Other materials stories that may be of interestPublished on March 19th, 2013 | By: Eileen De Guire
University of Delaware materials science professors Darrin Pochan and Kristi Kiick are taking a new approach to building new nanomaterials from biomolecules—namely peptides and proteins—that could increase the efficiency of photovoltaics, and other electronic devices. “Peptides and polypeptides offer unlimited potential in designing new materials that can uniquely address limitations in current electronic devices,” Kiick notes. This is because proteins can be engineered to display chemically reactive groups at desired positions. By constructing a nanomaterial with proteins, researchers can subsequently add inorganic nanoparticles that will “stick” to the nanomaterial surface in targeted locations. If successful, Pochan says the project could offer manufacturers a “dirt simple” processing and materials technique for creating a structured, protein-based backing that could be applied to photovoltaic devices to improve their efficiency. It may also create new opportunities to work with colleagues in energy disciplines – particularly those at UD – to test and refine the materials process. “Normal semiconductor manufacturing processes are extremely difficult and expensive at this small of a length scale, making this research area very important,” Pochan says.
Scientists at Johannes Gutenberg University Mainz (JGU) and the Max Planck Institute for Polymer Research (MPI-P) in Germany have created a new synthetic hybrid material with a mineral content of almost 90%, yet extremely flexible. They imitated the structural elements found in most sea sponges and recreated the sponge spicules using the natural mineral calcium carbonate and a protein of the sponge. Natural minerals are usually very hard and prickly, as fragile as porcelain. Amazingly, the synthetic spicules are superior to their natural counterparts in terms of flexibility, exhibiting a rubber-like flexibility. The synthetic spicules can, for example, easily be U-shaped without breaking or showing any signs of fracture. This highly unusual characteristic is mainly due to the part of organic substances in the new hybrid material. It is about ten times as much as in natural spicules. The synthetic spicules were made from calcite and silicatein-α. The synthetic material was self-assembled from an amorphous calcium carbonate intermediate and silicatein and subsequently aged to the final crystalline material. After six months, the synthetic spicules consisted of calcite nanocrystals aligned in a brick wall fashion with the protein embedded like cement in the boundaries between the calcite nanocrystals. The spicules were of 10 to 300 micrometers in length with a diameter of 5 to 10 micrometers.
(Oil & Gas Journal) Technological breakthroughs in the last few years have significantly improved the US energy situation, but more needs to be done, US President Barack Obama said on Mar. 15. He specifically called for creation of an Energy Security Trust to develop and deploy transportation alternatives that would be funded by federal crude oil leasing revenue. He acknowledged, as he did in his Feb. 12 State of the Union address, that the idea came from Securing America’s Future Energy (SAFE), which is committed to protecting US national and economic security by combating domestic dependence on oil for transportation fuels.
(Technology Review) Taking advantage of recent advances in flexible electronics, researchers have devised a way to “print” devices directly onto the skin so people can wear them for an extended period while performing normal daily activities. Such systems could be used to track health and monitor healing near the skin’s surface, as in the case of surgical wounds. So-called “epidermal electronics” were demonstrated previously in research from the lab of John Rogers, a materials scientist at the University of Illinois at Urbana-Champaign; the devices consist of ultrathin electrodes, electronics, sensors, and wireless power and communication systems. In theory, they could attach to the skin and record and transmit electrophysiological measurements for medical purposes. These early versions of the technology, which were designed to be applied to a thin, soft elastomer backing, were “fine for an office environment,” says Rogers, “but if you wanted to go swimming or take a shower they weren’t able to hold up.” Now, Rogers and his coworkers have figured out how to print the electronics right on the skin, making the device more durable and rugged.
When a crystal is hit by an intense ultrashort light pulse, its atomic structure is set in motion. A team of scientists from the Max Planck Institute of Quantum Optics, the Technischen Universität München (TUM), the Fritz-Haber Institute in Berlin (FHI) and the Universität Kassel can now observe how the configuration of electrons and atoms in titanium dioxide, a semiconductor, changes under the impact of an ultraviolet laser pulse, confirming that even subtle changes in the electron distribution caused by the excitation can have a considerable impact on the whole crystal structure. Knowledge regarding the interaction between light and solid matter on an atomic scale is still comparable to a map with many blank spots. A new, up to date unknown aspect of the interplay between light and matter has now been examined by a team of scientists using intensive ultraviolet laser pulses with only a few femtoseconds duration. The physicists illuminated a titanium dioxide crystal (consisting of titanium and oxygen atoms) with an intense ultraviolet laser pulse of less than five femtoseconds duration. The laser pulse excites the valence electrons in the crystal and generates a small number of hot electrons with a temperature of several thousand Kelvin. The continuous interplay between the positions of the atomic cores and the valence electrons determines the material characteristics such as electric conductivity, optical properties or the crystal lattice structure.
A twist on thin-film technology may provide a way to optically detect and analyze multiple substances simultaneously, leading to quicker diagnostics in such industries as health care and homeland security, according to Penn State researchers. One current optical-sensing technology can launch and guide a single light wave, called a surface-plasmon-polariton wave—SPP wave—that travels along the flat interface of the sample to be analyzed and a metal film. The SPP wave is launched by sending a light beam through a prism to the other face of the metal film. A photon detector eventually collects the beam that was reflected back into the prism. Any change in the optical properties of the sample critically alters the reflected beam. However, because the technology allows for only one SPP wave of a certain frequency to be guided through the device, the properties of only one substance can be analyzed for each sensor. The researchers designed a thin film that can create additional channels for the SPP waves. This thin film, which is attached to the metal surface, is porous and can be infiltrated by fluids that can later be analyzed. To make more channels for the SPP waves, they slowly rotated the substrate during the fabrication of the thin film, sculpturing it to create nanoscale springs, so that the regions between the springs can be infiltrated.
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