Posts belonging to Category electronics



Cloth That Produces Electricity

Fully flexible, foldable nanopatterned wearable triboelectric nanogenerator (WTNG) with high power-generating performance and mechanical robustness have been designed by researchers from the SKKU Advanced Institute of Nanotechnology (SAINT) (Korea). Triboelectric is an electrical charge produced by friction between two objects that are nonconductive. Very high voltage and current outputs with an average value of 170 V were obtained from a four-layer-stacked WTNG. The researchers created a novel tribo electric nano generator fabric out of a silvery textile coated with nanorods and a silicon-based organic material.
nanogenerator3
When they stacked four pieces of the cloth together and pushed down on the material, it captured the energy generated from the pressure. The material immediately pumped out that energy, which was used to power light-emitting diodes, a liquid crystal display and a vehicle’s keyless entry remote. The cloth worked for more than 12,000 cycles.

Source: http://pubs.acs.org/

Quantum Radar Can See The Invisble

A prototype quantum radar that has the potential to detect objects which are invisible to conventional systems has been developed by an international research team led by a quantum information scientist at the University of York (U.K.). The new breed of radar is a hybrid system that uses quantum correlation between microwave and optical beams to detect objects of low reflectivity such as cancer cells or aircraft with a stealth capability. Because the quantum radar operates at much lower energies than conventional systems, it has the long-term potential for a range of applications in biomedicine including non-invasive NMR scans.

radarA conventional radar antenna emits a microwave to scan a region of space. Any target object would reflect the signal to the source but objects of low reflectivity immersed in regions with high background noise are difficult to spot using classical radar systems. In contrast, quantum radars operate more effectively and exploit quantum entanglement to enhance their sensitivity to detect small signal reflections from very noisy regions.
Dr Stefano Pirandola, leader of the research team at the University’s Department of Computer Science said that while quantum radars were some way off, they would have superior performance especially at the low-photon regime.
Such a non-invasive property is particularly important for short-range biomedical applications. In the long-term, the scheme could be operated at short distances to detect the presence of defects in biological samples or human tissues in a completely non-invasive fashion, thanks to the use of a low number of quantum-correlated photons“.
“Our method could be used to develop non-invasive NMR spectroscopy of fragile proteins and nucleic acids. In medicine, these techniques could potentially be applied to magnetic resonance imaging, with the aim of reducing the radiation dose absorbed by patients.

Source: http://www.york.ac.uk/

New Cheap Catalyst For Hydrogen Electric Car

Graphene nanoribbons formed into a three-dimensional aerogel and enhanced with boron and nitrogen are excellent catalysts for fuel cells, used in hydrogen electric car, even in comparison to platinum, according to Rice University researchers. The reactions in most current fuel cells are catalyzed by platinum, but platinum’s high cost has prompted the search for alternative. A team led by materials scientist Pulickel Ajayan and chemist James Tour made metal-free aerogels from graphene nanoribbons and various levels of boron and nitrogen to test their electrochemical properties. In tests involving half of the catalytic reaction that takes place in fuel cells, they discovered versions with about 10 percent boron and nitrogen were efficient in catalyzing what’s known as an oxygen reduction reaction, a step in producing energy from feedstocks like methanol.
Ajayan’s Rice lab has excelled in turning nanostructures into macroscopic materials, like the oil-absorbing sponges invented in 2012 or, more recently, solid nanotube blocks with controllable densities and porosities.

hydrogen-electric car
The key to developing carbon-based catalysts is in the doping process, especially with elements such as nitrogen and boron,” he said. “The graphitic carbon-boron-nitrogen systems have thrown many surprises in recent years, especially as a viable alternative to platinum-based catalysts.”. The Rice process is unique, he said, because it not only exposes the edges but also provides porous conduits that allow reactants to permeate the material.
The research appeared in the American Chemical Society journal Chemistry of Materials.

Source: http://news.rice.edu/

Laboratories-On-a-Chip

Newly developed tiny antennas, likened to spotlights on the nanoscale, offer the potential to measure food safety, identify pollutants in the air and even quickly diagnose and treat cancer, according to the Australian scientists who created them. The new antennas are cubic in shape. They do a better job than previous spherical ones at directing an ultra-narrow beam of light where it is needed, with little or no loss due to heating and scattering, they say.

In a paper published in the Journal of Applied Physics, from AIP Publishing, Debabrata Sikdar of Monash University in Victoria, Australia, and colleagues describe these and other envisioned applications for their nanocubes in “laboratories-on-a-chip.” The cubes, composed of insulating, rather than conducting or semiconducting materials as were the spherical versions, are easier to fabricate as well as more effective, he says.

