When it comes to electronics, silicon will now have to share the spotlight. In a paper recently published in Nature Communications,
researchers from the USC Viterbi School of engineering describe how they have overcome a major issue in carbon nanotube technology by developing a flexible,
energy-efficient hybrid circuit combining carbon nanotube thin film transistors with other thin film transistors. This hybrid could take the place of silicon as the traditional transistor material used in electronic chips,
since carbon nanotubes are more transparent, flexible, and can be processed at a lower cost. Electrical engineering professor Dr. Chongwu Zhou and USC Viterbi graduate students Haitian Chen
Yu Cao, and Jialu Zhang developed this energy-efficient circuit by integrating carbon nanotube (CNT) thin film transistors (TFT) with thin film transistors comprised of indium, gallium and zinc oxide (IGZO)."
"I came up with this concept in January 2013, "said Dr. Chongwu Zhou, professor in USC Viterbi's Ming Hsieh Department of Electrical engineering."
"Before then, we were working hard to try to turn carbon nanotubes into n-type transistors and then one day,
the idea came to me. Instead of working so hard to force nanotubes to do something that they are not good for,
why don't we just find another material which would be ideal for n-type transistorsn this case,
IGZOO we can achieve complementary circuits?""Carbon nanotubes are so small that they can only be viewed through a scanning electron microscope.
This hybridization of carbon nanotube thin films and IGZO thin films was achieved by combining their types, p-type and n-type, respectively,
to create circuits that can operate complimentarily, reducing power loss and increasing efficiency. The inclusion of IGZO thin film transistors was necessary to provide power efficiency to increase battery life.
If only carbon nanotubes had been used, then the circuits would not be power-efficient. By combining the two materials,
their strengths have been joined and their weaknesses hidden. Zhou likened the coupling of carbon nanotube TFTS and IGZO TFTS to the Chinese philosophy of yin and yang."
"It's like a perfect marriage, "said Zhou.""We are excited very about this idea of hybrid integration
including Organic light Emitting Diodes (OLEDS), digital circuits, radio frequency identification (RFID) tags, sensors, wearable electronics, and flash memory devices.
Even heads-up displays on vehicle dashboards could soon be a reality. The new technology also has major medical implications.
Currently, memory used in computers and phones is made with silicon substrates, the surface on which memory chips are built.
To obtain medical information from a patient such as heart rate or brainwave data, stiff electrode objects are placed on several fixed locations on the patient's body.
With this new hybridized circuit however, electrodes could be placed all over the patient's body with just a single large but flexible object.
With this development, Zhou and his team have circumvented the difficulty of creating n-type carbon nanotube TFTS
and p-type IGZO TFTS by creating a hybrid integration of p-type carbon nanotube TFTS and n-type IGZO TFTS and demonstrating a large-scale integration of circuits.
As a proof of concept, they achieved a scale ring oscillator consisting of over 1, 000 transistors.
Up to this point, all carbon nanotube-based transistors had a maximum number of 200 transistors.""We believe this is a technological breakthrough,
as no one has done this before,"said Haitian Chen, research assistant and electrical engineering Phd student at USC Viterbi."
"This gives us further proof that we can make larger integrations so we can make more complicated circuits for computers and circuits."
"The next step for Zhou and his team will be to build more complicated circuits using a CNT
and IGZO hybrid that achieves more complicated functions and computations, as well as to build circuits on flexible substrates."
"The possibilities are endless, as digital circuits can be used in any electronics, "Chen said.""One day we'll be able to print these circuits as easily as newspapers."
"Zhou and Chen believe that carbon nanotube technology, including this new CNT-IGZO hybrid, will be commercialized in the next 5-10 years."
"I believe that this is just the beginning of creating hybrid integrated solutions, "said Zhou.""We will see a lot of interesting work coming up. g
#Sixteen nanometres in 3d Tomography enables the interior of a vast range of objects to be depicted in 3d from cellular structures to technical appliances.
Researchers from the Paul Scherrer Institut (PSI) have devised now a method that opens up new scales of tomographic imaging
and will thus make the detailed study of representative volumes of biological tissue and materials science specimens possible in future.
Until now, the relevant details on a scale of a few nanometres were only visible with methods that required very thin samples.
With the aid of a special prototype setup at the PSI's Swiss Light source (SLS) the researchers have achieved now a 3d resolution of sixteen nanometres on a nanoporous glass test sample
a feat that is unmatched for X-ray tomography. The measurement is non-destructive, so it allows to study small details in the context of their surroundings
or to analyse larger sample volumes in such a way that the information obtained is influenced less by locally induced variances.
