The synthesis, characterization and electroluminescent properties of zinc(II) complexes for single-layer organic light-emitting diodes

(E)-2-(2-(9-p-tolyl-9H-carbazol-3-yl)vinyl)-8-hydroxyl-quinoline, (E)-2-(2-(9-(4-methoxyphenyl)-9H-carbazol-3-yl)vinyl)-8-hydroxyquinoline and their respective zinc(II) complexes were synthesized and their structures confirmed using UV–vis, FT-IR, ESI-MS, FAB-MS, 1H NMR and elemental analysis. The two Zn(II) complexes displayed high thermal stability with thermal decomposition temperatures of 422 °C and 410 °C, respectively. Photoluminescence spectra revealed that the complexes possessed maximum emissions at 575 and 570 nm, respectively, in the green region. Single-layer, organic light-emitting diodes built using these complexes emitted yellow light, as a result of a red-shift, with maximum luminances of 489 cd/m2 and 402 cd/m2 as well as luminance efficiencies of 0.41 cd A−1 and 1.81 cd A−1, respectively.