#Mobile phones come alive with the sound of music thanks to nanogenerators Charging mobile phones with sound, like chants from at football ground, could become a reality, according to a new collaboration between scientists from Queen Mary University of London and Nokia.
but they have been limited by low energy density. Compared with traditional batteries, ECS typically have superior power density
A high-performance EC electrode must have high electrical conductivity, a high ion-accessible surface area, a high ionic transport rate and high electrochemical stability.
exceptional mechanical flexibility and unique hierarchical porosity, ensuring the efficient transport of electrons and ions and enabling the highest gravimetric energy densities of 127 watt hours per kilogram and volumetric energy density of 90 watt hours per liter.
Furthermore, the team has shown that a fully packaged EC exhibits unparalleled energy densities of 35 watt hours per kilogram (49 watt hours per liter) bout five to 10 times higher than current commercial supercapacitors and on a par
Under the guidance of Canada Research Chair in Materials science with Synchrotron radiation Dr. Alexander Moewes University of Saskatchewan researcher Adrian Hunt spent his Phd investigating graphene oxide a cutting-edge material that he hopes will shape the future
and SGM beamlines at the Canadian Light source as well as a Beamline 8. 0. 1 at the Advanced Light source Hunt set out to learn more about how oxide groups attached to the graphene lattice changed it
and how in particular they interacted with charge-carrying graphene atoms. Graphene oxide is fairly chaotic. You don't get a nice simple structure that you can model really easily but
Using the synchrotron Hunt could measure where electrons were on the graphene and how the different oxide groups modified that.
Moreover he studied how graphene oxide decays. Some of the oxide groups are not stable and can group together to tear the lattice;
and tested in a three-electrode system to see how well the material could adsorb electrolyte ions (charge) and then release electrolyte ions (discharge).
The method uses biodegradable nanoscale thin films laden with drug molecules that are absorbed into the body in an incremental process.
Any biodegradable mechanism intended to release a drug over a long time period must be sturdy enough to limit hydrolysis a process by which the body's water breaks down the bonds in a drug molecule.
Yet the drug-release mechanism needs to be designed such that a drug molecule does in fact decompose in steady increments.
which drug molecules are attached effectively to layers of thin-film coating. In this specific case the researchers used diclofenac a nonsteroidal anti-inflammatory drug that is often prescribed for osteoarthritis and other pain or inflammatory conditions.
To be sure in each case researchers will have to figure out how best to bind the drug molecule in question to a biodegradable thin-film coating.
One layer of tungsten is sandwiched between two layers of selenium atoms.""We had already been able to show that tungsten diselenide can be used to turn light into electric energy
When light shines on a photoactive material single electrons are removed from their original position. A positively charged hole remains
where the electron used to be. Both the electron and the hole can move freely in the material,
but they only contribute to the electrical current when they are kept apart so that they cannot recombine.
To prevent recombination of electrons and holes, metallic electrodes can be used, through which the charge is sucked away
"The holes move inside the tungsten diselenide layer, the electrons, on the other hand, migrate into the molybednium disulphide,
if the energies of the electrons in both layers are tuned exactly the right way. In the experiment, this can be done using electrostatic fields.
Florian Libisch and Professor Joachim Burgdörfer (TU Vienna) provided computer simulations to calculate how the energy of the electrons changes in both materials
"If there are any molecules between the two layers, so that there is no direct contact, the solar cell will not work."
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.
"Drug delivery systems tend to use magnetic particles which are very effective but they can't always be used
because these particles can be toxic in certain physiological conditions, "Dr Majumder said.""In contrast, graphene doesn't contain any magnetic properties.
and monitor the phase transformation that takes place in the cathode as lithium ions move from the cathode to the anode,
Getting as many lithium ions as possible to move from cathode to anode through this process,
pixel by pixel, where lithium ions remain in the material, where they've been removed leaving only iron phosphate,
The scientists used these methods to analyze samples made up of multiple nanoscale particles in a real battery electrode under operating conditions (in operando.
But because there can be a lot of overlap of particles in these samples, they also conducted the same in operando study using smaller amounts of electrode material than would be found in a typical battery.
This allowed them to gain further insight into how the delithiation reaction proceeds within individual particles without overlap.
