communications, Thomas and his UCF colleagues developed a ribbon-like device that can harvest light, convert it into electricity, and then store that electricity.

The work is remarkably reminescent of research presented back in September. Researchers created a woven material comprising two power-generating components: fiber solar cells and a triboelectric generator that produces energy through static electricity. However, that device did not have any energy storage element.

In this latest research, a power generation layer is joined to an energy-storage layer. The ribbon integrates a perovskite solar cell with a supercapacitor via a copper ribbon which functions as a shared electrode for direct charge transfer.

Supercapacitors are increasingly being considered a viable alternative for powering many of the things that now depend on batteries. However, there is a bit of a tradeoff. Though supercapacitors can release a large amount of energy very quickly and can be rapidly recharged, they pale in comparison to batteries when it comes to  storing large amounts of energy and discharging it over a long period of time. A lot of research has gone into maintaining that quick charge-discharge capability, while beefing up supercapacitors’ energy density.

In measurements taken by the UCF researchers, when the flexible solar ribbon was exposed to simulated sunlight, the perovskite solar cell achieved a 10 percent energy conversion ratio and the supercapacitor had a specific capacitance of 1193 farads per gram (F/g). To give you some context, a commercially available supercapacitor has a specific capacitance of around 100 F/g.

This means that the ribbon, when acting as a solar cell, can produce electricity pretty efficiently. And when it becomes a supercapacitor, it stores energy much longer than typical supercapacitors but still remains pretty short on capacity compared to chemical-based batteries.

In demonstrating the technology, the researchers made filaments from the ribbon and then weaved these filaments into a square of yarn using a loom. In real application, more advanced weaving techniques would be used. But the principle would be the same: the filaments would be woven into the material.

“A major application could be with our military,” Thomas said. “When you think about our soldiers in Iraq or Afghanistan, they’re walking in the sun. Some of them are carrying more than 30 pounds of batteries on their bodies. It is hard for the military to deliver batteries to these soldiers in this hostile environment. A garment like this can harvest and store energy at the same time if sunlight is available.”

In a telephone interview with IEEE Spectrum, Thomas did concede that at this point, the supercapacitor was not capable of storing enough energy to replace the batteries entirely, but could be used to make a hybrid battery that would certainly reduce the load a soldier carries.

Thomas added: “By combining a few sets of ribbons (2-3 ribbons) in parallel and connecting these sets (3-4) in a series, it’s possible to provide enough power to operate a radio for 10 minutes. Currently these devices are not optimized for providing the highest energy and power density. However, we are working on improving the energy density so that it can work as a hybrid battery-supercapacitor device.”

At just one atom thick, tungsten disulfide allows energy to switch off and on, but it also absorbs and emits light, which could find applications in optoelectronics, sensing, and flexible electronics.

Highest Performing Tungsten Disulfide Yet Brings Flexible 2D Circuits Closer

Layered two-dimensional (2D) transition metal dichalcogenides (TMDs)—like tungsten disulfide or molybdenum disulfide—are attractive for electronics applications because you can manipulate their band gap simply by adjusting the number of layers used.

But there’s a catch: it’s tricky to develop a processes that will lead to large-area synthesis of device quality TMDs. Now researchers at New York University’s (NYU) Tandon School of Engineering may have taken a big step toward closing down this issue with a new manufacturing process for tungsten disulfide that resulted in highest quality ever reported for the material.

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What looks like foil and wires wrapped around the back of a hand is a terahertz scanner made from carbon nanotubes

Flexible, Portable Terahertz Scanner Made From Carbon Nanotubes

Terahertz radiation can peer through objects to spot hidden items and analyze their chemistry, but today’s terahertz detectors are typically inflexible and bulky. Now scientists in Japan have for the first time created a portable, flexible, wearable terahertz scanner in order to better image objects with curves, including the human body.

Terahertz rays, which lie between the infrared and microwave bands of the electromagnetic spectrum, can pass through a wide variety of materials without damaging them. As such, terahertz cameras have great potential for noninvasive, high-resolution imaging. Promising applications include revealing hidden weapons, identifying explosives, and checking for defects in machined parts, among others.

However, conventional terahertz imaging technologies “use inflexible materials and therefore are adaptable only to flat samples,” says Yukio Kawano at the Tokyo Institute of Technology. So these imagers encounter difficulties when scanning most real-life samples—which possess 3D curvature—greatly limiting their use, he says. For instance, terahertz scanners at security checkpoints need to rotate detectors 360 degrees around human bodies to image them, a necessity that makes these systems very bulky.

