The accumulation of charge in certain materials in response to an applied mechanical stress was first discovered in 1880 by Pierre Curie and his brother Paul-Jacques. The effect, piezoelectricity, forms the basis of today’s microphones, quartz watches, and electronic components and constitutes an awesome scientific legacy. Research continues to develop further applications in a range of fields including imaging [1, 2], sensing [3] and, as reported in this issue of Nanotechnology , energy harvesting [4]. Piezoelectricity in biological tissue was first reported in 1941 [5]. More recently Majid Minary-Jolandan and Min-Feng Yu at the University of Illinois at Urbana-Champaign in the USA have studied the piezoelectric properties of collagen I [1]. Their observations support the nanoscale origin of piezoelectricity in bone and tendons and also imply the potential importance of the shear load transfer mechanism in mechanoelectric transduction in bone. Shear load transfer h…
Posts Tagged ‘Applications’
High performance under pressure
Posted in Nanotechnology 
Tags: Applications, brother, develop-further, forms-the-basis, Issue, load-transfer, Nanoscale, Nanotechnology, pierre-curie, Piezoelectric, Potential, quartz-watches, shear, the-potential, University 
Comments OffTheoretical characterization of the topology of connected carbon nanotubes in random networks
In recent years, a lot of attention has been paid to carbon nanotube (CNT) networks and their applications to electronic devices. Many studies concentrate on the percolation threshold and the characterization of the conduction in such materials. Nevertheless, no theoretical study has yet attempted to characterize the CNT features inside finite size CNT networks. We present a theoretical approach based on geometrical and statistical considerations. We demonstrate the possibility of explicitly determining some relations existing between two neighbor CNTs and their contact efficiency in random networks of identical CNTs. We calculate the contact probability of rigid identical CNTs and we obtain a probability of 0.2027, which turns out to be independent of the CNT density. Based on this probability, we establish also the dependence of the number of contacts per CNT as a function of the CNT density. All the theoretical results are validated by very good agreement with Monte Carlo simu…
Posted in Nanotechnology Tags: Applications, approach-based, conduction, features-inside, monte-carlo, possibility, the-possibility, the-theoretical Comments OffAmerican Chemical Society grant to study molecular gears
The American Chemical Society Petroleum Research Fund has awarded a grant to study the development of molecular gears for use in future molecular machines. From an Austin College news release “ Chemist awarded $50,000 grant “ Dr. Stephanie Gould, assistant professor of chemistry at Austin College, has been awarded a $50,000 grant from the American Chemical Society to further her research on solid-state nanogears. … Gould’s research, “Synthesis of New Tunable Porous Coordination Materials to Demonstrate Geared Motion in Solid-State Materials,” focuses on building molecular “gears” for future use in nanotechnology. “I’m trying to move our world from large scale machines, like bicycles, to molecular-scale machines, moving atoms at a time,” she said. Just like a mechanical gear, these molecular gears will have cogs that will turn and fit together. “The smaller you can make a machine,” she said, “the more advanced the applications you can envision and create.” The research is on the cutting-edge of solid-state chemistry. While gears that move in liquids exist, these would be the first crystal-based gears. Possible future uses could include highly targeted nanobots to deliver a cancer drug directly to malignant cells, protecting the healthy cells from damage. It almost sounds like science-fiction. “We’re trying to figure out how much of science-fiction is real,” Gould said with a smile. Dr. Gould’s research is apparently a continuation of her postdoctoral research at the University of California, Berkeley. Work on the rotational dynamics of certain metal-organic frameworks was published in 2008 [ abstract ].
