#Flexible paper electrodes with ultra-high loading for lithium-sulfur batteries With the rapid development of portable electronic devices, electric automobiles,
Recently, scientists from Tsinghua University have created a freestanding carbon nanotube paper electrode with high sulfur loading for lithium-sulfur batteries.
"CNTS are one of the most efficient and effective conductive fillers for electrode. We selected short multi-walled CNTS (MWCNTS) with lengths of 10-50 m as the shortrange electrical conductive network to support sulfur,
as well as super long CNTS with lengths of 1000-2000 m from vertically aligned CNTS (VACNTS) as both long-range conductive networks and inter-penetrated binders for the hierarchical freestanding paper electrode.""
"Such sulfur electrodes with hierarchical CNT scaffolds can accommodate over 5 to 10 times the sulfur species compared with conventional electrodes on metal foil current collectors
as well as modifying precursors in the electrode, which neutralized the advantage of Li-S system in high specific capacity.
"The areal capacity can be increased further to 15.1 mah cm-2 by stacking three CNT-S paper electrodes, with an areal sulfur loading of 17.3 mg cm-2 as the cathode in a Li
This proof-of-concept experiment indicates that the rational design of the nanostructured electrode offers the possibility of the efficient use of active materials as practical loading."
"The current bottom-up electrode fabrication procedure is effective for the preparation of large-scale flexible paper electrodes with good distribution of all functional compounds,
which is also favorable for graphene, CNT-graphene, CNTMETAL oxide based flexible electrodes, "Qiang said."
"The as-obtained freestanding paper electrode is promising for the ubiquitous applications of Li-S batteries with low cost,
high energy densities for future flexible electronic devices such as smart electronics and roll up displays. y
#New self-assembly method for fabricating graphene nanoribbons First characterized in 2004 graphene is a two-dimensional material with extraordinary properties.
The thickness of just one carbon atom and hundreds of times faster at conducting heat and charge than silicon graphene is expected to revolutionize high-speed transistors in the near future.
and edge configurations scientists have theorized that nanoribbons with zigzag edges are the most magnetic making them suitable for spintronics applications.
Spintronics devices unlike conventional electronics use electrons'spins rather than their charge. But this top-down fabrication approach is not yet practical
This new method of graphene fabrication by self-assembly is a stepping stone toward the production of self-assembled graphene devices that will vastly improve the performance of data storage circuits batteries and electronics.
three-dimensional (3d) structures for applications in devices such as batteries and supercapacitors. Their study was published recently in the journal Nature Communications.
which will be highly useful as electrodes and membranes for energy generation or storage. While we have demonstrated only the construction of graphene-based structures in this study we strongly believe that the new technique will be able to serve as a general method for the assembly of a much wider range of nanomaterials concluded Franklin Kim the principal investigator of the study y
#Engineers develop prototype of low-cost disposable lung infection detector Imagine a low-cost, disposable breath analysis device that a person with cystic fibrosis could use at home
Materials scientist Regina Ragan and electrical engineer Filippo Capolino have created a nano-optical sensor that can detect trace levels of infection in a small sample of breath.
They made the sensor in the laboratory but would like to see it become commercially available.
Nanotechnologies such as this sensor depend on extremely small nanometer scale building blocks. A nanometer is about 100,000 times smaller than the width of a human hair.
#Beyond LEDS: Brighter new energy saving flat panel lights based on carbon nanotubes Even as the 2014 Nobel prize in Physics has enshrined light emitting diodes (LEDS) as the single most significant and disruptive energy-efficient lighting solution of today scientists
around the world continue unabated to search for the even-better-bulbs of tomorrow. Electronics based on carbon especially carbon nanotubes (CNTS) are emerging as successors to silicon for making semiconductor materials.
And they may enable a new generation of brighter low-power low-cost lighting devices that could challenge the dominance of light-emitting diodes (LEDS) in the future
and help meet society's ever-escalating demand for greener bulbs. Scientists from Tohoku University in Japan have developed a new type of energy-efficient flat light source based on carbon nanotubes with very low power consumption of around 0. 1 Watt for every hour's operation
about a hundred times lower than that of an LED. In the journal Review of Scientific instruments from AIP publishing the researchers detail the fabrication
and optimization of the device which is based on a phosphor screen and single-walled carbon nanotubes as electrodes in a diode structure.
Then they painted the mixture onto the positive electrode or cathode and scratched the surface with sandpaper to form a light panel capable of producing a large stable and homogenous emission current with low energy consumption.