The resolution of 16 nm was achieved on a prototype of the OMNY instrument, which is still under construction.
The final version will enable the researchers to cool down the sample during the experiment to prevent X-ray induced sample damage.
In everyday life, we mostly know X-ray imaging as a medical procedure that enables physicians to see inside the human body without harming the patient.
Nowadays however, different imaging methods play a role in a wide range of research fields,
where they enable three-dimensional imaging for a vast array of applicationsranging from biological tissue, technical devices such as catalysts, fossils to antique works of art.
Researchers from the Paul Scherrer Institut have developed now an instrument that makes X-ray tomography possible at an unprecedented 3d resolution.
It is specialized for studies where researchers are interested in details that are a few nanometres in size, such as the fine structures of cell components or modern catalysts and batteries.
Until now, such fine details could only be rendered visible with the aid of electron microscopes which are not able to display the interior of the samples studied
unless ultra-thin samples or sectioning is used. Consequently, the preparation or measurement method could cause damage to the structures of interest.
Moreover, it was difficult to display the structures including their actual environment. For thick samples, hard X-ray tomography was limited to a resolution of around 150 nanometres.
For many years, X-ray tomography has been conducted at various synchrotron light sources, such as The swiss Light source at the PSI.
This kind of imaging involves screening the object from different directions with X-ray light in such a way that a fluoroscopic image a so-called radiograph is generated each time
much like a medical X-ray CT SCAN. With the aid of special computer software researchers combine these images to form a three-dimensional picture,
where the material distribution is visible in three dimensions. Researchers at the PSI have opted now for an alternative approach to achieve a considerably higher resolution.
The simple creation of a radiograph as a fluoroscopic image restricts the resolution that can be achieved.
As with all tomography methods, the sample is rotated also in small increments and studied from different directions.
During the measurement, they were able to achieve a spatial resolution of sixteen nanometres and achieve a world record."
"We are talking about an imaging scale here that bridges the gap between conventional X-ray and electron tomography.
So we had to know the position of the sample to within a few nanometres throughout the entire measurement,
"however due to its success access to this prototype is offered to users and is in high demand.
called OMNY (tomography Nano cryo), is the possibility of cooling the sample significantly during the measurement."
especially with sensitive objects such as biological materials,"explains Holler.""This effect is reduced vastly through cooling,
the prototype will continue to be used for scientific studies together with users from the SLS.
Thus far, for instance, materials such as chalk, cement, solar cells and fossils have been studied in collaboration with various research institutions n
#DNA-linked nanoparticles form switchable'thin films'on a liquid surface Scientists seeking ways to engineer the assembly of tiny particles measuring just billionths of a meter have achieved a new firsthe
formation of a single layer of nanoparticles on a liquid surface where the properties of the layer can be switched easily.
In addition, because the scientists used tiny synthetic strands of DNA to hold the nanoparticles together
the study also offers insight into the mechanism of interactions of nanoparticles and DNA molecules near a lipid membrane.
This understanding could inform the emerging use of nanoparticles as vehicles for delivering genes across cellular membranes."
"Our work reveals how DNA-coated nanoparticles interact and reorganize at a lipid interface, and how that process affects the properties of a"thin film"made of DNA-linked nanoparticles,
"said physicist Oleg Gang who led the study at the Center for Functional Nanomaterials (CFN) at the U s. Department of energy's Brookhaven National Laboratory.
The results will be published in the June 11, 2014 print edition of the Journal of the American Chemical Society.
Like the molecule that carries genetic information in living things, the synthetic DNA strands used as"glue"to bind nanoparticles in this study have a natural tendency to pair up
when the bases that make up the rungs of the twisted-ladder shaped molecule match up in a particular way.
Scientists at Brookhaven have made great use of the specificity of this attractive force to get nanoparticles coated with single synthetic DNA strands to pair up
"Many of the applications we envision for nanoparticles, such as optical coatings and photovoltaic and magnetic storage devices, require planar geometry,
"said Sunita Srivastava, a Stony Brook University postdoctoral researcher and the lead author on the paper.
Other groups of scientists have assembled such planes of nanoparticles, essentially floating them on a liquid surface,
but these single-layer arrays have all been explained static, she.""Using DNA linker molecules gives us a way to control the interactions between the nanoparticles."
"As described in the paper, the scientists demonstrated their ability to achieve differently structured monolayers,
from a viscous fluid-like array to a more tightly woven cross-linked elastic meshnd switch between those different statesy varying the strength of the pairing between COMPLEMENTARY DNA strands
a lipid, has a strong positive charge it attracts the negatively charged DNA strands that coat the nanoparticles.
