Poly(fluorenevinylene) copolymers containing bis(phenyl)oxadiazole and triphenylamine moieties: Synthesis, photophysics, and redox and electroluminescent properties

New fluorescent fluorenevinylene copolymers incorporating bis(phenyl)oxadiazole, triphenylamine, or both moieties were synthesized, characterized, and used as the emissive materials in efficient electroluminescent diodes. In dilute solutions, the copolymers had blue-green fluorescence with high quantum yields of 0.76-0.87. All the copolymers had high glass transition temperatures (T-g = 147-160 degrees C) and outstanding thermal stability. Light emitting diodes based on the neat copolymer thin films showed bright greenish-yellow electroluminescence, with luminances of up to 1360 cd/m(2), originating mostly from intramolecular charge-transfer excited states due to the presence of the donor/acceptor moieties in the copolymers. However, dilute (approximately 5 wt %) binary blends of the copolymers with poly(vinyl carbazole) gave stable blue electroluminescence (CIE = 0.17, 0.16) with higher luminances (1770-3400 cd/m(2)) and luminous efficiencies of up to 1.34 cd/A.