[LA-SiGMA] LASiGMA Seminar at Tulane, Wednesday, November 5, at 3:00 pm - Matt Sfeir

[shelley lee]

Dear All,

Dr. Matt Sfeir of Brookhaven National Laboratory, will be giving a talk,
Wednesday, November 5th at 3:00 pm in room 600 at the Lindy Boggs Building,
Tulane University. The title of his talk is " Novel Singlet Fission
Processes in Organic Semiconductors."

Abstract:
Singlet fission is a form of multiple exciton generation in which two
triplet excitons are produced from the decay of a photoexcited singlet
exciton. In a small number of organic materials, most notably pentacene,
this conversion process has been shown to occur with unity quantum yield on
sub-ps timescales. However, a poorly understood mechanism for fission along
with strict energy and geometry requirements have so far limited the
observation of this process to a few classes of organic materials, with only
a subset of these showing both efficient fission and long-lived triplets.
Here, we utilize novel organic materials to investigate how the efficiency
of the fission process depends on the coupling and the energetic driving
force between chromophores in both intra- and intermolecular singlet fission
materials. We report for the first time intramolecular fission yields above
100% and demonstrate how the triplet yield can be directly quantified as a
function of energetic driving force and degree of charge transfer character
of the singlet state. These results allow us to gain mechanistic insight
into the fission process and suggest general strategies for generating new
materials that can undergo efficient fission.
   
Biography:
My research focuses on using optics to probe the electronic structure and
interfacial interactions among novel nanoscale materials. This includes
measurements of fundamental carrier dynamics, photo physics of excitons and
other bound states, electron-phonon coupling, and as well as charge and
energy transfer processes. My interests include the development of broadband
time-resolved and optoelectronic spectroscopies and their application to
evaluate the potential of novel materials in light harvesting devices.  My
recent work has focused on exciton conversion processes in low band gap
organic semiconductors and the in-situ dynamics of nanostructured
heterogeneous photo catalytic materials. I received my Ph.D. in Chemical
Physics in 2005 from Columbia University under the supervision of Prof.
Louis Brus and have been a staff member at the Center for Functional
Nanomaterials since 2009.

UNO - 234, Liberal Arts Building
LATech - 122, Nethken Hall
SUBR - 211 J.B. Moore Hall
Xavier - 226 Qatar Pavillion
LSU - 1008B Digital Media Center

Please note, this seminar will ONLY be accessible through HD
videoconferencing. Adobe connect will NOT be offered.

Regards,
Shelley Lee
Project Coordinator
225-578-0465



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