however because conventional metal electrode technologies are too thick(>500 nm) to be transparent to light making them incompatible with many optical approaches.
The new device uses graphene a recently discovered form of carbon on a flexible plastic backing that conforms to the shape of tissue.
Moreover graphene is nontoxic to biological systems an improvement over previous research into transparent electrical contacts that are much thicker rigid difficult to manufacture and reliant on potentially toxic metal alloys.
To overcome this challenge the researchers from the Institute for Integrated Cell-Material Sciences (icems) at Kyoto University borrowed a principle from polymer chemistry
By putting graphene oxide (an oxidized form of graphene) into contact with an oppositely charged polymer the two components could form a stable composite layer a process also known as interfacial complexation.
Interestingly the polymer could continuously diffuse through the interface and induce additional reactions which allowed the graphene-based composite to develop into thick multilayered structures.
Hence we named this process'diffusion driven layer-by-layer assembly'explained Jianli Zou a co-investigator in the project.
and genetic diseases by combining the chemical specificity of the DNA with the signal readout of the metal.
The system is built around a polyethylene-glycol-based polymer that carries a small peptide component that allows it to bind preferentially to specific cell types The polymer itself serves as a photosensitizer that can be stimulated by light to release reactive oxygen species (ROS.
The natural fluorescence of the polymer assists with diagnosis and monitoring of therapy as it shows where nanoparticles have accumulated.
The ROS additionally break the link between the polymer and the doxorubicin. Thus cancer cells can be subjected to a two-pronged attack from the ROS therapy
their crystal structure is influenced not by the process. The UT scientists present their#findings in the journal Advanced Functional Materials.
because other patterning techniques have the risk of damaging the crystal structure and orientation and thus influence the properties of the material.
and consists of PDMS#a rubber like polymer with silicon in it. Via this mask a pattern of zinc oxide can be placed on the perovskite for example.
Using PLD a sandwich of different materials can be made. The properties of each layer are secured.
Kim tried adding different polymers to his nanosheets to make them responsive. For this experiment he incorporated a relatively simple polymer that responds to ph. He found that the resulting nanosheet would always curl in basic high ph conditions
and always flatten in acidic low ph conditions. Kim also made his nanosheets responsive to near-infrared light a wavelength of light that is harmless to humans.
creating a responsive nanosheet is just a matter of adding the right polymer. A nanosheet is like pizza dough Kim said.
A nanosheet with a heat-sensitive polymer could burn surrounding tumors to destroy them functioning as a kind of super-specific chemotherapy.
There are tons of smart polymers and metals Kim said explaining the many properties he hopes to incorporate into nanotechnology.
This new structure is composite which means it allows us to mix all different kinds of components.
Smart Composite Nanosheets with Adaptive Optical Properties Jeong-Hwan Kim Murtaza Bohra Vidyadhar Singh Cathal Cassidy and Mukhles Sowwan Applied materials & Interfaces2014.
The best carbon nanotubes (CNTS) have demonstrated conductivities far beyond those of the best metals. Thus future windings made of CNTS may have a double conductivity compared with the present-day copper windings.
which has the second best conductivity of metals at room temperature. Despite the high conductivity of copper a large proportion of the electrical machine losses occur in the copper windings.
Carbon nanotubes are rapidly becoming more common because of their usefulness in nanoelectric devices composite materials and biomedicine.
"Our study focused on a variety of crystals that have controlled differences in thermal transport properties, such as Si, doped Si,
and Sige alloys,"Wilson said.""We coated these crystals with a thin metal film, heated the surface with a laser beam,
and then recorded the temperature evolution of the sample.""On length-scales shorter than the phonon mean-free-paths of the crystal,
heat is transported ballistically, not diffusively. Interfaces between materials further complicate the heat-transfer problem by adding additional thermal resistance."
when the radius of the laser beam used to heat the metal coated crystals was above ten microns,
predicts that a cubic crystal like silicon will carry heat equally well in all directions.
In particularly for crystals with defects, the boundary resistance is distributed and strongly dependent on the defect concentration."
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.
but it also solves some instability problems where the materials in mixed blends of polymers tend to lose their phase-separated behavior over time degrading energy transfer the polymer chemist says.
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.
when an undergraduate chose the wrong substrate to grow crystals on. For over a week the student was growing vertical crystals
and we didn't even realize until we imaged the surface of the substrate with a scanning electron microscope.
