29 Mar
2016
29 Mar
'16
3:07 p.m.
Please post and forward to your groups:
CENTER FOR EXCITONICS SEMINAR SERIES presents:
Plasmonic metal oxide nanocrystals
April 5, 2016 at 4:30pm/34-401A
Delia Milliron
Department of Chemical Engineering, The University of Texas at Austin
[Delia-Milliron.01]
Degenerately doped metal oxide semiconductors, like ITO, exhibit plasmonic resonance at
near and mid-infrared wavelengths tunable by varying their composition. Nanocrystals of
many such materials have now been synthesized and applications are emerging that leverage
the responsiveness of their localized surface plasmon resonance (LSPR) to electronic
charging and discharging. For example, we are developing a new class of electrochromic
glass that can dynamically control heat loads and daylighting in buildings to save energy
and enhance comfort of building occupants. Further applications of these novel plasmonic
nanocrystals will hinge, in part, on their ability to concentrate infrared light into
nanoscale volumes and to enhance electronic and vibrational state transitions via
associated field enhancement effects. Through simulations, we have predicted high field
enhancement factors exceeding 300x for faceted nanocrystals. Experimentally, we can assess
the potential of plasmonic oxide nanocrystals for field enhancement by observing the
homogeneous LSPR linewidth, which is inversely related to the dephasing time. We have
sought to distinguish this intrinsic linewidth from the heterogeneous broadening that is
always present for colloidal nanoparticles. Measuring LSPR spectra of individual
nanocrystals by tip-enhanced synchrotron FTIR spectroscopy we find single nanocrystals can
have linewidths less than half of the corresponding ensembles. Thus, the dephasing times
are long and plasmonic oxide nanocrystals have great potential for diverse applications in
energy. I will conclude with an outlook on how materials chemistry enables the tuning of
LSPR properties by design.
Delia J. Milliron is an Associate Professor in the McKetta Department of Chemical
Engineering at the University of Texas at Austin and a Fellow of the Henry Beckman
Professorship. She also serves as an Associate Editor for the journal Nano Letters. Dr.
Milliron received her PhD in Chemistry from the University of California, Berkeley, in
2004. From 2004 to 2008 she worked for IBM's research division, initially as a
postdoctoral researcher and subsequently as a member of the research staff. In 2008, she
joined the research staff at the Molecular Foundry, Lawrence Berkeley National Lab, where
she served as the Director of the Inorganic Nanostructures Facility and later as the
Deputy Director. Dr. Milliron's awards include a Sloan Research Fellowship, a DOE
Early Career award and a Resonate Award from Caltech's Resnick Institute. Her
research is motivated by the potential for nanomaterials to introduce new functionality to
and reduce manufacturing costs of energy technologies. Her group's activities span
from the fundamental chemistry and assembly pathways of nanomaterials to device
integration and characterization.
The Center For Excitonics Is An Energy Frontier Research Center Funded By The U.S.
Department Of Energy,
Office Of Science And Office Of Basic Energy Sciences
Light refreshments will be served
