LBNL Masthead Berkeley Lab U.S. Department of Energy A-Z Index Phone Book Careers

MSD - Materials Sciences Division

Nanocrystal Transformers

Materials Science Division researchers have, for the first time, directly observed structural transformations in semiconductor nanocrystals. Studying structural transformations in ordered materials is of great interest in many applications, from light harvesting and materials manufacture to energy storage, in which such transformations affect device performance.
A team led by Materials Science Division researchers Paul Alivisatos and Haimei Zheng is breaking new ground for the design of novel materials with the first direct observation of structural transformations in semiconductor nanocrystals. Studying structural transformations in ordered materials is of great interest in many applications, ranging from light harvesting to materials manufacture and energy storage, in which such transformations affect device performance.

Using TEAM 0.5, one of the world's most powerful transmission electron microscopes, the group observed structural fluctuations in a copper sulfide nanocrystal as it transitioned between two solid-state phases. Phase transitions in nanoscale materials occur with changes in temperature or pressure, resulting in a change in materials properties.

By viewing these transformations, the team revealed atomic pathways of phase nucleation, propagation, and pinning of structural domains through defects. TEAM 0.5 enabled rapid sample imaging with single atom sensitivity, providing an opportunity to study structural transformation dynamics as they occur. Such structural changes hold important implications for numerous phenomena, including ion transport within electrodes during charging and discharging of batteries.

View Press Release »

---

Reference: H. Zheng, J.B. Rivest, T.A. Miller, B. Sadtler, A. Lindenberg, M. Toney, L.W. Wang, C. Kisielowski and A.P. Alivisatos. "Observation of transient structural-transformation dynamics in a Cu2S nanorod," Science 333; 206-209 (2011). DOI: 10.1126/science.1204713