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What's New in Nanotechnology?

January 12, 2012

Imagine dropping your phone on the hard concrete sidewalk—but when you pick it up, you find its battery has already healed itself. A team of researchers from the University of Illinois at Urbana-Champaign (UIUC) and the U.S. Department of Energy's (DOE) Argonne National Laboratory are exploring ways to design batteries that heal themselves when damaged. "This would help electronics survive daily use—both the long-term damage caused by charging over and over again, and also the inevitable physical damage of everyday life," said Jeff Moore, a UIUC scientist on the team. Scientists think that loss of electrical conductivity is what causes a battery to fade and die. Theories abound on the specific molecular failures; perhaps chemicals build up on electrodes, or the electrodes themselves pull away. Perhaps it's simply the inevitable stress fractures in materials forced to expand and contract repeatedly as the battery is charged and used. In any case, the battery's storage capacity drops due to loss of electrical conductivity. This is what the team wants to address. The idea is to station a team of "emergency repairmen" already contained in the battery. These are tiny microspheres, each smaller than a single red blood cell, and containing liquid metal inside. Added along with the battery components, they lie dormant for most of the battery's lifetime. But if the battery is damaged, the capsules burst open and release their liquid metal into the battery. The metal fills in the gaps in the electrical circuit, connecting the broken lines, and power is restored.

Categories : University News
December 13, 2011

Rice University chemists have found a way to load more than 2 million tiny gold particles, called nanorods, into a single cancer cell. The breakthrough could speed development of cancer treatments that would use nanorods like tiny heating elements to cook tumors from the inside. "The breast cancer cells that we studied were so laden with gold nanorods that their masses increased by an average of about 13 percent," said study leader Eugene Zubarev, associate professor of chemistry at Rice. "Remarkably, the cells continued to function normally, even with all of this gold inside them." Though the ultimate goal is to kill cancer, Zubarev said the strategy is to deliver nontoxic particles that become deadly only when they are activated by a laser. The nanorods, which are about the size of a small virus, can harvest and convert otherwise harmless light into heat. But because each nanorod radiates miniscule heat, many are needed to kill a cell.  Unfortunately, scientists who study gold nanorods have found it difficult to load large numbers of particles into living cells. For starters, nanorods are pure gold, which means they won't dissolve in solution unless they are combined with some kind of polymer or surfactant. The most commonly used of these is cetyltrimethylammonium bromide, or CTAB, a soapy chemical often used in hair conditioner.  CTAB is a key ingredient in the production of nanorods, so scientists have often relied upon it to make nanorods soluble in water. CTAB does this job by coating the surface of the nanorods in much the same way that soap envelopes and dissolves droplets of grease in dishwater. CTAB-encased nanorods also have a positive charge on their surfaces, which encourages cells to ingest them. Unfortunately, CTAB is also toxic, which makes it problematic for biomedical applications. In the new research, Zubarev, Rice graduate student Leonid Vigderman and former graduate student Pramit Manna, now at Applied Materials Inc., describe a method to completely replace CTAB with a closely related molecule called MTAB that has two additional atoms attached at one end. The additional atoms -- one sulfur and one hydrogen -- allow MTAB to form a permanent chemical bond with gold nanorods. In contrast, CTAB binds more weakly to nanorods and has a tendency to leak into surrounding media from time to time, which is believed to be the underlying cause of CTAB-encased nanorod toxicity. It took Zubarev, Vigderman and Manna several years to identify the optimal strategy to synthesize MTAB and substitute it for CTAB on the surface of the nanorods. In addition, they developed a purification process that can completely remove all traces of CTAB from a solution of nanorods.