They studied each system (multi-particle and individual particles) under two different charging scenarios-rapid (like you'd get at an electric vehicle recharging station),
and slow (used when plugging in your vehicle at home overnight). These animated images of individual particles, taken
while the electrode is charging, show that lithiated (red) and delithiated (green) iron phosphate phases coexist within individual particles.
This finding directly supports a model in which the phase transformation proceeds from one phase to the other without the existence of an intermediate phase.
all the lithium ions are removed leaving only iron phosphate behind, while particles in other areas show no change at all,
retaining their lithium ions. Even in the"fully charged"state, some particles retain lithium and the electrode's capacity is well below the maximum level."
"This is the first time anyone has been able to see that delithiation was happening differently at different spatial locations on an electrode under rapid charging conditions,
"Jun Wang said. Slower charging, in contrast, results in homogeneous delithiation, where lithium iron phosphate particles throughout the electrode gradually change over to pure iron phosphate
-and the electrode has a higher capacity. Scientists have known for a while that slow charging is better for this material,
so all particles can be involved in the reaction instead of just some, "he said. The individual-particle study also detected, for the first time, the coexistence of two distinct phases-lithiated iron phosphate and delithiated,
or pure, iron phosphate-within single particles. This finding confirms one model of the delithiation phase transformation-namely that it proceeds from one phase to the other without the existence of an intermediate phase."
"These discoveries provide the fundamental basis for the development of improved battery materials, "said Jun Wang."
that their motion can be affected by the motion of nearby molecules (known as Brownian motion). The team already knew that tiny propellers moved well through water,
just as if they were molecules. But because the nanopropellers are the same size as the mesh in the gel
Scientists could also attach"active molecules"to the tips of the propellers, or use the propellers to deliver tiny doses of radiation.
The applications seem wide, varied, and exciting i
#Existence of two-dimensional nanomaterial silicene questioned Sometimes scientific findings can shake the foundations of what was held once to be true causing us to step back
Silicene was proposed as a two-dimensional sheet of silicon atoms that can be created experimentally by super-heating silicon
and evaporating atoms onto a silver platform. Silver is the platform of choice because it will not affect the silicon via chemical bonding nor should alloying occur due to its low solubility.
During the heating process as the silicon atoms fall onto the platform researchers believed that they were arranging themselves in certain ways to create a single sheet of interlocking atoms.
This surprisingly acts a chemical barrier to prevent the decay of the lower layers. Because it consists of only one layer of silicon atoms silicene must be handled in a vacuum.
Exposure to any amount of oxygen would completely destroy the sample. This difference is one of the keys to the researchers'discovery.
After depositing the atoms onto the silver platform initial tests identified that alloy-like surface phases would form until bulk silicon layers
if we were dealing with multiple layers of silicon atoms we could bring it out of our ultra-high vacuum chamber
By examining and categorizing the top layers of the material the researchers discovered silicon oxide a sign of oxidation in the top layers They were surprised also to find that particles from the silver platform alloyed with the silicon at significant depths.
Materials are made up of systems of atoms that bond and vibrate in unique ways. Raman spectroscopy allows researchers to measure these bonds and vibrations.
Housed within the Center for Nanoscale Materials a DOE Office of Science User Facility the spectroscope allows researchers to use light to shift the position of one atom in a crystal lattice
which the atoms vibrate. The researchers noticed something oddly familiar when looking at the vibrational signatures and frequencies of their sample.
which wear particles and surface defects can form, "said Purdue postdoctoral research associate Anirban Mahato,
to show how the behavior leads to cracks and wear particles. The findings were counter-intuitive
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
In addition, the lithium-ion batteries that had applied modified graphenes to it, exhibited a higher capacity than the theoretical capacity of graphite
which was used previously in lithium-ion batteries. It presented high chemical stability which resulted in no capacity degradation in charge and discharge experiments.
In contrast to silicon, many of such semiconductors with extremely high electron mobility could improve performance of the most modern silicon-based CMOS technology.
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. The scientists initially needed to introduce a determined number of atoms precisely into the wires using ion implantation.
They then carried out the flash-lamp annealing of the silicon wires in their liquid-phase within a matter of only twenty milliseconds."
"A silicon oxide shell, measuring merely fifteen-nanometers-thick, maintains the form of the liquid nanowire,
"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."
Our technology could lead to a bomb-detecting chip for a handheld device that can detect the tiny-trace vapor in the air of the explosive's small molecules."