Our simple'diode'panel could obtain high brightness efficiency of 60 Lumen per Watt which holds excellent potential for a lighting device with low power consumption said Norihiro Shimoi the lead researcher and an associate professor of environmental studies at the Tohoku University.
For instance LEDS can produce 100s Lumen per Watt and OLEDS (organic LEDS) around 40. Although the device has a diode-like structure its light-emitting system is not based on a diode system
which are made from layers of semiconductors materials that act like a cross between a conductor and an insulator the electrical properties
of which can be controlled with the addition of impurities called dopants. The new devices have luminescence systems that function more like cathode ray tubes with carbon nanotubes acting as cathodes
and an anode with the improved phosphor screen in our diode structure obtained no flicker field emission current and good brightness homogeneity Shimoi said.
The resistance of cathode electrode with highly crystalline single-walled carbon nanotube is very low. Thus the new flat-panel device has compared smaller energy loss with other current lighting devices
Now the team led by Dzurak has discovered a way to create an artificial atom qubit with a device remarkably similar to the silicon transistors used in consumer electronics known as MOSFETS.
what is modified basically a version of a normal transistor is something that almost nobody believed possible until today Morello says.
The ability to mold inorganic nanoparticles out of materials such as gold and silver in precisely designed 3-D shapes is a significant breakthrough that has the potential to advance laser technology microscopy solar cells electronics environmental testing
Such systems may one day replace the electronic circuits we are using today
#Researchers develop green tea-based'missiles'to kill cancer cells more effectively Green tea has long been known for its antioxidant, anticancer, antiaging and antimicrobial properties.
The same prototype also crams 1900 emitters onto a chip that's only a centimeter square quadrupling the array size and emitter density of even the best of its predecessors.
or the height of deposits must be consistent across an entire chip. To control the nanotubes'growth the researchers first cover the emitter array with an ultrathin catalyst film
The new structures can lead to sensors and chips for future devices like smartphones computers and medical equipment.
#New absorber will lead to better biosensors Biological sensors or biosensors are like technological canaries in the coalmine.
#All directions are created not equal for nanoscale heat sources Thermal considerations are rapidly becoming one of the most serious design constraints in microelectronics, especially on submicron scale lengths.
The transistor spacing in RF devices is rapidly approaching length-scales where theory based on the diffusion of heat won't be valid,
#A new dimension for integrated circuits: 3-D nanomagnetic logic Electrical engineers at the Technical University Munich (TUM) have demonstrated a new kind of building block for digital integrated circuits.
Their experiments show that future computer chips could be based on three-dimensional arrangements of nanometer scale magnets instead of transistors.
As the main enabling technology of the semiconductor industry CMOS fabrication of silicon chips approaches fundamental limits, the TUM researchers and collaborators at the University of Notre dame are exploring"magnetic computing"as an alternative.
They report their latest results in the journal Nanotechnology. In a 3d stack of nanomagnets, the researchers have implemented a so-called majority logic gate
which could serve as a programmable switch in a digital circuit. They explain the underlying principle with a simple illustration:
Think of the way ordinary bar magnets behave when you bring them near each other, with opposite poles attracting
and synchronization in magnetic circuits, similar to latches in electrical integrated circuits.""All players in the semiconductor business benefit from one industry-wide cooperative effort:
developing long-range"roadmaps"that chart potential pathways to common technological goals. In the most recent issue of the International Technology Roadmap for Semiconductors, nanomagnetic logic is given serious consideration among a diverse zoo of"emerging research devices."
"Magnetic circuits are nonvolatile, meaning they don't need power to remember what state they are in.
The potential to pack more gates onto a chip is especially important. Nanomagnetic logic can allow very dense packing, for several reasons.
The most basic building blocks, the individual nanomagnets, are comparable in size to individual transistors. Furthermore, where transistors require contacts and wiring,
nanomagnets operate purely with coupling fields. Also, in building CMOS and nanomagnetic devices that have the same function for example
a so-called full-adder it can take fewer magnets than transistors to get the job done.
leader of the TUM research group within the Institute for Technical Electronics.""However, there might be applications where the nonvolatile,
#Blades of grass inspire advance in organic solar cells Using a biomimicking analog of one of nature's most efficient light-harvesting structures blades of grass an international research team led by Alejandro Briseno of the University of Massachusetts Amherst
has taken a major step in developing long-sought polymer architecture to boost power-conversion efficiency of light to electricity for use in electronic devices.
and vertical transistors he adds. Briseno explains: For decades scientists and engineers have placed great effort in trying to control the morphology of p-n junction interfaces in organic solar cells.
and packing at electrode surfaces the team combined knowledge about graphene and organic crystals. Though it was difficult Briseno says they managed to get the necessary compounds to stack like coins.
