Synthesis, characterization and electroluminescence studies of cyanopyridine-based π-conjugative polymers carrying benzo[c][1,2,5]thiadiazole and naphtho[1,2-c:5,6-c′]bis([1,2,5]thiadiazole) units

Abstract

Four new donor–acceptor type cyanopyridine-based conjugative polymers, i.e.TDPy_1–4, carrying different electron-donating aromatic/heteroaromatic moieties in the backbone were synthesized from their respective co-monomers by using the Suzuki cross-coupling polycondensation protocol. These polymers were designed to possess good control of color emission and to have balanced charge injection, and transport properties. Their structures were confirmed by spectroscopic studies and their thermal stability was evaluated using the TGA technique. The photophysical, electrochemical and electroluminescence properties of these materials were established in order to assess their suitability for PLED applications. DFT-based computational studies were performed to verify and elucidate the above-said properties. Evidently, they demonstrate good green fluorescence with optical band gap (E_g) values of 2.14–2.27 eV. Finally, new PLEDs based on TDPy_1–4 were fabricated with a structure of ITO/PEDOT:PSS/polymer/Al, wherein they are able to act as green light emitters with stable electroluminescence behaviors.