That electrostatic attraction and the repulsion between the negatively charged DNA molecules surrounding adjacent nanoparticles overpower the attractive force between COMPLEMENTARY DNA bases.
the particles form a rather loosely arrayed free-floating viscous monolayer. Adding salt changes the interactions
and link the nanoparticles together more closely, first forming string-like arrays, and with more salt, a more solid yet elastic mesh-like layer."
when the particle sizes and the DNA chain sizes are comparablen the order of 20-50 nanometers,
As part of the study, the scientists examined the different configurations of the nanoparticles on top of the liquid layer using x-ray scattering at Brookhaven's National Synchrotron Light source (NSLS.
They also transferred the monolayer produced at each salt concentration to a solid surface so they could visualize it using electron microscopy at the CFN."
"Creating these particle monolayers at a liquid interface is very convenient and effective because the particles'two-dimensional structure is very'fluid
By combining the synchrotron scattering and electron microscopy imaging we could confirm that the transfer can be done with minimal disruption to the monolayer."
"The switchable nature of the monolayers might be particularly attractive for applications such as membranes used for purification and separations,
or to control the transport of molecular or nanoscale objects through liquid interfaces. For example, said Gang,
when particles are linked but move freely at the interface, they may allow an object moleculeo pass through the interface."
Because of the nanoscale size-regime, we might envision using such membranes for filtering proteins or other nanoparticles,
Understanding how synthetic DNA-coated nanoparticles interact with a lipid surface may also offer insight into how such particles coated with actual genes might interact with cell membraneshich are composed largely of lipidsnd with one another in a lipid environment."
"Other groups have considered using DNA-coated nanoparticles to detect genes within cells, or even for delivering genes to cells for gene therapy
and such approaches,"said Gang.""Our study is the first of its kind to look at the structural aspects of DNA-particle/lipid interface directly using x-ray scattering.
I believe this approach has significant value as a platform for more detailed investigations of realistic systems important for these new biomedical applications of DNA NANOPARTICLE pairings,
#Charging portable electronics in 10 minutes Researchers at the University of California Riverside Bourns College of Engineering have developed a three-dimensional silicon-decorated cone-shaped carbon nanotube cluster architecture for lithium ion battery anodes that could enable charging of portable
electronics in 10 minutes instead of hours. Lithium ion batteries are the rechargeable battery of choice for portable electronic devices and electric vehicles.
But they present problems. Batteries in electric vehicles are responsible for a significant portion of the vehicle mass.
And the size of batteries in portable electronics limits the trend of downsizing. Silicon is a type of anode material that is receiving a lot of attention
because its total charge capacity is 10 times higher than commercial graphite based lithium ion battery anodes.
Consider a packaged battery full-cell. Replacing the commonly used graphite anode with silicon anodes will potentially result in a 63 percent increase of total cell capacity and a battery that is 40 percent lighter and smaller.
In a paper Silicon Decorated Cone Shaped Carbon nanotube Clusters for Lithium ion battery Anode recently published in the journal Small UC Riverside researchers developed a novel structure of three-dimensional silicon decorated cone-shaped
carbon nanotube clusters architecture via chemical vapor deposition and inductively coupled plasma treatment. Lithium ion batteries based on this novel architecture demonstrate a high reversible capacity and excellent cycling stability.
The architecture demonstrates excellent electrochemical stability and irreversibility even at high charge and discharge rates nearly 16 times faster than conventionally used graphite based anodes.
The researchers believe the ultrafast rate of charge and discharge can be attributed to two reasons said Wei Wang lead author of the paper.
One the seamless connection between graphene covered copper foil and carbon nanotubes enhances the active material-current collector contact integrity
which facilitates charge and thermal transfer in the electrode system. Two the cone-shaped architecture offers small interpenetrating channels for faster electrolyte access into the electrode
which may enhance the rate performance. Explore further: Silly Putty material inspires better batterie e
#Technology using microwave heating may impact electronics manufacture Engineers at Oregon State university have shown successfully that a continuous flow reactor can produce high-quality nanoparticles by using microwave-assisted heating essentially the same forces
that heat up leftover food with such efficiency. Instead of warming up yesterday's pizza, however, this concept may provide a technological revolution.
It could change everything from the production of cell phones and televisions to counterfeit-proof money, improved solar energy systems or quick identification of troops in combat.
The findings, recently published in Materials Letters, are essentially a"proof of concept"that a new type of nanoparticle production system should actually work at a commercial level."
