From molecular design to electroactive polymer: Synthesis, electropolymerization, and DFT analysis of a carbazole EDOT-based compound

A novel carbazole-EDOT-based monomer ( D ) was synthesized and its structure verified through several characterization methods, including UV-Vis, FT-IR, CHNS elemental analysis, and NMR spectroscopy. The monomer was obtained with a yield of 70% and designed to combine the extended π-conjugation of the EDOT moiety with the electron-donating nature of carbazole. Measurements of electrochemical polymerization of EDOT, carbazole and the novel monomer D were carried out. Various EDOT feed ratios were used to prepare copolymer (P( D -co-EDOT)). The electrochemical performance of these copolymers was examined with the help of cyclic voltammetry (CV). The electrochemical properties and reduction-oxidation potential were measured in a monomer-free electrolyte solution of TEABF4/ACN-DCM (3:2) solution. It should be noted that the most advantageous features were observed in the copolymer that was produced with the 1:10 ratio of monomer D to EDOT. The product formed by this particular ratio had better electrochemical stability and a significant low band gap of 1.40 eV. The SEM imaging revealed that the copolymer films have a homogeneous surface morphology and are strongly adsorbed to the substrate, unlike the homopolymer of monomer D , which forms poor films. The computational modelling of the material using DFT was another approach that helped to prove the physical observations by providing important information on the electronic properties of the material. Namely, computational analysis illuminated the HOMO-LUMO gaps and molecular electrostatic potential distribution of the polymer backbone. The combination of experimental and theoretical methods supports the potential of D -co-EDOT copolymers for electrochemical and optoelectronic applications, warranting further device-level investigation.