Synthesis and Blue Light Emitting Properties of Meta- and Para-Linked Hyperbranched Polymers Containing Oxadiazole Unit.

Abstract

Two meta-and para-linked hyperbranched polymers containing oxadiazole unit (end-capped by carbazole unit) (E-Hyper-MOXPPV and E-Hyper POXPPV) were synthesized through the Wittig poly-condensation polymerization. Both polymers showed excellent solubility in common organic solvents and exhibited good thermal stability up to 350 °C. An absorption maximum of E-Hyper-MOXPPV film was determined at 298 nm which was far blue shifted than that of E-Hyper-POXPPV film (349 nm). Light emitting properties of E-Hyper-MOXPPV and E-Hyper-POXPPV in solution and net solid film are investigated and compared each other. E-Hyper-MOXPPV and E-Hyper-POXPPV films showed blue photoluminescence (PL) peaks at 451 nm and 478 nm, respectively. Both polymers exhibited almost no excimer or aggregate emission even the films were annealed at 80 °C for 1 hr in air condition. No aggregate and excimer emission are due to inhibition of intramolecular or intermolecular interaction by the introduction of hyperbranched network into the meta-and para-linked oxadiazole containing poly(phenylene vinylene) backbone.