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From the astronomically large, the second prize shifted focus to the molecularly small. The two "celebrities" of nanotechnology — quantum dots and carbon nanotubes — earned their respective discoverers the shared Kavli Prize in nanoscience.

Louis Brus (left), a physical chemist at Columbia University in New York, won the prize for inventing quantum dots, tiny bits of semiconductor materials roughly 10 to 50 atoms across. "I was originally motivated by wondering what happened to the transistor when it became extremely small," Brus said during a conference call with reporters. In 1983 Brus found that, as semiconductors reach very small sizes, their electrons become confined and exhibit quantum behaviors similar to those exhibited by electrons in a single molecule.

The color of light emitted by these quantum dots depends solely on their size, a property that scientists have already exploited to create new ways to watch molecules moving inside living cells for biological research. Scientists are also exploring quantum dots as a light source for computer displays with more accurate colors and for solar cells that generate electricity more efficiently.

Carbon nanotubes are undoubtedly the other high-profile fruit of nanotech research. Consisting of carbon atoms arranged in a chicken wirelike pattern and rolled up into tubes as little as about 10 atoms wide, nanotubes can act as tiny wires for molecular-scale electronic circuits and have been used to make super-strong materials.

Physicist Sumio Iijima (right) of Meijo University in Nagoya, Japan, shared the prize for seminal work on nanotubes that he published in 1991. By adapting a technique for making soccer-ball–shaped spheres of 60 carbon atoms, Iijima produced a black soot that contained tube-shaped variants of those spheres. Iijima was the first to recognize the potential of nanotubes, and his work sparked tremendous interest and research in the area. "This is probably the most important discovery made in materials, in electronic materials, in the last 15 years," Brus commented.


- Patrick Barry
Credit: Nec Corporation
Found in: Materials Science