Customized conjugation: Tailored Π-systems for organic electronic applications

The versatility of the conjugated π-system allows it to be structurally tailored and imbued with properties relevant for organic electronics. Judicious selection of synthons and synthetic methodologies enables the modular construction of small to large conjugated materials at high synthetic efficiency. Three examples highlight the successful implementation of these design concepts, leading to high performance materials for three different prospective device applications. First, three triphenylene-based π-conjugated materials gave rise to large energy gaps, sufficient triplet energies, moderate transport characteristics, excellent thermal properties, and stable amorphous morphologies. The materials yielded high efficiency green OLED devices, comparable in performance to well-established host materials in the literature. Second, three twisted thiophene-based donor-acceptor chromophores show zwitterionic-aromatic ground states, due to both steric and electronic effects. All chromophores showed significantly lower Ege, enhanced Mge, and large Δμ, resulting in large third-order polarizabilities for optical switching applications. Finally, dioxythiophene-based donor-acceptor small molecules show neutral and charged states with well-defined optical and electrochemical transitions, reflecting the discrete nature of the π-systems. The small molecules showed narrow oxidized state transitions in the near-IR, making them promising for high contrast electrochromics applications.Ph.D