Unstable and hungry for electrons The nanoscale plasmon sensor used in the lab experiments is much smaller than other explosive detectors on the market.
they are also characteristically electron deficient, the researchers said. This quality increases the interaction of the molecules with natural surface defects on the semiconductor.
The device works by detecting the increased intensity in the light signal that occurs as a result of this interaction.
Potential use to sense hard-to-detect explosive"We think that higher electron deficiency of explosives leads to a stronger interaction with the semiconductor sensor"
and is more electron deficient than the DNT we detected in our experiments, so the sensitivity of our device should be even higher than with DNT,
the oscillating electrons found at the surface of metals, researchers were able to squeeze light into nanosized spaces,
These atom-thin sheets including the famed super material graphene feature exceptional and untapped mechanical and electronic properties.
Within the honeycomb-like lattices of monolayers like graphene boron nitride and graphane the atoms rapidly vibrate in place.
As the perfect hexagonal structures of such monolayers are strained they enter a subtle soft mode the vibrating atoms slip free of their original configurations
and never returns that's like this soft mode where the vibrating atoms move away from their positions in the lattice.
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.
Engineers envision an electronic switch just three atoms thick More information: Eric B. Isaacs and Chris A. Marianetti.
causing the nanoparticle to self-assemble into a much larger particle so that it is more visible on the scan.
#Nanophotonics experts create powerful molecular sensor Nanophotonics experts at Rice university have created a unique sensor that amplifies the optical signature of molecules by about 100 billion times.
and structure of individual molecules containing fewer than 20 atoms. The new imaging method, which is described this week in the journal Nature Communications, uses a form of Raman spectroscopy in combination with an intricate but mass reproducible optical amplifier.
Researchers at Rice's Laboratory for Nanophotonics (LANP) said the single-molecule sensor is about 10 times more powerful that previously reported devices."
"Ours and other research groups have been designing single-molecule sensors for several years, but this new approach offers advantages over any previously reported method,
"The ideal single-molecule sensor would be able to identify an unknown moleculeven a very small oneithout any prior information about that molecule's structure or composition.
When light strikes a molecule, most of its photons bounce off or pass directly through,
By measuring and analyzing these re-emitted photons through Raman spectroscopy, scientists can decipher the types of atoms in a molecule as well as their structural arrangement.
Scientists have created a number of techniques to boost Raman signals. In the new study LANP graduate student Yu Zhang used one of these,
Halas and Zhang were able to measure single molecules in a powerful new way. LANP has dubbed the new technique"surface-enhanced CARS,"or SECARS."
"In a conventional single-laser setup, photons go through two steps of absorption and re-emission, and the optical signatures are amplified usually around 100 million to 10 billion times.
That's an added advantage over current techniques for single-molecule sensing, which generally require a prior knowledge about a molecule's resonant frequency before it can be measured accurately.
Another key component of the SECARS process is the device's optical amplifier, which contains four tiny gold discs in a precise diamond-shaped arrangement.
"the optical signatures of molecules caught in that gap are amplified dramatically because of the efficient light harvesting and signal scattering properties of the four-disc structure.
and we can measure molecules anywhere in that target area, not just in the exact center.""Halas, the Stanley C. Moore Professor in Electrical and Computer engineering and a professor of biomedical engineering, chemistry, physics and astronomy at Rice, said the potential applications for SECARS include chemical and biological sensing as well as metamaterials research.
"Amplification is important for sensing small molecules because the smaller the molecule, the weaker the optical signature,
and they are singling out its ability to be applied to lightweight temperature-sensitive structures such as aluminum absorbing 99.96%of incident radiation;
when even a few photons can throw off an experiment. What are some applications for this material?
and particle fallout eliminating a key source of contamination in sensitive imaging systems. It withstands launch shock staging
what is currently achievable using conventional electron-beam lithography techniques).""On a fundamental level, our work demonstrates electron-beam based manipulation of nanoparticles an order of magnitude larger than previously possible,
using a simple SEM operating at only a fraction of the electron energies of previous work,
"said Brian Roxworthy, who earned his Phd in electrical and computer engineering (ECE) at Illinois and was first author of the paper published in Nature Communications."
