#A nanosized hydrogen generator (Phys. org) esearchers at the US Department of energy's (DOE) Argonne National Laboratory have created a small scale"hydrogen generator"that uses light
and a two-dimensional graphene platform to boost production of the hard-to-make element. The research also unveiled a previously unknown property of graphene.
and receives electrons, but can also transfer them into another substance. Hydrogen is virtually everywhere on the planet,
and pump protons through a membrane, creating a form of chemical energy. They also know that water can be split into oxygen
The new material would need enough surface area to move electrons across quickly and evenly and boost the overall electron transfer efficiency.
The researchers also needed a platform on which biological components, like br, could survive and connect with the titanium dioxide catalyst:
which totally changes how the electrons move throughout our system.""Rozhkova's mini-hydrogen generator works like this:
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.
These protons make their way to the platinum nanoparticles 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. Examinations using a technique called Electron Paramagnetic Resonance (EPR)
and time-resolved spectroscopy at the Center for Nanoscale Materials verified the movements of the electrons within the system,
while electrochemical studies confirmed the protons were transferred. Tests also revealed a new quirk of graphene behavior."
"The majority of the research out there states that graphene principally conducts and accepts electrons,
"said Argonne postdoctoral researcher Peng Wang.""Our exploration using EPR allowed us to prove, experimentally,
that graphene also injects electrons into other materials.""Rozhkova's hydrogen generator proves that nanotechnology,
merged with biology, can create new sources of clean energy. Her team's discovery may provide future consumers a biologically-inspired alternative to gasoline."
"This research,"Photoinduced Electron Transfer pathways in Hydrogen-Evolving Reduced graphene oxide-Boosted Hybrid Nano-Bio Catalyst,
#Graphene sensor tracks down cancer biomarkers An ultrasensitive biosensor made from the wonder material graphene has been used to detect molecules that indicate an increased risk of developing cancer.
The researchers then patterned graphene devices using semiconductor processing techniques before attaching a number of bioreceptor molecules to the graphene devices.
or target a specific molecule present in blood saliva or urine. The molecule 8-hydroxydeoxyguanosine (8-OHDG) is produced
when DNA is damaged and in elevated levels has been linked to an increased risk of developing several cancers.
In their study the researchers used x-ray photoelectron spectroscopy and Raman spectroscopy to confirm that the bioreceptor molecules had attached to the graphene biosensor once fabricated
When 8-OHDG attached to the bioreceptor molecules on the sensor there was a notable difference in the graphene channel resistance
The graphene biosensor was also considerably faster at detecting the target molecules completing the analysis in a matter of minutes.
and monitor a whole range of diseases as it is quite simple to substitute the specific receptor molecules on the graphene surface.
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.
The material is made of graphene nanoribbons atom-thick strips of carbon created by splitting nanotubes a process also invented by the Tour lab
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;
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,
to what extent it resists or conducts electricity. Doping typically effects this change by increasing the number of available electrons,
but this study was different. The Harvard team manipulated the band gap, the energy barrier to electron flow."
"By a certain choice of dopantsn this case, hydrogen or lithiume can widen or narrow the band gap in this material, deterministically moving electrons in and out of their orbitals,
"Ramanathan says. 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,
"If you have two electrons in adjacent orbitals, and the orbitals are filled not completely, in a traditional material the electrons can move from one orbital to another.
But in the correlated oxides, the electrons repulse each other so much that they cannot move, "Ramanathan explains."
"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."
In these highly efficient devices individual molecules would take on the roles currently played by comparatively-bulky wires resistors and transistors.
a molecule called picene. In a paper published September 16 in The Journal of Chemical Physics from AIP Publishing they characterize the structural and electronic properties of a thin layer of picene on a silver surface demonstrating the molecule's potential for electronic applications.
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.
But pentacene made of five benzene molecules joined in a line breaks down under normal environmental conditions.