We were shocked to see little crystals standing upright! We ultimately optimized the conditions and determined the mechanism of crystallization the polymer chemist adds.
Vertical nanopillars are ideal geometries for getting around these challenges Briseno says because charge separation/collection is most efficient perpendicular to the plastic device.
#Nanoengineering enhances charge transport promises more efficient future solar cells Solar cells based on semiconducting composite plastics and carbon nanotubes is one of the most promising novel technology for producing inexpensive printed solar cells.
They can be mixed in a semiconducting polymer and deposited from solution by simple and inexpensive methods to form thin and flexible solar cells.
In this new study, Dr. Barbero and his team at Umeå University show that this threshold can be reduced by more than 100 times in a semiconducting polymer
Earlier lab demonstrations of similar systems could only produce devices a few centimeters on a side with expensive metal substrates so were not suitable for scaling up to commercial production he says.
While the team has demonstrated working devices using a formulation that includes a relatively expensive metal ruthenium we're very flexible about materials Chou says.
In theory you could use any metal that can survive these high temperatures. This work shows the potential of both photonic engineering
The group is now working to optimize the system with alternative metals. Chou expects the system could be developed into a commercially viable product within five years.
Molybdenum disulfide is a member of a family of materials known as transition metal dichalcogenides which are currently the focus of intense research because of the unusual electronic properties they display
Okuno and his colleagues fabricated silicon nanowire arrays by metal-assisted chemical etching an approach that is simple and cost-effective.
Another potential application comes from the fact that silicon crystals at dimensions of 5 nanometers
Guo's team drilled hundreds of 1-millimeter-diameter holes into the surface of a thin sheet of an aluminum alloy.
Placing the nanoparticles in the sheet prior to the friction stir processing step significantly increased the concentration of nanoparticles in the composite.
or crystals of the aluminum matrix that recrystallized after being plasticized were extremely small; smaller aluminum matrix grains can flow past each other more smoothly than larger particles enhancing the strength of the material.
The best nanoparticle distribution and smallest aluminum alloy grains were obtained after passing the rotating tool through the sheet four times.
The team then demonstrated that the composite made in this way had improved significantly hardness and tensile strength compared to untreated aluminum alloy sheets.
We plan to continue this research to further improve the mechanical and thermal properties as well as the wear resistance of the nanocomposites says Guo.
#Researchers uncover properties in nanocomposite oxide ceramics for reactor fuel Nanocomposite oxide ceramics have potential uses as ferroelectrics fast ion conductors
A composite is a material containing grains or chunks of several different materials. In a nanocomposite the size of each of these grains is on the order of nanometers roughly 1000 times smaller than the width of a human hair.
In the context of nuclear energy composites have been proposed for the fuel itself as a way for example to improve the basic properties of the material such as the thermal conductivity.
Composites have also been created to store the by-products of the nuclear energy cycle nuclear waste where the different components of the composite can each store a different part of the waste.
However composites have much broader applications. The interfaces provide regions of unique electronic and ionic properties
#Experts create unique nanoparticles for aerospace industry A development of three universities enables improved thermal and electronic properties on devices with nickel-titanium alloys.
Federal Universities of Pernambuco and Campina Grande, both in Brazil, were responsible for obtaining physical media for the shape memory titanium-nickel metal alloy (with the ability to return to its original state after being deformed.
Manufacturing methods of the alloys are very specific, so the Brazilian universities obtained them by vacuum melting the titanium to make it react with oxygen.
Then nanoparticles were obtained by thermal evaporation techniques where the molecular bonds of the metals degraded as a powder
another goal of this proyect is to train high level human resources in the areas of metallurgy alloys with shape memory,
and mechanical strength but made from a metal (in this case molybdenum combined with sulphur). This new class of thin metal/sulphide materials known as transition metal di-chalcogenides (TMDCS) has become an exciting complimentary material to graphene.
However unlike graphene TMDCS can also emit light allowing applications such as photodetectors and light emitting devices to be manufactured.
The patch is attached to a polymer backbone that can hold a stitch and keep it in place to cover a hole in the heart.
Instead they grew graphene onto a silicon carbide substrate under extremely high temperatures and low pressure to form the basis of the biosensor.
which are made with gold and other precious metals. The second-generation technology could allow people to use noninvasive methods to test their glucose levels through saliva tears or urine.
and polyurethane paint to melt ice on sensitive military radar domes which need to be kept clear of ice to keep them at peak performance.
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
but testing showed the graphene nanoribbons themselves formed an active network when applied directly to a surface.
