www.nanopicoftheday.org
July 27, 2004
Nanorattles
Source: Younan
Xia
References:
"Synthesis and Optical Properties of Nanorattles and
Multiple-Walled Nanoshells/Nanotubes Made of Metal Alloy"
Yugang Sun, Benjamin Wiley, Zhi-Yuan Li, Younan Xia. J.Am. Chem. Soc..; 2004; ASAP Web Release Date:
10-Jul-2004;
Description:
The galvanic replacement reaction between silver and chloroauric acid has
been exploited as a powerful means for preparing metal nanostructures with
hollow interiors. Here, the utility of this approach is further extended to
produce complex core/shell nanostructures made of metals by combining the
replacement reaction with electroless deposition of silver. Nanorattles were
fabricated consisting of Au/Ag alloy cores and Au/Ag alloy shells by starting
with Au/Ag alloy colloids as the initial template. Multiple-walled nanoshells/nanotubes
(or nanoscale Matrioshka) were also prepared with a variety of shapes,
compositions, and structures by controlling the morphology of the template and
the precursor salt used in each step of the replacement reaction. There are a
number of interesting optical features associated with these new core/shell
metal nanostructures. For example, nanorattles made of Au/Ag alloys displayed
two well-separated extinction peaks, a feature similar to that of gold or silver
nanorods. The peak at ~510 nm could be attributed to the Au/Ag alloy cores,
while the other peak was associated with the Au/Ag alloy shells and could be
continuously tuned in the spectral range from red to near-infrared.
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