Simplified Synthesis of Conjugated Polymers Enabled via 1,4-Dihydropyrrolo[3,2-b]pyrrole

Author

Kenneth-John Jack Bell, Kennesaw Sate UniversityFollow

Date of Award

Spring 4-22-2022

Track

Chemistry

Degree Type

Thesis

Degree Name

Master of Science in Chemical Sciences (MSCB)

Department

Chemistry

Committee Chair/First Advisor

Graham S. Collier

Committee Member

Carl Saint-Louis

Committee Member

Bharat Bharuah

Abstract

Conjugated polymers have attracted significant attention as the active layer material in organic electronics, such as organic photovoltaics and light-emitting diodes, partly due to the ability to influence a broad range of properties through structural design motifs. However, high performance conjugated polymers suffer from numerous synthetic steps, generation of toxic waste, and harsh reaction conditions all of which impart additional costs that inhibit their widespread utilization. Therefore, an emphasis on reducing synthetic complexity and utilizing abundant, commercially available starting materials is needed for organic electronics to reach their full potential. Dihydropyrrolo[3,2-b]pyrrole (H₂DPP) chromophores offer a simple one-pot synthesis to access electron-rich scaffolds for incorporation into a new class of conjugated polymers with tunable optoelectronic properties. Motivated by the simple synthesis, ease of purification, and an overall lower synthetic complexity for accessing monomers, dihalogenated H₂DPP monomers are synthesized and subsequently polymerized with electron-rich and electron-deficient comonomers. Through the choice of comonomers, H₂DPP polymers demonstrate facile optical tunability, evident by absorbance and fluorescence across the visible spectrum. Additionally, polymers demonstrate suitable thermal stability for standard processing protocols and motivate exploration of film properties. The synthetic complexity of the resulting polymers also is calculated and H₂DPP copolymers are quantified to be synthetically simpler compared to many conventional polymers used in solid-state and electrochemical applications. In total, this work shows that the incorporation of H₂DPP into polymeric materials simplifies the synthesis of conjugated polymers, maintains tailorability through functionality and comonomer choice, and lays the foundation for the continued development of a novel class of organic electronic materials.