Chemistry and Chemical Biology ETDs

Publication Date

Spring 4-9-2021

Abstract

Poly(thienylene vinylene)s (PTVs) is special a class of conjugated polymers (CPs) that show remarkable optoelectronic properties and promising applications. The main reason that hinders their application, is the lack of synthetic methodologies for preparing new derivatives with various functionality. Developing new PTVs with improved structures based on structure-property relationships increases the potential of utilizing this type of polymers in advanced applications. Most available preparation methods lead to regio-random PTVs (ra-PTVs) structures due to the different placement of the sidechain in the polymer backbone, which results in reduced crystallinity. In this study, we developed a novel strategy that produces a series of regio-regular PTVs (rr-PTVs) bearing various alkyl chains and bromine atoms on each thiophene ring, we concluded that the bulky-silyl ether and the long-branched chains afforded highly soluble polymers with greater molecular weight than the linear and slightly branched chains that precipitated out during the polymerization. Then, we performed additional modification on the rr-PTV that bears the bulky-silyl ether group by replacing the bromine atom with electron-drawing side chains like a thienyl group attached either to a formyl (ThCHO), methyl 2-cyanoacrylate (ThCN), or 2-methylenemalononitrile (Th-2CN) sub-units. Additionally, we synthesized model compounds possessing similar repeating units of the prepared polymers in order to confirm the structures and understand the electrical and physical properties. Interestingly, we found that incorporation of rr-PTVs with ThCN and Th-2CN led to the lowest solid-film bandgaps (1.4 eV and 1.2 eV) among all developed polymers of this class, and fluorescent responses in the long-wavelength regions between 620-750 nm and 650-825 nm, respectively. Our developed methodologies provide a straightforward tool for synthesizing PTVs in novel structures. These developed PTVs can increase our understanding about structure-property relationships and allow for further structural modifications that make this class of polymer a better candidate for optoelectronic applications.

Language

English

Document Type

Dissertation

Degree Name

Chemistry

Level of Degree

Doctoral

Department Name

Department of Chemistry and Chemical Biology

First Committee Member (Chair)

Prof. Jeremy S.Edwards

Second Committee Member

Prof. Yang Qin

Third Committee Member

Prof. David Whitten

Fourth Committee Member

Prof. Yi He

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