Development of Novel Macromolecular Organic Semiconductors for their Applications in Organic Electronics

Abstract

Organic semiconducting (OSC) materials are now more than ever being exploited in modern technology for the development of next-generation organic electronic devices. These types of materials hold many advantages over their inorganic counterparts such as their mechanical flexibility, solution processibility, lighter density and strong light-matter interactions, to name a few. Nevertheless, their most attractive feature remains their ease of functionalization to adjust and optimize their optical and electronic properties. The slightest change in molecular structure can have a significant impact on the materials' ability to interact with analytes, absorb light and transport charges. This has led OSCs to be exploited in a wide array of fields including optoelectronics, sensors and actuators, energy storage, printed electronics, biomedical applications and more. This thesis looks to developing new donor-acceptor (D-A) small molecules and porphyrinoid macrocycles and evaluate their potential as n-type and p-type OSCs in organic thin-film transistors (OTFTs) as well as their potential in chemical sensing. I synthesized and characterized each novel material at the molecular level and in the solid state when processed into thin-films. The chemical derivatizations allowed to adjust the frontier molecular orbitals (FMOs) and molecular bandgap adopted by each material. I also studied their semiconducting potential in different OTFT device architectures as well as explored different device fabrication conditions to optimize their semiconducting abilities. In the latter work of this thesis, I also explored electropolymerization of silicon phthalocyanine materials to create sensing films onto quartz microbalance (QMB) sensors for mass-based detection and interdigitated electrode (IDE) sensors for electronic-based detection of various gases and volatile organic compounds (VOCs). Overall, this thesis demonstrates the design and functionalization of OSC materials and portrays the importance of structure-property relationships adopted by these materials as they are processed into thin-films for specific organic electronic applications.