Poly(p-phenylenevinylene)-Based Alternating Copolymers With Hole Transport Moiety

Phenylenevinylene and aromatic amine segments-based alternating copolymers were synthesized by Horner-Wittig-Emmons polymerisation reaction. The molecular weights of the copolymers were in the range of 39,500 - 26,100 and higher than those of conventional Wittig polymerization method. The maximum absorption and photoluminescence (PL) spectrum of the copolymers are shown at 420, 442 nm and 529, 545 nm with alkyl and alkyloxy substitutents into the phenylenevinylene backbone, respectively. The phenylenevinylene part acts as the emission role and the aromatic amine portions impart the hole transporting mobility and increase the thermal stability. Polymer light emitting diodes (PLEDs) were fabricated by sandwitching the emissive copolymers between ITO and calcium electrodes. The emission colors could be tuned from 492 nm to 530 nm by introducing the alkyl and alkoxy substitutents into the phenylenevinylene ring with applied electric field.