Posted in Nanotechnology Tags: Applications, berkeley-work, California, figure-out-how, geared-motion, molecular nanotechnology, NANOTECH, Research, rotational, Society, these-molecular, University Comments OffFirst Practical Nanogenerator
After six years of intensive effort, Georgia Institute of Technology scientists are reporting development of the first commercially viable nanogenerator, a flexible chip that can use body movements to generate electricity. At the 241st National Meeting of the American Chemical Society, they described boosting the device’s power output by thousands times and its voltage by 150 times to finally move it out of the lab and toward everyday life. “This development represents a milestone toward producing portable electronics that can be powered by body movements without the use of batteries or electrical outlets,” said Dr. Zhong Lin Wang. “Our nanogenerators are poised to change lives in the future. Their potential is only limited by one’s imagination.” The latest improvements have resulted in a nanogenerator powerful enough to drive commercial liquid-crystal displays, light-emitting diodes and laser diodes. By storing the generated charges using a capacitor, the output power is capable to periodically drive a sensor and transmit the signal wirelessly. “If we can sustain the rate of improvement, the nanogenerator may find a broad range of other applications that require more power,” he added. Wang cited, for example, personal electronics devices powered by footsteps activating nanogenerators inside the sole of a shoe; implanted insulin pumps powered by a heart beat; and environmental sensors powered by nanogenerators. Wang and colleagues demonstrated commercial feasibility of the latest nanogenerator by using it to power an LED light and a liquid crystal display like those widely used in many electronic devices, such as calculators and computers. The power came from squeezing the nanogenerator between two fingers. The key to the technology is zinc oxide (ZnO) nanowires. ZnO nanowires are piezoelectric — they can generate an electric current when strained or flexed. That movement can be virtually any body movement, such as walking, a heartbeat, or blood flowing through the body. The wires can also generate electricity in response to wind, rolling tires, or other kinds of movement. The diameter of a ZnO nanowire is so small that 500 of the wires can fit inside the width of a single human hair. Wang’s group found a way to capture and combine the electrical charges from millions of the nanoscale zinc oxide wires. They also developed an efficient way to deposit the nanowires onto flexible polymer chips, each about a quarter the size of a postage stamp. Five nanogenerators stacked together produce about 1 micro Ampere output current at 3 volts — about the same voltage generated by two regular AA batteries (about 1.5 volts each). “While a few volts may not seem like much, it has grown by leaps and bounds over previous versions of the nanogenerator,” said Wang, a scientist at Georgia Institute of Technology. “Additional nanowires and more nanogenerators, stacked together, could produce enough energy for powering larger electronics, such as an iPod or charging a cell phone.” Wang said the next step is to further improve the output power of the nanogenerator and find a company to produce the nanogenerator. It could hit the market in three to five years, he estimated. The device’s first application is likely to be as a power source for tiny environmental sensors and sensors for infrastructure monitoring. Read More
Posted in Nanotechnology Tags: Applications, Development, Georgia, inside-the-sole, nanogenerator, output, such-as-walking, Technology Comments Off13 Leti Annual Review will be on June 27-28, 2011
CEA Leti ( CEA’s Laboratory for Electronics and Technology) is focusing on micro and nanotechnologies, latest developments and various state of the art techniques and their applications and basically it works with the companies so that they can perform well in the nanotechnology areas. CEA is the French research and technology public organization and it works
Posted in Nanotechnology Tags: Applications, basically-it-works, cea, Companies, electronics, focusing-on-micro, French, Laboratory, latest-developments, Nanotechnology, Technology, the-art, the-companies Comments OffNanoparticles Boost Thermoelectric Efficiency