Kawano and his colleagues devised their new flexible terahertz imaging device from films of carbon nanotubes, which are pipes of carbon only nanometers or billionths of a meter wide. At room temperature, their imager could detect a wide band of terahertz rays, ranging in frequency from 0.14 to 39 terahertz. This work marks "the first realization of a flexible terahertz camera," Kawano says.

The scientists developed portable terahertz scanners that they could wrap around objects. Using these scanners, they could image hidden items such as metal washers or paper clips concealed behind paper sheets or germanium plates or find a piece of chewing gum hidden in a plastic box. They could also identify metal impurities in a plastic bottle and a break in a syringe. These findings suggest this scanner could find use in “high-speed and multi-view inspections of industrial products, especially non-flat samples,” such as plastic bottles and pharmaceutical products, Kawano says.

In addition, the scientists developed a wearable scanner that could detect terahertz rays emitted by a human hand. “The wearable terahertz imaging of human hand without external terahertz sources is an important step for future medical applications,” Kawano says. For instance, this scanner could help inspect a broad range of things including cancer cells, sweat glands, and tooth decay, enhancing “real-time monitoring of daily health conditions,” Kawano says.

"We are planning to integrate our terahertz camera with a signal read-out circuit and a wireless communication device into a single chip and to develop a high-speed terahertz inspection system," Kawano says. "Real-time medical monitoring applications are our next step."

The scientists detailed their findings online 14 November issue of Nature Photonics.

DNA-based nanowires

Nanoscale Interconnects Come to Self-Assembling DNA Origami

DNA origami structures are essentially DNA strands that have been folded into structures using the techniques of the Japanese art of paper folding for which it is named. These DNA origami structures have been hotly pursued as a way to keep shrinking the feature sizes of chips. 

One could really get a sense of how seriously researchers were taking this approach for electronics when IBM researchers reported seven years ago that they were able to use such folded nanostructures to create a scaffold that served as a kind of quasi circuit board. That board allowed them to assemble components with features as small as 6 nanometers.

Despite this research interest, some aspects of the DNA origami technique have not been fully developed for electronics applications. One issues pressing the brakes has been interconnects: Nobody has produced well-defined electrical contacts between macroscopic electrodes and the DNA-based origami nanodevices.

Now researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and Paderborn Universities in Germany have taken on this gap in research and have developed a technique that will make it possible to build interconnects on the nanoscale between electronic components.  The researchers believe that their technique represents an important first step on the way to building electronic circuits by self-assembly.

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Basic setup that enables researchers to use lasers as optical “tweezers” to pick individual atoms out from a cloud and hold them in place

Large Number of Atoms Trapped In an Array Bolsters Quantum Computing

Digital logic depends on bits. The binary states of “0” or “1” form the basis of computing. In quantum computers, the bit is replaced by something called a quantum bit (or, qubit), which is an atomic particle that can be coerced into being both 0 and 1 simultaneously, at least for a time.

But one of the problems for quantum computing has been how to get restless atomic particles, like electrons, to sit down together in large groups long enough so that they can be used to carry out calculations.

Researchers at MIT and Harvard University have devised a way to capture atomic particles using optical “tweezers” and hold them in place long enough to take a picture of them so that their locations can be determined and lasers can be directed at them based on that information. Optical tweezers—more formally known as “single-beam gradient force traps”—have been a key instrument in manipulating matter in biology and quantum optic applications since Bell Labs first described that instrument in 1986.

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A nanostructured transistor for a transparant glucose sensor.

Nanostructred Transistor Enables Glucose Sensing Contact Lens

Various nanomaterials have been enlisted for creating improved glucose sensors that help diabetics determine when their blood sugar levels are too high or low. There have also been various ways in which nanomaterials have been incorporated into contact lenses to enable a variety of new capabilities.

Now, a research team at Oregon State University (OSU) has brought together nano-enabled contact lenses and glucose sensors into a single device that may someday do double duty as a blood glucose monitor and a contro mechanism for deciding when to deliver insulin injections. The device, say the researchers, will be a transparent sensor embedded in a contact lens.

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This topological insulator, doped with chromium (Cr) atoms, conducts electricity on its surface and possesses desirable magnetic properties at a higher range of temperatures t

Topological Insulators Move a Step Closer to Computing Uses

With this year’s Nobel Prize in Physics going to three physicists for their “theoretical discoveries of topological phase transitions and topological phases of matter,” it would appear that things are looking up for the nascent prospects of topological insulators.

Topological insulators (TIs) are materials that behave like conductors near their surfaces but act as insulators throughout the bulk of their interiors. While such materials had long been thought theoretically possible, only recently have research labs around the world begun producing materials with these properties. This has buoyed hopes that they could someday be used in technologies ranging from “spintronics” to quantum computers.

