Typically a highly conductive material, graphene becomes a semiconductor when prepared as an ultra-narrow ribbon. Recent research has now developed a new method to selectively dope graphene molecules with nitrogen atoms. By seamlessly stringing together doped and undoped graphene pieces, ”heterojunctions” are formed in the nanoribbons, allowing electric current to flow in only one direction when voltage is applied.
A team of U.S. and Swiss researchers have built a...
When metallic lithium forms and deposits during...
Physicists studying the effects of embedding magnetic spins onto the surface of a superconductor recently report that the spins can interact differently than previously thought. This hybrid platform could be useful for quantum simulations of complex spin systems, having the special feature that the interactions may be controllable, something quite unusual for most condensed matter systems.
Sensors made with copper could be cheap, light, flexible and highly conductive. Making such concepts affordable enough for general use remains a challenge but a new way of working with copper nanowires and a PVA “nano glue” could be a game-changer. Engineers in Australia have found a way of making flexible copper conductors cost-effective enough for commercial applications.
Electronic devices with unprecedented efficiency and data storage may someday run on ferroelectrics—remarkable materials that use built-in electric polarizations to read and write digital information, outperforming the magnets inside most popular data-driven technology. But ferroelectrics must first overcome a few key stumbling blocks, including a curious habit of "forgetting" stored data.
Researchers at the National Physical Laboratory in the U.K. have discovered that the conductivity at the edges of graphene devices is different to the central material. The group used local scanning electrical techniques to examine the local nanoscale electronic properties of epitaxial graphene, in particular the differences between the edges and central parts of graphene Hall bar devices.
Graphene has excellent biocompatibility thanks to its great flexibility and chemical durability, and its conducting properties suggest uses for prosthetic devices in humans. Physicists are now developing key components of an artificial retina made of graphene. These retina implants may one day serve as optical prostheses for blind people whose optical nerves are still intact.
Sun, wind and other renewable energy sources could make up a larger portion of the electricity America consumes if better batteries could be built to store the intermittent energy for cloudy, windless days. Now a new material could allow more utilities to store large amounts of renewable energy and make the nation's power system more reliable and resilient.
Graphene has become a focus of research on a variety of potential uses. Now researchers at Massachusetts Institute of Technology have found a way to control how the material conducts electricity by using extremely short light pulses, which could enable its use as a broadband light detector.
Using a new method to track the electrochemical reactions in a common electric vehicle battery material under operating conditions, scientists at Brookhaven National Laboratory have revealed new insight into why fast charging inhibits this material's performance. The study also provides the first direct experimental evidence to support a particular model of the electrochemical reaction.
In a recent paper, a team at Stanford Univ. which includes materials science expert Yi Cui and 2011 R&D Magazine Scientist of the Year Steven Chu report that they have taken a big step toward accomplishing what battery designers have been trying to do for decades: design a pure lithium anode.
Research led by Penn State Univ. and Cornell Univ. physicists is studying "spintorque" in devices that combine a standard magnetic material with a new material known as a topological insulator. The new insulator, which is made of bismuth selenide and operates at room temperature, overcomes one of the key challenges to developing a spintronics technology based on spin-orbit coupling.
The doubling of transistors on a microprocessor occurs roughly every two years, and is the outcome of what is called Moore’s Law. In a bid to continue this trend of decreasing transistor size and increasing computation and energy efficiency, chip-maker Intel has partnered with Lawrence Berkeley National Laboratory to design an entirely new kind of photoresist, one that combines the best features of two existing types of resist.
Perovskites continue to entice materials scientists with their mix of conductivity, ferroelectricity, ferromagnetism, and catalytic activity. In recent years, scientists realized that they could vastly improve the properties of perovskites by assembling them into thin films, but nobody knew the reason why. But studying the chemistry layer-by-layer, experts working with x-ray beamline at Argonne National Laboratory are getting close.
A research group based in Japan has developed a new methodology that can easily and precisely control the timing, structure, and functions in the self-assembly of pi-conjugated molecules, which are an important enabling building block in the field of organic electronics. One of the key steps is keeping these molecules in a liquid form at room temperature.
First developed five years ago at Rice Univ., silicon oxide memories are a type of two-terminal, “resistive random-access memory” (RRAM) technology that beats flash memory’s data density by a factor of 50. At Rice, the laboratory of chemist and 2013 R&D Magazine Scientist of the Year James Tour has recently developed a new version of RRAM that Tour believes outperforms more than a dozen competing versions.
A team in the U.K. has found that by sandwiching a 7-nm thick layer of a phase change material between two layers of a transparent electrode they could use a tiny current to “draw” images within the sandwich “stack”. The discovery could make it possible to create pixels just a few hundred nanometers across and pave the way for extremely high-resolution and low-energy thin, flexible displays.
A new type of catalyst, based on carbon, can facilitate two opposite reactions: electrolysis of water and combustion of hydrogen with oxygen. This bi-functionality, developed by researchers in Germany, is made possible from its construction: manganese-oxide or cobalt-oxide nanoparticles which are embedded in specially modified carbon, then integrated with nitrogen atoms in specific positions.
Researchers at the Univ. of California, Riverside have used a quartz-rich material to fabricate a lithium-ion battery that outperforms the current industry standard by three times. This key material? Sand. Through a heating process with salt and magnesium, the scientists created a porous nano-silicon sponge that greatly increases active surface area.
Researchers at Pacific Northwest National Laboratory have developed a porous material to replace the graphite traditionally used in a battery's electrodes. Made from silicon, which has more than 10 times the energy storage capacity of graphite, the sponge-like material can help lithium-ion batteries store more energy and run longer on a single charge.
An international research collaboration has designed a miniscule cooling element that uses spin waves to transport heat in electrical insulators. Although physicists have used spin for cooling purposes before, this is the first time that they have successfully done this in insulating materials. The cooling element could be used to dissipate heat in the increasingly smaller electrical components of computer chips.
Experts don't fully understand how “plastic” solar panels work, which complicates the improvement of their cost efficiency and hinders wider use of the technology. However, an international team has now determined how light beams excite the chemicals in solar panels, enabling them to produce charge. Their findings were made possible with the use of femtosecond Raman spectroscopy.
Recent research at the Rice Univ. lab of materials scientist Pulickel Ajayan has discovered that nanotubes that hit a target end first turn into mostly ragged clumps of atoms. But nanotubes that happen to broadside the target unzip into handy ribbons that can be used in composite materials for strength and applications that take advantage of their desirable electrical properties.
Computer simulation has shown Stanford Univ. engineers how to make a crystal that would toggle like a light switch between conductive and non-conductive structures. This flexible, switchable lattice, just three atoms thick, can be turned on or off by mechanically pushing or pulling, and could lead to flexible electronic materials.
Researchers in Germany have produced a new material the size of a sugar cube that has a surface area equivalent to more than seven tennis courts. This novel type of nanofiber has a highly ordered and porous structure gives it an extraordinarily high surface-to-volume ratio and could be a key enabling technology for lithium-sulfur batteries.
A group of researchers from Russia, Belarus and Spain, including MIPT professor Yury Lozovik, have developed a microscopic force sensor based on carbon nanotubes. The device consists of two nanotubes placed so that their open ends are opposite to each other. Voltage of just 10 nA is then applied to the nanocircuit and force is measured by the change in position of the nanotubes.
The electrons in graphene behave as “massless” particles, yet these electrons also seem to have dual personalities. Phenomena observed in the field of graphene plasmonics suggest that when the electrons move collectively, they must exhibit mass. After two years of effort, researchers at Harvard Univ. have successfully measured the collective mass of “massless” electrons in motion in graphene.
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