Book Description
Conjugated polymers and small molecules are gaining a growing attention as the active materials for flexible and printed electronics. The present work discusses the exploration of novel conjugated polymers and small molecules with latent hydrogen-bonding on the conjugated backbone for electronic applications. In the first study, we synthesized a class of conjugated polymers with latent hydrogen-bonding utilizing Suzuki coupling reactions. The resulting polymers can be converted into actual hydrogen-bonded polymers upon thermal or UV removal of the t-butoxyl carbonyl (t-Boc) protection groups on the main chains. Large bathochromic absorption shift and dramatically decreased material solubility of the polymer were shown after the formation of hydrogen-bonding, indicating their enhanced interchain interactions. Photolithographic patterned electrochromic devices was fabricated and tested with the latent hydrogen-bonded conjugated polymers. The second study extends in assessing the field-effect transistor performance of two diketopyrrolopyrrole-based conjugated small molecules with latent hydrogen-bonding. Effects of the activation of latent hydrogen-bonding networks on the small molecule film properties, including UV/Vis absorption, band gap, solvent resistance, film morphology, molecular packing mode, and charge mobility are investigated. Highly crystalline films and improved field-effect mobility of the device was observed for both small molecules after the hydrogen-bonding activation, suggesting an efficient control of molecular organization and device performance of the latent hydrogen-bonding strategy. Based on similar principles, a series of conjugated statistical copolymers with varied latent hydrogen-bonding content on the main chain were studied in the third part of this work. Increased hole mobility was observed for the organic field-effect transistor devices of polymers in which higher percentage of hydrogen-bonded repeating units were comprised, which suggested the potential of latent hydrogen-bonding strategy in constructing solution-processed conjugated polymers with improved semiconducting performance.