Tag Archives: crystals

Scientists grow organic semiconductor crystals vertically for first time

UCLA-led breakthrough could literally reshape solar cells and electronic devices

Our smartphones, tablets, computers and biosensors all have improved because of the rapidly increasing efficiency of semiconductors. (more…)

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New Advance in Biofuel Production

Joint BioEnergy Institute Researchers Develop Enzyme-free Ionic Liquid Pre-treatment

Advanced biofuels – liquid fuels synthesized from the sugars in cellulosic biomass – offer a clean, green and renewable alternative to gasoline, diesel and jet fuels. Bringing the costs of producing these advanced biofuels down to competitive levels with petrofuels, however, is a major challenge. Researchers at the U.S. Department of Energy (DOE)’s Joint BioEnergy Institute (JBEI), a bioenergy research center led by Berkeley Lab, have taken another step towards meeting this challenge with the development of a new technique for pre-treating cellulosic biomass with ionic liquids – salts that are liquids rather than crystals at room temperature. This new technique requires none of the expensive enzymes used in previous ionic liquid pretreatments, and makes it easier to recover fuel sugars and recycle the ionic liquid. (more…)

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Researchers Create Semiconductor ‘Nano-Shish-Kebabs’ With Potential for 3-D Technologies

Researchers at North Carolina State University have developed a new type of nanoscale structure that resembles a “nano-shish-kebab,” consisting of multiple two-dimensional nanosheets that appear to be impaled upon a one-dimensional nanowire. However, the nanowire and nanosheets are actually a single, three-dimensional structure consisting of a seamless series of germanium sulfide (GeS) crystals. The structure holds promise for use in the creation of new, three-dimensional (3-D) technologies.

The researchers believe this is the first engineered nanomaterial to combine one-dimensional and two-dimensional structures in which all of the components have a shared crystalline structure. (more…)

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Crystals for Efficient Refrigeration

Washington, D.C.-– Researchers at the Carnegie Institution have discovered a new efficient way to pump heat using crystals. The crystals can pump or extract heat, even on the nanoscale, so they could be used on computer chips to prevent overheating or even meltdown, which is currently a major limit to higher computer speeds. The research is published in the Physical Review Letters.

Ronald Cohen, staff scientist at Carnegie’s Geophysical Laboratory and Maimon Rose, originally a high school intern now at the University of Chicago carried out the research. They performed simulations on ferroelectric crystals—materials that have electrical polarization in the absence of an electric field. The electrical polarization can be reversed by applying an external electrical field. The scientists found that the introduction of an electric field causes a giant temperature change in the material, dubbed the electrocaloric effect, far above a temperature to a so-called paraelectric state. (more…)

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How Ion Bombardment Reshapes Metal Surfaces

Ion bombardment of metal surfaces is an important, but poorly understood, nanomanufacturing technique. New research using sophisticated supercomputer simulations has shown what goes on in trillionths of a second. The advance could lead to better ways to predict the phenomenon and more uses of the technique to make new nanoscale products.

PROVIDENCE, R.I. [Brown University] — To modify a metal surface at the scale of atoms and molecules — for instance to refine the wiring in computer chips or the reflective silver in optical components — manufacturers shower it with ions. While the process may seem high-tech and precise, the technique has been limited by the lack of understanding of the underlying physics. In a new study, Brown University engineers modeled noble gas ion bombardments with unprecedented richness, providing long-sought insights into how it works.

“Surface patterns and stresses caused by ion beam bombardments have been extensively studied experimentally but could not be predicted accurately so far,” said Kyung-Suk Kim, professor of engineering at Brown and co-author of the study published May 23 in the Proceedings of the Royal Society A. “The new discovery is expected to provide predictive design capability for controlling the surface patterns and stresses in nanotechnology products.” (more…)

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Berkeley Lab Scientists Generate Electricity From Viruses

New approach is a promising first step toward the development of tiny devices that harvest electrical energy from everyday tasks

Imagine charging your phone as you walk, thanks to a paper-thin generator embedded in the sole of your shoe. This futuristic scenario is now a little closer to reality. Scientists from the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have developed a way to generate power using harmless viruses that convert mechanical energy into electricity.

The scientists tested their approach by creating a generator that produces enough current to operate a small liquid-crystal display. It works by tapping a finger on a postage stamp-sized electrode coated with specially engineered viruses. The viruses convert the force of the tap into an electric charge. (more…)

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