Press releases
Please quote Nature Materials as the source of these items.
May 2003
Nanoscale arms control
Some of the tiniest structures over which scientists exert control, such as nanowires and nanocrystals, are key building blocks for the future development of nanotechnology. Semiconductor nanocrystals now come in many forms: from spheres to discs and rods, with interesting mechanical, optical and electrical properties. In the June issue of Nature Materials, Paul Alivisatos and colleagues add nanocrystal tetrapods to this list and demonstrate impressive control over their specific size and shape.
Tetrapods have four arms, and Alivisatos and co-workers are able to independently control the length and width of the arms by varying the growth conditions of the semiconductor colloid used to make the nanocrystal. They achieve this level of control by exploiting the relative stability of two different crystal phases, which allows them to grow one phase at a time.
The authors suggest that their tetrapods could make useful additives for plastic composites or to improve the efficiency of polymer-based solar cells. As Charles Lieber and Deli Wang of Harvard University describe in an accompanying News and Views article: "it is interesting to see that the branched structures of both nanocrystals and nanowires are converging to a very similar point". And before long, multi-branched structures may be developed with novel electronic and optical properties.
