Synthesis and photoluminescence properties of novel copolymers containing salenAlQ-complex moieties and N-vinylcarbazole segments

Two novel salenAlQ-complex monomers and the corresponding copolymers are synthesized and characterized by 1H NMR, 13C NMR, FT-IR spectroscopy, and elemental analysis. The properties of the copolymers are investigated by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), cyclic voltammetry (CV), UV–vis absorption and photoluminescence (PL) spectra. The results indicate that the copolymers exhibit appropriate molecular weight, good solubility-processability, perfect thermal stability, and improved hole-transporting performance. Particularly, since two ligands (salen and quinoline) coordinate with aluminum ions simultaneously, the copolymers exhibit exciting photoluminescence phenomenons. The solution emission is mainly salen-centered, while the solid emission is mainly quinoline-centered. In addition, the PL emission intensities, efficiencies and decay lifetimes of the copolymers are higher than those of the corresponding monomers. These results demonstrate that the incorporated NVK segments are used as multiple roles (hole-transport group, light-harvesting groups and luminescence protection) in the copolymers.