Nicotinonitrile centered luminescent polymeric materials: Structural, optical, electrochemical, and theoretical investigations

Abstract

Herein, we describe the design, synthesis, and structural characterization of three new push-pull type conjugative polymers, that is, VPPy1-3 comprising strong electron-withdrawing N-heterocyclic nicotinonitrile scaffold coupled with electron-donating phenylene units through vinylene bridges, as promising candidates for optoelectronic applications. They were successfully synthesized from their respective co-monomers by simple polycondensation synthetic routes, viz. Knoevenagel and Wittig reactions. All the polymers were subjected to photophysical, electrochemical, thermal, and theoretical studies in order to ascertain their suitability in polymer light-emitting diode applications as blue emitters. Evidently, they are readily soluble in most of the organic solvents, enabling them easy solution-processable. These new polymers display strong blue photoluminescence at the peak in the range of 431 to 462 nm with a wide optical bandgap in the order of 2.55 to 2.63 eV. The obtained electrochemical data were employed to evaluate their HOMO/LUMOs. The density functional theory calculations generated useful information on their FMO, molecular geometries, and electronic properties. Also, the influence of their structural modification on the above-said properties was discussed in detail to reveal the structure-property relationship. Conclusively, these results illustrate the great prospective of this class of polymeric materials for the application in solution-processable blue LEDs. © 2020 Society of Plastics Engineers