Categories : University News
December 06, 2011

(Image Credit: University of Pittsburgh )

Researchers at the University of Pittsburgh have invented a new type of electronic switch that performs electronic logic functions within a single molecule.  The incorporation of such single-molecule elements could enable smaller, faster, and more energy-efficient electronics. “This new switch is superior to existing single-molecule concepts,” said Hrvoje Petek, principal investigator and professor of physics and chemistry in the Kenneth P. Dietrich School of Arts and Sciences and codirector of the Petersen Institute for NanoScience and Engineering (PINSE) at Pitt. “We are learning how to reduce electronic circuit elements to single molecules for a new generation of enhanced and more sustainable technologies.” The switch was discovered by experimenting with the rotation of a triangular cluster of three metal atoms held together by a nitrogen atom, which is enclosed entirely within a cage made up entirely of carbon atoms. Petek and his team found that the metal clusters encapsulated within a hollow carbon cage could rotate between several structures under the stimulation of electrons. This rotation changes the molecule’s ability to conduct an electric current, thereby switching among multiple logic states without changing the spherical shape of the carbon cage. Petek says this concept also protects the molecule so it can function without influence from outside chemicals. Because of their constant spherical shape, the prototype molecular switches can be integrated as atom-like building blocks the size of one nanometer (100,000 times smaller than the diameter of a human hair) into massively parallel computing architectures. The prototype was demonstrated using an Sc3N@C80 molecule sandwiched between two electrodes consisting of an atomically flat copper oxide substrate and an atomically sharp tungsten tip. By applying a voltage pulse, the equilateral triangle-shaped Sc3N could be rotated predictably among six logic states.

Categories : University News
November 09, 2011


AMikael Fogelström and Sergey Kubatkin are two of the Chalmers researchers investigating the supermaterial graphene. The cryostat in the picture is used to cool graphene samples to one hundredth of a degree above absolute zero.(Image Credit: Jan-Olof Yxell,Chalmers University of Technology)

Chalmers University of Technology will receive the lion's share of a new Swedish research grant of SEK 40 million for the supermaterial graphene. Following the new financing from the Knut and Alice Wallenberg Foundation, a group of some 30 Swedish graphene researchers will be formed, in a close collaboration between Chalmers and the universities of Uppsala and Linköping. The effort will form the Swedish spearhead in international graphene research – a hot topic ever since the Nobel Physics Prize in 2010. “The money will be used for everything from producing graphene to developing a variety of products, with basic research into experimental and theoretical physics along the way,” says Mikael Fogelström, the project coordinator. The graphene production process needs to be improved and made more reproducible. The researchers will develop reliable synthesis methods designed to produce high-quality graphene surfaces. Following that, the material will be investigated and processed at the nano level, ultimately to be used for specific components with far better performance than today's electronic devices.
Graphene can enable the best quantum resistance standard. This is one of many advances emerging from the active research into graphene at Chalmers. The researchers have already achieved several important breakthroughs with graphene, despite the fact that the material was first produced as recently as 2004. One example is a new standard for the quantum of resistance – a “tuning fork” for calibrating the correct resistance in electrical instruments and devices. State-of-the-art resistance standards are based on silicon or gallium arsenide. These are difficult to manufacture, and the method only works at extremely low temperatures and in large magnetic fields. A new generation of resistance standards based on graphene are at least as accurate as those in use today, while benefitting from being substantially easier to produce and use.

Categories : University News
October 30, 2011

It’s been said that big things come in small packages. But according to experts at the 11th annual IEEE NANO 2011 Conference, some of the technology innovations and devices that could make the biggest impact in our world are so small millions of them could fit on the head of a pin. These game-changing advancements in nanotechnology, or the science of small things, are transforming the way researchers are approaching how to solve some of our world’s greatest challenges. How about solar cells embedded in paint to turn your house into one big solar panel? Or quantum dots that attack cancer, cell by cell, while leaving healthy tissue untouched? Or batteries for mobile phones that charge in seconds instead of hours? “The challenge to making all these nanotechnology applications mainstream comes down to how we affordably and efficiently get them in the hands of people for practical use,” said Jo-Won Lee, IEEE Member and chair professor at the Department of Convergence Nanoscience, Hanyang University in Seoul, South Korea. Traditional manufacturing doesn’t usually work at the nano-level, but there is a better way being developed, he said. It’s called self-assembly, which essentially means the nanodevices build themselves, much like molecules form in nature to create larger systems. IEEE and its members are playing a major role in making nanotechnology work in the real world. For example, the IEEE Nanotechnology Council advances and coordinates work in the field, including the theory, design, and development of nanotechnology and its scientific, engineering, and industrial applications.  Dr. Alexander Balandin, IEEE Senior Member, Chair of the Materials Science and Engineering (MS&E) program at the University of California, Riverside and recipient of the IEEE Pioneer of Nanotechnology Award for 2011, offers one intriguing example: “Research is being done to achieve better control of electron interaction with photons, which could lead to much more efficient and less expensive photovoltaic solar cells. This not only benefits existing solar applications, but in the future these nanomaterials could be commercialized as a solar paint that is sprayed on homes and buildings, forever changing the dynamics of our existing electrical grid.”  Read a profile of Dr. Balandin here, and watch a clip of IEEE member Jose Delgado-Frias speaking about nanotechnology below.


