Fluorene-Centered, Ethynylene-Linked Carbazole Oligomers: Synthesis, Photoluminescence, and Electroluminescence

Two monodisperse fluorene-centered, ethynylene-linked carbazole oligomers ( Cz4F and Cz6F ) were synthesized and fully characterized. They were highly fluorescent and emitted bright blue in solutions and in films. Single- and double-layer devices based on them were fabricated to investigate their electroluminescence (EL) as well as their hole-transport properties. