Scientists from the U.S. Department of Energy’s National Renewable Energy Laboratory and other labs have demonstrated a process whereby quantum dots can self-assemble at the apex of a gallium arsenide-aluminum gallium arsenide core-shell nanowire interface. This activity at optimal locations in nanowires could improve solar cells, quantum computing, and lighting devices.
Researchers have tried for decades to replicate the effects of transistors in transition metal oxides by using a voltage to convert the material from an insulator to a metal, but the induced change only occurs within a few atomic layers of the surface. Recently, however, scientists in Japan have discovered that applying a voltage to a vanadium dioxide film several tens of nanometers thick converts the entire film from an insulator to a metal.
Research by an international team of physicists has produced new methods for controlling magnetic order in a particular class of materials known as "magnetoelectrics", which have their magnetic and electric properties couple to each other. This link offers the possibility of controlling electric behavior with a magnetic signal, or vice versa. Scientists recently demonstrated this ability in europium-titanium oxide.
Thermoelectric efficiency has improved enough to enable limited commercial use, but lack of better materials has prevented widespread adoption. New development work at Massachusetts Institute of Technology could help reduce thermal conductivity while keeping electrical conductivity high. In addition to computer modeling, the researchers draw upon methods developed by optics researchers who have been attempting to create invisibility cloaks—ways of making objects invisible to certain radio waves or light waves using nanostructured materials that bend light.
Iridescence, or sheen that shifts color depending on your viewing angle, is pretty in peacock feathers. But it's been a nuisance for engineers trying to mimic the birds' unique color mechanism to make high-resolution, reflective, color display screens. Researchers at the University of Michigan have found a way to lock in so-called structural color, which is made with texture rather than chemicals. The finding could lead to advanced color e-books, electronic paper, and screens that don't need their own light to be readable.
For years, scientists have studied the potential benefits of a new branch of solar energy technology that relies on incredibly small nanosized antenna arrays that are theoretically capable of harvesting more than 70% of the sun’s electromagnetic radiation and simultaneously converting it into usable electric power. A new fabrication technique developed by University of Connecticut engineering professor Brian Willis could provide the breakthrough for this technology.
Organic semiconductors hold promise for making low-cost flexible electronics—if they can perform in spite of frequent flexing and sharp bending. Scientists have recently demonstrated extremely flexible organic semiconductors that withstood multiple bending cycles in which the devices were rolled to a radius as small as 200 μm. The scientists worked with numerous crystalline devices they made and found no degradation in their performance.
An international team of researchers affiliated with Göttingen University in Germany has found a way to store vast amounts of data—up to one petabyte—per square inch. The scientists developed a unique molecule with an exploitable electron that carries a spin. This serves as the memory for their electronic device, which can be read out by a magnetic reference electrode at room temperature.
Scientists from the University of Cambridge, U.K., have created, for the first time, a new type of microchip which allows information to travel in three dimensions. The chip’s design relies on spintronics, a technology that makes use of an electron's tiny magnetic moment, or “spin”, to store information. Currently, microchips can only pass digital information in a very limited way—from either left to right or front to back.
Two Rutgers University physics professors have proposed an explanation for a new type of order, or symmetry, in an exotic material made with uranium—a theory that may one day lead to enhanced computer displays and data storage systems and more powerful superconducting magnets for medical imaging and levitating high-speed trains.
Found in flat screens, solar modules, or in new organic light-emitting diode (LED) displays, transparent electrodes have become ubiquitous. But since raw materials like indium are becoming more and more costly, researchers have begun to look elsewhere for alternatives. A new review article sheds some light on the different advantages and disadvantages of established and new materials for use in these kinds of contact electrodes.
Physicists have recently demonstrated that the application of a very strong alternating electric field to thin liquid crystal cells leads to a new distinct nonlinear dynamic effect in the response of the cells. Researchers were able to explain this result through spatio-temporal chaos theory. The finding has implications for the operation of liquid crystal devices because their operation depends on electro-optic switch phenomena.
