Novel Strategies for Nanoparticle Assemblies

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Novel Strategies for Nanoparticle
Assemblies Stephanie L. Brock, Wayne State
University, DMR-0094213
Recent NSF-supported work published in the
journal Science (2005, 307, 397) describes how to
prepare assemblies of quantum dot nanoparticles
without losing the unique, size-dependent optical
properties that are the hallmark of nanoscale
semiconductors. The trick is to obtain a
low-density, fractal-like structure of particles,
wherein the particles are physically connected,
yet remain dimensionally isolated.
Macrostructure (left) and microstructure (right)
of a CdS aerogel. The difference is scales is 106
In this work, nanoparticles are assembled by a
sol-gel strategy, and the polymeric wet-gel
structure is retained by supercritical drying,
yielding an aerogel. This technique has been
applied to CdS, CdSe, ZnS and PbS, providing the
first examples of chalcogenide-based aerogels.
Importantly, they all behave optically just like
the individual nanoparticles! This methodology
may be appropriate for assembling a wide range of
materials. The chalcogenide aerogels produced
here are currently being investigated for
photovoltaic and sensing applications
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Novel Strategies for Nanoparticle
Assemblies Stephanie L. Brock, Wayne State
University, DMR-0094213
Introducing Nanomaterials to Undergrads Getting
students involved in Nanochemistry early in their
studies is important for the development of this
new interdisciplinary science, but is not
addressed in traditional Chemistry curricula.
Over the course of the CAREER proposal, three new
laboratories and several lecture segments focused
on nanomaterials have been integrated into the
undergraduate inorganic courses at Wayne State.
Additionally, a total of ten undergraduate
students have participated in original research
projects in the Brock lab. In the process, these
students have acquired hands-on experience with
state of the art instrumentation, including X-ray
powder diffraction, and electron and atomic force
microscopes.
Michele Tague, an undergraduate from Keene State
College, NH, and participant in the NSF Summer
Research Program in Solid State Chemistry, seals
a sample in a glass ampoule.
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Novel Strategies for Nanoparticle
Assemblies Stephanie L. Brock, Wayne State
University, DMR-0094213
Laboratories on ferrofluids, metal chalcogenide
nanoparticles, and sol-gel chemistry have been
added to the senior level undergraduate inorganic
chemistry lab/lecture course. Additionally,
modules on solid state structure, band theory,
and physical properties of nanomaterials have
been incorporated in both the sophomore and
senior level inorganic chemistry courses. A total
of ten undergraduates (including three current
students and a 2004 summer fellow, Michele Tague)
contributed to the NSF funded research. The most
recent graduate, Christina Sweeney, participated
in NSF Summer Research Program in Solid State
Chemistry in 2004, working in the lab of Joanna
Aitzenburg at Lucent Technologies. She is now a
first year graduate student at Northwestern
University and first author on a recently
submitted manuscript.