Nanocrystal Transformers

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Moderators, please note, this is from a Government Laboratory.

http://newscenter.lbl.gov/feature-stories/2011/07/08/nanocrystal-transformers/

Nanocrystal Transformers

Berkeley Lab Researchers Observe Structural Transformations in Single Nanocrystals

July 08, 2011

While a movie about giant robots that undergo structural transformations is breaking box office records this summer, a scientific study about structural transformations within single nanocrystals is breaking new ground for the design of novel materials that will serve next-generation energy storage batteries and solar energy harvesting devices. Researchers at the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) have reported the first direct observation of structural transformations within a single nanocrystal of copper sulfide, a semiconductor expected to play an important role in future energy technologies.

Using TEAM 0.5, one of the world’s most powerful transmission electron microscopes, a research group led by Berkeley Lab director Paul Alivisatos, observed structural fluctuations in a copper sulfide nanocrystal as it transitioned between the low- and high-chalcocite solid-state phases. These fluctuations are highly relevant to understanding such phenomena as how ion transport occurs within electrodes during the charging and discharging of batteries, or how the structures of a solid material might change at the interface between an electrode and an electrolyte.

“TEAM 0.5, with its advanced electron optics and recording systems, enables rapid sample imaging with single atom sensitivity across the periodic table and greater collection efficiency. This provides extraordinary opportunities to study structural transformation dynamics in situ with atomic resolution,” Alivisatos says.

“In this study,” he adds, “we observed structural transformation dynamics in a copper sulfide nanorod from a low- to a high-chalcocite structure with unprecedented detail, and found these dynamics to be strongly influenced by defects in the nanorod crystal. Our findings suggest strategies for suppressing or assisting such transformations that should aid in the future design of materials with new and controlled phases.”

TEAM 0.5 micrographs showing the low-chalcocite (left) and high-chalcocite atomic structures of a copper sulfide nanorod.

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That’s just cool!

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