Enter picene in which these same five benzene rings are bonded instead together in A w shape. This simple structural change alters some of the molecule's other properties:
Picene retains pentacene's high carrier mobility but is more chemically stable and therefore better suited to practical applications.
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.
Though previous studies had shown a strong interaction between pentacene and metal surfaces we found that the zigzag-shaped picene basically just sits on the silver said University of Tokyo researcher Yukio Hasegawa.
Interactions between molecules can alter their shape and therefore their behavior but picene's weak connection to the silver surface left its properties intact.
The weak interaction is advantageous for molecular electronics applications because the modification of the properties of molecular thin film by the presence of the silver is negligible
and therefore the original properties of the molecule can be preserved very close to the interface said Hasegawa.
A successful circuit requires a strong connection between the electronic componentsf a wire is frayed electrons can't flow.
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
The results challenge the prevailing view that supercharging batteries is always harder on battery electrodes than charging at slower rates according to researchers from Stanford university and the Stanford Institute for Materials & Energy Sciences (SIMES) at the Department of energy's SLAC National Accelerator Laboratory.
and release ions from the electrolyte during charging and discharging. For this study scientists looked at a positive electrode made of billions of nanoparticles of lithium iron phosphate.
If most or all of these particles actively participate in charging and discharging they'll absorb
and release ions more gently and uniformly. But if only a small percentage of particles sop up all the ions they're more likely to crack
and get ruined degrading the battery's performance. Previous studies produced conflicting views of how the nanoparticles behaved.
Analyzing the data using a sophisticated model developed at MIT the researchers discovered that only a small percentage of nanoparticles absorbed and released ions during charging even
As the discharge rate increased above a certain threshold more and more particles started to absorb ions simultaneously switching to a more uniform and less damaging mode.
and can be done at synchrotrons such as ALS or SLAC's Stanford Synchrotron radiation Lightsource also a DOE Office of Science User Facility.
with three-dimensional (3d) electron transfer pathways interconnected ion diffusion channels and enhanced interfacial affinity and activity.
NH3 was introduced simultaneously during the CVD growth for the incorporation of nitrogen atoms into the carbon framework.
Org''Thereby the seamless connection of high-quality aligned CNTS and graphene provided 3d electron transfer pathways and interconnected ion diffusion channels.
and graphene provides rapid electron transfer and mechanical robustness. The 3d interconnected mesoporous space improves the penetration and diffusion of electrolytes.
It is expected highly that the N-ACNT/G sandwiches hold various potential applications in the area of nanocomposite energy storage environmental protection electronic device as well as healthcare because of their robust hierarchical structure 3d electron transfer
pathways and ion diffusion channels and enhanced interfacial affinity and activity as well. Prof. Zhang said Because such design
which could help ease the world's current shortage of helium, can only be made if a new material existed that was strong enough to sustain the pressure generated by forcing out all that air
"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
"This is more like an ultrasound, providing immediate results without radiation and not as uncomfortable as a mammogram."
#Team uses nanotechnology to help cool electrons with no external sources A team of researchers has discovered a way to cool electrons to#228°C without external means and at room temperature,
The process involves passing electrons through a quantum well to cool them and keep them from heating.
The team details its research in"Energy-filtered cold electron transport at room temperature, "which is published in Nature Communications on Wednesday, Sept. 10."
"We are the first to effectively cool electrons at room temperature. Researchers have done electron cooling before,
but only when the entire device is immersed into an extremely cold cooling bath, "said Seong Jin Koh, an associate professor at UT Arlington in the Materials science & Engineering Department,
"Obtaining cold electrons at room temperature has enormous technical benefits. For example, the requirement of using liquid helium
or liquid nitrogen for cooling electrons in various electron systems can be lifted.""Electrons are excited thermally even at room temperature,
which is a natural phenomenon. If that electron excitation could be suppressed, then the temperature of those electrons could be lowered effectively without external cooling,
Koh said. The team used a nanoscale structure which consists of a sequential array of a source electrode, a quantum well,
a tunneling barrier, a quantum dot, another tunneling barrier, and a drain electrode to suppress electron excitation
and to make electrons cold. Cold electrons promise a new type of transistor that can operate at extremely low energy consumption."
