Wednesday, February 8, 2012

Kitchen gadget inspires scientist to make more effective plastic electronics

 One day in 2010, Rutgers physicist Vitaly Podzorov watched a store employee showcase a kitchen gadget that vacuum-seals food in plastic. The demo stuck with him. The simple concept -- an airtight seal around pieces of food -- just might apply to his research: developing flexible electronics using lightweight organic semiconductors for products such as video displays or solar cells.


"Organic transistors, which switch or amplify electronic signals, hold promise for making video displays that bend like book pages or roll and unroll like posters," said Podzorov. But traditional methods of fabricating a part of the transistor known as the gate insulator often end up damaging the transistor's delicate semiconductor crystals.


Drawing inspiration from the food-storage gadget, Podzorov and his colleagues tried an experiment. They suspended a thin polymer membrane above the organic crystal and created a vacuum underneath, causing the membrane to collapse gently and evenly onto the crystal's surface. The result: a smooth, defect-free interface between the organic semiconductor and the gate insulator.


The researchers reported their success in the journal Advanced Materials. In the article,Podzorov and three colleagues describe how a single-crystal organic field effect transistor (OFET) made with this thin polymer gate insulator boosted electrical performance. The researchers further reported that they could remove and reapply membranes to the same crystal several times without degrading its surface.


Organic transistors electrically resemble silicon transistors in computer chips, but they are made of flexible carbon-based molecules that can be printed on sheets of plastic. Silicon transistors are made in rigid, brittle wafers of silicon.


The methods that scientists previously applied to organic transistor fabrication were based on silicon semiconductor processing, explained Podzorov, assistant professor in the Department of Physics and Astronomy, School of Arts and Sciences. These involved high temperatures, high-energy plasmas or chemical reactions, all of which could damage the delicate organic crystal surface and hinder the transistor's performance.


"People have tendencies to go with something they've known for a long time," he said. "In this case, it doesn't work right."


Podzorov's innovation builds upon a decade of Rutgers research in this field, including his invention of the first single crystal organic transistor in 2003. While his latest innovation is still a ways from commercial reality, he sees an immediate application in the classroom.


"Our technique takes 10 minutes," he said. "It should be exciting for students to actually build these devices and immediately see them work, all within one lab session."


Podzorov was actually trying to solve another problem when he first recalled the food packaging demo. He was thinking about how to protect organic crystals from airborne impurities when his lab shipped samples to collaborating scientists in California and overseas.


"We could place our samples between plastic sheets and pull a vacuum," he said. "Then I thought, 'why don't we try doing this for our gate insulator?'"


Funding for the research was provided by the U. S. Department of Energy and the Rutgers Institute for Advanced Materials and Devices for Nanotechnology. Collaborators in Podzorov's lab were postdoctoral researchers Hee Taek Yi and Yuanzhen Chen, and undergraduate student Krzysztof Czelen. The department's machine shop made a custom-designed vacuum chamber for the project.


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The above story is reprinted from materials provided by Rutgers University.


Note: Materials may be edited for content and length. For further information, please contact the source cited above.


Journal Reference:

H. T. Yi, Y. Chen, K. Czelen, V. Podzorov. Vacuum Lamination Approach to Fabrication of High-Performance Single-Crystal Organic Field-Effect Transistors. Advanced Materials, 2011; 23 (48): 5807 DOI: 10.1002/adma.201103305

Trevira: sale completed

The takeover of polyester manufacturer Trevira by the consortium of Indorama Ventures PCL (Thailand) and Sinterama (Italy) is complete. After receiving the green light from the relevant cartel authorities in Brussels and Turkey, the change in ownership finally took place on 01.07.2011. While the contract with auditor, Werner Schneider, to acquire the company had been signed by both investors in February 2011, it had still to await the approval of the cartel authorities.


All those involved expressed their satisfaction with the final stages of the takeover process. „Trevira is a traditional enterprise with a qualified workforce and great potential for the future“, declared Schneider. With a company sale there was always also the question of the people involved and of preserving expertise. The sale to the consortium of strategic investors with direct links to the textile industry provided the best opportunity for sustained development in the future, Schneider said.
Trevira’s Supervisory Board member Hans-Joachim Becker, who had played a decisive role in supporting Schneider during the sales process, also sees this takeover positively: "The new owners are a guarantee for continuity."


Trevira MD Klaus Holz thanked Schneider for his commitment to the company over the last two years and praised his close cooperation with Trevira and his support for important restructuring measures. It had been his declared intent to find investors able to offer Trevira a basis for longterm profitability and with a willingness to support investment in extending the business and the brand. „We are very pleased that all the formalities are at last completed and that we can now together concentrate with our new owners on our business operations“, says Holz. The aim was to rapidly thrash out details of the future strategic pathway, where the main focus now would remain on expanding business in specialty fibres and filament yarns.


