It’s a well-known phenomenon in electronics: Shining light on a semiconductor, such as the silicon used in computer chips and solar cells, will make it more conductive. But now researchers have discovered that in a special semiconductor, light can have the opposite effect, making the material less conductive instead. This new mechanism of photoconduction could lead to next-generation excitonic devices.
Axons are the shafts of neurons, on the tips of which connections are made with other neurons or cells. In a new study in Texas, researchers were able to use microfluidic stimulations to change the path of an axon at an angle of up to 90 degrees. The publication adds insight to the long accepted idea that chemical cues are primarily responsible for axonal pathfinding during human development and nervous system regeneration.
Massachusetts Institute of Technology researchers have developed a new way of creating surfaces on which droplets of any desired shape can spontaneously form. They say this approach could lead to new biomedical assay devices and light-emitting diode display screens, among other applications. The new work represents the first time that scientists can control the shape of the contact area of the droplets.
Imagine being able to tune the properties of a solid material just by flashing pulses of light on it. That is one potential payoff of electrons and atoms interacting with ultrashort pulses of light. The technology of ultrafast spectroscopy is a key to understanding this phenomenon and now a new wrinkle to that technology, observations of electron self-energy, has been introduced by Lawrence Berkeley National Laboratory researchers.
Nanoparticles could revolutionize the medical industry, but they must first target a specific region in the body, be trackable, and perform their function at the right moment. Researchers in Japan have made progress in this direction with a new type of nanomaterial: the nanosheet. Specifically, they have designed a strong, stable and optically traceable smart 2-D material that responds to pH, or the acidity or basicity of its environment.
Arrays of tiny conical tips that eject ionized materials are being made at the Massachusetts Institute of Technology. The technology, which harnesses electrostatic forces, has a range of promising applications, such as spinning out nanofibers for use in “smart” textiles or propulsion systems for fist-sized “nanosatellites.” The latest prototype array that generates 10 times the ion current per emitter that previous arrays did.
Individuals in industrial associations, educational institutions and government organizations who are interested in composites, or materials made from constituent materials with different physical or chemical properties, now have free, 24/7 access to simulation tools through an online community with offices in the Purdue Research Park.
You can brush your teeth, and wash yourself and your clothes with a clear conscience. The most common soaps, shampoos and detergents actually pose a minimal risk to the environment. This is the conclusion of a comprehensive survey that covers more than 250 scientific studies over several decades.
The world’s first “solar battery”, invented by researchers at Ohio State Univ., is a battery and a solar cell combined into one hybrid device. Key to the innovation is a mesh solar panel, which allows air to enter the battery, and a special process for transferring electrons between the solar panel and the battery electrode. Inside the device, light and oxygen enable different parts of the chemical reactions that charge the battery.
Nanostructures of virtually any possible shape can now be made using a combination of techniques developed to exploit the unique properties of so-called perovskites. The group based in the Netherlands, developed a pulsed laser deposition technique to create patterns in ultra thin layers, one atomic layer at a time. The perovskites’ crystal structure is undamaged by this soft lithography technique, maintaining electrical conductivity.
Drawn relentlessly by their electrical charges, lithium ions in a battery surge from anode to cathode and back again. Yet, no one really understands what goes on at the atomic scale as lithium ion batteries are used and recharged. Using transmission electron microscopy, researchers are now glimpsing what can happen to anodes as lithium ions work their way into them. The “atomic shuffling” these ions perform leads to rapid anode failure.
A Duke Univ. team has found that nanoparticles called single-walled carbon nanotubes accumulate quickly in the bottom sediments of an experimental wetland setting, an action they say could indirectly damage the aquatic food chain. According to the research, the risk to humans ingesting the particles through drinking water is slight, but aquatic food chains might be harmed by molecules "piggybacking" on the carbon nanoparticles.
Cancer vaccines have recently emerged as a promising approach for killing tumor cells before they spread. But so far, most clinical candidates haven’t worked that well. Now, scientists have developed a new way to deliver vaccines that successfully stifled tumor growth when tested in laboratory mice. And the key is in the vaccine’s unique stealthy nanoparticles.
Ice contains many atoms and molecules trapped inside its structure. A team of Univ. of Chicago and Loyola Univ. researchers has discovered a new mechanism they call "stable energetic embedding" of atoms and molecules within ice. This mechanism explains how some molecules, such as CF4, or "carbon tetrafluoride", interact with and become embedded beneath ice surfaces.
Graphene quantum dots created at Rice Univ. grab onto graphene platelets like barnacles attach themselves to the hull of a boat. But these dots enhance the properties of the mothership, making them better than platinum catalysts for certain reactions within fuel cells.
Mathematicians from Brown Univ. have introduced a new element of uncertainty into an equation used to describe the behavior of fluid flows. Ironically, allowing uncertainty into a mathematical equation that models fluid flows makes the equation much more capable of correctly reflecting the natural world, including the formation, strength, and position of air masses and fronts in the atmosphere.
In a rare case of having their cake and eating it too, scientists from NIST and other institutions have developed a toolset that allows them to explore the complex interior of tiny, multi-layered batteries they devised. It provides insight into the batteries’ performance without destroying them, which results in both a useful probe for scientists and a potential power source for micromachines.
A novel x-ray technique used at the U.S. Department of Energy’s Advanced Photon Source has revealed surprising dynamics in the nanomechanics of operating batteries and suggests a way to mitigate battery failures by minimizing the generation of elastic energy. The method could open a path to wider use of these batteries in conjunction with renewable energy sources.
A little change in temperature makes a big difference for growing a new generation of hybrid atomic-layer structures, according to scientists. Rice Univ. scientists led the first single-step growth of self-assembled hybrid layers made of two elements that can either be side by side and one-atom thick or stacked atop each other. The structure’s final form can be tuned by changing the growth temperature.
The key to creating a material that would be ideal for converting solar energy to heat is tuning the material’s spectrum of absorption just right: It should absorb virtually all wavelengths of light that reach Earth’s surface from the sun—but not much of the rest of the spectrum, since that would increase the energy that is reradiated by the material, and thus lost to the conversion process.
Electricity and magnetism rule our digital world. Semiconductors process electrical information, while magnetic materials enable long-term data storage. A Univ. of Pittsburgh research team has discovered a way to fuse these two distinct properties in a single material, paving the way for new ultrahigh density storage and computing architectures.
The excessive atmospheric carbon dioxide that is driving global climate change could be harnessed into a renewable energy technology that would be a win for both the environment and the economy. That is the lure of artificial photosynthesis in which the electrochemical reduction of carbon dioxide is used to produce clean, green and sustainable fuels.
Concrete can be better and more environmentally friendly by paying attention to its atomic structure, according to researchers at Rice Univ., the Massachusetts Institute of Technology and Marseille Univ. The international team of scientists has created computational models to help concrete manufacturers fine-tune mixes for general applications.
If it's true that good things come in small packages, then NIST can now make anyone working with nanoparticles very happy. The institute recently issued Reference Material (RM) 8027, the smallest known reference material ever created for validating measurements of man-made, ultrafine particles between 1 and 100 nm in size.
Blue organic light-emitting diodes (OLEDs) are one of a trio of colors used in OLED displays such as smartphone screens and high-end TVs. In a step that could lead to longer battery life in smartphones and lower power consumption for large-screen televisions, researchers at the Univ. of Michigan have extended the lifetime of blue organic light emitting diodes by a factor of 10.