Zoom Link:  https://kaust.zoom.us/j/94669261358

Abstract

The thesis focuses on the development of conjugated polymers for n-type organic thermoelectrics (OTEs) and accumulation mode organic electrochemical transistors (OECTs). The studied polymers are electron-deficient lactam/lactone acceptor-acceptor type polymers. First, the research explores optimizing dopant diffusion within the polymer matrix to improve doping efficiency and electrical conductivity. This was achieved by investigating two polymers, with one incorporating a side-chain-free lactone unit. The N-DMBI-doped polymers were then characterized using experimental methods and molecular dynamic (MD) simulations. Results revealed that films of the polymer containing the side-chain-free unit exhibited electrical conductivity three orders of magnitude higher than those without, after doping with N-DMBI. Second, the thesis addresses the challenge of ambient stability in n-type Organic Mixed Ionic-Electronic Conductors (OMIECs) for OECT applications. This involved adding an ion-membrane layer between the OMIEC layer and the electrolyte, which blocked the passage of O₂ and H₂O molecules, leading to stable OECT performance. Additionally, this approach allowed for the use of hydrophobic conjugated polymers in aqueous environments for OECT applications. The above work offers guidelines from both a chemical design and a device engineering point of view, in order to enhance the electrical properties and the stability of the conjugated polymers.