Categories : Conference/Events
October 05, 2011

The Royal Swedish Academy of Sciences has awarded the Nobel Prize in Chemistry for 2011 to Dan Shechtman, of Technion, the Israel Institute of Technology, in Haifa, Israel “for the discovery of quasicrystals.” In quasicrystals, we find the fascinating mosaics of the Arabic world reproduced at the level of atoms: regular patterns that never repeat themselves. However, the configuration found in quasicrystals was considered impossible, and Dan Shechtman had to fight a fierce battle against established science. The Nobel Prize in Chemistry 2011 has fundamentally altered how chemists conceive of solid matter. On the morning of 8 April 1982, an image counter to the laws of nature appeared in Dan Shechtman’s electron microscope. In all solid matter, atoms were believed to be packed inside crystals in symmetrical patterns that were repeated periodically over and over again. For scientists, this repetition was required in order to obtain a crystal. Shechtman’s image, however, showed that the atoms in his crystal were packed in a pattern that could not be repeated. His discovery was extremely controversial. In the course of defending his findings, he was asked to leave his research group. However, his battle eventually forced scientists to reconsider their conception of the very nature of matter. When scientists describe Shechtman’s quasicrystals, they use a concept that comes from mathematics and art: the golden ratio. This number had already caught the interest of mathematicians in Ancient Greece, as it often appeared in geometry. In quasicrystals, for instance, the ratio of various distances between atoms is related to the golden mean. Following Shechtman’s discovery, scientists have produced other kinds of quasicrystals in the lab and discovered naturally occurring quasicrystals in mineral samples from a Russian river. A Swedish company has also found quasicrystals in a certain form of steel, where the crystals reinforce the material like armor. Scientists are currently experimenting with using quasicrystals in different products such as frying pans and diesel engines.


Categories : Competitions/Awards
September 10, 2011

Stanford researchers have developed a new method of attaching nanowire electronics to the surface of virtually any object, regardless of its shape or what material it is made of. The method could be used in making everything from wearable electronics and flexible computer displays to high-efficiency solar cells and ultrasensitive biosensors. Nanowire electronics are promising building blocks for virtually every digital electronic device used today, including computers, cameras and cell phones.  The electronic circuitry is typically fabricated on a silicon chip. The circuitry adheres to the surface of the chip during fabrication and is extremely difficult to detach, so when the circuitry is incorporated into an electronic device, it remains attached to the chip.  But silicon chips are rigid and brittle, limiting the possible uses of wearable and flexible nanowire electronics. The key to the new method is coating the surface of the silicon wafer with a thin layer of nickel before fabricating the electronic circuitry. Nickel and silicon are both hydrophilic, or "water-loving," meaning when they are exposed to water after fabrication of nanowire devices is finished, the water easily penetrates between the two materials, detaching the nickel and the overlying electronics from the silicon wafer.
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Categories : University News
August 30, 2011

The robots, just half a millimeter wide, are composed of microparticles. Confined between two liquids, they assemble themselves into star shapes when an alternating magnetic field is applied. (Credit: Argonne National Lab)

