Synthesis and optical and electrochemical properties of a bispyrimidinium-dibenzothiophene-S,S-dioxide-based cationic conjugated polymer

A novel n-type cationic conjugated polymer (PFSOmiCl), consisting of bispyrimidinium-dibenzothiophene-S,S-dioxide and fluorene scaffolds, was developed from its polymeric precursor (PFSOmi) through an intramolecular cyclization reaction. In comparison with PFSOmi, PFSOmiCl exhibits significant bathochromical absorption and photoluminescence spectra in both solution and film form, as well as a more hydrophilic film surface. Cyclic voltammetry tests demonstrate that PFSOmiCl possesses a deep lowest unoccupied molecular orbital (LUMO) energy level of −4.18 eV, which is comparable to the LUMO energy levels of common fullerene derivatives. These unique properties endow PFSOmiCl with great utilization potential in organic optoelectronic devices. Moreover, this research offers a novel guideline for designing new conjugated polyelectrolytes.

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