"This might be the big step that takes continuous flow reactors to large-scale manufacturing, "said Greg Herman, an associate professor and chemical engineer in the OSU College of Engineering."
"We're all pretty excited about the opportunities that this new technology will enable.""Nanoparticles are extraordinarily small particles at the forefront of advances in many biomedical, optical and electronic fields,
but precise control of their formation is needed and"hot injection"or other existing synthetic approaches are slow, costly, sometimes toxic and often wasteful.
A"continuous flow"system, by contrast, is like a chemical reactor that moves constantly along. It can be fast, cheap, more energy-efficient,
and offer lower manufacturing cost. However, heating is necessary in one part of the process, and in the past that was done best only in small reactors.
The new research has proven that microwave heating can be done in larger systems at high speeds.
And by varying the microwave power it can precisely control nucleation temperature and the resulting size and shape of particles."
"For the applications we have in mind, the control of particle uniformity and size is crucial, and we are also able to reduce material waste,
"Herman said.""Combining continuous flow with microwave heating could give us the best of both worlds large, fast reactors with perfectly controlled particle size."
"The researchers said this should both save money and create technologies that work better. Improved LED lighting is one possibility,
as well as better TVS with more accurate colors. Wider use of solid state lighting might cut power use for lighting by nearly 50 percent nationally.
Cell phones and other portable electronic devices could use less power and last longer on a charge.
The technology also lends itself well to creation of better"taggants, "or compounds with specific infrared emissions that can be used for precise,
instant identification whether of a counterfeit $20 bill or an enemy tank in combat that lacks the proper coding.
In this study researchers worked with lead selenide nanoparticles, which are particularly good for the taggant technologies.
Other materials can be synthesized using this reactor for different applications, including copper zinc tin sulfide and copper indium diselenide for solar cells.
New Oregon jobs and businesses are already evolving from this work. OSU researchers have applied for a patent on aspects of this technology,
and are working with private industry on various applications. Shoei Electronic Materials, one of the collaborators, is pursuing"quantum dot"systems based on this approach,
and recently opened new manufacturing facilities in Eugene, Ore.,to use this synthetic approach for quantum dot enabled televisions, smartphones and other devices d
#Antimicrobial coatings with a long-term effect for surfaces Researchers at the INM Leibniz Institute for New Materials have produced now antimicrobial abrasion-resistant coatings with both silver
and copper colloids with a long-term effect that kill germs reliably and at the same time prevent germs becoming established.
Hygienic conditions and sterile procedures are particularly important in hospitals, kitchens and sanitary facilities, air conditioning and ventilation systems, in food preparation and in the manufacture of packaging material.
In these areas, bacteria and fungi compromise the health of both consumers and patients. Researchers at the INM Leibniz Institute for New Materials have produced now antimicrobial abrasion-resistant coatings with both silver
and copper colloids with a long-term effect that kill germs reliably and at the same time prevent germs becoming established.
Silver or copper colloids which gradually release germicidal metal ions into the environment are incorporated in the coating."
"The metal colloids are only a few nanometers in size, but their particular ratio of size to surface area produces a distinctive long-term effect.
The"consumption"of metals to metal ions is then so low that the coating can be effective for several years,
As a result, the coating primarily counteracts the formation of an extensive biofilm. The researchers were able to prove the double microbicidal
and biofilm-inhibiting action using the standardised ASTM E2 180 test process. The new material can be applied to a variety of substrates such as plastic,
ceramic or metal using conventional techniques such as spraying or dipping, and cures thermally or photochemically.
Selective variation of the individual components allows the developers to react to the particular and different needs of potential users.
As part of the EU-sponsored Cuvito project, the developers are now looking at increasingly using copper colloids and copper ions as well as silver
#New class of nanoparticle brings cheaper lighter solar cells outdoors Think those flat glassy solar panels on your neighbour's roof are the pinnacle of solar technology?
Researchers in the University of Toronto's Edward S. Rogers Sr. Department of Electrical & Computer engineering have designed
and tested a new class of solar-sensitive nanoparticle that outshines the current state of the art employing this new class of technology.
This new form of solid stable light-sensitive nanoparticles called colloidal quantum dots could lead to cheaper and more flexible solar cells as well as better gas sensors infrared lasers infrared light emitting diodes and more.
The work led by postdoctoral researcher Zhijun Ning and Professor Ted Sargent was published this week in Nature Materials.
