Measuring the band offset faced by electrons jumping from one material to another is a key component of a nanoscale design process because it guides redesign and prototyping. Current methods don’t work on the nanoscale, however. Using laser-induced current in a nanowire device and its dependence on the wavelength of the laser, a team at Drexel Univ. devised a new method to derive the band offset.
Electronic devices with touchscreens rely on transparent conductors made of indium tin oxide, or ITO. But cost and the physical limitations of this material are limiting progress in developing flexible touchscreens. A research collaboration between the Univ. of Pennsylvania and Duke Univ. is exploring the use of nanowires to replace ITO, and are using simulation tools to determine how they might work.
Researchers not only confirmed several theoretical predictions about topological crystalline insulators (TCIs), but made a significant experimental leap forward that revealed even more details about the crystal structure and electronic behavior of these newly identified materials. The findings reveal the unexpected level of control TCIs can have over electrons by creating mass.
Titanium dioxide is an inexpensive, yet versatile material. The use of titanium oxide in the electronics industry is currently being investigated. An international team of researchers has confirmed theoretically-predicted interactions between single oxygen molecules and crystalline titanium dioxide and the implications of these findings could be important for a variety of applications.
Quantum point contacts in electrical circuits are narrow constrictions that can impede the passage of electrons in unexpected ways. Using a combination of experimental measurements and numerical modeling, physicists have recently provided the first detailed microscopic explanation of the associated conductance anomalies.
Researchers from the RIKEN Center for Life Science Technologies and Chiba Univ. have developed a high-temperature superconducting wire with an ultrathin polyimide coating only 4 micrometers thick, more than 10 times thinner than the conventional insulation used for high-temperature superconducting wires. The breakthrough should help the development of more compact superconducting coils for medical and scientific devices.
In recent years, thermoelectric materials have enabled the re-use of otherwise wasted thermal energy as electrical power. But this ability is limited to materials, typically complex crystals, exhibiting high electrical conductivity and low thermal conductivity. Scientists have now discovered a way of suppressing thermal conductivity in sodium cobaltate, opening new paths for energy scavenging.
A RMIT Univ. research collaboration with top scientists in Australia and Japan is advancing next-generation solar cells. Currently, cadmium or lead elements dominate colloidal nanocrystals synthesis, despite toxicity concerns. In its research, the team has discovered a new selective synthesis of tetrahedrite and famatinite copper antimony sulphide nanocrystals, which could be promising for printable solar cell applications.
Most solar cells today are inorganic and made of crystalline silicon. These cells tend to be expensive, rigid and relatively inefficient when it comes to converting sunlight into electricity. Work by a team of chemical engineers at Penn State Univ. and Rice Univ. may lead to a new class of inexpensive organic solar cells, one that skips difficult-to-scale fullerene acceptors and relies on molecular self-assembly instead.
A team led by Oak Ridge National Laboratory’s Amit Goyal, a former R&D Scientist of the Year, has demonstrated that superconducting wires can be tuned to match different operating conditions by introducing small amounts of non-superconducting material, or defects, that influences how the overall material behaves. A wire sample grown with this process exhibited new levels of performance in terms of engineering critical current density.
Researchers in Israel have developed a simple magnetization progress that depends on electron spin to eliminate the need for permanent magnets in memory devices. The new technique, called magnetless spin memory (MSM), drives a current through chiral material and selectively transfers electrons to magnetize nanomagnetic layers or nanoparticles.
Polymer, or plastic, solar cells contain Earth-abundant and environmentally benign materials, can be made flexible and lightweight, and can be fabricated using roll-to-roll technologies. But the cells’ power-conversion efficiency has been limited. A Northwestern Univ. research reports the design and synthesis of new polymer semiconductors a plastic solar cells with fill factors of 80%. This number is close to that of silicon solar cells.
Flexible thin film solar cells that can be produced by roll-to-roll manufacturing are a highly promising route to cheap solar electricity. Researchers in Switzerland report that they have designed a low-cost cadmium telluride solar cell technology based on metal foil substrates. By doping the cells with cooper, they have elevated efficiency from 8 to 11.5%.
What happens to a resonant wireless power transfer system in the presence of complex electromagnetic environments, such as metal plates? A team of researchers has explored the influences at play in this type of situation, and they describe how efficient wireless power transfer can be achieved in the presence of metal plates.
Many of today’s semiconductor technologies hinge upon the absorption of light. Absorption is critical for nano-sized structures at the interface between two energy barriers called quantum wells, in which the movement of charge carriers is confined to two dimensions. Working with the semiconductor indium arsenide, a team of researchers has discovered a quantum unit of photon absorption that should be general to all 2-D semiconductors.
Using a simple solar cell and a photo anode made of a metal oxide, scientists in Europe have successfully stored nearly 5% of solar energy chemically in the form of hydrogen. The significance of the advance is based on the design of the solar cell, which is much simpler than that of the high-efficiency triple-junction cells based on amorphous silicon or class III-V semiconductors.
Scientists in Spain have developed a cementitious material incorporating carbon nanofibers in its composition, turning cement into an excellent conductor of electricity capable of performing functions beyond its usual structural function. The transformation relies on the addition of carbonaceous materials.
Researchers in South Korea have reported the development of a new plasmonic material that can be applied to both polymer light-emitting diodes (PLEDs) and polymer solar cells (PSCs), resulting in high performance from a low-cost fabrication process. They say the material is easy to synthesize with basic equipment and has low-temperature solution processability.
Flexible electronics have a wide variety of possibilities, from bendable displays and batteries to medical implants that move with the body. Networks of spherical nanoparticles embedded in elastic materials may make the best stretchy conductors yet, engineering researchers at the Univ. of Michigan have discovered.
Researchers at Arizona State Univ. have successfully manufactured the world’s largest flexible color organic light emitting display prototype using advanced mixed oxide thin film transistors. Measuring 7.4 diagonal inches, the device was developed at ASU’s Flexible Display Center in conjunction with Army Research Labs scientists.
Antennas that are capable of transmitting radio waves turn components into intelligent objects. Researchers in Germany have now found a way to embed these antennas in fiber composites. As a result, the technology also works with carbon and glass fibers.
Using carpets of aligned carbon nanotubes, researchers from Rice University and Sandia National Laboratories have created a solid-state electronic device that is hardwired to detect polarized light across a broad swath of the visible and infrared spectrum.
The Air Force Office of Scientific Research has been working with Jim Tour’s laboratory at Rice University to make graphene suitable for a variety of organic chemistry applications. Recently, the partnership made another technological advance. Their work has shown that graphene nanoribbons can significantly increase the storage capacity of lithium ion by combining these 2D ribbons with tin oxide.
A team led by Rice University chemist James Tour has built a 1-kilobit rewritable device with diodes that eliminate data-corrupting crosstalk. This chip, which uses cheap, plentiful silicon oxide to store data, shows it should be possible to surpass the limitations of flash memory in packing density, energy consumption per bit and switching speed.
A research collaboration in Europe is the first to successfully create perfect 1-D molecular wires of which the electrical conductivity can almost entirely be suppressed by a weak magnetic field at room temperature. The underlying mechanism is possibly closely related to the biological compass used by some migratory birds to find their bearings in the geomagnetic field.