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Nano World: Quantum dot battle inevitable

By CHARLES Q. CHOI   |   June 20, 2005 at 2:45 PM
NEW YORK, June 20 (UPI) -- As the nanotech devices known as quantum dots grow ever more popular with the electronics and life-sciences industries, analysts fear the complicated patents underlying the field will trigger an expensive set of legal battles that benefit no one.

"The likelihood there will be a legal battle over quantum dots to me approaches certainty over a three-year timeframe," Matthew Nordan, vice president of Lux Research in New York City, told UPI's Nano World.

Still, other experts said, there may be a way to avoid these battles.

"It should be possible for the companies to work things out with cross-licensing to avoid the distraction of litigation, with millions of dollars going to research instead of years of lawsuits," said Stephen Maebius, chair of the nanotechnology industry team at Foley & Lardner in Washington.

Quantum dots are semiconductor crystals only billionths of a meter wide and made up of as few as 10 atoms. They fluoresce brightly when they absorb even tiny amounts of light. Scientists can engineer the exact colors of light quantum dots absorb, and they can fluoresce with extraordinary precision by adjusting the size and makeup of the dot. For instance, a cadmium-selenide quantum dot more than 6 nanometers -- or billionths of a meter -- in diameter would emit red light, while one less than 3 nanometers wide would release green light.

Quantum dots could help scientists image the behavior of cells and organs to a level of detail never seen before in the $500 million worldwide market for biological detection agents. The conventional fluorescent dyes used in the life sciences as tags for molecules that help researchers monitor how cells and organs grow and develop normally lose their ability to emit light within seconds. Quantum dots, on the other hand, last far longer, allowing investigators to monitor cells and organs in diseased and healthy conditions on a molecular scale in real time.

Quantum Dot Corp., a start-up in Hayward, Calif., already is collaborating with industry giants Genentech, Roche and GlaxoSmithKline.

Quantum dots also can produce electrons upon absorbing light. This could lead to solar energy devices nearly twice as efficient as the best modern solar cells, explain researchers at the National Renewable Energy Laboratory in Golden, Colo. When today's solar cells absorb a photon of sunlight, they convert the energy to, at most, one electron, with the rest lost as heat. Quantum dots can generate as many as three electrons from one high-energy photon of sunlight. This means solar cells based on quantum dots could theoretically convert more than 65 percent of the sun's energy into electricity, where the best cells today perform at about 33 percent efficiency, the scientists reported in the May issue of the journal Nano Letters.

Of the 319 quantum dot patents, many very clearly overlap.

"There are some very broad patents that claim all semiconductor nanocrystals, even though in their patent applications they only describe particular materials such as cadmium selenide," explained John Miller, a managing editor of the Nanotechnology Law & Business Journal.

Along with Quantum Dot, another start-up, Nanosys in Palo Alto, Calif., claims exclusive licenses to all key patents for quantum dots -- Quantum Dot for life sciences applications, and Nanosys for everything else, Nordan said.

"If anyone gets in our way in terms of intellectual property, then they're going to be taken out," George Dunbar, chief executive officer of Quantum Dot, told Nano World.

Several companies in the quantum dot arena think have devised a way around these claims of exclusivity, however.

"We don't see there are overlapping claims," Clinton Ballinger, CEO of Evident Technologies in Troy, N.Y., told Nano World. "We feel we have different technologies every step of the way. We spend a lot of time studying this minefield, and we feel we have the map to navigate this minefield. It's very difficult to get a stranglehold here."

For instance, last month Evident released the first quantum dots made of non-heavy metals.

"Japan and Europe have a strong resistance of cadmium, and most quantum dots are based on cadmium or lead," Ballinger said, adding that the United States will follow soon.

"If you want to use quantum dots for solar cells or LEDs or any other thing that might find its way into a dump, you can't have cadmium or lead -- period," he said. "We launched the first indium gallium phosphide dots, which address these environmental concerns directly. We should be up to kilogram quantities by the end of this year."

Nordan noted that, "With quantum dots, the first recourse people talk about is litigation, not licensing. That puts a big dark cloud over the field. You don't really find that with other arenas such as fullerenes, where you are much more likely to hear about cross-licensing between companies rather than an all-out legal war."

He said the correct solution to the issue is cross-licensing.

"This is what companies in IT are exceedingly good at. You have to swallow your pride to be economic," Nordan said.

Evident is selling quantum dots for life-sciences applications, but Ballinger does not think there will be a legal battle with Quantum Dot. "We're open to cross-licensing. It makes business sense," he said.

Dunbar did not rule out cross-licensing, but added: "Licensing really only works if you are dealing between financially stable enterprises. Not many that I know come close to falling into that category today."

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Nano World is a series examining the exploding field of nanotechnology, by Charles Choi, who covers research and technology issues for UPI Science News. E-mail: sciencemail@upi.com

Topics: John Miller
© 2005 United Press International, Inc. All Rights Reserved. Any reproduction, republication, redistribution and/or modification of any UPI content is expressly prohibited without UPI's prior written consent.
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