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A fully automated robot arm pours molten glass into the sample mold. Credit: Knud Dobberke; Fraunhofer ISC.
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Instant-on computers may be possible with modified materials
Researchers from three NSF-supported Materials Research Science and Engineering Centers at Penn State and Cornell recently added ferroelectric capability to materials used in common computer transistors–a feat that scientists have tried to achieve for more than half a century. Ferroelectric materials—found in subway, ATM, fuel and other “smart cards”—may eliminate time-consuming booting and rebooting of computer operating systems by providing an “instant-on” capability. Besides reducing the waiting time for everyday computer users, the discovery could pave the way for memory devices that are lower power, higher speed, and more convenient to use. The materials may also help prevent losses from power outages.
A super-absorbent solar material
A new nanostructured material that absorbs a broad spectrum of light from any angle could lead to the most efficient thin-film solar cells ever. Researchers at Caltech are applying the design to semiconductor materials to make solar cells that they hope will save money on materials costs while still offering high power-conversion efficiency. Initial tests with silicon suggest that this kind of patterning can lead to a fivefold enhancement in absorbance.
Robot speeds up glass development
Model by model, the electronics in a car are being moved closer to the engine block. This is why the materials used for the electronics must resist increasing heat - so the glass solder being used as glue must be continually optimized. For the first time ever, a robot takes on the task of developing new types of glass and examining their characteristics. Researchers will introduce this robot at the “productronica” trade fair to be held in Munich, Germany, from November 15 - 18, 2011
A team of engineers at Northwestern University has created an electrode for lithium-ion batteries — rechargeable batteries such as those found in cellphones and iPods — that allows the batteries to hold a charge up to 10 times greater than current technology. Batteries with the new electrode also can charge 10 times faster than current batteries. The researchers combined two chemical engineering approaches to address two major battery limitations — energy capacity and charge rate — in one fell swoop. In addition to better batteries for cellphones and iPods, the technology could pave the way for more efficient, smaller batteries for electric cars.
New journal on disruptive science and technology launching in 2012
Mary Ann Liebert, Inc., publishers is launching a new journal, the Journal of Disruptive Science and Technology, a highly innovative, bimonthly peer-reviewed journal that seeks to publish game-changing research that has the potential to significantly improve human health, well-being, and productivity. The Journal will present new and innovative results, essential data, cutting-edge discoveries, thorough syntheses and analyses, and publish out-of-the-box concepts that will improve the way we live.
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Other materials stories that may be of interest
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How to increase the data storage density of HDDs: Just add salt
A team of researchers from Singapore has moved the goalposts yet again and shown that traditional hard disk drives still have some life in them by developing a process that can increase the data recording density of HDDs to six times that of current models. The researchers from the Institute of Materials Research and Engineering, who worked in collaboration with the National University of Singapore and the Data Storage Institute, liken the new process to packing a suitcase—the neater you pack, the more you can carry. Joel Yang, the IMRE scientist who heads the project, found that adding sodium chloride—or table salt—to a developer solution used in existing lithography processes produced highly defined nanostructures down to 4.5 nm half pitch, without the need for expensive equipment upgrades.
Algorithm said to identify best natural-gas storage materials
Northwestern University researchers claim they have developed an algorithm that can identify the best materials to store natural gas in. A recent Nature Chemistry article reports that in 72 hours researchers generated more than 137,000 hypothetical metal-organic framework structures. This number is much larger than the total number of MOFs reported to date by all researchers combined (approximately 10,000 MOFs). The Northwestern team then reduced that number down to the 300 most-promising candidates for high-pressure, room-temperature methane storage.
Big Innovations from Small Science
In an article in Ceramic Industry, Scott Rickert says nanotechnology is changing the rules in ceramics. It’s the key to new and enhanced properties that have applications across the spectrum of the industry, from piezoelectrics and whitewares to refractories and fuel cells. Problems long thought to be unsolvable begin to unravel with nanotechnology. Performance that seemed unattainable looms on the horizon. The potential is vast, and the science is delivering results now. In some cases, the news is what nanoscale ceramics can bring to other fields. In other cases, the story is nanotechnology’s impact on the ceramic industry.
Shirt capable of converting body heat into electricity
The engineers at electronics company Imec claim that the completely hidden thermoelectric generator can harness the body’s heat to generate electricity that could power low-energy wearable electronics. The TEG comprises 16 ‘thermopiles’, which are the individual electronic components responsible for converting heat into electricity. The voltage they generate is directly proportional to the temperature gradient across them.
ITRI (Industrial Technology Research Institute), a Taiwanese high-tech research and development institution, introduces Spray-IT, the first eco-friendly, thermal spray coating for use on glass and building material to lower energy costs. Spray-IT provides an inexpensive lithium-fluorine codoped tin oxide coating material called LiFTO that is suitable for spraying directly onto glass or tile surfaces, to form an insulation layer. The LiFTO coating can be applied easily either indoors or in open-air conditions. Both manufacturing of the coating material and deployment are easy and economical, making it more affordable for businesses and individuals to use the technology to reduce energy bills.
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New speedy, high-res nanolithography method to allow the rapid prototyping of electronics
A new nanolithography process promises to speed up the “printing” of nanoscale patterns, which could soon allow investigators to quickly make prototypes of test electronic devices.
Of course, various forms of fairly high resolution nanolithography have been around for a while. But, heretofore, they have been relatively time consuming. These have usually employed a single “pen” that slowly deposits materials on a substrate.
