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.
Germanium monosulfide (GeS) is emerging as one of the most important class "IV–VI" semiconductor materials with potential in optoelectronics applications for telecommunications and computing. Adding a new element of control to preparation of this material, researchers in China have found a convenient way to selectively prepare GeS nanostructures, including nanosheets and nanowires, that are more active than their bulk counterparts
Using an acoustic metadevice that can influence the acoustic space and can control any of the ways in which waves travel, engineers have demonstrated, for the first time, that it is possible to dynamically alter the geometry of a 3-D colloidal crystal in real time. The crystals designed in the study, called metamaterials, are artificially structured materials that extend the properties of naturally occurring materials and compounds.
Combatting the tissue degrading enzymes that cause lasting damage following a heart attack is tricky. Each patient responds to a heart attack differently and damage can vary from one part of the heart muscle to another, but existing treatments can’t be fine-tuned to deal with this variation. Univ. of Pennsylvania researchers have developed a way to address this problem via a material that can be applied directly to the damaged heart tissue.
Researchers in Sweden have designed a paper filter which is capable of removing virus particles with the efficiency matching that of the best industrial virus filters. The paper filter, which is manufactured according to traditional paper making processes, consists of 100% high purity cellulose nanofibers directly derived from nature.
The fundamental laws of thermodynamics do not apply to objects on the nanoscale to the extent they do in our macroscopic world, and researchers are working to accurately describe the differences. A team of scientists have recently made progress in this area by determining how heat transfers from cold to hot objects in the nanoworld.
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.
The shells of a sea creature, the mollusk Placuna placenta, are not only exceptionally tough, but also clear enough to read through. Now, researchers at Massachusetts Institute of Technology have analyzed these shells to determine exactly why they are so resistant to penetration and damage; even though they are 99% calcite, a weak, brittle mineral.
Polymer materials are usually thermal insulators. But by harnessing an electropolymerization process to produce aligned arrays of polymer nanofibers, researchers have developed a thermal interface material able to conduct heat 20 times better than the original polymer. The modified material can reliably operate at temperatures of up to 200 C.
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.
A research team led by SLAC National Accelerator Laboratory scientists has uncovered a potential new route to produce thin diamond films for a variety of industrial applications, from cutting tools to electronic devices to electrochemical sensors. The scientists added a few layers of graphene to a metal support and exposed the topmost layer to hydrogen.