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Keywords:

  • atom transfer radical polymerization (ATRP);
  • block copolymer;
  • electroluminescence;
  • light-emitting diodes (LEDs);
  • liquid-crystalline polymers (LCP);
  • living radical polymerization (LRP);
  • luminescence;
  • oxadiazole;
  • thiophene

Abstract

Block copolymers containing thiophene units in one block and oxadiazole (OXD) units in the other were prepared. Atom transfer radical polymerization method was used to obtain the thiophene-containing mesogen-jacketed polymers, and the kinetic study indicated that the polymerization was controllable and the polymers could be used to initiate the polymerization of the OXD-containing monomers. Photoluminescent spectra indicated that the fluorescence quantum yields of the polymers increased with increasing content of OXD. And, more OXD domains, that is, more interfaces between the hole-transport parts and electron-transport parts, resulting in the higher probability of exciplex formation. The electroluminescent devices containing the block copolymer with 64 mol % OXD as the emissive layer had a maximum brightness of 127 cd/m2 and an extremely low onset voltage of 7.7 V, which indicated that the injection and transport of charge carriers were facilitated and the number of charge carriers was sufficiently high in early time after the voltage was turned on. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010