Now an international team of researchers from the National Institute of Standards and Technology (NIST), the University of California Los Angeles (UCLA), and the Beijing Institute of Technology in China have developed a way that makes it far easier to magnetize TIs, improving the odds that they’ll be applied to computing.

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Cutting the material in battery form

Printable Electronics That Self Heal Before Your Eyes

While printed electronics conjure up notions of being able to manufacture electronic devices far more simply and cheaply than traditional electronics, the reality is that the resulting devices are so delicate that they are prone to an early demise that all but snuffs out any savings that might have been gained.

Now, researchers at the University of California San Diego (UCSD) have developed a new type of magnetic ink that produces electronic devices with self-healing capabilities. The UCSD researchers believe that this self-healing quality will make printed electronics far more robust, and therefore more viable for a number of new applications.

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Gordon Moore's Foundation Funds First of 50 Fellows in $34 Million Plan

When our own Tekla Perry interviewed him in 2008, Gordon Moore wanted to be remembered for “Anything, but Moore’s Law.” Today, through his and his wife Betty’s foundation, he made some strides to be remembered for something else—supporting promising inventors.

The Gordon and Betty Moore Foundation announced the first five of what will eventually be 50 Moore Inventor Fellows. Each fellow will receive a total of US $825,000 over three years to drive their invention forward, including $50,000 per year from their institution. All told, the Moore Foundation plans to invest $34 million.

“We are investing in promising scientist-problem solvers with a passion for inventing—like Gordon Moore himself,” said Harvey V. Fineberg, president of the Gordon and Betty Moore Foundation, in a press release. “By providing support to these early-career researchers, we can give them the freedom to try out new ideas that could make a real and positive difference.”

The inaugural Moore Fellows include:

Deji Akinwande, a professor at the University of Texas, Austin, and an IEEE senior member, was recognized for his work on two-dimensional silicon, otherwise known as silicene. In 2015, his group created the first silicene transistor. But he’s also been involved in developing devices made from other 2D materials including graphene, black phosphorus, and molybdenum disulfide. (He’s also winner of the 2015 IEEE Nanotechnology Early Career Award.)

Shane Ardo is an assistant professor of chemistry at University of California, Irvine. According to the Foundation, his materials invention uses sunlight to drive a novel ion-pumping mechanism that could be used to boost the power output and efficiency of electrochemical technologies. His new materials will also enable sustainable, affordable and efficient polymer devices to desalinate water.

Xingjie Ni, an assistant professor of electrical engineering at Penn State, is an expert in optical metamaterials. According to the Moore Foundation, Xingjie’s invention is a brighter quantum light source that could ultimately increase the speed, scale, and security of information transmission in quantum communication and computing. But he is perhaps best known for the development in 2015 of an ultrathin invisibility cloak that works in visible light.

Joanna Slusky is an assistant professor of molecular biosciences and computational biology at the University of Kansas. Slusky’s invention is a protein that will re-sensitize bacteria to common antibiotics, thereby overcoming drug-resistant superbugs and re-establishing the efficacy of antibiotics.

Mona Jarrahi is an associate professor of electrical engineering at UCLA and leader of the university’s terahertz electronics lab. The Moore Foundation is backing Jarrahi for her terahertz imaging tool. The instrument should help researchers understand how fundamental biological molecules behave in their natural environment and answer other fundamental questions. Her lab recently reported creating a metamaterial lens that allows terahertz beams to be steered electronically. She’s a senior member of IEEE, and, like Akinwande, has received IEEE’s Early Career Award in Nanotechnology.

The fellows will be recognized at an event later today at The Tech Museum of Innovation in San Jose, Calif.

“We cannot know in advance that an invention we support will change the world, but giving passionate inventors the resources to develop a good idea can accelerate progress in the areas we care about,” Robert Kirshner, chief program officer for science at the Moore Foundation, said in a press release.

Graphite/PMMA/Li trilayer electrode

Nanostructure Makes Batteries Better on Very First Charge

Various nanomaterials have been drafted into the quest to improve the charge capacity of anodes (negative electrodes) in lithium-ion batteries. Their role primarily has been to help silicon—which offers ten times the charge capacity of graphite—last more than just a few charge/discharge cycles. Everything from graphene to nanofibers have been enlisted into help silicon better survive the rigors of the expansion and then contraction that occurs when silicon anodes are charged and discharged.

Now scientists at Columbia University have developed a nanostructure for the silicon anode of Li-ion batteries that will help them overcome one of their most challenging moments: the very first charge/discharge cycle that occurs during manufacturing.

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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.

 
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Dexter Johnson
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