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.
Researchers from North Carolina State Univ. and the Univ. of Eastern Finland have developed new “sensing skin” technology designed to serve as an early warning system for concrete structures, allowing authorities to respond quickly to damage in everything from nuclear facilities to bridges.
Organic semiconductors have tremendous potential for complementing conventional, inorganic semiconductors, but energy losses or barriers at the connection interfaces have blocked development efforts. Physicists have now implemented a detailed electrostatic model which is capable of covering the full phenomenological range of interfacial energy-level alignment regimes within a single, consistent framework.
Researchers the world over are investigating solar cells which imitate plant photosynthesis, with the goal of using sunlight and water to create synthetic fuels such as hydrogen. Scientists in Switzerland have developed this type of photoelectrochemical cell, but this one recreates a moth’s eye to drastically increase its light collecting efficiency. The cell is made of cheap raw materials: iron and tungsten oxide.
In semiconductor-based components, high mobility of charge-carrying particles is important. In organic materials, however, it is uncertain to what degree the molecular order within the thin films affects the mobility and transport of charge carriers. Using a new imaging method, researchers have shown that thin-film organic semiconductors contain regions of structural disorder that could inhibit the transport of charge and limit efficiency.
Engineers at the Univ. of Arkansas have designed integrated circuits that can survive at temperatures greater than 350 C—or roughly 660 F. The team achieved the higher performance by combining silicon carbide with wide temperature design techniques. In the world of power electronics and integrated circuits, their work represents the first implementation of a number of fundamental analog, digital and mixed-signal blocks.
At the 2014 Symposium on VLSI Technology in Triangle Park, N.C., researchers from the Univ. of California, Santa Barbara introduced the highest-performing class III-V metal-oxide semiconductor field-effect transistors (MOSFETs) yet demonstrated. The new MOSFETs exhibit, in an industry first, on-current, off-current and operating voltage comparable to or exceeding production silicon devices, while also staying relatively compact.
Researchers at the University of California, Riverside Bourns College of Engineering have developed a 3-D, silicon-decorated, cone-shaped carbon-nanotube cluster architecture for lithium ion battery anodes that could enable charging of portable electronics in 10 minutes. It also increases cell capacity and reduces size and weight by 40%.
Since the early 1970s, lithium has been the most popular element for batteries because of it’s low weight and good electrochemical potential. But it is also highly flammable. Researchers have recently married two traditional theories in materials science that can explain how the charge dictates the structure of the material. And using this they may be able to move to other materials, such as block copolymers, for use in batteries.
Researchers in California have created a nanoscale magnetic component for computer memory chips that could significantly improve their energy efficiency and scalability. The design brings spintronics one step closer to being used in computer systems by adopting a new strategy called “spin-orbit torque” that eliminates the need for a magnetic field for switching processes.
Faster electronic device architectures are in the offing with the unveiling of the world’s first fully 2-D field-effect transistor (FET) by researchers at Lawrence Berkeley National Laboratory. Unlike conventional FETs made from silicon, these 2-D FETs suffer no performance drop-off under high voltages and provide high electron mobility, even when scaled to a monolayer in thickness.
The basic element of modern electronics, namely the transistor, suffers from significant current leakage. By enveloping a transistor with a shell of piezoelectric material, which distorts when voltage is applied, researchers in the Netherlands were able to reduce this leakage by a factor of five compared to a transistor without this material.
Materials that control heat flow are available with both high and low conductivities, but materials with variable and reversible thermal conductivities are rare. For the first time, researchers at the Univ. of Illinois have experimentally shown that the thermal conductivity of lithium cobalt oxide, an important material for electrochemical energy storage, can be reversibly electrochemically modulated over a considerable range.
Rensselaer Polytechnic Institute scientists have developed a method that can predict how subjecting metals to severe pressure can lower their electrical resistance. The finding which involved theoretical predictions, use of a supercomputer, and equipment capable of exerting pressures up to 40,000 atmospheres, could have applications in computer chips and other materials that could benefit from specific electrical resistance.
Research published in the Proceedings of the National Academy of Sciences makes it possible to predict how subjecting metals to severe pressure can lower their electrical resistance, a finding that could have applications in computer chips and other materials that could benefit from specific electrical resistance.
Saudi Arabian-based petrochemical company SABIC and Cima NanoTech have announced the joint development of a new transparent conductive polycarbonate film. The collaboration leverages both Cima NanoTech’s proprietary SANTE nanoparticle technology and SABIC’s LEXAN film to produce a film that outperforms indium tin oxide by a factor of ten.
In order to see the true polarization of ferroelectric materials quickly and efficiently, researchers at Argonne National Laboratory have developed a new technique called charge gradient microscopy. Charge gradient microscopy uses the tip of a conventional atomic force microscope to scrape and collect the surface screen charges.
Modern supercapacitors store ten times less energy than a lithium-ion battery but can last a thousand times longer. The main drawback of supercapacitors, however, is the inability to cope with stresses such as pressure and vibration. Researchers have developed a new supercapacitor that operates flawlessly in storing and releasing electrical charge while subject to stresses or pressures up to 44 psi and vibrational accelerations over 80 g.
Researchers at the Univ. of California, Riverside have developed a new nanometer scale ruthenium oxide anchored nanocarbon graphene foam architecture that improves the performance of supercapacitors. They found that the new structure could operate safely in aqueous electrolyte and deliver two times more energy and power compared to supercapacitors commercially available today.