"The dramatic deformation of the nanoantennas we observe is facilitated by strong in-gap plasmonic modes excited by the passing electrons,
which give rise to nanonewton-magnitude gradient forces on the constituent metal particles.""The interdisiciplinary research teamhat included Abdul Bhuiya (MS student in ECE student), Xin Yu (ECE post-grad),
what is currently achievable using conventional electron-beam lithography techniques). The team demonstrated that an electron beam from a standard scanning electron microscope (SEM) can be used to deform either individual p-BNA structures
or groups of p-BNAS within a sub-array with velocities as large as 60 nanometers per second.
it could lead to unique, spatially addressable nanophotonic devices for sensing and particle manipulation, for example;
along with a significant thermal contribution, permit sufficient compliance of the pillars to be actuated by electron-beam-induced gradient forces.
His lab already made its way into the Guinness Book of World records for inventing the world's sharpest object microscope tip just one atom wide at its end.
when they created the smallest-ever quantum dots single atom of silicon measuring less than one nanometre widesing a technique that will be awarded a U s. patent later this month.
are vessels that confine electrons, much like pockets on a pool table. The dots can be spaced
so that electrons can be in two pockets at the same time, allowing them to interact and share electrons level of control that makes them ideally suited for computer-like circuitry."
"It could be as important as the transistor, "says Wolkow.""It lays the groundwork for a whole new basis of electronics,
modifying scanning tunnelling microscopes with their atom-wide microscope tip, which emits ions instead of light at superior resolution.
Like the needle of a record player, the microscopes can trace out the topography of silicon atoms, sensing surface features on the atomic scale.
In a new paper published in Physical Review Letters, postdoctoral fellow Bruno Martins together with Wolkow and other members of the team,
Wolkow says silicon crystals are mostly smooth except for these atomic staircaseslight imperfections with each step being one atom high.
the research team observed how single electrons jump in and out of the quantum dots, and devised a method of monitoring how many electrons fit in the pocket and measuring the dot's charge.
In the past, such observations were impossible because the very act of trying to measure something so extraordinarily small changes it,
"Much of their efforts initially will focus on creating hybrid technologiesdding atom-scale circuitry to conventional electronics such as GPS devices
It could take a decade before it's possible to mass-produce atom-scale circuitry, but the future potential is very strong,
However, currently the detection of these molecules still requires specialised laboratories and is costly. Thanks to the EU-funded research project called NANOANTENNA
By shining light onto such a nanoantenna, the electrons inside start moving back and forth, amplifying the light radiation in hot spots regions of the antenna,
explains Pietro Giuseppe Gucciardi, a physicist at the Institute for Chemical-Physical Processes, affiliated with the Italian National Research Council CNR, in Messina,
tiny waves of electrons in metallic surfaces that appear when such surfaces are illuminated, also amplify the light in an area close to that surface.
If these molecules are close to nanoparticles, the plasmons in the nanoparticles enhance the Raman signal coming from the molecules that have to be detected with several orders of magnitude.
The nanoantennas developed in this project only enhance the emitted Raman signal if the biomolecules are close to the hot spots Therefore,
the molecules have to be trapped to be detected. To do so, the researchers attached bioreceptors, fragments of DNA engineered to recognise specific proteins, to the nanoantennas.
because photons can ricochet many times inside these openings until absorption occurs. Yet a practical understanding of how to fabricate these tiny structures is still lacking.
Next, the nanosphereilicon complex was immersed into a solution of hydrogen peroxide and hydrofluoric acid mixture that eats away at silicon atoms directly underneath the catalytic silver nanospheres.
Subsequent removal of the silver particles with acid produced the final, nanohole-infused silicon surface (see image).
Moreover, thanks to the inclusion of sulfur atoms, they are cheaper to make and less toxic than conventional lithium-ion power packs.
For example, both the rate and the number of possible charge-discharge cycles need to be increased before the lithium-sulfur battery can become a realistic alternative to lithium-ion batteries.
which involve both electrons and ions, are highly dependent on the total surface area available, "as Benjamin Mandlmeier, a postdoc in Bein's Institute and a first co-author on the new study,
explains. The secret recipe A novel recipe and a cleverly designed mode of synthesis are the key factors that determine the properties of the new materials.