They were coated subsequently with a thin layer of polyurethane for protection. Samples were spread onto glass slides that were iced then.
Doping is the process of introducing different atoms into the crystal structure of a material, and it affects how easily electrons can move through ithat is,
"The occupancy of the orbitals and the ability of electrons to move in the crystal are tied very closely togetherr'correlated.'
'Fundamentally, that's what dictates whether the material behaves as an insulator or a metal."
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.
The combination of CNTS and graphene into 3d hybrid composites can usually mitigate the self-aggregation
#Ceramics don't have to be brittle: Materials scientists are creating materials by design Imagine a balloon that could float without using any lighter-than-air gas.
the Caltech researchers explain how they used the method to produce a ceramic (e g.,, a piece of chalk or a brick) that contains about 99.9 percent air yet is incredibly strong
"Ceramics have always been thought to be heavy and brittle, "says Greer, a professor of materials science and mechanics in the Division of Engineering and Applied science at Caltech."
"The researchers use a direct laser writing method called two-photon lithography to"write"a three-dimensional pattern in a polymer by allowing a laser beam to crosslink
and harden the polymer wherever it is focused. The parts of the polymer that were exposed to the laser remain intact
while the rest is dissolved away, revealing a three-dimensional scaffold. That structure can then be coated with a thin layer of just about any kind of material metal, an alloy, a glass, a semiconductor, etc.
Then the researchers use another method to etch out the polymer from within the structure
leaving a hollow architecture. The applications of this technique are practically limitless, Greer says. Since pretty much any material can be deposited on the scaffolds,
they coated the polymer scaffold with a ceramic called alumina (i e.,aluminum oxide), producing hollow-tube alumina structures with walls ranging in thickness from 5 to 60 nanometers and tubes from 450 to 1, 380 nanometers in diameter.
That was not surprising given that ceramics especially those that are porous, are brittle. However, compressing lattices with a lower ratio of wall thickness to tube diameterhere the wall thickness was only 10 nanometersroduced a very different result."
"To understand why, consider that most brittle materials such as ceramics, silicon, and glass shatter because they are filled with flawsmperfections such as small voids and inclusions.
In research funded with a grant from the National institutes of health, Saraf and Nguyen perfected a thin film made of nanoparticles and polymers
Using a silicone breast model identical to those used to train doctors in manual breast exams,
Teflon is fluorinated a carbon polymer so we thought fluorinated graphene might be like two-dimensional Teflon.
Researchers from Empa and the Max Planck Institute for Polymer Research have developed now a new method to selectively dope graphene molecules with nitrogen atoms.
and negative charges across different regions of the semiconductor crystal thereby creating the basic structure allowing the development of many components used in the semiconductor industry.
Fasel's team and colleagues at the Max-Planck-Institute for Polymer Research in Mainz have succeeded in showing that graphene nanoribbons can be transferred efficiently
to open up single layers of solid boron nitride, a compound with a structure similar to graphite.
"Mallouk believes the results of this new understanding of intercalation in boron nitride and graphene could apply to many other layered materials of interest to researchers in the Penn State Center for Two-dimensional and Layered Materials who are investigating
The light in these terahertz wavelengths can pass through materials that we normally think of as opaque such as skin plastics clothing and cardboard.
The prototype uses two electrical leads made of different metals which conduct electrons at different rates.
with the transistor and display processing steps that Plastic Logic has developed already for flexible electronics.
except it is made of flexible plastic instead of Glass in contrast to conventional displays, the pixel electronics,
Graphene is more flexible than conventional ceramic alternatives like indium-tin oxide (ITO) and more transparent than metal films.
The new 150 pixel per inch (150 ppi) backplane was made at low temperatures (less than 100°C) using Plastic Logic's Organic Thin Film Transistor (OTFT) technology.
"This demonstration puts Plastic Logic at the forefront of this development, which will soon enable a new generation of ultra-flexible and even foldable electronics"This joint effort between Plastic Logic
because it uses inert gold#silica SERS nanoparticles and a hand-held Raman scanner that can guide brain tumor resection in the operating room o
but immensely powerful batteries) and an array of new materials that could make many of today's common metals and polymers redundant.
which was key to creating the composite two-dimensional semiconductor. Collaborators from the electron microscopy center at the University of Warwick in England found that all the atoms in both materials formed a single honeycomb lattice structure, without any distortions or discontinuities.
and deposited as single-layer crystals in the shape of triangles. After a while, evaporated atoms from the second material then attached to the edges of the triangle to create a seamless semiconducting heterojunction."
