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<p class="MsoNormal"><span style="font-size:11.0pt">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.</span><o:p></o:p></p>
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<p class="MsoNormal"><b><i><span style="font-size:14.0pt">Professor Laura Kaufman<br>
</span></i></b><i><span style="font-size:14.0pt">Columbia University</span></i><o:p></o:p></p>
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<p class="MsoNormal"><b><span style="font-size:14.0pt">Single Molecules, Probes and Probed
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<p class="MsoNormal"><i>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.
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<p class="MsoNormal"><b><span style="font-size:10.5pt;font-family:Tahoma;color:black">Christine Brooks</span></b><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;color:black">Administrative Assistant</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;color:black">Massachusetts Institute of Technology</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;color:black">Department of Chemistry</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;color:black">77 Massachusetts Ave, 6-333</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;color:black">Cambridge, MA 02139</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;color:black">p: 617.253.7239</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;color:black">e: cbrooks@mit.edu</span><o:p></o:p></p>
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