High-performance electronic circuits made entirely from transparent materials could have countless applications, from head-up displays on car windscreens to transparent TV sets and smart windows in homes and offices. Researchers at the King Abdullah University of Science & Technology (KAUST) in Saudi Arabia have now found a way to make transparent transistors and other essential components of electronic circuitry using inexpensive and readily available materials with a simple fabrication technique. They report this work in a paper in Advanced Materials. Indium tin oxide (ITO) is the current material of choice for transparent electronics, with uses ranging from touch-sensitive smartphone screens to light-harvesting solar panels. Indium is in short supply, however, and as demand increases for ITO-containing devices, so does the price of indium. One promising low-cost ITO alternative is a transparent material known as aluminum-doped zinc oxide (AZO). "The elements that make up this material are more abundant than indium, making AZO a commercially sensible option," said Husam Alshareef, a professor in the KAUST Physical Science and Engineering Division, who led the research. "However, electronic devices made using AZO have traditionally shown inferior performance to devices made using ITO." To overcome this limitation, Alshareef and his research team took advantage of a high-precision technique called atomic layer deposition, which can build up circuits a single layer of atoms at a time. Using this technique, the researchers applied volatile vapors of aluminum and zinc in the form of trimethyl aluminum and diethyl zinc to a transparent substrate, where the aluminum and zinc adhere to the surface in a single layer before reacting in situ to form AZO. "Using atomic layer deposition to grow all active layers simplifies the circuit fabrication process and significantly improves circuit performance by controlling layer growth at the atomic scale," Alshareef explained. For many electronic devices, the key component is the thin-film transistor. When combined in great numbers, these devices allow computers to do calculations, drive displays and act as active sensors. Alshareef used a transparent material called hafnium oxide, sandwiched between layers of AZO, to form the highly-stable transistors used to fabricate the transparent circuits. "Our transistor properties are the best reported so far for fully transparent transistors using AZO contacts," said PhD student Zhenwei Wang, who carried out much of the experimental work. Another advantage of Alshareef's approach is that atomic layer deposition only requires a temperature of 160°C to form each layer. This is low enough for the transparent circuitry to be formed on flexible plastic substrates, as well as on rigid glass. This story is adapted from material from KAUST, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.
News Article | June 3, 2015
Eurofinsa: "La exclusión social de la infancia es un tema especialmente sensible" Lola Arias, directora de Comunicación y Responsabilidad Social Corporativa del Grupo Eurofinsa, explica en esta entrevista porque su compañía colabora con Grupo AMÁS. Lo hace desde julio de 2013. Lola Arias, directora de Comunicación y Responsabilidad Social Corporativa del Grupo Eurofinsa, explica en esta entrevista porque su compañía colabora con Grupo AMÁS. Lo hace desde julio 2013. ¿Cómo surgió la idea de colaborar con Grupo AMÁS? La responsabilidad e implicación con la que venimos desarrollando nuestra actividad en estos 37 años de actividad cristaliza ahora con nuestra incorporación al Pacto Mundial de Naciones Unidas. Dicha adhesión ha reforzado nuestra filosofía de trabajo y aporta valor añadido a la gestión y ejecución de nuestros proyectos que se relacionan directamente con el bienestar y la calidad de vida de las personas y, en consecuencia, confirmamos nuestro compromiso con el desarrollo local en todos los países donde estamos presentes. A través de los empleados conocimos la labor que el Grupo AMÁS está llevando a cabo en la Comunidad de Madrid. ¿Por qué habéis decidido colaborar con el centro de Atención Temprana? La exclusión social de la infancia es un tema especialmente sensible dentro de nuestra organización. Por ello, Eurofinsa decidió apostar por el proyecto que la Asociación AFANDEM realiza en la zona suroeste de la Comunidad. Nos parece impactante la calidad de los servicios y de los profesionales dentro de una modesta estructura que atiende anualmente a más de 300 niños con necesidades especiales. Desde nuestra posición, queremos aportar nuestro granito de arena para favorecer el mejor desarrollo posible de los niños y facilitar su integración social. Eurofinsa sólo presta apoyo a aquellas organizaciones que cuenten con una reputación intachable y que puedan garantizar la buena administración de los recursos asignados. Para nosotros es fundamental que la colaboración sea transparente y de confianza y que tengamos la garantía de que los recursos que destinamos estén bien empleados y sean sostenibles en el tiempo. Junto al desafío permanente de competir en el mercado global, nos guiamos por la convicción de que nuestras actividades estén alineadas con la sostenibilidad económica, social y medioambiental. Por ello, además de desarrollar una gestión empresarial responsable y comprometida, promocionamos aquellos proyectos sociales en los que la compañía proporcione un valor añadido y que estén dentro de la dinámica de los proyectos que hacemos alrededor del mundo. Nuestro objetivo es implicar y beneficiar al máximo a las comunidades locales. ¿Cómo animarías a otras a organizaciones a colaborar? Les animaría a que involucraran a sus empleados en sus decisiones y a que escogieran aquellos proyectos relacionados con su negocio que es donde más pueden ayudar y que mejor saben hacer. ¿Qué papel deben jugar entidades cómo la vuestra para mejorar la sociedad? Más allá del beneficio económico, las empresas tienen un papel esencial para encontrar el equilibrio necesario entre el crecimiento económico, la protección del medio ambiente y el desarrollo de una sociedad más justa. Además, las empresas no son entes sino que están compuestas de personas a las que se les debería involucrar directamente en acciones concretas, tales como donaciones conjuntas, voluntariado, apoyo a la participación individual en proyectos, participación en eventos y campañas a favor de causas sociales, etc.