We envision that our nanopillar solar cells will appeal to low-end energy applications such as gadgets toys sensors and short lifetime disposable devices s
To see as much detail as possible the team decided to use a set of electron detectors to collect electrons in a wide range of scattering angles an arrangement that gave them plenty of structural information to assemble a clear picture of the battery's interior down to the nanoscale level.
Using a simple scalable and inexpensive method the researchers produced hybrid electrodes the building blocks of touchscreen technology from silver nanowires and graphene.
and could replace existing touchscreen technologies in electronic devices. Even though this material is cheaper and easier to produce it does not compromise on performance.
Conductive nanofiber networks for flexible unbreakable and transparent electrode e
#Harnessing an unusual'valley'quantum property of electrons Yoshihiro Iwasa and colleagues from the RIKEN Center for Emergent Matter Science the University of Tokyo and Hiroshima University have discovered that ultrathin films of a semiconducting material have properties that form the basis for a new kind of low-power electronics termed'valleytronics'.
'Electronic components store transmit and process information using the electrical charge of an electron. The use of charge
however requires physically moving electrons from one point to another which can consume a great deal of energy particularly in computing applications.
Semiconductors and insulators derive their electrical properties from a gap between the highest band occupied by electrons known as the valence band
#Solar cell compound probed under pressure Gallium arsenide Gaas a semiconductor composed of gallium and arsenic is well known to have physical properties that promise practical applications.
and optoelectronics in many of the same applications that silicon is used commonly. But the natural semiconducting ability of Gaas requires some tuning
Fine-tuning of this band gap has the potential to improve gallium arsenide's commercial potential.
It had already been demonstrated on nanowires made from one crystalline form of gallium arsenide the cubic so-called zincblende structure that the band gap widens under pressure.
The team subjected wurtzite gallium arsenide to up to about 227000 times normal atmospheric pressure (23 gigapascals) in diamond anvil cells.
Significantly they discovered that around 207000 times normal atmospheric pressure (21 gigapascals) the wurtzite gallium arsenide nanowires underwent a structural change that induced a new phase the so-called orthorhombic one
but resulting in significant differences in the size of the'band gap'between the two crystalline structures of gallium arsenide suggests that both types of Gaas structures could theoretically be incorporated into a single device
We believe these findings will stimulate further research into gallium arsenide for both basic scientific and practical purposes s
Although the researchers did not have precise control over the nanowire morphology they did observe that higher concentrations of H2o2 led to thicker nanowires.
As the researchers conclude in their report These results of Si nanowire arrays are believed to be useful for future optoelectronic and photovoltaic applications.
Mixing silicon with other materials improves the diversity of nanoscale electronic devices More information: Oda K. Nanai Y. Sato T. Kimura S. & Okuno T. Correlation between photoluminescence and structure in silicon nanowires fabricated by metal-assisted etching.
Silicon nanoparticles such as those in RM 8027 are being studied as alternative semiconductor materials for next-generation photovoltaic solar cells and solid-state lighting,
#Self-organized indium arsenide quantum dots for solar cells Kouichi Yamaguchi is recognized internationally for his pioneering research on the fabrication and applications of'semiconducting quantum dots'(QDS.
and photovoltaic devices arise from the unique optoelectronic properties of the QDS when irradiated with light or under external electromagnetic fields.
#Enabling bendable optoelectronics devices: Gallium nitride micro-rods grown on graphene substrates Bendy light-emitting diode (LED) displays
and solar cells crafted with inorganic compound semiconductor micro-rods are moving one step closer to reality thanks to graphene and the work of a team of researchers in Korea.
Currently most flexible electronics and optoelectronics devices are fabricated using organic materials. But inorganic compound semiconductors such as gallium nitride (Gan) can provide plenty of advantages over organic materials for use in these devices#including superior optical electrical and mechanical properties.
One major obstacle that has prevented so far the use of inorganic compound semiconductors in these types of applications was the difficulty of growing them on flexible substrates.
In the journal APL Materials from AIP Publishing a team of Seoul National University (SNU) researchers led by Professor Gyu-Chul Yi describes their work growing Gan micro-rods
on graphene to create transferrable LEDS and enable the fabrication of bendable and stretchable devices.
