Tag Archives: Nature Photonics

University of Toronto researchers publish on quantum dots and ‘artificial molecules’

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Professors Shana Kelley and Ted Sargent (he was last mentioned in my June 28, 2011 posting on colloidal quantum dots) have published their findings on quantum dots, self-assembly, and luninescence in Nature Nanotechnology. From the July 10, 2011 news item on Nanowerk,

“Nanotechnologists have for many years been captivated by quantum dots – particles of semiconductor that can absorb and emit light efficiently, and at custom-chosen wavelengths,” explained co-author Kelley, a Professor at the Leslie Dan Faculty of Pharmacy, the Department of Biochemistry in the Faculty of Medicine, and the Department of Chemistry in the Faculty of Arts & Science. “What the community has lacked – until now – is a strategy to build higher-order structures, or complexes, out of multiple different types of quantum dots. This discovery fills that gap.”

The team combined its expertise in DNA and in semiconductors to invent a generalized strategy to bind certain classes of nanoparticles to one another.

“The credit for this remarkable result actually goes to DNA: its high degree of specificity – its willingness to bind only to a complementary sequence – enabled us to build rationally-engineered, designer structures out of nanomaterials,” said Sargent, a Professor in The Edward S. Rogers Sr. Department of Electrical & Computer Engineering at the University of Toronto, who is also the Canada Research Chair in Nanotechnology. “The amazing thing is that our antennas built themselves – we coated different classes of nanoparticles with selected sequences of DNA, combined the different families in one beaker, and nature took its course. The result is a beautiful new set of self-assembled materials with exciting properties.”

For anyone who can get past Nature Nanotechnology’s paywall, the article is titled, “DNA-based programming of quantum dot valency, self-assembly and luminescence”, and it was released on July 10, 2011.

Textiles used as batteries at UC Berkeley; University of Calgary, quantum entanglement and building blocks; Raymor Industries has a nano problem with its shareholders?

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There seems to be a race to get our clothes electrified so we can become portable recharging devices. From the news item on Azonano,

In research that gives literal meaning to the term “power suit,” University of California, Berkeley, engineers have created energy-scavenging nanofibers that could one day be woven into clothing and textiles.

These nano-sized generators have “piezoelectric” properties that allow them to convert into electricity the energy created through mechanical stress, stretches and twists.

“This technology could eventually lead to wearable ‘smart clothes’ that can power hand-held electronics through ordinary body movements,” said Liwei Lin, UC Berkeley professor of mechanical engineering and head of the international research team that developed the fiber nanogenerators.

This announcement is on the heels of a similar announcement (noted in my posting of Jan.22.10 here)  from researchers at the University of Stanford in California.

Meanwhile, scientists at the University of Calgary are playing with construction toys (they use the lego metaphor, which seems quite popular right now). From the news release on the University of Calgary website (thanks to Azonano where I first found notice of the item),

While many of us enjoyed constructing little houses out of toy bricks, this task is much more difficult if the bricks are elementary particles. It is even harder if these are particles of light—photons—which can only exist while flying at an incredible speed and vanish if they touch anything.

Yet a team at the University of Calgary has accomplished exactly that. By manipulating a mysterious quantum property of light known as entanglement, they are able to mount up to two photons on top of one another to construct a variety of quantum states of light—that is, build two-story quantum toy houses of any style and architecture.

The research has just (yesterday, Feb.14.10) been published in Nature Photonics. You can read the abstract (here after you scroll down) but the rest of the article is behind a paywall.

I found something rather odd this morning about Raymor Industries. It’s a Canadian nanotechnology company (their products are based on single-walled carbon nanotubes) traded on the TSX that is currently experiencing difficulty with, at least some, shareholders. From the item on PRNewsWire,

RAYMOR INDUSTRIES INC. (TSX Venture RAR, RAYRF) is a leading Canadian developer of high technology and a producer of advanced materials and nanomaterials for high value-added applications. Raymor holds the exclusive rights to more than 20 patents throughout the world, with other patents pending. Shareholders have formed a group to fight to protect our shareholder rights and prevent the current board of directors from delisting and the eliminating the common shares of the corporation.  The group is called The Raymor Investors Special Action Group.  The group is sending out this communication to get the attention of the 8000 shareholders and advise them that an appeal to the recent January 27, 2010 court ruling has been launched and is underway.  A strong and reasonable chance exists that the appeal can be won.

If you’re curious about the company and its products, you can read more here at their website, although they offer no additional information about the contretemps.