Paolo Piana, the designated future Chairman of the Supervisory Board of Trevira GmbH and CEO of Trevira Holdings GmbH, the holding company founded by the new owners, spoke of the objectives of the new owners: “The main issues will be to recover a global vision and ambition, competitiveness and capability to lead the market, innovation and quality leadership. Our customers' satisfaction, their success with our products, their pride to be our partners have to be our first and only target.”


“I am energized to know that Trevira employees will be contributing their knowledge and skills to our growth”, comments Aloke Lohia, Group CEO of IVL. “In return, we hope to make the Trevira brand globally recognized for quality and innovation and ensure that the business grows through the synergy of the comprehensive worldwide network that we and our partners Sinterama have.”


As announced earlier, Robert Gregan (46) is now joining Trevira as CEO. He is to manage the company along with Klaus Holz, who has acted as MD since January. Gregan has spent most of his career in various companies in the man-made fibre industry. Starting with Trevira means a return to his roots for him, since he had begun his working life in the former Hoechst AG. After completing his business studies course, he was active in a variety of functions and sectors, including the fibres division. He subsequently managed Business Lines at fibre manufacturers KoSa and Invista, was CEO of Kelheim Fibres and Dolan and also Head of the Nonwoven Business Unit at Lenzing. He finally worked independently as a consultant.Gregan says that he is looking forward to starting at Trevira. “I have been following the acquisition over the last ten months and have gained a good insight. It’s now a matter of implementing the projects step by step, together with the workforce and the management team. My predecessors and the experienced team have already set many good and important things in motion, and now we have to strengthen Trevira for future crises. I look forward to this challenge and I am sure that together we will achieve our goals”.


The company reports that operations in the first six months of 2011 were running satisfactorily and according to plan. The situation in the raw materials markets continued to present a great challenge for all downstream stages, but capacities were being well exploited. Demand in most market segments was holding at a high level, with home textiles and hygiene showing the main positive signs.

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Wolfgang Büchele has been appointed Kemira Oyj's President and CEO following Harri Kerminen's retirement

11-02-2011: Harri Kerminen will retire on April 1, 2012 after successfully leading the company through a major strategic change into a water chemistry company and turning the company around to a profitable path. This last assignment completes his 26 years of successful career at Kemira.


Wolfgang Büchele (PhD, Chemistry) has been appointed Kemira Oyj's President and CEO as of April 1, 2012. He has been a member of Kemira's Board of Directors since 2009.


"Kemira's Board of Directors started the CEO succession process this summer due to Harri Kerminen's anticipated retirement in 2013. The process was faster than expected and therefore we agreed with Harri Kerminen that he will retire earlier than planned. As a member of Kemira's pension fund he has the right for this", says Pekka Paasikivi, the Chairman of the Board.


Wolfgang Büchele will bring to Kemira extensive and broad industrial knowledge combined with international experience and network, especially in the fast developing Asian markets. He has spent most of his career, from 1993 until 2007 in BASF's Fine Chemicals organization in Europe, China and United States. Since 2009 he has been member of the Board and CEO of BorsodChem Zrt. in Hungary. He and his family will move to Finland.


 

The world's smallest magnetic data storage unit

Scientists from IBM and the German Center for Free-Electron Laser Science (CFEL) have built the world's smallest magnetic data storage unit. It uses just twelve atoms per bit, the basic unit of information, and squeezes a whole byte (8 bit) into as few as 96 atoms. A modern hard drive, for comparison, still needs more than half a billion atoms per byte. CFEL is a joint venture of the research centre Deutsches Elektronen-Synchrotron DESY in Hamburg, the Max-Planck-Society (MPG) and the University of Hamburg. "With CFEL the partners have established an innovative institution on the DESY campus, delivering top-level research across a broad spectrum of disciplines," says DESY research director Edgar Weckert.


The nanometre data storage unit was built atom by atom with the help of a scanning tunneling microscope (STM) at IBM's Almaden Research Center in San Jose, California. The researchers constructed regular patterns of iron atoms, aligning them in rows of six atoms each. Two rows are sufficient to store one bit. A byte correspondingly consists of eight pairs of atom rows. It uses only an area of 4 by 16 nanometres (a nanometre being a millionth of a millimetre). "This corresponds to a storage density that is a hundred times higher compared to a modern hard drive," explains Sebastian Loth of CFEL, lead author of the Science paper.