Now, however, according to a Northwestern University press release, researchers have come up with a method of using an array of millions of tiny light-beam pens on photosensitive material that can operate simultaneously. It is essentially massively parallel scanning probe microscopy that can create any pattern by shining 400-nanometer light through nanoscopic apertures at each pen tip in the array.
Details of the “beam-pen lithography” method appear in a letter published in Nature Nanotechnology. According to the authors, beam-pen lithography might do for nanofabrication what the desktop printer has done for printing and information transfer.
“It’s all about miniaturization,” says Chad Mirkin, director of Northwestern University’s International Institute for Nanotechnology. “Rapid and large-scale transfer of information drives the world. But conventional micro- and nanofabrication tools for making structures are very expensive. We are trying to change that with this new approach to photolithography and nanopatterning.”
To demonstrate some of the power of beam-pen lithography, Mirkin’s group patterned 15,000 replicas of the Chicago skyline simultaneously. The demonstration used fifteen thousand tiny pens to create the skylines over square centimeters of space. Each skyline pattern is made up of 182 dots, with each dot approximately 500 nanometers in diameter. It took 20 seconds of light exposure to create each dot in the photosensitive material.
Resolution-wise, the method can toggle between near- and far-field distances, allowing both subdiffraction limit (100 nanometer) and larger features to be generated. They also say that since their paper was accepted by the journal, they have learned how to create an array of 11 million pens in an area only a few centimeters square.
“Such an instrument would allow researchers at universities and in the electronics industry around the world to rapidly prototype-and possibly produce-high-resolution electronic devices and systems right in the lab. They want to test their patterns immediately, not have to wait for a third-party to produce prototypes, which is what happens now,” Mirkin says.
The pens, themselves, are tiny polymer pyramids. The news release says the pyramids’ points serve as the printing tips:
The researchers coat the pyramids with a very thin layer of gold and then remove a tiny amount of gold from each tip. The large open tops of the pyramids (the back side of the array) are exposed to light, and the gold-plated pyramids channel the light to the tips. A fine beam of light comes from each tip, where the gold was removed, exposing the light-sensitive material at each point
“Another advantage is that we don’t have to use all the pens at once. We can shut some off and turn on others,” says Mirkin. “Because the tops of the pyramids are on the microscale, we can control each individual tip.”
Mirkin’s history suggests that this technique may be a big success. He developed two other commercially successful lithography techniques: polymer-pen lithography in 2008 and dip-pen nanolithography in 1999.
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Can basic chemistry concepts explain oxide surfaces?
Researchers at Northwestern University and the University of Oxford say that relatively simple methods of explaining chemical bond mechanisms typically taught at undergraduate levels turns out to be an accurate way to understand the arrangement of atoms on a oxide’s surface.
“For a long time we have not understood oxide surfaces,” said Laurence Marks, professor of materials science and engineering in the McCormick School of Engineering and Applied Science at Northwestern. “We only have had relatively simple models constructed from crystal planes of the bulk structure, and these have not enabled us to predict where the atoms should be on a surface.
“Now we have something that seems to work,” Marks said. “It’s the bond-valence-sum method, which has been used for many years to understand bulk materials. The way to understand oxide surfaces turns out to be to look at the bonding patterns and how the atoms are arranged and then to follow this method.”
These findings are published in Nature Materials.
According to a news release, NU graduate student James Enterkin matched the electron diffraction patterns from a strontium titanate surface with the patterns with scanning-tunneling microscopy images obtained by Bruce Russell at Oxford. Enterkin then combined these with density functional calculations and bond-valence sums, showing that those that had bonding similar to that found in bulk oxides were those with the lowest energy.
Ulrike Diebold, an expert in the investigation of metal oxide surfaces at the Institute of Applied Physics in Vienna, Austria, commented on the significance of this research in a separate article in Nature Materials. She writes, “This simple and intuitive, yet powerful concept [the bond-valence-sum method] is widely used to analyze and predict structures in inorganic chemistry. Its successful description of the surface reconstruction of SrTiO3 (110) shows that this approach could be relevant for similar phenomena in other materials.”
NU provides a fun 3D model of the surface of SrTiO3 (110) here. (Be sure to try to manipulated the model with your mouse.)
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X-rays reported to trigger crystal formation
A network with crystalline bundles of filaments. Credit: Yuri S. Velichko.
A team from Northwestern University reports in the new issue of Science about the role that X-rays can play in crystal formation. The researchers say they accidentally discovered that X-rays can trigger the formation of a new type of crystal that is composed of charged cylindrical filaments. These crystals are ordered like a bundle of pencils experiencing repulsive forces.
They hope their work will expand the use of X-rays from not just an analytical tool but also a method to control the structure of materials.
In a NU press release, Samuel Stupp, one of the paper’s authors, describes what the group thinks is going on with the X-rays. “The filaments are charged so one would expect them to repel each other, not to organize into a crystal. Even though they are repelling each other, we believe the hundreds of thousands of filaments in the bundles are trapped within a network and form a crystal to become more stable,” says Stupp, who is a professor of chemistry, materials science and engineering and medicine.
The discovery happened when members of Stupp’s research team, working on a separate organic project, zapped a solution of peptide nanofibers with synchrotron X-ray radiation. Unexpectedly, the solution turned opaque. “There was a dramatic change in the way filaments scattered the radiation,” says coauthor Honggang Cui. “The X-rays turned a disordered structure into something ordered - a crystal.”
The group theorizes that the X-rays increase the charge of the material and causes a hexagonal stacking of filaments. They say that because of repulsive forces, the filaments are positioned far apart from each other, with as much as 320 angstroms separating the filaments.
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