Gan microstructures and nanostructures are garnering attention within the research community as light-emitting devices because of their variable-color light emission
To create the actual Gan microstructure LEDS on the graphene substrates the team uses a catalyst-free metal-organic chemical vapor deposition (MOCVD) process they developed back in 2002.
and reliability of Gan micro-rod LEDS fabricated on graphene to the test they found that the resulting flexible LEDS showed intense electroluminescence (EL)
This represents a tremendous breakthrough for next-generation electronics and optoelectronics devices#enabling the use of large-scale and low-cost manufacturing processes.
By taking advantage of larger-sized graphene films hybrid heterostructures can be used to fabricate various electronics
and optoelectronics devices such as flexible and wearable LED displays for commercial use said Yi. Explore further:
Scientists grow a new challenger to graphene More information: Growth and characterizations of Gan micro-rods on graphene films for flexible light-emitting diodes by Kunook Chung Hyeonjun Beak Youngbin Tchoe Hongseok Oh Hyobin Yoo Miyoung Kim and Gyu
-Chul Yi APL Materials September 23 2014: scitation. aip. org/content/aip/#/9/10.1063/1. 489478 1
Experts collaborated to produce nanoparticles made of a titanium-nickel alloy used in the development of thermal and electrical sensors that control the operation of high-tech devices such as those used in aerospace,
Meanwhile, the team at the UANL manufactured nanoparticles used in the sensors, and after a series of tests confirmed the effectiveness of the titanium-nickel as an electrical and thermal conductor.
the sensor stops dilating and enters a paused state; minutes later, when its temperature and size return to normal it activates again to control the operation of valves,
Besides generating nanoparticles for sensors, another goal of this proyect is to train high level human resources in the areas of metallurgy alloys with shape memory,
a special machine in which the sensors are located between two points of electrical contacts, electric power is applied
#Scientists grow a new challenger to graphene A team of researchers from the University of Southampton's Optoelectronics Research Centre (ORC) has developed a new way to fabricate a potential challenger to graphene.
Graphene a single layer of carbon atoms in a honeycomb lattice is increasingly being used in new electronic and mechanical applications such as transistors switches
and related materials rather than just microscopic flakes as previously was the case greatly expands their promise for nanoelectronic and optoelectronic applications.
The scientists would also like to integrate their photonic biodetector into optical microchips for use in clinical diagnostics s
The ability to mechanically control photon movement as opposed to controlling them with expensive and cumbersome optoelectronic devices could represent a significant advance in technology said Huan Li the lead author of the paper.
and consume less power than traditional integrated circuits. Explore further: Breakthrough in light sources for new quantum technology More information:
and hydrogen by combining these proteins with titanium dioxide and platinum and then exposing them to ultraviolet light.
titanium dioxide only reacts in the presence of ultraviolet light, which makes up a mere four percent of the total solar spectrum.
and connect with the titanium dioxide catalyst: in short, a material like graphene. Graphene is a super strong, super light, near totally transparent sheet of carbon atoms and one of the best conductors of electricity ever discovered.
Electrons from this reaction are transmitted to the titanium dioxide on which these two materials are anchored, making the titanium dioxide sensitive to visible light.
Simultaneously, light from the green end of the solar spectrum triggers the br protein to begin pumping protons along its membrane.
which sit on top of the titanium dioxide. Hydrogen is produced by the interaction of the protons and electrons as they converge on the platinum.
The researchers then patterned graphene devices using semiconductor processing techniques before attaching a number of bioreceptor molecules to the graphene devices.
When 8-OHDG attached to the bioreceptor molecules on the sensor there was a notable difference in the graphene channel resistance
Now that we've created the first proof-of-concept biosensor using epitaxial graphene we will look to investigate a range of different biomarkers associated with different diseases and conditions as well as detecting a number of different biomarkers on the same chip.
and supercapacitors An official of a materials technology and manufacturing startup based on a Purdue University innovation says his company is addressing the challenge of scaling graphene production for commercial applications.
Our graphene electrodes are created using a roll-to-roll chemical vapor deposition process and then they are combined with other materials utilizing a different roll-to-roll process he said.
We can give the same foundational graphene electrodes entirely different properties utilizing standard or custom materials that we are developing for our own commercial products.
In essence what we've done is developed scalable graphene electrodes that are foundational pieces and can be customized easily to unique customer applications.
biosensors and supercapacitors. Johnson said the company's first-generation glucose monitoring technology could impact the use of traditional testing systems like lancets
Supercapacitors are Bluevine Graphene Industries'second application under development for its Folium graphene. Johnson said the company's graphene supercapacitors are reaching the energy density of lithium-ion batteries without a similar energy fade over time.
Our graphene-based supercapacitors charge in just a fraction of the time needed to charge lithium-ion batteries.