A new chemical route for potential antimalarial compounds has been pioneered by chemists at KAUST. It offers hope for improved treatment of malaria, a disease that kills more than a million people each year. "The parasites that cause the disease continuously evolve and become resistant to existing drugs, so we need to constantly design and synthesize new drugs to treat malaria," noted Xinbo Wang, a chemist in Associate Professor Zhiping Lai's group in the KAUST Physical Science and Engineering Division. The work could also lead to the development of new drugs against bacterial infections, cancer and other diseases. A chemical structure called the alpha-amino peroxide group, which is found in existing anti-malarial compounds, is a good basis for building potential new drugs. However, there are significant problems with existing methods for making such compounds because they require difficult chemical conditions. Lai and his colleagues devised a simple and efficient procedure1 and showed that the alpha-amino peroxide group can be combined with an "indole" chemical grouping to make the "N-(alpha-peroxy)-indole" structure. "There are lots of reports on the synthesis of indole or peroxide-containing compounds, but there are no general methodologies for combining the two functional groups in one molecule that had been previously reported," stated Wang. The KAUST team took things a step further by adding a carbazole group. The indole, carbazole and peroxide groups occur separately in many antimalarial, antibacterial and anti-tumor compounds. "Merging these functional groups in one molecular structure may offer great potential for the discovery of new types of drugs," Wang said. The reactions proceed in "one-pot, open atmosphere" conditions, meaning everything occurs in one vessel without complicated intermediate steps. The vessel is also open to the air rather than protected by unreactive gases, as is required for many similar chemical processes. "Our procedure could be easily handled and scaled-up to allow the construction of a new library of molecules for drug screening," he noted. Upscaling is the challenge that the KAUST researchers plan to turn to next to make a wide variety of compounds that can be tested for useful biological activity against a variety of diseases, and especially against malaria. In developing their new chemical procedures, the researchers drew inspiration from a chemical reaction used by another research project at KAUST. "Our story proves the importance of a multidisciplinary research environment, which we consider is the treasure of KAUST," Lai said. "Here, experts from different fields work closely together." More information: Wang, X., Pan, Y., Huang, K.-W. & Lai, Z.; One-pot synthesis of N‑(α-peroxy)indole/carbazole via chemoselective three-component condensation reaction in open atmosphere; Organic Letters 17, 5630 - 5633 (2015);
"Explaining the Moon's volatile depletion has been a long-standing mystery, and yet it is a key piece of evidence about how the Earth-Moon system formed," said Dr. Robin Canup, associate vice president in SwRI's Space Science and Engineering Division and lead author of the Nature Geoscience paper detailing the findings. Scientists think the Moon formed from an Earth-orbiting disk of vapor and molten matter produced by a giant impact between Earth and another Mars-sized body approximately 4.5 billion years ago. Previously, scientists had considered that volatiles vaporized by the impact might have escaped before the Moon formed. "However, few volatiles may have actually been lost because the velocity needed to escape the Earth's gravity is quite high," said Canup. "The new research suggests instead that as the Moon completed its growth, volatile-rich melt was preferentially deposited onto the Earth, rather than onto the growing Moon." Canup's team—which included researchers from SwRI, Dordt College, and Washington University—began with an existing computer simulation of the Moon's accumulation from the disk. This was combined with models for how the temperature and chemical composition of the disk material evolve with time. The models show that the Moon acquires about the final half of its mass from melt condensed in the inner portions of the disk, close to the Earth and just inside the Moon's initial orbit. Over time, the Moon's orbit expands due to dynamical interactions with inner disk material. When the Moon is distant enough, it can no longer efficiently accumulate inner disk melt, which is instead scattered inward and assimilated by the Earth. "We find that the inner disk melt remains hot and volatile-poor as it accretes onto the Moon. Eventually the disk cools and volatiles condense. But by the time this occurs the Moon's accumulation from this inner disk region has essentially terminated," said Canup. "So the final materials the Moon accumulates are lacking in volatile elements, even in the absence of escape." The authors suggest that the materials the Moon initially accumulates from the outer disk could be volatile-rich, followed by a final 100- to 500-kilometer layer of volatile-poor material. In that case, the Moon's volatile content could then increase with depth, depending on the extent of mixing in the Moon's interior. Explore further: New model reconciles the Moon's Earth-like composition with the giant impact theory of formation More information: Lunar Volatile Depletion Due to Incomplete Accretion Within an Impact-Generated Disk, Nature Geoscience, Nov. 9, 2015. nature.com/articles/doi:10.1038/ngeo2574