Sikdar’s paper presents analysis and simulation of 200-nanometer dielectric (nonconductive) nanoncubes placed in the path of visible and near-infrared light sources. The nanocubes are arranged in a chain, and the space between them can be adjusted to fine-tune the light beam as needed for various applications. As the separation between cubes increases, the angular width of the beam narrows and directionality improves, the researchers say.

nanoantennas
Unidirectional nanoantennas induce directionality to any omnidirectional light emitters like microlasers, nanolasers or spasers, and even quantum dots,” Sikdar said in an interview. Spasers are similar to lasers, but employ minute oscillations of electrons rather than light. Quantum dots are tiny crystals that produce specific colors, based on their size, and are widely used in color televisions. “Analogous to nanoscale spotlights, the cubic antennas focus light with precise control over direction and beam width,” he said.
Source: http://www.aip.org/

Solar Film: How To Increase The Absorption Of Sunlight

A biological structure in mammalian eyes has inspired a team headed by Silke Christiansen to design an inorganic counterpart for use in solar cells. With the help of conventional semiconductor processes, they etched micron-sized vertical funnels shoulder-to-shoulder in a silicon substrate. Using mathematical models and experiments, they tested how these kind of funnel arrays collect incident light and conduct it to the active layer of a silicon solar cell. Their result: this arrangement of funnels increases photo absorption by about 65% in a thin-film solar cell fitted with such an array and is reflected in considerably increased solar cell efficiency, among other improved parameters. This closely packed arrangement of cones has now inspired the team headed by Prof. Silke Christiansen to replicate something similar in silicon as a surface for solar cells and investigate its suitability for collecting and conducting light. Christiansen heads the Institute for Nanoarchitectures for Energy Conversion at the Helmholtz-Zentrum Berlin (HZB) and a research team at the Max Planck Institute for the Science of Light (MPL) – Germany..

solar funnelThe simulation shows how the concentration of light (red = high concentration, yellow= low concentration) rises in the funnels with declining diameter of the lower end of the funnel
We’ve shown in this work that the light funnels absorbs considerably more light than other optical architectures tested over the last while”, says Sebastian Schmitt, one of the two first authors of the publication that has appeared in journal Nature Scientific Reports.

Source: http://www.helmholtz-berlin.de/

How To Boost Electric Vehicle Batteries

Researchers from the Professor Mihri Ozkan lab at the University of California, Riverside’s Bourns College of Engineering have developed a novel paper-like material for lithium-ion batteries. It has the potential to boost by several times the specific energy, or amount of energy that can be delivered per unit weight of the battery.
This paper-like material is composed of sponge-like silicon nanofibers more than 100 times thinner than human hair. It could be used in batteries for electric vehicles and personal electronics.

electric carThe problem with silicon is that is suffers from significant volume expansion, which can quickly degrade the battery. The silicon nanofiber structure created in the Ozkan’s labs circumvents this issue and allows the battery to be cycled hundreds of times without significant degradation. This technology also solves a problem that has plagued free-standing, or binderless, electrodes for years: scalability. Free-standing materials grown using chemical vapor deposition, such as carbon nanotubes or silicon nanowires, can only be produced in very small quantities (micrograms). However, the team was able to produce several grams of silicon nanofibers at a time even at the lab scale.

The nanofibers were produced using a technique known as electrospinning, whereby 20,000 to 40,000 volts are applied between a rotating drum and a nozzle, which emits a solution composed mainly of tetraethyl orthosilicate (TEOS), a chemical compound frequently used in the semiconductor industry. The nanofibers are then exposed to magnesium vapor to produce the sponge-like silicon fiber structure.

The findings were just published in the journal Nature Scientific Reports.
Source: http://www.mse.ucr.edu/

Silicon Valley Made in Sweden

A production facility for start-ups in the field of nanotechnology may be built in the Science Village in Lund, a world-class research and innovation village that is also home to ESS, the European Spallation Source.
The project originates from the successful research into nanowires at Lund University, which has resulted in nanotechnology companies like Glo AB and Sol Voltaics AB. Glo was forced to move to Silicon Valley, however, to launch large-scale mass production.

The infrastructure would be intended for companies and researchers in the whole of Sweden who want to develop products with industry standards without needing to invest in expensive equipment themselves.
nano industry
With this new facility, we want to create the conditions to enable new companies to develop from the R&D phase to full production, without needing to leave Sweden,” says Lars Samuelson, Professor of Nanophysics at Lund University.

