Structural‐Functional Properties of Asymmetric Fluoro‐Alkoxy Substituted Benzothiadiazole Homopolymers with Flanked Chalcogen‐Based Heterocycles

The synthesis and characterization of asymmetric alkoxy‐ are reported, fluoro‐benzothiadiazole (BT) acceptor core derivatized with a series of six different heterocycles (selenophene, thiophene, furan, 5‐thiazole, 2‐thiazole and 2‐oxazole). The effect of the flanked‐heterocycles containing different chalcogen atoms of the six homopolymers (HPX) is studied using optical, thermal, electrochemical, and computational analysis. Computational calculations indicate a strong relationship between the most stable conformation for each homopolymer and their bearing heterocycle, thus homopolymers HPSe’, HPTp’, HPFu’, and HPTzC5, adopted the syn‐syn and syn‐anti conformations due to their noncovalent interactions with shorter distances, while HPTzC2’ and HPOx’ demonstrate preference for the anti‐anti conformation. Optical property studies of the homopolymers reveal a strong red‐shift in solution and film upon exchanging the chalcogen atom from Oxygen < Sulfur < Selenium in HPFu, HPTp, and HPSe, respectively. In addition, deeper highest occupied molecular orbital (HOMO) energy levels are observed when the donor‐acceptor moieties (HPSe, HPTp, and HPFu) are substituted for the acceptor‐acceptor systems such as HPTzC5, HPTzC2, and HPOx. Improved packing and morphology are exhibited for the donor‐acceptor homopolymers. Thus, having a flanked heterocycle containing different chalcogen‐atoms in polymeric systems is one way of tuning the physicochemical properties of conjugated materials for optoelectronic applications.

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Published in: Macromolecular Rapid Communications
License: http://creativecommons.org/licenses/by/4.0/
See article on publisher's website: https://dx.doi.org/10.1002/marc.202200731