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Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Polymer Science and Engineering

Year Degree Awarded

2018

Month Degree Awarded

September

First Advisor

Dr. Kenneth R. Carter

Second Advisor

Dr. E. Bryan Coughlin

Third Advisor

Dr. Sankaran Thayumanavan

Subject Categories

Polymer Chemistry

Abstract

Conjugated polymers offer a unique opportunity to develop high performing, flexible, lightweight, and large area electronic devices. With advances in conjugated polymer understanding and synthesis, the use of polymers as active layer materials in electronic applications, rather than just substrate materials, has become more promising. However, defects in morphological stability, as well as imperfect electronic understanding, are still present, limiting the use of these materials in commercializable electronics. Fundamental understanding of structure-property relationships can allow for facile synthetic solutions to major drawbacks of conjugated polymer integration in standard device architectures. Chapter 1 presents background research on the history of conjugated polymer development and the electronic device architectures these materials are typically incorporated in.

Chapter 2 presents the use of thiol-ene chemistry to stabilize poly(3-alkylthiophene) films through a grafting-to procedure. This offers a simple way to produce highly oriented, insoluble, semi-conducting films through facile synthetic tuning of the polymers end-groups and side chains. In Chapter 3, the photophysics of carborane containing poly(dihexylfluorene) polymers is discussed. These unique class of materials experience drastic solvatochromism making them highly coveted for simple sensing applications. Through extensive spectroscopic investigations, a complete understanding of the excited-state dynamics is presented. Chapter 4 extends on Chapter 3 by demonstrating a straightforward method to synthesize carborane containing poly(dihexylfluorene)s with emissive properties that change with fluorene conjugation length, allowing for emission color tuning of the polymer solid and solution states. Lastly, Chapter 5 presents the synthesis of novel poly(bisthienyl carborane) and poly(bisthienyl carborane-alt-thiophene) is presented. This is the first example of a soluble conjugated polymer implementing a strong donor aromatic group and a strong acceptor carborane junction in the repeat unit. The fascinating excited-state characteristics are determined through femtosecond and nanosecond spectroscopy, showing the polymer can promote triplet formation on the carborane unit, making it useful for triplet sensitization applications.

The work presented in this thesis shows that straightforward synthetic techniques can be used to highly affect the properties of common conjugated polymers, making them more robust or beneficial for electronic applications. Side-chain and backbone engineering is a necessary technique for furthering the development of useful and applicable “plastic” electronics.

Available for download on Sunday, September 01, 2019

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