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Center for Excitonics
Seminar Series Announcement
Tuesday, February 15, 2011
3:00 PM
RLE Conference Room: 36-428
Rachel Segalman, University of California, Berkeley
"Molecular and Hybrid Solution Processable Thermoelectrics"
Abstract Thermoelectric materials for energy generation have several
advantages over conventional power cycles including lack of moving parts,
silent operation, miniaturizability, and CO2 free conversion of heat to
electricity. Excellent thermoelectric efficiency requires a combination of
high thermopower (S, V/K), high electrical conductivity (σ, S/cm), and low
thermal conductivity (κ, W/mK). To date the best materials available have
been inorganic compounds with relatively low earth abundance and highly
complex, vacuum processing routes (and hence greater expense), such as
Bi2Te3. Molecular materials and hybrid organic-inorganics bring the promise
of inexpensive, solution processible, mechanically durable devices. While
highly conductive polymers are now common place, they generally demonstrate
low thermopower. Our work on molecular scale junctions that nanostructuring
of organics allows them to act as thermionic filters between inorganic
junctions which can lead to enhanced thermoelectric properties. We have
taken inspiration from this fundamental understanding to design material
systems in which we combine a high electrical conductivity, low thermal
conductivity polymer with a nanoparticle that contributes high thermopower.
Additionally, the work functions of the two materials are well-aligned which
introduces the possibility of thermionic filtering at the interface and an
additional boost to the power factor. The combination of these effects
results in a new hybrid, solution processible material with a thermoelectric
figure of merit within an order of magnitude of the Bi2Te3. In this talk,
I will discuss both the use of thermoelectric measurements to gain insight
to molecular junctions and how this insight translates to design principles
for polymer and hybrid thermoelectrics.
Bio Rachel A. Segalman is an Associate Professor of Chemical Engineering
at the University of California, Berkeley and an Associate Faculty Scientist
in the Materials Science Division of Lawrence Berkeley National
Laboratories. Segalman received her B.S. in Chemical Engineering with
highest honors from the University of Texas at Austin. She then performed
her doctoral work in Chemical Engineering (polymer physics) at the
University of California, Santa Barbara. Following her PhD, Segalman was a
postdoctoral fellow at the Universite Louis Pasteur in Strasbourg France.
She then joined the faculty of UC Berkeley in the spring of 2004 as the
Charles Wilke Assistant Professor of Chemical Engineering. Segalman is the
author of more than 50 refereed publications including 3 invited reviews and
one book chapter. She has been also been granted three patents in the
field of energy research. She is an Alfred P. Sloan Fellow, a Camille
Dreyfus Teacher Scholar, and has received the Presidential Early Career
Award for Science and Engineering (PECASE), MDV Innovators Award, TR35:
Technology Review's Top Innovators Under 35, Hellman Family Young Faculty
Award, 3M Untenured Faculty Award, NSF CAREER Award, Intel Young Faculty
Seed Award, and Chateaubriand Postdoctoral Fellowship. She is currently
serving on the Science and Technology Committee of the Board of Governors
for Los Alamos and Livermore National Laboratory LLC and is an Associate
Editor for the Annual Reviews of Chemical Engineering and is on the
Editorial Board of Macromolecules. Segalman is also an active member of
APS, ACS, MRS, and AIChE and is a Member at Large for the Forum on
Industrial and Applied Physics (FIAP) of the American Physical Society.
Light refreshments will be served
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
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