Data are written into and read out from the nano storage unit with the help of an STM. The pairs of atom rows have two possible magnetic states, representing the two values '0' and '1' of a classical bit. An electric pulse from the STM tip flips the magnetic configuration from one to the other. A weaker pulse allows to read out the configuration, although the nano magnets are currently only stable at a frosty temperature of minus 268 degrees Centigrade (5 Kelvin). "Our work goes far beyond current data storage technology," says Loth. The researchers expect arrays of some 200 atoms to be stable at room temperature. Still it will take some time before atomic magnets can be used in data storage.


For the first time, the researchers have managed to employ a special form of magnetism for data storage purposes, called antiferromagnetism. Different from ferromagnetism, which is used in conventional hard drives, the spins of neighbouring atoms within antiferromagnetic material are oppositely aligned, rendering the material magnetically neutral on a bulk level. This means that antiferromagnetic atom rows can be spaced much more closely without magnetically interfering with each other. Thus, the scientist managed to pack bits only one nanometre apart.


"Looking at the shrinking of electronics components we wanted to know if this can be driven into the realm of single atoms," explains Loth. But instead of shrinking existing components the team chose the opposite approach: "Starting with the smallest thing - single atoms - we built data storage devices one atom at a time," says IBM research staff member Andreas Heinrich. The required precision is only mastered by few research groups worldwide.


"We tested how large we have to build our unit to reach the realm of classical physics," explains Loth, who moved from IBM to CFEL four months ago. Twelve atoms emerged as the minimum with the elements used. "Beneath this threshold quantum effects blur the stored information." If these quantum effects can somehow be employed for an even denser data storage is currently a topic of intense research.


With their experiments the team have not only built the smallest magnetic data storage unit ever, but have also created an ideal testbed for the transition from classical to quantum physics. "We have learned to control quantum effects through form and size of the iron atom rows," explains Loth, leader of the Max Planck research group 'dynamics of nanoelectric systems' at CFEL in Hamburg and the Max-Planck-Institute for Solid State Research at Stuttgart, Germany. "We can now use this ability to investigate how quantum mechanics kicks in. What seperates quantum magnets from classical magnets? How does a magnet behave at the frontier between both worlds? These are exciting questions that soon could be answered."


A new CFEL laboratory offering ideal conditions for this research will enable Loth to follow up these questions. "With Sebastian Loth, one of the world's leading scientists in the field of time-resolved scanning tunneling microscopy has joined CFEL," stresses CFEL research coordinator Ralf Köhn. "This perfectly complements our existing expertise for the investigation of the dynamics in atomic and molecular systems."


Original publication:
Sebastian Loth, Susanne Baumann, Christopher P. Lutz, D. M. Eigler, Andreas J. Heinrich; Bistability in Atomic-Scale Antiferromagnets; Science, 13. Januar 2012

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Thermo Fisher Scientific Announces New Method for Low Level Detection of Volatile Nitrosamines in Tobacco

 Thermo Fisher Scientific Inc. announced a new comprehensive method that uses triple quadrupole GC-MS/MS to achieve lower levels of detection of volatile nitrosamines (VNA) in tobacco. The new method allows environmental laboratories, tobacco companies and government agencies to efficiently separate VNAs while lowering detection limits, increasing specificity and enabling the analysis of many other contaminants in tobacco, including pesticides. The new method is detailed in an application note entitled “Lower Detection Limits of Volatile Nitrosamines in Tobacco by Triple Quadrupole GC-MS/MS,”.


Volatile nitrosamines are a class of compounds that can form in tobacco smoke, as well as during the curing and processing of tobacco. These compounds have been proven to have adverse effects on human health; and two of the VNAs found in tobacco, N-nitrosodiethylamine (NDEA) and N-nitrosodimethylamine (NDMA), are classed as known human carcinogens by regulatory authorities. As a result, these compounds must be thoroughly monitored in order to safeguard human health and comply with increasingly stringent regulations.


The new Thermo Fisher method is a powerful alternative to other traditionally used techniques. By coupling a gas chromatograph to a triple quadrupole mass spectrometer, the new method makes detection limits of 1ng/mL achievable, enabling users to satisfy the increasingly lower detection limits required by governments and regulatory bodies. The method also increases contaminant specificity within a classification and allows many other organic contaminants and chemicals in tobacco to be analyzed simultaneously, including pesticides.


The new method includes GC-MS/MS analysis on the Thermo Scientific TSQ Quantum XLS triple quadrupole GC-MS/MS system using timed selected reaction monitoring (t-SRM). This unique feature enables easy method set-up and allows users to run samples while the instrument automatically determines the optimal time for SRM parameters.