Alexey Snezhko and Igor Aronson, physicists at the U.S. Department of Energy's (DOE) Argonne National Laboratory, have coaxed "micro-robots" to do their bidding. The robots, just half a millimeter wide, are composed of microparticles. Confined between two liquids, they assemble themselves into star shapes when an alternating magnetic field is applied. Snezhko and Aronson can control the robots' movement and even make them pick up, transport and put down other non-magnetic particles—potentially enabling fabrication of precisely designed functional materials in ways not currently possible. Snezhko and Aronson suspended the tiny ferromagnetic particles between two layers of immiscible, or non-mixing, fluids. Without a magnetic field, the particles drift aimlessly or clamp together. But when an alternating magnetic field is applied perpendicular to the liquid surface, they self-assemble into spiky circular shapes that the scientists nicknamed "asters", after the flower. Left to their own devices, the asters don't swim. "But if you apply a second small magnetic field parallel to the surface, they begin to move," said Aronson. "The field breaks the symmetry of the asters' hydrodynamic flow, and the asters begin to swim." By changing the magnetic field, the researchers discovered they could remotely control the asters' motion. "We can make them open their jaws and close them," said Snezhko. "This gives us the opportunity to use these creatures as mini-robots performing useful tasks. You can move them around and pick up and drop objects." The research is a part of the ongoing effort, funded by the DOE, to understand and design active self-assembled materials. These structures can assemble, disassemble, and reassemble autonomously or on command and will enable novel materials capable of multi-tasking and self-repair.

Categories : Government Research
August 01, 2011

Suenne Kim, Nazanin Bassiri-Gharb, and Yaser Bastani have developed a way to draw nanostructures directly on plastic. (Credit: Georgia Tech)

Using a technique known as thermochemical nanolithography (TCNL), researchers at Georgia Tech have developed a new way to fabricate nanometer-scale ferroelectric structures directly on flexible plastic substrates that would be unable to withstand the processing temperatures normally required to create such nanostructures. The technique, which uses a heated atomic force microscope (AFM) tip to produce patterns, could facilitate high-density, low-cost production of complex ferroelectric structures for energy harvesting arrays, sensors and actuators in nano-electromechanical systems (NEMS) and micro-electromechanical systems (MEMS).

"We can directly create piezoelectric materials of the shape we want, where we want them, on flexible substrates for use in energy harvesting and other applications," said Nazanin Bassiri-Gharb, assistant professor in the School of Mechanical Engineering at the Georgia Institute of Technology. "This is the first time that structures like these have been directly grown with a CMOS-compatible process at such a small resolution. Not only have we been able to grow these ferroelectric structures at low substrate temperatures, but we have also been able to pattern them at very small scales." In addition to the Georgia Tech researchers, the work also involved scientists from the University of Illinois Urbana-Champaign and the University of Nebraska Lincoln. Ultimately, arrays of AFM tips under computer control could produce complete devices, providing an alternative to current fabrication techniques.

June 15, 2011

A graphene waveguide and splitter.(Image Credit: University of Pennsylvania)

Two University of Pennsylvania engineers have proposed the possibility of two-dimensional metamaterials. These one-atom-thick metamaterials could be achieved by controlling the conductivity of sheets of graphene, which is a single layer of carbon atoms. Professor Nader Engheta and graduate student Ashkan Vakil, both of the Department of Electrical and Systems Engineering in Penn’s School of Engineering and Applied Science, have recently published their theoretical research. The study of metamaterials is an interdisciplinary field of science and engineering that has grown considerably in recent years. It is premised on the idea that materials can be designed so that their overall wave qualities rely not only upon the material they are made of but also on the pattern, shape and size of irregularities, known as “inclusions,” or “meta-molecules” that are embedded within host media. These unusual properties generally have to do with manipulating electromagnetic (EM) or acoustic waves; in this case, it is EM waves in the infrared spectrum. Changing the shape, speed and direction of these kinds of waves is a subfield of metamaterials known as “transformation optics” and may find applications in everything from telecommunications to imaging to signal processing. Engheta and Vakil’s research shows how transformation optics might now be achieved using graphene, a lattice of carbon a single atom thick.

Categories : University News