Nanostructured diamond films for efficient solar cells

from the the-diamond-age dept.
An article on Space Daily.com reports researchers at Vanderbilt University have created a prototype diamond-based thermionic solar cell that is potentially 3 to 4 times more efficient than conventional silicon-based cells. The operation of the diamond cells depends on their nanoscale properties.

The cells use diamond films covered with millions of microscopic pyramids: about 10 million per square centimeter. When heated, the tips of these pyramids, which are only a few atoms across, emit streams of high-energy electrons. At the nanoscale, the laws of physics favor the efficient production of high-energy electrons. "It is this nanoscale physics that makes the device work," says Vanderbilt Prof. Timothy S. Fisher, who led the research. He collaborated with Weng Poo Kang, an associate professor of electrical engineering and computer science. The bottom of the diamond film is laminated to a metal sheet that acts as a cathode. When heated, the tips of the tiny pyramids emit streams of electrons that flow across the intervening vacuum to the anode, creating an electric current.

New Mexico researchers create "smart nanostructures"

from the active-materials dept.
Researchers at Sandia National Laboratory and the University of New Mexico report they have created what they call self-assembling "intelligent nanostructures" that report on their environment by changing color from blue to fluorescent red under mechanical, chemical, or thermal stress.
According to their press release, the material can distinguish between different solvents by changing color. The material also can report changes in mechanical stress and temperature. When the environmental disturbance is removed, the structures change back to their original color in some cases, making them potentially reusable.
The Sandia/UNM fabrication method evenly pre-distributes monomers — simpler precursors of polymers — within a silica matrix through self-assembly. Exposure to UV light polymerizes the monomers into conjugated polymers housed in nanoscopic channels that penetrate the matrix of the material. The result is a nanocomposite that is mechanically robust, optically transparent, and produces telltale changes of color under changing environmental conditions. The researchers claim they also can control interactions between polymer units that affect a materialís electrical and optical properties.
Aspects of the work are also reported in the 19 April 2001 issue of Nature.

Nanotube "roll-ups" in non-carbon flavors

from the alternatives dept.
A simple method of producing non-carbon nanotubes has been developed by O.G. Schmidt and K. Eberl, scientists at the Max Planck Institute for Solid State Research in Stuttgart, Germany. The new technique makes it possible to prepare tubes from very different substances, such as silicon, as well as to vary their dimensions and to deposit the nano objects very exactly. Their method employs a strained semiconductor sheet that springs free of a crystalline substrate that holds it flat; the sheet then curls up into a nanotube.

According to the researchers, "Deposition techniques are capable of combining materials of almost unlimited diversity, including semiconductors, insulators, metals, polymers, etc. This richness will create new nano-objects of unknown diversity, which will find their fortune in the wide and interdisciplinary fields of micro- and nano-electromechanical systems."

Details of the work are reported in Nature, v410:168 (8 March 2001).

Quantum-Dot Nano-Lasers

from the can-they-use-that-name? dept.
TanMauWu writes "An article in the April 2001 issue of Technology Review reports the creation of "Nanodot Lasers". These lasers can potentially output coherent light in a very wide range of frequencies, as opposed to the limited frequencies modern lasers can provide."

The lasers are semiconductor particle quantum dots — just a few nanometers across — and quantum effects tune the color of the glow to the size of the particle. The work was conducted by MIT chemist Moungi Bawendi and Victor Klimov, a laser expert at Los Alamos National Lab in New Mexico.

Micro (nano) Assembly Proposed by metal industry

from the Industry-outlook dept.
ErenNano writes:
"I found this article while surfing the web. Itís a collection of predictions about where technology is leading, and nano assemblers were mentioned under the term Micro Assembly. An excerpt:
ìThe period of 2030 through the 2050s in manufacturing will be typified by the developments of microfabrication, virtual marketing and testing, and biocomputing. Microfabrication will be the most sweeping transformation for manufacturing since the advent of the computer. It will allow the fabrication of materials and parts at the molecular level, building them with the features we desire (strength, weight, flexibility, and so forth) at incredible levels of material efficiency . . . [W]ith the advent of nanotechnology, microscopic assemblers will grasp reactive molecules and combine them only in preplanned and controlled ways. Through these controlled and repetitive combinations, complex structures may be built up a few atoms at a time . . . The resulting material, and therefore the structure produced, will be many times stronger and lighter than traditional ones. Indeed, they will be stronger and lighter than anything we can build today."

"Pick-and-place" nanoassembly system wins prize

from the 1,000,000-dpi dept.
epw wrote in about the "Pick-and-Place" Nanoassembly System that was discussed on Slashdot as "Hubert's Interesting Nanoassembler." Brian Hubert won the Lemelson-MIT Student Prize for this invention, as reported by Nando Media/AP. His Úwebsite has good pictures and diagrams. It's not molecular nanotechnology as in precise control of individual atoms, but still seems like an interesting development using atomic force microscopes. Read more for the introductory text from the website. "Unlike the prior art, this system can be used to pattern essentially any type of material. …"

Self-healing materials: first steps

from the if-it's-broke-no-need-to-fix-it dept.
JohnPierce writes about work at UIUC published in Nature:"An AP article on Yahoo says: 'Researchers have developed the first material that automatically repairs itself, offering a potential way of fixing the hairline cracks that develop in the space-age composites used in everything from tennis rackets to aircraft. The scientists' secret: tiny capsules of glue that are added to the composite material… To heal tiny cracks automatically, the Illinois researchers sprinkled capsules about the thickness of a human hair throughout an experimental fiberglass-like compound. When a crack appeared, capsules in its path broke open, spilled their contents and sealed the cracks.'
Food for thought: Micro encapsulation is already in widespread use in medicine and food, so using it in construction materials is a natural progression. Nanotechnology will be able to encapsulate high strength repair substances that will survive high temperatures. Self repair will no doubt become a standard Nano application."

UK Nanotech Degree

from the mastering-the-technology dept.
warlock writes " Cranfield University is starting what it claims is the first nanotechnology degree course in Europe this year, for those of you who want to check it out. I'd be interested in hearing what you guys think of this course."

David Deutsch and quantum constructor theory

from the putting-the-multiverse-to-work dept.

David Coutts writes "David Deutsch, founder of the quantum computer field, believes that quantum computers will work by drawing upon the processing power of the multiverse. His book "The Fabric Of Reality" is a great read. Deutsch is working on a theoretical framework to prove whether or not quantum computers can be built. He calls this the 'quantum constructor theory'." Deutsch also hopes that his theory would answer questions about nanotechnology. In this interview, "It's a much bigger thing than it looks," posted last November on the Third Culture section of The Edge, he explains some of his ideas.

CNN on Hong Kong Nanotech

from the gearing-up-for-applications dept.

Michael Mehrle writes "CNN has this articleabout how recent advances in nano technology could be used in consumer appliances (CRTs, Hard drives, etc) as soon as next year. It's nice to see some nanotech applications that could be seen in the real world sooner than the '5-10' year range." Sachin Karol also wrote in about the article, and it was discussed in a Slashdot article on Nanotech of the Nearly-Now. This is the same Hong Kong University of Science and Technology research mentioned inan earlier Nanodot article

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