Nanoparticle-Mediated Assembly of Colloidal Crystals

1
Nanoparticle-Mediated Assembly of Colloidal
Crystals J.A. Lewis (PI), University of Illinois,
DMR 0071645
We have assembled 3-D colloidal gels and
crystals from binary mixtures of colloidal
microspheres and highly charged nanoparticles on
epitaxially patterned and non-patterned
substrates. Their structural evolution was
observed directly by confocal microscopy during
the assembly process. We then generated full 3-D
reconstructions of their structure, including
defects, as a function of initial suspension
composition and pitch of the patterned features
(see right images) and compared our experimental
observations to predictions made by novel Monte
Carlo simulations. Through proper control over
these parameters, we created 3-D colloidal
crystals with low defect densities suitable for
use as templates for photonic crystals and
photonic band gap materials. Ultimately, our
efforts may lead to new optical devices for
chemical and/or biological sensing,
opto-electronics, optical computing, and
telecommunication networks.
gel
fnano
crystal
3D reconstructions
C.J. Martinez, J. Liu, S.K. Rhodes, E. Luijten,
E.R. Weeks, and J.A. Lewis, Langmuir (in press) -
invited