New cyanopyridine-based π-conjugative poly(azomethine)s: Synthesis, characterization and electroluminescence studies

Four new Schiff-base type conjugative polymers (CPs), that is,Py(1-4)carrying a strong electron-withdrawing cyanopyridine scaffold coupled with different electron-donating aromatic/heteroaromatic moieties were synthesized from their respective co-monomers by simple poly-condensation route. They were subjected to structural, thermal, photophysical, and electrochemical characterizations and theoretical investigations in order to identify their suitability in polymer light-emitting diode (PLED) application. All these polymers showed good film-forming ability and exhibited favorable photophysical behaviors with an optical bandgap in the order of 2.54-2.68 eV. Further, their electrochemical data were used to evaluate highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels. Finally,Py(1-4)were successfully employed as blue-light emitter in the construction of new ITO/PEDOT:PSS/Py1-4/Al configured light-emitting diodes (LED), and the fabricated devices demonstrated stable blue electroluminescence behavior endorsing an effective electrons injection in the PLEDs.