There are many consumer industrial and military applications he said. Wouldn't it be great if mobile phones could be recharged fully in only a matter of minutes
and supercapacitor applications he said. Explore further: Graphene reinvents the futur t
#Nanoribbon film keeps glass ice-free: Team refines deicing film that allows radio frequencies to pass Rice university scientists who created a deicing film for radar domes have refined now the technology to work as a transparent coating for glass.
but can be used to coat glass and plastic as well as radar domes and antennas. In the previous process the nanoribbons were mixed with polyurethane
He said nanoribbon films also open a path toward embedding electronic circuits in glass that are both optically and RF transparent a
#For electronics beyond silicon a new contender emerges Silicon has few serious competitors as the material of choice in the electronics industry.
Yet transistors, the switchable valves that control the flow of electrons in a circuit, cannot simply keep shrinking to meet the needs of powerful, compact devices;
it would be easy to integrate them into existing electronic devices and fabrication methods. The discovery, published in Nature Communications,
therefore firmly establishes correlated oxides as promising semiconductors for future three-dimensional integrated circuits as well as for adaptive, tunable photonic devices.
Challenging silicon Although electronics manufacturers continue to pack greater speed and functionality into smaller packages the performance of silicon-based components will soon hit a wall."
"Traditional silicon transistors have fundamental scaling limitations, "says Ramanathan.""If you shrink them beyond a certain minimum feature size,
"Yet silicon transistors are hard to beat, with an on/off ratio of at least 10 4 required for practical use."
But Ramanathan and his team have crafted a new transistor, made primarily of an oxide called samarium nickelate,
that in practical operation achieves an on/off ratio of greater than 10 5hat is, comparable to state-of-the-art silicon transistors.
"Our orbital transistor could really push the frontiers of this field and say, you know what?
which is a foundational step in the use of any semiconductor, "says Ramanathan. Doping is the process of introducing different atoms into the crystal structure of a material,
That's a fundamentally different approach than is used in other semiconductors. The traditional method changes the energy level to meet the target;
In this orbital transistor, protons and electrons move in or out of the samarium nickelate when an electric field is applied, regardless of temperature,
so the device can be operated in the same conditions as conventional electronics. It is solid-state,
but in principle it's highly compatible with traditional electronic devices.""Quantum materials Unlike silicon, samarium nickelate and other correlated oxides are quantum materials,
Similarly, samarium nickelate is likely to catch the attention of applied physicists developing photonic and optoelectronic devices."
aim to develop an entirely new class of quantum electronic devices and systems that will transform signal processing and computation.
when transistors were invented newly and physicists were still making sense of them.""We are basically in that era for these new quantum materials,
In these highly efficient devices individual molecules would take on the roles currently played by comparatively-bulky wires resistors and transistors.
A team of researchers from five Japanese and Taiwanese universities has identified a potential candidate for use in small-scale electronics:
Picene's sister molecule pentacene has been studied widely because of its high carrier mobilityts ability to quickly transmit electrons a critical property for nanoscale electronics.
To test picene's properties when juxtaposed with a metal as it would be in an electronic device the researchers deposited a single layer of picene molecules onto a piece of silver.
According to Hasegawa picene's weak interactions with the silver allow it to deposit directly on the surface without a stabilizing layer of molecules between a quality he said is essential for achieving high-quality contact with metal electrodes.
#Study sheds new light on why batteries go bad A comprehensive look at how tiny particles in a lithium ion battery electrode behave shows that rapid-charging the battery
They also suggest that scientists may be able to modify electrodes or change the way batteries are charged to promote more uniform charging
The fine detail of what happens in an electrode during charging and discharging is just one of many factors that determine battery life
and graphite electrodes used in today's commercial lithium ion batteries and in about half of those under development.
The team included collaborators from Massachusetts institute of technology Sandia National Laboratories Samsung Advanced Institute of technology America and Lawrence Berkeley National Laboratory.
and shrinking of the negative and positive electrodes as they absorb and release ions from the electrolyte during charging
For this study scientists looked at a positive electrode made of billions of nanoparticles of lithium iron phosphate.
Then they cut the electrode into extremely thin slices and took them to Berkeley Lab for examination with intense X-rays from the Advanced Light source synchrotron a DOE Office of Science User Facility.
We were able to look at thousands of electrode nanoparticles at a time and get snapshots of them at different stages during charging
This suggests that scientists may be able to tweak the electrode material or the process to get faster rates of charging
Li said the group has also been working with industry to see how these findings might apply in the transportation and consumer electronics sectors.
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