On a small scale, it takes about five minutes to grow the crystals, with up to two hours of heating and cooling time."
MX2 monolayers consist of a single layer of transition metal atoms, such as molybdenum (Mo) or tungsten (W), sandwiched between two layers of chalcogen atoms,
Two-dimensional aluminum (Al) nanofiber networks offering transparent conductors were fabricated by simple wet chemical etching of Al metalized polymer films using an electrospun polystyrene nanofiber mask template.
and could be embedded further into polymeric elastomers extremely flexible, stretchable materials to obtain conducting rubbers."
In contrast to other dichroic effects produced by some crystals, such as precious opals, the colorful effects of the Lycurgus cup have little dependence on the position of the observer.
In fact, the dichroism found in the Lycurgus cup has a different origin than crystals and so far this'plasmonic effect'has not been observed in naturally occurring materials."
#Eco-friendly'prefab nanoparticles'could revolutionize nano manufacturing A team of materials chemists polymer scientists device physicists
For photovoltaics Venkataraman points out The next thing is to make devices with other polymers coming along to increase power conversion efficiency
The'seeds'are multiple crystals of elongated gold decahedrons, joined together by shared facesn arrangement known as multiply-twinning.
however, regardless of the ratio of metals used. The ability to control the size and composition of the nanorods means it is easier to control the properties of the bimetallic goldopper nanoparticles compared to nanoparticles made of just one metal,
Yang explains. Next, the team evaluated the catalytic activity of these goldopper nanorods in a carbonitrogen-bond-forming reactionhe direct alkylation of an amine using an alcohol."
The team used the key properties of zinc oxide, a material that when squashed or stretched creates a voltage by converting energy from motion into electrical energy, in the form of nanorods.
whereby they could spray on the nanorod chemicals almost like nanorod graffiti to cover a plastic sheet in a layer of zinc oxide.
and it's extremely strong its tensile strength is even stronger than steel Hunt said. Air doesn't damage it.
"Quite often, two-dimensional crystals have electronic properties that are completely different from those of thicker layers of the same material,
But a solar cell made only of tungsten diselenide would require countless tiny metal electrodes tightly spaced only a few micrometers apart.
graphene is a 2d sheet of carbon just one atom Thick with a'honeycomb'structure the'wonder material'is 100 times stronger than steel, highly conductive and flexible.
Under certain PH conditions they found that graphene behaves like a polymer-changing shape by itself.
made of silica and nickel, is only 70 nm in diameter; the entire propeller is 400 nm long.
The hyaluronan gel contains a mesh of long proteins called polymers; the polymers are large enough to prevent micrometer-sized propellers from moving much at all.
But the openings are large enough for nanometer-sized objects to pass through. The scientists were able to control the motion of the propellers using a relatively weak rotating magnetic field.
After depositing the atoms onto the silver platform initial tests identified that alloy-like surface phases would form until bulk silicon layers
#Discovery is key to metal wear in sliding parts (w/Video) Researchers have discovered a previously unknown mechanism for wear in metals:
a swirling, fluid-like microscopic behavior in a solid piece of metal sliding over another.
"Using high-resolution imaging of sliding contacts in metals, we have demonstrated a new way by which wear particles and surface defects can form,
and the sliding conditions did not generate enough heat to soften the metal. Yet, the swirling flow is more like behavior seen in fluids than in solids,
The team observed what happens when a wedge-shaped piece of steel slides over a flat piece of aluminum or copper.
The metals are used commonly to model the mechanical behavior of metals.""We speculated in the earlier paper that the swirly fluid-like surface flow discovered on sliding metal surfaces is likely to impact wear in sliding metal systems,
"he said.""Now we are confirming this speculation by direct observations
#Graphene and related materials promise cheap flexible printed cameras Dr Felice Torrisi University Lecturer in Graphene technology has been awarded a Young International Researchers'Fellowship from the National Science Foundation
or stamped on plastic or paper. For example it might eventually be embed possible to these printed flexible optoelectronic devices into clothes packaging wall papers posters touch screens or even buildings.
and characterize inkjet printed 2d crystal-based flexible photodetectors and study their integration with commercial electronics.
