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.
Instead of silicon transistors, the electronics of the future could use molecules to do their arithmetic. Every transistor would still need a connection, however, and researchers at the Max Planck Society have built an example from a narrow band of graphene. Using scanning tunnelling microscopy, the team was able to determine how the conductance of the carbon strip depends on its length and the energy of the electrons.
Catalysis is an incredibly valuable tool in the field of chemistry, but it typically requires precious metals that are both expensive and potentially harmful to the environment. Researchers in Sweden say they have discovered that copper, which is not typically known for its catalytic properties, had unexpectedly been responsible for catalytic activity as part of research into iron catalysts.
A sensor invented by Tufts University bioengineers, when attached temporarily to a tooth, could one day help dentists fine-tune treatments for patients with chronic periodontitis, for example, or even provide a window on a patient’s overall health. The thin foil-like sensor is built from gold, silk, and graphite, has a built-in antenna to receive power and signals, and is applied directly to a tooth.
When it comes to imaging, every single photon counts if there is barely any available light. This is the point where the latest technologies often reach their limits. Researchers have now developed a single photon avalanche photodiode that can read individual photons in just a few picoseconds. The speed allows the image sensor to capture high quality images with very low light levels.
Engineers in Israel have created a radically new design for a concentrator solar cell that, when irradiated from the side, generates solar conversion efficiencies which rival, and may eventually surpass, the most efficient photovoltaics. The design, the developers say, can exceed 40% conversion efficiency at intensities of 10,000 suns.
Conventional giant magnetoresistive devices or ferromagnetic tunnel junction devices provide only low frequency oscillation and have been deemed unsuitable for applications requiring millimeter-wave (30-300 GHz) oscillation, including radar. Researchers in Japan have recently demonstrated, however, that oscillations of 5 to 140 GHz is theoretically possible in these devices by supplying direct current.
Scientists at NIST have created the first controllable atomic circuit that functions analogously to a superconducting quantum interference device (SQUID) and allows operators to select a particular quantum state of the system at will. By manipulating atoms in a superfluid ring thinner than a human hair the investigators were able for the first time to measure rotation-induced discrete quantized changes in the atoms’ state, thereby providing a proof-of-principle design for an “atomtronic” inertial sensor.
Wireless sensor networks monitor machinery and equipment in factories, cars and power stations. They increasingly “harvest” the energy they need to transmit measurement data from the environment, thus making them self-sufficient. At the Electronica 2012 trade fair, researchers will present a printed thermogenerator, which they say will be able to generate energy supply for sensors through temperature differences.
An experimental device invented at the University of Michigan is able to convert energy from a beating heart, enough to provide electricity to power a pacemaker. The innovation, which relies on piezoelectricity, could eliminate the need for surgeries to replace pacemakers with depleted batteries.
Scientists have recently developed a high-performance superconducting material by mixing iron and selenium in a new chemistry. Although this class of superconductors has already existed, the new material is the first to break the 44 Kelvin barrier. It also shows that iron-selenium superconductors can be successfully synthesized to a high degree of purity.