Counterfeiters, beware! Scientists are reporting the development of a new type of inexpensive barcode that, when added to documents or currency, could foil attempts at making forgeries. Although the tags are easy for researchers to make, they still require ingredients you can’t exactly find at the local hardware store.
The chemistry of lithium-ion batteries limits how much energy they can store, and one promising solution is the lithium-sulfur battery, which can hold as much as four times more energy per mass. However, problematic polysulfides usually cause lithium-sulfur batteries to fail after a few charges. Researchers at Pacific Northwest National Laboratory, however, have developed a new powdery nanomaterial that could solve the issue.
Researchers in Finland have succeeded in creating a surface on nano-sized cellulose crystals that imitates a biological structure. The surface adsorbs viruses and disables them, preventing their spread into cells. The results could prove useful in the development of antiviral ointments and surfaces.
Researchers in California have created, for the first time, compounds made from mixtures of calcium hexaboride, strontium and barium hexaboride. They also demonstrated that these ceramic materials could be manufactured using a simple, low-cost manufacturing method known as combustion synthesis.
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.
One of the great problems in physics is the detection of electromagnetic radiation—that is, light—which lies outside the small range of wavelengths that the human eye can see. Think x-rays, for example, or radio waves. Now, researchers have discovered a way to use existing semiconductors to detect a far wider range of light than is now possible, well into the infrared range.
A house window that doubles as a solar panel could be on the horizon, thanks to recent quantum dot work by Los Alamos National Laboratory researchers in collaboration with scientists from Univ. of Milano-Bicocca, Italy. Their project demonstrates that superior light-emitting properties of quantum dots can be applied in solar energy by helping more efficiently harvest sunlight.
For more than a quarter of a century, high-temperature superconductors have perplexed scientists who seek to understand the physical phenomena responsible for their unique properties. Thanks to a new study by Argonne National Laboratory, researchers have identified and solved at least one paradox in the behavior of high-temperature superconductors.
Scientists at Yale Univ. have devised a dramatically faster way of identifying and characterizing complex alloys known as bulk metallic glasses (BMGs), a versatile type of pliable glass that's stronger than steel. Using traditional methods, it usually takes a full day to identify a single metal alloy appropriate for making BMGs.
For optical communication to happen, it is essential to convert electrical information into light, using emitters. On the other end of the optical link, one needs to translate the light stream into electrical signals using detectors. Current technologies use different materials to realize these two distinct functions, but this might soon change thanks to a new discovery by researchers at IBM.
Porous silicon manufactured in a bottom up procedure using solar energy can be used to generate hydrogen from water, according to a team of Penn State Univ. mechanical engineers, who also see applications for batteries, biosensors and optical electronics as outlets for this new material.
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.
In steel making, two desirable qualities, strength and ductility, tend to be at odds: Stronger steel is less ductile, and more ductile steel is not as strong. Engineers at Brown Univ., three Chinese universities, and the Chinese Academy of Sciences have shown that when cylinders of steel are twisted, their strength is improved without sacrificing ductility.
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.
Nanoengineering researchers at Rice Univ. and Nanyang Technological Univ. in Singapore have unveiled a potentially scalable method for making one-atom-thick layers of molybdenum diselenide—a highly sought semiconductor that is similar to graphene but has better properties for making certain electronic devices like switchable transistors and light-emitting diodes.
Materials scientists have long known that introducing defects into 3-D materials can improve their mechanical and electronic properties. Now a new Northwestern Univ. study finds how defects affect 2-D crystalline structures, and the results hold information for designing new materials.
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.
Solid-state dye-sensitized solar cells have shown their potential in achieving high efficiency with a low cost of fabrication. Degradation of these cells shortens lifespan dramatically, however, and the causes of this are not well understood. After a detailed analysis, researchers in Okinawa have determined which material in the cells was degrading, and why.
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.
Carbon nanotubes are reinforcing bars that make 2-D graphene much easier to handle in a new hybrid material grown by researchers at Rice Univ. The Rice laboratory of chemist James Tour set nanotubes into graphene in a way that not only mimics how steel rebar is used in concrete but also preserves and even improves the electrical and mechanical qualities of both.
In the future, the clothes you wear could be made from sugar. Researchers have discovered a new chemical process that can convert adipic acid directly from sugar.
In the ongoing search for new materials for fuel cells, batteries, photovoltaics, separation membranes, and electronic devices, one newer approach involves applying and managing stresses within known materials to give them dramatically different properties.
Biomass is a good alternative for fossil fuels, but converting biomass into useful chemicals and fuels is difficult in practice. The metal oxide CeO2 can help the process by activating water, but until recent research in the Netherlands, it was not clear in which form the reactivity of this catalyst was highest.
Recent research in Japan, China and U.S. has revealed through theoretical simulations that the molecular mechanism of carbon nanotube growth and hydrocarbon combustion actually share many similarities. In studies using acetylene molecules as feedstock, a highly reactive molecular intermediate was found to play an important role in both processes forming CNTs and soot, which are two distinctively different structures.