"Implementing our findings to fabricating energy-efficient transistors is currently under way,"Koh added. Khosrow Behbehani, dean of the UT Arlington College of Engineering, said this research is representative of the University's role in fostering innovations that benefit the society,
such as creating energy-efficient green technologies for current and future generations.""Dr. Koh and his research team are developing real-world solutions to a critical global challenge of utilizing the energy efficiently
and developing energy-efficient electronic technology that will benefit us all every day, "Behbehani said.""We applaud Dr. Koh for the results of this research
Future research could include identifying key elements that will allow electrons to be cooled even further.
The most important challenge of this future research is to keep the electron from gaining energy as it travels across device components.
such as gold or silver, to give molecules a lot of freedom to diffuse and react on the surface,
"But this also means that the way these molecules assemble is determined completely by the intermolecular forces and by the molecular chemistry."
"Currently, there is no molecule that can assemble to produce zigzag-edge GNRS. To target the zigzag edge,
or silvero introduce new substrate-to-molecule interactions, in addition to the intermolecular interactions. The effects of this strategy were demonstrated using a precursor molecule known to form armchair-edge GNRS.
On copper, scanning tunneling microscope images revealed a molecular assembly that is entirely different than that on gold or silver, yielding GNRS with periodic zigzag-edge regions.
On the macroscale adding fluorine atoms to carbon-based materials makes for water-repellant nonstick surfaces such as Teflon.
Made up of fewer atoms than their macroscale counterparts each atom is that much more important to the component's overall structure and function.
We wanted to better understand the fundamental mechanisms of how the addition of other atoms influences the friction of graphene.
The addition of fluorine atoms to graphene's carbon lattice makes for an intriguing combination
but there are few enough atoms that we can model how they behave with a high degree of accuracy.
In fluorinated graphene the fluorine atoms do stick up out of the plane of carbon atoms but the physical changes in height paled in comparison to the changes of local energy each fluorine atom produced.
At the nanoscale Carpick said friction isn't just determined by the placement of atoms
but also how much energy is in their bonds. Each fluorine atom has so much electronic charge that you get tall peaks
and deep valleys in between them compared to the smooth plane of regular graphene. You could say it's like trying slide over a smooth road versus a bumpy road.
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.
Instead of always using the same pure carbon molecules they used additionally doped molecules molecules provided with foreign atoms in precisely defined positions in this case nitrogen.
A p-n junction causes current to flow in only one direction Because of the sharp transition at the heterojunction interface the new structure also allows electron/hole pairs to be separated efficiently
in which guest molecules or ions are inserted between the carbon layers of graphite to pull the single sheets apart.
Using the special properties of graphene a two-dimensional form of carbon that is only one atom thick a prototype detector is able to see an extraordinarily broad band of wavelengths.
Using a new operating principle called the hot-electron photothermoelectric effect the research team created a device that is as sensitive as any existing room temperature detector in the terahertz range
Graphene a sheet of pure carbon only one atom thick is suited uniquely to use in a terahertz detector
because when light is absorbed by the electrons suspended in the honeycomb lattice of the graphene they do not lose their heat to the lattice
Light is absorbed by the electrons in graphene which heat up but don't lose their energy easily.
These heated electrons escape the graphene through electrical leads much like steam escaping a tea kettle.
which conduct electrons at different rates. Because of this conductivity difference more electrons will escape through one than the other producing an electrical signal.
This electrical signal detects the presence of terahertz waves beneath the surface of materials that appear opaque to the human eye or even x-rays.
and low-cost biosensors that can eventually allow single-molecule detectionhe holy grail of diagnostics and bioengineering research said Samir Mitragotri co-author and professor of chemical engineering and director of the Center for Bioengineering at UCSB.
