[MOS] TODAY: 4/18: Modern Optics and Spectroscopy seminar with Professor Laura Kaufman (Columbia)

[Christine Brooks]

Please join us for a Modern Optics and Spectroscopy seminar today, Tuesday, April 18, with Professor Laura Kaufman of Columbia University. The seminar will be held in MIT 34-401 at 12pm, with refreshments served immediately afterward.

Professor Laura Kaufman
Columbia University

Single Molecules, Probes and Probed

In this talk I highlight two projects underway in my group that use single molecule (SM) fluorescence imaging to study complex, physical systems. In the first, single molecules are used as probes of heterogeneous dynamics in supercooled liquids. In particular, we investigate the time scales over which temporal heterogeneity exists using BODIPY and perylene diimide based probes in the small molecule glass former ortho-terphenyl (OTP) and in a polymeric glass former. These measurements show unequivocally that supercooled liquids are ergodic (where the time average equals the spatial average) down to the glass transition temperature and allow us to resolve seeming discrepancies between ensemble and single molecule measurements characterizing time scales of heterogeneities in this supercooled liquid. In the second project, single semi-conducting polymers serve as both the probe and the probed, providing a setting in which to study the fate of excitons, bound electron-hole pairs. We use a super-resolution technique to clarify the correlation between polymer conformation and photophysics at the single molecule level. Then, towards understanding such molecules in the context of their environment as it exists in devices, we perform controlled solvent vapor swelling to create aggregates of these molecules. This approach allows us to characterize semi-conducting polymer aggregate physical and optical anisotropy and suggests ways in which these properties may be controlled.


Christine Brooks
Administrative Assistant
Massachusetts Institute of Technology
Department of Chemistry
77 Massachusetts Ave, 6-333
Cambridge, MA 02139
p: 617.253.7239
e: cbrooks at mit.edu

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