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.
A new study by Berkeley Lab researchers shows that nearly 90% of the electrons generated by a hybrid material designed to store solar energy in hydrogen are being stored in the target hydrogen molecules. Interfacing the semiconductor gallium phosphide with a cobaloxime catalyst provides an inexpensive photocathode for bionic leaves that produce energy-dense fuels from nothing more than sunlight, water and carbon dioxide.
A new mechanism of controlling magnetic states by electric currents has been discovered by an international team of researchers who have exploited a quantum phenomenon to control magnetic states with electrical currents. The research hinges on a quantum geometrical phase, called the Berry phase, that exists in the momentum space of electronic band structures in specific materials.
Light-emitting diodes (LEDs) are durable and save energy. Now, researchers have found a way to make LED lamps even more compact while supplying more light than commercially available models. The key to this advance are a new type of transistors made of the semiconductor material gallium nitride.
According to recent findings by an international team of computer engineers, optical data storage does not require expensive magnetic materials because synthetic alternatives work just as well. The team’s discovery that synthetic ferrimagnets can be switched optically brings a much cheaper method for storing data using light a step closer.
A Chinese-U.S. research team is exploring the use of metamaterials to create devices that manipulate sound in versatile and unprecedented ways. In a recently published paper, the team reports a simple design for a device, called an acoustic field rotator, which can twist wave fronts inside it so that they appear to be propagating from another direction.
Last year, a physicist and a mechanical engineer at Northeastern Univ. combined their expertise to integrate electronic and optical properties on a single electronic chip, enabling them to switch electrically using light alone. Now, they have built three new devices that implement this fast technology: an AND-gate, an OR-gate and a camera-like sensor made of 250,000 miniature devices.
There is a big effort in industry to produce electrical devices with more and faster memory and logic. Magnetic memory elements, such as in a hard drive, and in the future in what is called MRAM (magnetic random access memory), use electrical currents to encode information. However, the heat which is generated is a significant problem, since it limits the density of devices and hence the performance of computer chips.
An undesired effect in thin film amorphous silicon solar cells has puzzled the scientific community for the last 40 years. This effect, known as light-induced degradation, is responsible for reducing solar cell efficiency over time. Researchers in Germany have recently demonstrated that tiny voids within the silicon network are partly responsible for 10 to 15% efficiency loss as soon as they are used.
A team in France has greatly miniaturized the light-emitting diode (LED) by creating one from a single polythiophene wire placed between the tip of a scanning tunneling microscope and a gold surface. This nanowire, which is made of the same hydrogen, carbon and sulfur components found in much larger LEDs, emits light only when the current passes in a certain direction.
Modern electronics relies on utilizing the charge properties of the electron. The emerging field of atomtronics, however, uses ensembles of atoms to build analogs to electronic circuit elements. Physicists have built a superfluid atomtronic circuit that have allowed them to demonstrate a tool that is critical to electronics: hysteresis. It is the first time that hysteresis has been observed in an ultracold atomic gas.