Graphene has been used among other things to design FETSEVICES that regulate the flow of electrons through a channel via a vertical electric field directed into the channel by a terminal called a gate.
and the current in the channel is modulated by the binding between embedded receptor molecules and the charged target biomolecules to
whose surface potential (or conductivity) can be modulated by the interaction (known as conjugation) between the receptor and target molecules that results in net accumulation of charges over the gate region.
Electrons travel freely across a graphene FETENCE it cannot be switched offhich in this case results in current leakages and higher potential for inaccuracies.
and label-free detection of biomoleculesemoving the step and expense of labeling target molecules with florescent dye.
Going in the other direction as the excited electrons relaxed they were collected by the wire and converted back into plasmons
and atomically thin material that can be exploited for nanophotonic integrated circuits said Nick Vamivakas assistant professor of quantum optics and quantum physics at the University of Rochester and senior author of the paper.
In bulk Mos2 electrons and photons interact as they would in traditional semiconductors like silicon and gallium arsenide.
As Mos2 is reduced to thinner and thinner layers the transfer of energy between electrons and photons becomes more efficient.
The key to Mos2's desirable photonic properties is in the structure of its energy band gap.
which allows electrons to easily move between energy bands by releasing photons. Graphene is inefficient at light emission
"Every single protein chain that forms our particle displays one of the pathogen's protein molecules that are recognized by the immune system,
and buy an impedance spectrometer and do this measurement with our paper in hand because it tells them how,"Gundlach states."
which results in a temporary high-voltage that decays over a time from nanosecond to seconds.
They use electrons which are hundreds of times smaller than the wavelengths of light to map the landscape all the way down to molecules and even atoms.
We've been taking images at the atomic and nanoscale for decades but it's usually done with the sample in a vacuum Zaluzec said.
When you're looking for atoms and molecules any extra molecules even the ones in air can cloud the picture.
But the most interesting objects or processes On earth generally aren't found in a vacuum
#Graphene reinvents the future For many scientists the discovery of one-atom-thick sheets of graphene is hugely significant something with the potential to affect just about every aspect of human activity and endeavour.
At the molecular level it is a unique two-dimensional molecule: an electrically conductive latticelike layer just one carbon atom thick.
a new class of nanoscale materials made in sheets only three atoms thick. The University of Washington researchers have demonstrated that two of these single-layer semiconductor materials can be connected in an atomically seamless fashion known as a heterojunction.
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 the evaporated atoms from one of the materials were carried toward a cooler region of the tube
After a while, evaporated atoms from the second material then attached to the edges of the triangle to create a seamless semiconducting heterojunction."
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,
such as sulfur (S). The resulting heterostructure is bound by the relatively weak intermolecular attraction known as the Van der waals force.
The separation of photoexcited electrons and holes is essential for driving an electrical current in a photodetector or solar cell."
and MX2 semiconductors provide an ideal way to spatially separate electrons and holes for electrical collection and utilization."
Using electron-beam evaporation which is a common technique in CMOS processing Zheng deposited a thin layer of aluminum onto a silicon photodetector topped with an ultrathin oxide coating.
The metallic nanostructures use surface plasmons waves of electrons that flow like a fluid across metal surfaces.
#Scientists fabricate defect-free graphene set record reversible capacity for Co3o4 anode in Li-ion batteries Graphene has already been demonstrated to be useful in Li-ion batteries,
Wrapping a large sheet of negatively charged df-G around a positively charged Co3o4 creates a very promising anode for high-performance Li-ion batteries.
so that the potassium molecules become intercalated into the graphite interlayers. The resulting potassium graphite compounds were placed then in a pyridine solution,
because when a single graphene sheet is wrapped around a bundle of Co3o4 particles, the Co3o4 particles are prevented from becoming pulverized
and then electrically detaching from the anode, which would otherwise occur. Because of this protective effect, the anode's capacity is preserved even after 200 cycles,
#Scientists unveil new technology to better understand small clusters of atoms Physicists at the University of York,
working with researchers at the University of Birmingham and Genoa, have developed new technology to study atomic vibration in small particles,
revealing a more accurate picture of the structure of atomic clusters where surface atoms vibrate more intensively than internal atoms.
and quantum mechanics calculations to simulate the electron microscopy of gold particles. By modelling the atomic vibration of individual atoms in such clusters realistically
external atoms on the surface of the structure can be seen'to vibrate more than internal atoms.
