Chemistry and Chemical Biology ETDs

Publication Date

Summer 6-20-2019

Abstract

The conventional understanding of intersystem crossing in multichromophoric conju- gated polymers is usually depicted via a pure electronic model, neglecting contributions of vibrations or conformational order. Obtaining accurate structure-function correlations on spin-conversion processes involving photogenerated singlet excitons to triplet excitons and the excited state dynamics requires sensitivity to the subtle conformational ordering within conjugated polymers. This dissertation seeks to understand the kinetics of multi-exciton singlet-triplet interactions and the excited state relaxation of chalcogen containing (S, Se) conjugated polymers. Utilizing single molecule modulation spectroscopy allows determi- nation of triplet formation of individual conjugated polymer chains and aggregates. This technique resolves triplet-induced fluorescence quenching to ascertain the dynamics of the triplet population. In parallel, we have utilized the solutions to the probabilistic master equation describing the time-dependent kinetics of triplet formation. Finally, investigat- ing the excited state relaxation of strongly aggregating, non-emissive poly(3-decylthieneyl- enevinylene) (P3DTV)anditsheavyatomanalogpoly(3-decyl-seleneylenevinylene) (P3DSV) we demonstrate an alternative hypothesis for the observed ultrafast excited state dynamics.

Language

English

Keywords

conjugated polymers, single molecule spectroscopy, chemical master equation

Document Type

Dissertation

Degree Name

Chemistry

Level of Degree

Doctoral

Department Name

Department of Chemistry and Chemical Biology

First Committee Member (Chair)

John K. Grey

Second Committee Member

Jeff Rack

Third Committee Member

Terefe G. Habteyes

Fourth Committee Member

David Dunlap

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