At the heart of computing are tiny crystals that transmit and store digital information's ones and zeroes. Today these are hard and brittle materials. But cheap, flexible, nontoxic organic molecules may play a role in the future of hardware. A team led by the University of Washington and the Southeast University discovered a molecule that shows promise as an organic alternative to today's silicon-based semiconductors.
Researchers in Germany have developed a new generation of image sensors that are more sensitive to light than the conventional silicon versions. Simple and cheap to produce, they consist of electrically conductive plastics which are sprayed onto the sensor surface in an ultra-thin layer. The chemical composition of the polymer spray coating can be altered so that even the invisible range of the light spectrum can be captured.
Silica microwires are the tiny and as-yet underutilized cousins of optical fibers. If precisely manufactured, however, these hair-like slivers of silica could enable applications and technology not currently possible with comparatively bulky optical fiber. By carefully controlling the shape of water droplets with an ultraviolet laser, a team of researchers from Australia and France has found a way to coax silica nanoparticles to self-assemble into much more highly uniform silica wires.
Existing optical beamsteering assemblies for technologies like LADAR, which scans a field of view with a laser to determine distance, are typically mechnical, bulky, slow, and inaccurate. In an effort to design a better, scalable technology, DARPA researchers have recently demonstrated the most complex optical phased array ever built onto a 2D chip.
When it comes to high-temperature superconductors, a class of materials called cuprates is king, and it is science's ongoing quest to determine their exact physical subtleties. Cornell University physicists and materials scientists have now verified that cuprates respond differently when adding electrons versus removing them, resolving a central issue about the compounds' most fundamental properties.
Making the one-atom thick sheets of carbon known as graphene in a way that could be easily integrated into mass production methods has proven difficult. Now, research from the Beckman Institute at the University of Illinois is giving new insight into the electronics behavior of graphene. They have obtained information about electron scattering at graphene’s boundaries that shows it significantly limits the electronic performance compared to grain boundary free graphene.
The world's love affair with gadgets—many of which contain hazardous materials—is generating millions of tons of electronic waste annually. Now, Purdue and Tuskegee universities are leading an international effort to replace conventional electronics with more sustainable technologies and train a workforce of specialists to make the transition possible.
It may be possible soon to charge cell phones, change the tint on windows, or power small toys with peel-and-stick versions of solar cells. A partnership between Stanford University and the National Renewable Energy Laboratory aims to produce water-assisted transfer printing technologies that support thin-film solar cell production.
Researchers from North Carolina State University have created conductive wires that can be stretched up to eight times their original length while still functioning. To make the wires, researchers start with a thin tube made of an extremely elastic polymer and then fill the tube with a liquid metal alloy of gallium and indium, which is an efficient conductor of electricity.
In two complementary experiments a collaboration of physicists has demonstrated that, under certain conditions, ultrashort light pulses of extremely high intensity can induce electric currents in otherwise insulating dielectric materials. The findings hold promise for reaching electronic switching rates up to the petahertz domain.
Inductors are essential components of integrated circuits. The sprawling metal spirals store magnetic energy, acting as a buffer against changes in current and modulating frequency. However, because inductance depends on the number of coils, they take up a lot of space. Researchers have recently build a 3D rolled-up inductor with a footprint more than 100 times smaller without sacrificing performance.
Organic solar cells have advanced a great deal since they were first invented nearly 20 years ago, but the fullerene component has remained largely the same and this has had a braking effect on the evolution of the technology. Researchers in the U.K. have pinpointed an unappreciated property of fullerenes which could be replicated to create a new class of fullerene “mimics”.
Photoelectrochemical (PEC) tandem solar cells offer a way to produce hydrogen directly from water. But efforts to produce an efficient cell have only resulted in extremely expensive prototypes. Researchers in Switzerland have recently developed a PEC, however, that is made from inexpensive materials and achieves up to 16% efficiency.