Event Information
Dave Yaron
(Carnegie Mellon University)
Modeling the Effects of Disorder on the Photophysics of Organic Materials
Departmental Seminar
Modeling the Effects of Disorder on the Photophysics of Organic Materials
- Abstract:
- Various methods for modeling the effects of disorder on the photophysics of amorphous organic materials will be presented. Both inner-sphere (structural) disorder and outer-sphere (environmental) disorder will be discussed. Inner-sphere disorder is dominated by the torsional degrees of freedom. In phenylacetylene oligomers (nanowires), we will show that the unusual evolution of the absorption spectra with chain length arises from a large change in torsional barrier on excitation, from nearly free rotation in the ground state to a highly planar structure in the excited state. A simple one-dimensional model can account for these effects and provides an alternative interpretation of phenomena that currently attributed to effective conjugation lengths. We will also show that outer-sphere disorder dominates disorder-induced symmetry breaking in PPV and other conjugated polymers.
Host: David Beratan
Departmental Seminar