As materials that can convert heat directly into electricity, thermoelectrics sound highly promising to reduce global energy consumption. In addition to possibly finding their way into cars, they could also be used to recover useful energy from waste heat from nuclear reactors. Other applications including improving the effectiveness of solar cells and cooling computer chips and other electronic devices. To be of practical use, however, a thermoelectric material must be good at conducting electricity, but poor at conducting heat. Thirdly, it must also have a large thermopower (the ratio of the voltage to temperature difference across a material to its temperature difference). These three requirements are expressed in the thermoelectric figure of merit ZT. Any practical material must also operate at the appropriate ambient temperature, which in the case of vehicle exhausts can be hundreds of degrees. One promising group of thermoelectric materials are known as half-Heuslers , which are robust alloys of several metallic elements. They do suffer, however, from having relatively high thermal conductivities. One way of reducing their conductivity is to squish together a fine powder of the material to form a nanocomposite containing many tiny grains. Heat has a hard time traveling across the boundaries between grains, thereby reducing the overall thermal conduction of the nanocomposite. Now, a team of researchers from Boston College, MIT , the University of Virginia, and Clemson University has used this technique on an extremely fine powder, producing a nanocomposite with the best ZT yet for a half-Heusler. The team began with a cast ingot of the half-Heusler Zr0.5Hf0.5CoSb0.8Sn0.2, which was then crushed to make a powder with a particle size between 5 and 10 nm. Heat and pressure were then applied to press the powder into millimeter-sized bars and discs. This was done very carefully to try to minimize the number of nanoparticles that fuse together to create much larger grains in the finished product. The resulting solid had an average grain size of 100–200 nm. While this was larger than the original powder, it was about one-tenth the grain size of previous attempts at making similar materials. By measuring the thermopower of the nanocomposite along with its electrical and thermal conductivities, the team found that it had a ZT of 0.8 at temperatures of 700 °C, which is about 60% higher than the best previous value for a half-Heusler thermoelectric. One reason for the high ZT was that the thermal conductivity was about 30% less than the cast ingot from which it was made. The ZT value was also boosted by a small increase in the thermopower of the nanocomposite compared to the cast ingot. Both these effects more than compensated for the small measured drop in the electrical conductivity of the material, which, all other things being equal, would have reduced the ZT. Read More Paper
Posted in Nanotechnology Tags: Applications, boston, boston-college, Boundaries, cast, Conductivity, effectiveness, Material, Nanocomposite, tenth-the-grain, thermoelectric, thermopower, University, virginia Comments OffThe fabrication of highly ordered silver nanodot patterns by platinum assisted nanoimprint lithography
Silver has been widely used for optical sensing and imaging applications which benefit from localized surface plasmon resonance (LSPR) in a nanoscale configuration. Many attempts have been made to fabricate and control silver nanostructures in order to improve the high performance in sensing and other applications. However, a fatal mechanical weakness of silver and a lack of durability in oxygen-rich conditions have disrupted the manufacturing of reproducible nanostructures by the top-down lithography approach. In this study, we suggest a steady fabrication strategy to obtain highly ordered silver nanopatterns that are able to provide tunable LSPR characteristics. By using a protecting layer of platinum on a silver surface in the lithography process, we successfully obtained large-area (2.7 × 2.7 mm 2 ) silver nanopatterns with high reproducibility. This large-area silver nanopattern was capable of enhancing the low concentration of a Cy3 fluorescence signal (~10 − …
Posted in Nanotechnology Tags: Applications, control-silver, from-localized, lithography, Manufacturing, ordered-silver, provide-tunable, Study, surface-plasmon, the-lithography, the-top-down Comments OffNanowires For Stretchable Electronics
Researchers at North Carolina State University have created the first coils of silicon nanowire on a substrate that can be stretched to more than double their original length, moving us closer to incorporating stretchable electronic devices into clothing, implantable health-monitoring devices, and a host of other applications. “In order to create stretchable electronics, you need to put electronics on a stretchable substrate, but electronic materials themselves tend to be rigid and fragile,” says Dr. Yong Zhu, one of the researchers who created the new nanowire coils and an assistant professor of mechanical and aerospace engineering at NC State. “Our idea was to create electronic materials that can be tailored into coils to improve their stretchability without harming the electric functionality of the materials.” Zhu’s research team has created the first coils of silicon nanowire on a substrate that can be stretched to more than double their original length, moving us closer to developing stretchable electronic devices. Other researchers have experimented with buckling electronic materials into wavy shapes, which can stretch much like the bellows of an accordion. However, Zhu says, the maximum strains for wavy structures occur at localized positions – the peaks and valleys – on the waves. As soon as the failure strain is reached at one of the localized positions, the