Samuelson sees more business opportunities for nanowires. In addition to Glo’s light-emitting diodes and Sol Voltaicssolar cells, Lars Samuelson believes there is potential for new companies focused on applications within electronics, UV light-emitting diodes and biomedicine.

Alongside this project, Lund University is working to extend the Lund Nano Lab which is a pure research laboratory for research on nanowires. This is run by Lund University, whereas the industrial facility is a project outside the University. Together, these two initiatives constitute a way of generating the whole value chain from research to market.

Source: http://www.lunduniversity.lu.se/

How To Produce Graphene Massively

With properties that promise faster computers, better sensors and much more, graphene has been dubbed the ‘miracle material’. But progress in producing it on an industrial scale without compromising its properties has proved elusive. University of Groningen (Netherlands) scientists may now have made a breakthrough.

Graphene is a special material with crystals that are just one atom thick. Electrons pass through it with hardly any resistance at all, and despite being very flexible, it is stronger than any metal. The discoverers of graphene, Andre Geim and Konstantin Novoselov, famously made it by peeling graphite with Scotch tape until they managed to isolate a single atomic layer: graphene. It won them the 2010 Nobel Prize in Physics.

grapheneManchestergraphene-nanosheets
The challenge is to find a substrate that not only preserves the properties of graphene, but also enables scalable production’, says Stefano Gottardi, PhD student at the University of Groningen Zernike Institute for Advanced Materials. A good candidate is chemical vapour deposition. Here heat is used to vaporize a carbon precursor like methane, which then reacts with a catalytically active substrate to form graphene on its surface. A transition metal is normally used as the substrate. However, not only does the transition metal act as a support, but it also tends to interact with the graphene and modify – or even deteriorate – its outstanding properties. To restore these properties after growth on the metal, the graphene has to be transferred to a non-interacting substrate. Gottardi and his colleagues have managed to successfully grow graphene on copper oxide. This achievement together with an in-depth characterization of graphene’s properties will be published in Nano Letters.

Source: http://www.rug.nl/

Li-Ion Batteries Mimick Shells To Last Longer

Scientists are using biology to improve the properties of lithium ion batteries. Researchers at the University of Maryland, Baltimore County (UMBC) have isolated a peptide, a type of biological molecule, which binds strongly to lithium manganese nickel oxide (LMNO), a material that can be used to make the cathode in high performance batteries. The peptide can latch onto nanosized particles of LMNO and connect them to conductive components of a battery electrode, improving the potential power and stability of the electrode.

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Biology provides several tools for us to solve important problems,” said Evgenia Barannikova, a graduate student at UMBC. Barannikova works in the lab of Mark Allen and studies how biological molecules in general can improve the properties of inorganic materials in batteries.

Biology provides several tools for us to solve important problems,” said Evgenia Barannikova, a graduate student at UMBC. Barannikova works in the lab of Mark Allen and studies how biological molecules in general can improve the properties of inorganic materials in batteries.
By providing a new nanoscale architecture for lithium-ion batteries, the researchers say that the approach could improve the power and cycling stability of lithium-ion batteries.
The researchers will present their results at the 59th annual meeting of the Biophysical Society, held Feb. 7-11 in Baltimore, Maryland.
Source: http://phys.org/

Ultra Bendable Electronics

Electronic devices have shrunk rapidly in the past decades, but most remain as stiff as the same sort of devices were in the 1950s — a drawback if you want to wrap your phone around your wrist when you go for a jog or fold your computer to fit in a pocket. Researchers from South Korea have taken a new step toward more bendable devices by manufacturing a thin film that keeps its useful electric and magnetic properties even when highly curved.

nanoparticles od bismuth
This electron microscope image shows tiny nanoparticles of bismuth ferrite embedded in a polymer film. The film enhances the unique electric and magnetic properties of bismuth ferrite and preserves these properties even when bent
Bulk bismuth ferrite has crucial problems for some applications, such as a high leakage current which hinders the strong electric properties,” said YoungPak Lee, a professor at Hanyang University in Seoul, South Korea. Mixing nanoparticles of bismuth ferrite into a polymer improved the current-leakage problem, he said, and also gave the film flexible, stretchable properties.

Flexible multiferrorics could enable new wearable devices such as health monitoring equipment or virtual reality attire, Lee said. The multiferroric materials could be used in high-density, energy efficient memory and switches in such devices, he said.
The researchers describe the film in a paper published in the journal Applied Physics Letters, from AIP Publishing.

Source: http://www.aip.org/