Synthesis and opto-electrical properties of carbazole functionalized quinoline based conjugated oligomer for luminescent devices

Abstract

Carbazole and quinoline combined donor-acceptor (QUI-OCZ) conjugated oligomer was synthesized by Wittig route. The resulting oligomer structure was well established by FTIR, NMR, Gel permeation chromatography (GPC) and elemental analysis. The resulting oligomer exhibits good solubility in common organic solvents.The optical and potential charge transporting properties of the oligomer were investigated by UV-visible, fluorescence spectroscopy and cyclic voltammetry. The UV-visible spectrum of the oligomer exhibited a sharp absorption band at 275-325 nm with shoulder peak at 374 nm. The oligomer also showed the fluorescence emission at 420 - 451 nm. The optical energy band gap and quantum yield of the oligomer was found to be 2.58eV and 0.237. In addition, quenching effect of QUI-OCZ was carried out by adding N, N-dimethyl aniline (electron donor) and dimethyl terephthalate (electron acceptor). The morphology of the oligomer film was examinedby atomic force microscopy (AFM) and observed spherical shape of particles with micrometre in size. The electrochemical studies of QUI-OCZ revealed that the HOMO and LUMO energy level was -5.74 and -3.17 eV respectively. Preliminary reports suggested that the oligomer will behighly useful for organic light emitting diode application.