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.
By applying pressure to a semiconductor, researchers have been able to transform a semiconductor into a “topological insulator” (TI), an intriguing state of matter in which a material’s interior is insulating but its surfaces or edges are conducting with unique electrical properties. This is the first time that researchers have used pressure to gradually “tune” a material into the TI state.
Hydrogen is a “green” fuel that burns cleanly and can generate electricity via fuel cells. One way to sustainably produce hydrogen is by splitting water molecules using the renewable power of sunlight, but scientists are still learning how to control and optimize this reaction with catalysts. At the National Synchrotron Light Source, a research group has determined key structural information about a potential catalyst.
Sometimes big change comes from small beginnings. That’s especially true in the research of Anatoly Frenkel, a prof. of physics at Yeshiva Univ., who is working to reinvent the way we use and produce energy by unlocking the potential of some of the world’s tiniest structures: nanoparticles.
As microelectronics get smaller and smaller, one of the biggest challenges to packing a smartphone or tablet with maximum processing power and memory is the amount of heat generated by the tiny “switches” at the heart of the device. A complex metal-oxide film could help reduce the voltage required to switch electronic signals, and thus the excessive energy they require.
When it comes to designing extremely water-repellent surfaces, shape and size matter. That's the finding of a group of scientists at Brookhaven National Laboratory, who investigated the effects of differently shaped, nanoscale textures on a material's ability to force water droplets to roll off without wetting its surface.
Scientists at Brookhaven National Laboratory have developed a general approach for combining different types of nanoparticles to produce large-scale composite materials. The technique opens many opportunities for mixing and matching particles with different magnetic, optical or chemical properties to form new, multifunctional materials or materials with enhanced performance for a wide range of potential applications.
Scientists at Brookhaven National Laboratory have identified the key genes required for oil production and accumulation in plant leaves and other vegetative plant tissues. Enhancing expression of these genes resulted in vastly increased oil content in leaves, the most abundant sources of plant biomass—a finding that could have important implications for increasing the energy content of plant-based foods and renewable biofuel feedstocks.
Kids grumble about homework. But their complaints will hold no water with a group of theoretical physicists who’ve spent almost 50 years solving one homework problem: a calculation of one type of subatomic particle decay aimed at helping to answer the question of why the early universe ended up with an excess of matter. Without that excess, the matter and antimatter created in the Big Bang would have completely annihilated one another.
Carbon monoxide is a poisoning impurity in hydrogen derived from natural gas. If a catalyst could be developed that can handle this impure fuel, it could be a substantially less expensive alternative to pure hydrogen produced from water. Scientists at Brookhaven National Laboratory have used a simple, “green” process to create a new core-shell catalyst that tolerates carbon monoxide in fuel cells.
To get a better understanding of the subatomic soup that filled the early universe, and how it “froze out” to form the atoms of today’s world, scientists are taking a closer look at the nuclear phase diagram. Like a map that describes how the physical state of water morphs from solid ice to liquid to steam with changes in temperature and pressure, the nuclear phase diagram maps out different phases of the components of atomic nuclei.
Researchers at Brookhaven National Laboratory and Stony Brook Univ. have developed a way to map out the degree of "traffic congestion" on the electron highways within the photoactive layer of organic solar cells. Their new measurement and tracking technique uses optical-guided modes to help scientists better understand how the materials used in the photoactive layers influence the speed and efficiency of electron travel.
The international Daya Bay Collaboration has announced new results about the transformations of neutrinos. The latest findings include the collaboration’s first data on how neutrino oscillation, in which neutrinos mix and change into other “flavors,” or types, as they travel, varies with neutrino energy, allowing the measurement of a key difference in neutrino masses known as mass splitting.
Scientists at Brookhaven National Laboratory have discovered an unexpected and anomalous pattern in the behavior of one high-performing class of HTS materials. In the new frontier of interface physics, two non-conducting materials can be layered to produce HTS behavior, with tantalizing and mystifying results.
Scientists at Brookhaven National Laboratory and other collaborating institutions have discovered a surprising twist in the magnetic properties of high-temperature superconductors, challenging some of the leading theories. In a new study, scientists found that unexpected magnetic excitations—quantum waves believed by many to regulate HTS—exist in both non-superconducting and superconducting materials.
It skipped tolls. It had a Twitter hashtag and a GPS tracker. It even posed for photos with groupies. Yet the 15-ton shrink-wrapped cargo remained a mystery to most who saw it along the slow, delicate 3,200-mile journey from New York to suburban Chicago. Now that it has arrived at the Fermi National Accelerator Laboratory, the giant electromagnet will be unveiled to help study fast particles.
Catalysts are everywhere. They make chemical reactions that normally occur at extremely high temperatures and pressures possible within factories, cars and the comparatively balmy conditions within the human body. Developing better catalysts, however, is mainly a hit-or-miss process. Now, researchers have shown a way to precisely design the active elements of a certain class of catalysts.
More than a decade ago, two researchers uncovered a counter-intuitive property of zeolites. When they put these porous minerals in water, and then put the water under high pressure, the tiny cavities within the zeolites actually grew in size. Recent x-ray diffraction studies by the team have revealed the interior geometry of the cavities and the arrangement of the cations and water molecules held within, before and after pressurization.
In the search for understanding how some magnetic materials can be transformed to carry electric current with no energy loss, scientists have used an experimental technique to measure the energy required for electrons to pair up and how that energy varies with direction. The method measures energy levels as small as one ten-thousandth the energy of a single light photon.
The U.S. LHC Accelerator Program (LARP) has successfully tested a powerful superconducting quadrupole magnet that will play a key role in developing a new beam focusing system for CERN’s Large Hadron Collider (LHC). This advanced system, together with other major upgrades to be implemented over the next decade, will allow the LHC to produce 10 times more high-energy collisions than it was originally designed for.
In the constant push for smaller transistors, researchers have been investigating oxides with higher K, or dielectric constant, values. Materials such as germanium, hafnium, and titanium are being investigated for this role, but many prototypes leak electrons. At the National Synchrotron Light Source, x-rays are being used to probe the electronic behavior of a germanium-based transistor structure that could offer a solution.
Scientists at Brookhaven National Laboratory have identified two promising candidates for the development of drugs against human adenovirus, a cause of ailments ranging from colds to gastrointestinal disorders to pink eye. A recently published paper describes how the researchers sifted through thousands of compounds to determine which might block the effects of a key viral enzyme they had previously studied in atomic-level detail.
John Hill, a Brookhaven National Laboratory scientist, and his team watched with eager anticipation as controllers ramped up the power systems driving SLAC National Accelerator Laboratory's x-ray laser in an attempt to achieve the record high energies needed to make his experiment a runaway success. To reach the high x-ray energies they were aiming for, all of the 80 klystrons associated with LCLS would need to operate at near-peak levels.
Scientists on Long Island are preparing to move a 50-foot-wide electromagnet 3,200 miles over land and sea to its new home at the U.S. Department of Energy's Fermi National Accelerator Laboratory in Illinois. The trip, starting at Brookhaven National Laboratory, is expected to take more than a month.
Gold bars may signify great wealth, but gold packs a much more practical punch when shrunk down to nanoscale. Unfortunately, unlocking its potential often requires complex synthesis techniques that produce delicate structures with sensitivity to heat. Now, scientists have discovered a process of creating uniquely structured gold-indium nanoparticles that combine high stability, great catalytic potential and a simple synthesis process.