The Solar Wind Around Pluto (SWAP) instrument, operated by Southwest Research Institute (SwRI), collected three years' worth of measurements before the July 15 Pluto flyby. Data showed that the tumultuous flow of solar particles, which in the inner solar system is structured by the interaction of fast and slow flows as well as eruptive events on the Sun, becomes more uniform by the time the solar wind has traversed the 3 billion miles to Pluto's orbit. SWAP measures the solar wind and ions created as the neutral interstellar material becomes ionized and is "picked up" by the solar wind. These interstellar pickup ions can have up to twice the speed and four times the energy of the solar wind. Farther out in space, these ions may be the seeds of the extremely fast energetic particles called anomalous cosmic rays, which pose a radiation threat to astronauts closer to Earth. These ions also play an important role in shaping the boundary where the solar wind hits interstellar space. New Horizons is currently at about 35 astronomical units (about 35 times farther than the Earth to the Sun). It is the only operating spacecraft in the outer solar system. Only Voyager 2 has measured the solar wind farther away from the Sun; however, SWAP on New Horizons will be the first to measure the interstellar pickup ions in the outer solar system. The results will appear in a study to be published April 6 by the Astrophysical Journal Supplement. Lead author Dr. Heather Elliott, a principal scientist in SwRI's Space Science and Engineering Division, said the SWAP instrument was busy even when the rest of New Horizon's instruments were "hibernating" to save energy on the long, nine-year voyage to Pluto. "The instrument was only scheduled to power on for annual checkouts after the Jupiter flyby in 2007," she said. "We came up with a plan to keep the particle instruments on during the cruise phase while the rest of the spacecraft was hibernating. We started observing in 2012." The plan yielded three years of near-continuous observations, capturing detailed measurements of the space environment in a region few spacecraft have ever visited. Because the Sun is the source of the solar wind, events on the Sun are the primary force that shapes the space environment. Shocks in the solar wind—which can produce space weather, such as auroras, on worlds with magnetic fields—are created either by fast, dense clouds of material called coronal mass ejections or by the collision of two different-speed solar wind streams. These individual features are easily observed in the inner solar system, but New Horizons didn't see the same level of detail. "At this distance, the scale size of discernible solar wind structures increases, since smaller structures are worn down or merge together," said Elliott. "It's hard to predict if the interaction between smaller structures will create a bigger structure, or if they will flatten out completely." Subtler signs of the Sun's influence are also harder to spot in the outer solar system. Characteristics of the solar wind—speed, density, and temperature—are shaped by the region of the Sun it flows from. As the Sun and its different wind-producing regions rotate, patterns form. New Horizons didn't see patterns as defined as they are when closer to the Sun, but it nevertheless did spot some structure. "Differences in speed and density average together as the solar wind moves out," said Elliott. "But the wind is still being heated as it travels and faster wind runs into slower wind, so you see evidence of the Sun's rotation pattern in the temperatures even in the outer solar system." New Horizons is the first mission in NASA's New Frontiers program, managed by the agency's Marshall Space Flight Center in Huntsville, Ala. The Johns Hopkins University Applied Physics Laboratory designed, built, and operates the New Horizons spacecraft and manages the mission under Principal Investigator Dr. Alan Stern's direction for NASA's Science Mission Directorate. SwRI leads the science mission, payload operations, and encounter science planning. The NASA Heliophysics program also supported the analysis of these observations. Explore further: Scientists simulate the space environment during New Horizons flyby More information: "New Horizons Solar Wind Around Pluto (SWAP) Observations of the Solar Wind From 11-33 AU," H. A. Elliott et al., 2016, Astrophysical Journal Supplement Series , arxiv.org/abs/1601.07156