Inspired by how beetles and tree frogs keep their feet attached to submerged leaves, researchers in Singapore have revealed a new method that allows both the growth and transfer steps of graphene on a silicon wafer. This technique enables the graphene to be applied in photonics and electronics, for devices such as optoelectronic modulators, transistors, on-chip biosensors, and tunnelling barriers.
A research group based in Japan has succeeded for the first time in fabricating a 3-D structure of a quasicrystal composed of a single element. Discovered in 1984, quasicrystals have been found in more than 100 kinds of alloy, polymer and nanoparticle systems. However, a quasicrystal composed of a single element has not yet been found.
In two complementary studies, an international team of physicists has now established that superconductivity in high-temperature superconductors, known as cuprates, collapses at a maximum of -135 C due to the formation of charge-density waves. Consequently, in order to find superconductors that drop to zero resistance at realistic temperatures, materials scientists must search for substances that are not subject to charge-density waves.
According to new research at the Massachusetts Institute of Technology, graphene, under an extremely powerful magnetic field and at extremely low temperature, can effectively filter electrons according to the direction of their spin. This is something that cannot be done by any conventional electronic system and could render graphene suitable for exotic uses such as quantum computing.
In earlier studies, a team from the Univ. of Pennsylvania produced nanoscale grids and rings of “defects,” or useful disruptions in the repeating patterns found in liquid crystals. Their latest study adds a more complex pattern out of an even simpler template: A 3-D array in the shape of a flower. This advances the use of liquid crystals as a medium for assembling structures.
A team of researchers with Lawrence Berkeley National Laboratory has demonstrated a micro-sized robotic torsional muscle/motor made from vanadium dioxide that for its size is a thousand times more powerful than a human muscle. It is able to catapult objects 50 times heavier than itself over a distance five times its length within just 60 milliseconds.
Researchers from the Max Planck Institute for Intelligent Systems in Stuttgart have developed a new method for the active degradation of organic pollutants in solution by using swimming microengines. These tiny “engines” are made from platinum and iron and are highly efficient in removing organic pollutants from water using hydrogen peroxide.
In 2007 and 2008, two research papers reported in the journal Nature that a suite of zircons from the Jack Hills included diamonds, requiring a radical revision of early Earth history. The papers posited that the diamonds formed, somehow, before the oldest zircons, or more than 4.3 billion years ago. A research team now claims the oldest “diamonds” on the Earth are simply fragments of polishing compound.
A new method for extracting titanium significantly reduces the energy required to separate it from its tightly bound companion, oxygen. Scientists have discovered that they could eliminate the energy-intensive steps of the Kroll process, a finding that could lower cost and accessibility of future titanium products.
Quantum dots have potential for applications that make use of their ability to absorb or emit light and/or electric charges. Examples include more vividly colored light-emitting diodes (LEDs), photovoltaic solar cells, nanoscale transistors and biosensors. But because these applications have differing, sometimes opposite, requirements, finding ways to control the dots’ optical and electronic properties is crucial to their success.
Modern epoxies are frequently made stronger, lighter and more resilient with the addition of multiwalled carbon nanotubes (MWCNTs), a special form of carbon that under a microscope looks like rolls of chicken wire. Few analytical methods have been employed, however, to determine the effect this material has on environmental or health safety. NIST has developed a suite of tests for evaluating the performance of these nanocomposite materials.
Supramolecular chemistry is just beginning to come into its own with the emergence of nanotechnology. Metal organic frameworks (MOFs) are commanding much of the attention because of their appetite for greenhouse gases, but a new player has joined the field—supramolecular organic frameworks (SOFs). Researchers have unveiled the first 2-D SOFs that self-assemble in solution.
The Ulsan National Institute of Science and Technology in Korea has developed a new method for the mass production of boron/nitrogen co-doped graphene nanoplatelets, which could lead to the fabrication of a graphene-based field-effect transistor with semiconducting nature. This opens up opportunities for practical use in electronic devices.
Lithium-ion batteries could have significantly higher energy density if their graphite anodes were to be replaced by lithium metal anodes. Hampering this change, however, has been the persistent growth of dendrites that eventually short-circuit the battery. Researchers have recently discovered that the bulk of dendrite material lies below the surface of the lithium electrode, underneath the electrode/electrolyte interface.
Graphene, a two-dimensional array of carbon atoms, has shown great promise for a variety of applications, but for many suggested uses the material requires treatments that can be expensive and difficult to apply predictably. Now, a team of researchers has found a simple, inexpensive treatment that may help to unleash the material’s potential.
Stanene is the name given by researchers to 2-D sheets of tin that are only one atom thick. A Stanford Univ. team predicts stanene would be the first topological insulator to demonstrate zero heat dissipation properties at room temperature, conducting charges around its edges without any loss. Experiments are underway to create the material in the laboratory. If successful, stanene will enhance devices being built under a DARPA program.
Researchers have created a new type of molecular motor made of DNA and demonstrated its potential by using it to transport a nanoparticle along the length of a carbon nanotube. The design was inspired by natural biological motors that have evolved to perform specific tasks critical to the function of cells.
Ribbons of ultrathin graphene combined with polyurethane paint meant for cars is just right for deicing sensitive military radar domes, according to scientists at Rice Univ. The Rice lab of chemist James Tour, in collaboration with Lockheed Martin, developed the compound to protect marine and airborne radars with a robust coating that is also transparent to radio frequencies.
Metal-organic frameworks (MOFs) are commanding considerable research attention because of their appetite for greenhouse gases. But now supramolecular organic frameworks (SOFs), held together by non-covalent bonds, have joined the field. Researchers have unveiled the first 2-D SOFs that self-assemble in solution, an important breakthrough that holds implications for sensing, separation technologies, and biomimetics.
Medical diagnostics seeks to learn early on whether a serious disease is developing or what its course will be. In many cases, treacherous molecules are present only in trace amounts, however. Researchers in Germany have come up with a new method of detection which has allowed them to notice the presence of only 17 dye molecules. The highly sensitive method might one day be used to scan a tiny drop of blood for potential diseases.
Scientists from the Hamburg Center for Free-Electron Laser Science have devised a novel way to boil water in less than a trillionth of a second. The theoretical concept, which uses terahertz radiation but has not yet been demonstrated in practice, could heat a small amount of water by as much as 600 C in just half a picosecond.
The goal of fabricating fixed-size one-dimensional silica structures and being able to precisely control the diameter during growth has long eluded scientists. Now, Oak Ridge National Laboratory researchers Panos Datskos and Jaswinder Sharma have demonstrated what they describe as the addressable local control of diameter of each segment of the silica rod.
The same tiny cellulose crystals that give trees and plants their high strength, light weight and resilience, have now been shown to have the stiffness of steel. Calculations using precise models based on the atomic structure of cellulose show the crystals have a stiffness of 206 gigapascals, which is comparable to steel.
Physicists in Germany have developed a “planet-satellite model” to precisely connect and arrange nanoparticles in 3-D structures. Inspired by the photosystems of plants and algae, these artificial nanoassemblies of DNA strands might in the future serve to collect and convert energy.
Scientists working to advance imaging useful to medicine and security are capitalizing on the same phenomenon behind the lingering "ghost" image that appeared on old television screens. A team of researchers has created a way to control the length of time light from a luminescent nanocrystal lingers, adding a new dimension of time to color and brightness in optical detection technology.