entire structure fails. “An ideal shape to accommodate large deformation would lead to a uniform strain distribution along the entire length of the structure – a coil spring is one such ideal shape,” Zhu says. “As a result, the wavy materials cannot come close to the coils’ degree of stretchability.” Zhu notes that the coil shape is energetically favorable only for one-dimensional structures, such as wires. Zhu’s team put a rubber substrate under strain and used very specific levels of ultraviolet radiation and ozone to change its mechanical properties, and then placed silicon nanowires on top of the substrate. The nanowires formed coils upon release of the strain. Other researchers have been able to create coils using freestanding nanowires, but have so far been unable to directly integrate those coils on a stretchable substrate. While the new coils’ mechanical properties allow them to be stretched an additional 104 percent beyond their original length, their electric performance cannot hold reliably to such a large range, possibly due to factors like contact resistance change or electrode failure, Zhu says. “We are working to improve the reliability of the electrical performance when the coils are stretched to the limit of their mechanical stretchability, which is likely well beyond 100 percent, according to our analysis.” Read More Paper
Posted in Nanotechnology Tags: Analysis, Applications, coils, Electrical, entire, Mechanical, North, reliability Comments OffFluorographene: A Two-Dimensional Counterpart Of Teflon
Researchers from the UK, China, the Netherlands, Poland and Russia have created a fully-fluorinated graphene material that shows similar properties to Teflon, including chemical inertness and thermal stability. The team hopes that the one-molecule-thick material, called fluorographene , could be used as a thinner, lighter version of Teflon, but could also be used in electronics, such as new types of electronic LED devices. “Electronic quality of fluorographene has to be improved before speaking about applications in electronics but other applications are there up for grabs,” said Professor Geim of the University of Manchester. Rahul Nair added: “Properties of fluorographene are remarkably similar to those of Teflon but this is not a plastic. It is essentially a perfect one-molecule-thick crystal and, similar to its parent, fluorographene is also mechanically strong. This makes a big difference for possible applications. We plan to use fluorographene an ultra-thin tunnel barrier for development of light-emitting devices and diodes. More mundane uses can be everywhere Teflon is currently used, as an ultra-thin protective coating, or as a filler for composite materials if one needs to retain the mechanical strength of graphene but avoid any electrical conductivity or optical opacity of a composite.” Industrial scale production of fluorographene is not seen as a problem as it would involve following the same steps as mass production of graphene. The Manchester researchers believe that the next important step is to make proof-of-concept devices and demonstrate various applications of fluorographene. “There is no point in using it just as a substitute for Teflon,” said Geim. “The mix of the incredible properties of graphene and Teflon is so inviting that you do not need to stretch your imagination to think of applications for the two-dimensional Teflon. The challenge is to exploit this uniqueness.” Read More Paper
Posted in Nanotechnology Tags: Applications, China, improved-before, mass-production, Mechanical, netherlands, optical-opacity, Professor, professor-geim, steps-as-mass, uniqueness, University Comments OffHow graphene could complement or replace silicon in electronic applications
As a follow up to the posts last week on new developments with graphene, Nanodot readers might want to check out an overview of the marvelous properties of this form of carbon currently featured in IEEE Spectrum, “ Graphene Electronics, Unzipped ” ( all-on-one-page-version ). Authors Alexander Sinitskii and James M. Tour ( Foresight Feynman Prize winner 2008 Experimental ) conclude: To be sure, silicon will reign supreme in many of the applications in which it is now found. But carbon, silicon’s little brother, has new realms to conquer. And if graphene keeps progressing as fast as it has in the past two years, it will surely attract the immense weight of investment in research and development that has so far gone almost exclusively to silicon. If that happens, then little brother will at first supplement silicon and at last supplant it, as little brothers often do. The title of the review derives from a method discovered in Prof. Tour’s laboratory of making nanoribbons of graphene from 3 to 300 nm in width (a promising size for use as building blocks for electronic devices) by using acid and oxidation to unzip a carbon nanotube along its length.
Posted in Nanotechnology Tags: Applications, carbon-nanotube, electronics, graphene-keeps, last-supplant, little-brother, little-brothers, marvelous, Nano, Nanotechnology, promising-size, will-at-first Comments Off