Vanadium dioxide is called a "wacky oxide" because it transitions between a conducting metal and an insulating semiconductor and with the addition of heat or electrical current. A device created by Penn State engineers uses a thin film of vanadium oxide on a titanium dioxide substrate to create an oscillating switch that could form the basis of a computational device that uses a fraction of the energy necessary for today’s computers.
As news reports of lithium-ion battery (LIB) fires in Boeing Dreamliner planes and Tesla electric cars remind us, these batteries, which are in everyday portable devices, like tablets and smartphones, have their downsides. Now, scientists have designed a safer kind of lithium battery component that is far less likely to catch fire and still promises effective performance.
An experiment sponsored for students by the European Space Agency has recently shown that carbon nanomaterials are built differently under conditions of hypergravity. They found that there was a distinct change in nanostructures that were built at 1g , 6g and 15g. Both surface growth and volume growth were observed at the higher gravity levels.
Northwestern Univ. researchers are the first to develop a new solar cell with good efficiency that uses tin instead of lead perovskite as the harvester of light. The low-cost, environmentally friendly solar cell can be made easily using "bench" chemistry, with no fancy equipment or hazardous materials.
Current approaches to flexible electronics, in which very thin semiconductor materials are applied to a thin, flexible substrate in wavy patterns and then applied to a deformable surface such as skin or fabric, are still built around hard composite materials that limit their elasticity. Researchers in California have made several discoveries, however, that could lead to electronics that are "molecularly stretchable."
Transparent conductive (TCO) films, present in tablets, laptops, flat screens and solar cells, are now an integral part of our lives. Yet they are expensive and complex to manufacture. Researchers in Europe have recently succeeded in developing a method of producing TCO films that relies on molecular self-organization. The technique is cheaper, simpler and more environmentally friendly than the traditional sputtering approach.
By combining the powers of two single-atom-thick carbon structures, researchers at the George Washington Univ.'s Micro-propulsion and Nanotechnology Laboratory have created a new ultracapacitor that is both high performance and low cost. The device capitalizes on the synergy brought by mixing graphene flakes with single-walled carbon nanotubes, two carbon nanostructures with complementary properties.
Scientists are facing a number of barriers as they try to develop circuits that are microscopic in size, including how to reliably control the current that flows through a circuit that is the width of a single molecule. Recent work at the Univ. of Rochester may have solved this problem through the addition of a second, inert layer of molecules that can act like a plastic casing on the wires.
Recent research using free-electron laser sources has enhanced the understanding of the interface of two materials, where completely new properties can arise. For instance, two insulators and non-magnetic materials can become metallic and magnetic at their interface. The breakthrough was the discovery of a discrepancy in the number of charge carriers of two promising electronic materials.
Traditionally, scientists discover new materials, and then probe them to understand their properties. Theoretical materials physicist Craig Fennie does it in reverse. He creates new materials by employing a "first principles" approach based on quantum mechanics, in which he builds materials atom by atom, starting with mathematical models, in order to gain the needed physical properties.
Recent experiments in Austria have explained the behavior of electrons at tiny step edges on titanium oxide surfaces. The finding, which shows why oxygen atoms attach so well to these edges, is important for solar cell technology and novel, more effective catalysts.
Using a new trick, researchers in Germany have been able to induce synchronous motion of the domain walls in a ferromagnetic nanowire. This is an important breakthrough for controlled movement of domain walls that allows permanent data to be stored using nanomagnets. The advance involved applying a pulsed magnetic field that was perpendicular to the plane of the domain walls.
New research shows that nanostructures could enable more light to be directed into the active layer of solar cells, increasing their efficiency. Prof. Martina Schmid of Freie Univ. in Berlin has measured how irregularly distributed silver particles influence the absorption of light. Nanoparticles interact with one another via their electromagnetic near-fields, so that local “hot spots” arise where light is concentrated especially strongly.
A new theoretical study shows the conductivity conditions under which graphene nanoribbons can become switches in externally controlled electronic devices. The results, obtained by researchers in Argentina and Brazil, yield a clearer theoretical understanding of conductivity in graphene samples of finite size, which have applications in externally controlled electronic devices.
Chemists have found that cellulose, the most abundant organic polymer on Earth, can be heated in a furnace in the presence of ammonia and turned into the building blocks for supercapacitors. The new process produces nitrogen-doped, nanoporous carbon membranes, which act as the electrodes of a supercapacitor. The only byproduct is methane, which could be used immediately as a fuel or for other purposes.
Engineers have demonstrated thin, soft stick-on patches that stretch and move with the skin and incorporate commercial, off-the-shelf chip-based electronics for sophisticated wireless health monitoring.
A medical device, once its job is done, could harmlessly melt away inside a person’s body. Or, a military device could collect and send its data and then dissolve away, leaving no trace of an intelligence mission. Or, an environmental sensor could collect climate information, then wash away in the rain. It’s a new way of looking at electronics.
Interest in oxide-based semiconductor electronics has exploded in recent years, fueled largely by the ability to grow atomically precise layers of various oxide materials. One of the most important materials in this burgeoning field is strontium titanate, a nominally nonmagnetic wide-bandgap semiconductor, and researchers have found a way to magnetize this material using light, an effect that persists for hours at a time.
New research on perovskite-based solar cells pioneered in the U.K. suggests that they can double up as a laser as well as photovoltaic device. By sandwiching a thin layer of the lead halide perovskite between two mirrors, the Univ. of Cambridge team produced an optically driven laser which proves these cells “show very efficient luminescence”, with up to 70% of absorbed light re-emitted.
Topological insulators are considered a very promising material class for the development of future electronic devices because they are insulators inside but conductors at the surface. A research team in Germany has discovered how light can be used to alter the physical properties of the electrons in these materials by using it to alter electron spin at the surface.
Lithium-ion batteries power a vast array of modern devices, from cell phones, laptops, and laser pointers to thermometers, hearing aids, and pacemakers. The electrodes in these batteries typically comprise three components: active materials, conductive additives, and binders. Now, a team of researchers at the Univ. of Delaware has discovered a “sticky” conductive material that may eliminate the need for binders.
In what was almost a chance discovery, researchers in Singapore have developed a solar cell material which can emit light in addition to converting light to electricity. This solar cell is developed from perovskite, a promising material that could hold the key to creating high-efficiency, inexpensive solar cells. The new cells not only glow when electricity passes through them, they can also be customized to emit different colours.
Imagine a computer so efficient that it can recycle its own waste heat to produce electricity. While such an idea may seem far-fetched today, significant progress has already been made to realize these devices. Researchers at the Univ. of Utah have fabricated spintronics-based thin film devices which do just that, converting even minute waste heat into useful electricity.
Researchers in California have used a beam of intense ultraviolet light to look deep into the electronic structure of a material made of alternating layers of graphene and calcium. While it's been known for nearly a decade that this combined material is superconducting, the new study offers the first compelling evidence that the graphene layers are instrumental in this process. The finding could lead to super-efficient nanoelectronics.
Organic solar cells are a compelling thin-film photovoltaic technology in part because of their compatibility with flexible substrates and tunable absorption window. Belgium-based chipmaker imec has set a new conversion efficiency record of 8.4% for this type of cell by developing fullerene-free acceptor materials and a new multilayer semiconductor device structure.