The research is published in the latest issue of Physical Review Letters. Currently, electron microscopy only allows scientists to estimate the average position of atoms in a three-dimensional structure.
This new technique means that, for the first time, the difference in individual atomic motion can also be considered,
enabling more accurate measurements of an atom's position and vibration in small particle structures.
This new development paves the way for a new field of dynamical study in the position dependence of atomic vibration in small particles
and is also likely to benefit the catalytical study of particles. Richard Aveyard, Postdoctoral Research Associate in the Department of physics at York, said:"
We believe that it will also prompt new experiments focusing on the dynamical properties of the atoms at nanostructures,
but rather are extensions of the bacteria's outer membrane equipped with proteins that transfer electrons called cytochromes.
During the formation of nanowires scientists noted an increase in the expression of electron transport genes but no corresponding increase in the expression of pilin genes.
Generating videos of the nanowires stretching out required new methods to simultaneously label multiple features keep a camera focused on the wriggling bacteria and combine the optical techniques with atomic force microscopy to gain higher resolution.
and Air force Office of Scientific research and made possible by facilities at the USC Centers of Excellence in Nanobiophysics and Electron Microsopy and Microanalysis.
Shewanella oneidensis MR-1 nanowires are outer membrane and periplasmic extensions of the extracellular electron transport components PNAS www. pnas. org/cgi/doi/10.1073
And you can order characteristics that you need for example a certain electron flow direction or strength.
All the modules can be tuned to have the ability to provide electron availability in a certain way.
The particles are collected in a magnetic field undeposited contaminants are washed away and the purified antibodies recovered by removing the polyethylene glycol.
#Watching molecules'dance'in real time (Phys. org) A new technique which traps light at the nanoscale to enable real-time monitoring of individual molecules bending
and flexing may aid in our understanding of how changes within a cell can lead to diseases such as cancer.
A new method which uses tightly confined light trapped between gold mirrors a billionth of a metre apart to watch molecules'dancing'in real time could help researchers uncover many of the cell processes that are essential to all life
Researchers from the University of Cambridge have demonstrated how to use light to view individual molecules bending
but allowing select molecules such as drugs to get through. This critical front line of cellular defence is made up of a layer of fatty lipids just a few nanometres thick.
The ability to watch how individual lipid molecules interact with their environment can help researchers understand not only how these
In order to view the behaviour of the cell membrane at the level of individual molecules the Cambridge team working with researchers from the University of Leeds squeezed them into a tiny gap between the mirrored gold facets of a nanoparticle sitting just above a flat gold surface.
Through highly precise control of the geometry of the nanostructures and using Raman spectroscopy an ultra-sensitive molecular identification technique the light can be trapped between the mirrors allowing the researchers to'fingerprint'individual molecules.
Analysing the colours of the light which is scattered by the mirrors allowed the different vibrations of each molecule to be seen within this intense optical field.
Probing such delicate biological samples with light allows us to watch these dancing molecules for hours without changing
The molecules stand shoulder to shoulder like trees in a forest while a few jitter around sideways.
By continuously observing the scattered light individual molecules are seen moving in and out of the tiny gaps between the mirrors.
Carefully analysis of the signatures from different parts of each molecule allowed any changes in the molecule shape to be observed
It is completely astonishing to watch the molecules change shape in real time said Richard Taylor lead author of the paper.
Synthetic molecule makes cancer self-destruc c
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