The current generation of flexible photoactive materials based on organic polymers have a slow response time (few milliseconds)
Moreover organic polymers suffer from chemical instability at room conditions temperature and pressure) thus requiring extra protective layers
Graphene the ultimate thin membrane along with a wide range of two-dimensional (2d)- crystals (e g. hexagonal Boron nitride (h-BN) Molybdenum Disulfide (Mos2) and Tungsten Disulfide (WS2)) have changed radically the landscape
These 2d crystals can be exfoliated from layered compounds. The layered compounds can be conductive semiconducting
and it is superior to conductive polymers in terms of cost stability and performance; whereas Mos2 is optically active once reduced to a single 2d layer with a fast response time and excellent environmental stability.
Other conductive inks are made from precious metals such as silver which makes them very expensive to produce
and the team at the Cambridge Graphene Centre have been looking to formulate a set of inks based on various 2d crystals setting a new platform for printed electronics.
When light impinges on a semiconducting 2d crystal (e g. Mos2) due to their 2d nature electrons and holes are generated with a higher efficiency than the current photodetectors based on siliconthe project funded by the National Natural science Foundation of China looks into how to design printed flexible photodetectors
#A crystal wedding in the nanocosmos Researchers at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), the Vienna University of Technology and the Maria Curie-Sklodowska University Lublin have succeeded in embedding nearly perfect semiconductor crystals
they integrated compound semiconductor crystals made of indium arsenide (Inas) into silicon nanowires, which are suited ideally for constructing increasingly compact chips.
This integration of crystals was the greatest obstacle for such"hetero-nanowires"until now: beyond the nanometer range, crystal lattice mismatch always led to numerous defects.
and embedding of the Inas crystals into the nanowires for the first time. Implanted atoms form crystals in the liquid-Phase in order to carry out this process,
ion beam synthesis and heat treatment with xenon flash-lamps were used, two technologies in which the Ion beam Center of the HZDR has held experience for many years.
"while the implanted atoms form the indium arsenide crystals.""Dr. Wolfgang Skorupa, the head of the research group adds:"
"The atoms diffuse in the liquid-silicon-phase so rapidly that within milliseconds they form flawless mono-crystals delineated from their surroundings with nearly perfect interfaces."
and also optimize the size and distribution of the crystals a
#Tiny laser sensor heightens bomb detection sensitivity New technology under development at the University of California,
the oscillating electrons found at the surface of metals, researchers were able to squeeze light into nanosized spaces,
because light tends to dissipate at a metal's surface. The new device builds upon earlier work in plasmon lasers by Zhang's lab that compensated for this light leakage by using reflectors to bounce the surface plasmons back and forth inside the sensor similar to the way sound waves are reflected across the room
Fortunately researchers have pinpointed now the breaking mechanism of several monolayer materials hundreds of times stronger than steel with exotic properties that could revolutionize everything from armor to electronics.
The team virtually examined this exotic phase transition in graphene boron nitride molybdenum disulfide and graphane all promising monolayer materials.
and whether they acted as metals semiconductors or insulators under strain. Toggling between or sustaining those conductive properties are particularly important for future applications in microelectronics.
Within the honeycomb-like lattices of monolayers like graphene boron nitride and graphane the atoms rapidly vibrate in place.
In the case of graphene boron nitride and graphane the backbone of the perfect crystalline lattice distorted toward isolated hexagonal rings.
The soft mode distortion ended up breaking graphene boron nitride and molybdenum disulfide. As the monolayers were strained the energetic cost of changing the bond lengths became significantly weaker in other words under enough stress the emergent soft mode encourages the atoms to rearrange themselves into unstable configurations.
observed for the first time how an electrical current flows across the skin of a silicon crystal and also measured electrical resistance as the current moved over a single atomic step.
Wolkow says silicon crystals are mostly smooth except for these atomic staircaseslight imperfections with each step being one atom high.
One possibility is to use hybrid solar cells that combine silicon nanowires with low-cost, photoresponsive polymers. The high surface area and confined nature of nanowires allows them to trap significant amounts of light for solar cell operations.
The team analyzed the solar cell activity of their nanohole interfaces by coating them with a semiconducting polymer and metal electrodes.
along with Dr. Seok-In Na at Chonbuk National University and Dr. Byoung Gak Kim at KRICT synthesized carbon nanosheets similar to graphene using polymer
However this method requires intensive postprocessing (transfer process) as it has to remove used metal after the manufacturing process
After it is done the metal has to be removed and graphene has to be transported to another board.
The research team synthesized a polymer with a rigid ladder structure namely PIM-1 (Polymer of intrinsic microporosity-1) to form the#through the simpole process
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