Date of Award

8-17-2023

Publication Type

Dissertation

Degree Name

Ph.D.

Department

Chemistry and Biochemistry

Keywords

Automation;Crosslinking;Organic Chemistry;Organic Semiconductors;Polymer Chemistry;Self-Assembly

Supervisor

Simon Rondeau-Gagné

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Abstract

Organic semiconductors are a class of materials that are uniquely positioned to be the platform for next generation technologies that possess properties that transcend the limitations of silicon materials such as inherent biocompatibility, stretchability and degradability, all while being manufactured sustainably and at lower cost. These materials have good electronic properties that arise from their π-delocalized network, which when combined with rational chemical design allow for highly specialized materials for targeted applications and properties. Furthermore, their ability to be solution processed provides an avenue for low-cost, scalable mass production techniques, such as printing and roll-to-roll coating. Despite these advantages, however, these materials face the challenges of having low intrinsic stability as well as poor resistance to chemical and mechanical stress, resulting in devices with compromised performance and low lifetimes. In this dissertation, we report the development of a new crosslinking methodology for organic semiconductors at three molecular length scales: small molecule, oligomer, and polymer. This new methodology for crosslinking involves the incorporation of 1,3-butadiyne containing alkyl motifs within electroactive molecules that when exposed to mild UV irradiation are capable of polymerizing to form polydiacetylene when the right self-assembled parameters are met. In Chapter 1, a review of recently reported crosslinking strategies of organic semiconductors is reported to position the various strategies in the field and the unique advantages/disadvantages each confers. In Chapter 2, we report the synthesis and characterization and self-assembly and electronic properties of a diketopyrrolopyrrole (DPP) based organic gelator that can undergo the topochemical reaction, upon which its physical and optoelectronic properties are looked at. In Chapter 3, we expand this study by designing a conjugated oligomer to further probe the effects of crosslinking of physical and electronic characterization, as well as investigate the controllability of this technique using photolithography. In Chapter 4, we further expand this scope to a DPP based conjugated polymer using conjugated breaking spacers (CBS) and investigating the role of crosslinking density of optical and mechanical properties. In Chapter 5, we investigate the influence of a hydrogen bond containing DPP based conjugated polymer and the role of processing on its morphological and electronic properties using an automated high throughput robotic system called Polybot, ultimately with the goal of understanding the influence of this supramolecular interaction for designing future materials for targeted application. In Chapter 6, we summarize our investigations and discuss future steps taken from our ideas.

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