[MOS] April 14, 2009

[Zina Queen]

Seminar on

Modern Optics and Spectroscopy

Thiophene photophysics:
  oligomers, dendrimers, and polymers

David Blank,
University of Minnesota

Tuesday, April 14, 2009

12:00 - 1:00 p.m.


Conjugated organic systems have been demonstrated as successful 
primary components in organic optical and electronic devices such as 
photovoltaics. These materials offer some significant potential 
advantages in term of cost and processing over the traditional 
alternatives, but their performance has yet to become competitive. 
Using a variety of ultrafast time-resolved electronic spectroscopies, 
including pump-probe, time resolved fluorescence, and 2-color 3-pulse 
photon echos, we have investigated the dynamics of light absorption, 
molecular relaxation, and energy (exciton) migration in a range of 
thiophene based systems. The substituted oligomers and dendrimers 
offer well defined structures for study while the series of size 
selected polymers includes the typical distribution of molecular 
sizes found in actual devices. These systems span the range from 
molecular excited states that are the same size as the molecule to 
molecules that are much larger than the excitation (exciton). Once 
the molecular dimensions exceeds the exciton size, coupled relaxation 
and migration of the exciton (intramolecular energy transfer) becomes 
a key aspect of the dynamics.



Grier Room, MIT Bldg 34-401
Refreshments served after the lecture
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.mit.edu/pipermail/mos/attachments/20090413/54829e2d/attachment.htm