Collecting sunlight using these tiny colloidal quantum dots depends on two types of semiconductors: n-type which are rich in electrons;
and p-type which are poor in electrons. The problem? When exposed to the air n-type materials bind to oxygen atoms give up their electrons
and turn into p-type. Ning and colleagues modelled and demonstrated a new colloidal quantum dot n-type material that does not bind oxygen
when exposed to air. Maintaining stable n -and p-type layers simultaneously not only boosts the efficiency of light absorption it opens up a world of new optoelectronic devices that capitalize on the best properties of both light and electricity.
For the average person this means more sophisticated weather satellites remote controllers satellite communication or pollution detectors.
This is a material innovation that's the first part and with this new material we can build new device structures said Ning.
Iodide is almost a perfect ligand for these quantum solar cells with both high efficiency and air stabilityo one has shown that before.
But improved performance is just a start for this new quantum dot-based solar cell architecture. The powerful little dots could be mixed into inks
The field of colloidal quantum dot photovoltaics requires continued improvement in absolute performance or power conversion efficiency said Sargent.
but we need to work toward bringing performance to commercially compelling levels. Explore further: New breed of solar cells:
Quantum dot photovoltaics set new record for efficiency in such devices More information: Air-stable n-type colloidal quantum dot solids DOI:
10.1038/nmat400 a
#Shatterproof screens that save smartphones University of Akron polymer scientists have developed a transparent electrode that could change the face of smartphones, literally,
by making their displays shatterproof. In a recently published scientific paper, researchers demonstrated how a transparent layer of electrodes on a polymer surface could be extraordinarily tough and flexible,
withstanding repeated scotch tape peeling and bending tests. This could revolutionize and replace conventional touchscreens, according to Yu Zhu, UA assistant professor of polymer science.
Currently used coatings made of indium tin oxide (ITO) are more brittle, most likely to shatter,
and increasingly costly to manufacture.""These two pronounced factors drive the need to substitute ITO with a cost-effective and flexible conductive transparent film,
"Zhu says, adding that the new film provides the same degree of transparency as ITO,
Due to its flexibility, the transparent electrode can be fabricated in economical, mass-quantity rolls.""We expect this film to emerge on the market as a true ITO competitor,
"The annoying problem of cracked smartphone screens may be solved once and for all with this flexible touchscreen. The team's findings are published in the American Chemical Society's journal ACS Nano in the article titled"A Tough and High-performance Transparent Electrode from a Scalable and Transfer-Free Method
#Researchers develop an invisible type of bar code to thwart criminals (Phys. org) A team of researchers at Worcester Polytechnic institute in Massachusetts has developed a type of bar coding system that would be almost impossible for criminals to thwart.
As the team describes in their paper published in the journal Scientific Reports the new system is based on adding certain types of nanoparticles to materials as part of the manufacturing process that can be read later using a special device.
Everyone is familiar with bar codes they allow for quick scanning at checkout counters. But they are used also to track the movement of merchandise
The idea revolves around several types of metal nanoparticles each of which has a unique melting point. Mixing the nanoparticles together allows for creating unique thermal signatures.
To use the nanoparticles manufacturers would simply add them into the mix when creating metals papers and even fluids.
The researchers say the addition of the nanoparticles doesn't change how a material looks doesn't react with anything in it
or impact how a finished product performs. Reading the new type of bar code requires a device capable of performing differential scanning calorimetry (DSC) a technique based on assessing the difference in the amount of heat required to heat different parts of a sample material.
For criminals to circumvent the process they would have to somehow find out which nanomaterials were added to a product to create its unique thermal signature then add the right mix of nanoparticles to their own counterfeit product to recreate it no easy feat.
The researchers claim their nanoparticle bar codes could be used with paper metals fluids and even drugs.
As a demonstration the team used their new technique on a sample of dinitrotoluene one of the ingredients in TNT.
They report being able to identify the thermal signature of the original mixture even after an explosion has occurred.
Taox-capped Pt nanoparticles as efficient catalysts for polymer electrolyte fuel cells More information: Covert thermal barcodes based on phase change nanoparticles Scientific Reports 4 Article number:
5170 DOI: 10.1038/srep05170abstractan unmet need is to develop covert barcodes that can be used to track-trace objects
This paper describes a new nanoparticle-based covert barcode system in which a selected panel of solid-to-liquid phase change nanoparticles with discrete and sharp melting peaks is added in a variety of objects such as
explosive derivative drug polymer and ink. This method has high labeling capacity owing to the small sizes of nanoparticles sharp melting peaks
and large scan range of thermal analysis. The thermal barcode can enhance forensic investigation by its technical readiness structural covertness and robustness s
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