'Relying on the fantastic structure and property, especially the extremely high mobility for both electrons and holes,
and the arrangement of the atoms in one of the planes of the nanocrystal catalyst facilitates the (n,
The Rice lab of materials scientist Pulickel Ajayan discovered that nanotubes that hit a target end first turn into mostly ragged clumps of atoms.
This pressure-regulated fine-tuning of particle separation enables controlled investigation of distance-dependent optical and electrical phenomena.
#Scientists develop a'nanosubmarine'that delivers complementary molecules inside cells With the continuing need for very small devices in therapeutic applications there is a growing demand for the development of nanoparticles that can transport
Recently researchers created nanoparticles that under the right conditions self-assemble trapping complementary guest molecules within their structure.
and transport their guest molecules through the membrane of living cells to sequentially deliver their cargo.
Although the transport of molecules inside cells with nanoparticles has been achieved previously using various methods researchers have developed nanoparticles capable of delivering
and exchanging complementary molecules. For practical applications these nanocarriers are highly desirable explains Francisco Raymo professor of chemistry in the University of Miami College of Arts and Sciences and lead investigator of this project.
These nanocarriers hold the guest molecules within the confines of their water-insoluble interior and use their water-soluble exterior to travel through an aqueous environment.
As a result these nanovehicles are ideal for transferring molecules that would otherwise be insoluble in water across a liquid environment.
Once inside a living cell the particles mix and exchange their cargo. This interaction enables the energy transfer between the internalized molecules says Raymo director of the UM laboratory for molecular photonics.
If the complementary energy donors and acceptors are loaded separately and sequentially the transfer of energy between them occurs exclusively within the intracellular space he says.
These weak bonds exist between molecules with complementary shapes and electronic properties. They are responsible for the ability of the supramolecules to assemble spontaneously in liquid environments.
Similarly, there are numerous functional units that can interact with water molecules in organisms. The protein-based ion channels are the good examples for these functional units
biological ion channels played key roles for high efficient energy conversion in organisms due to its nanoscale effect and ion selectivity.
#Bacterial nanometric amorphous Fe-based oxide as lithium-ion battery anode material Leptothrix ochracea is a species of iron-oxidizing bacteria that exists in natural hydrospheres where groundwater outwells worldwide.
Intriguingly the bacterium produces Fe3+-based amorphous oxide particles (ca 3 nm diameter; Fe3+:+Si4+:
but Jun Takada and colleagues at Okayama University discovered unexpected industrial functions of L-BIOX such as a great potential as an anode material in lithium-ion battery.
and easily-handled electrode material since its basic texture is composed of nanometric particles. The charge-discharge properties of simple L-BIOX/Li-metal cells were examined at current rates of 33. 3ma/g (0. 05c)
Notably the presence of minor components of Si and P in the original L-BIOX nanometric particles resulted in specific and well-defined electrode architecture.
Takada and colleagues proposed a unique approach to develop new electrode materials for Li-ion battery.
A Potential Lithium-Ion Battery Anode Material. Hideki Hashimoto Genki Kobayashi Ryo Sakuma Tatsuo Fujii Naoaki Hayashi Tomoko Suzuki Ryoji Kanno Mikio Takano and Jun Takada.
to heat up and destroy cancer cells in the lab. The team used the new photothermal delivery method in lab experiments to introduce impermeable dyes and small DNA molecules into human prostate cancer and fibroblast sarcoma cells."
or other small molecules directly into cells is essential for some of the most advanced methods being developed in gene therapy,
#Metal particles in solids aren't as fixed as they seem memristor study shows In work that unmasks some of the magic behind memristors and"resistive random access memory,
"or RRAMUTTING-edge computer components that combine logic and memory functionsesearchers have shown that the metal particles in memristors don't stay put as previously thought.
"Most people have thought you can't move metal particles in a solid material, "said Wei Lu, associate professor of electrical and computer engineering at the University of Michigan."
and colleagues at U-M and the Electronic Research Centre Jülich in Germany used transmission electron microscopes to watch and record what happens to the atoms in the metal layer of their memristor
They observed the metal atoms becoming charged ions, clustering with up to thousands of others into metal nanoparticles,
Memristor researchers like Lu and his colleagues had theorized that the metal atoms in memristors moved,
"Also the fact that we observed particle movement driven by electrochemical forces within dielectric matrix is in itself a sensation."
Overtext Web Module V3.0 Alpha
Copyright Semantic-Knowledge, 1994-2011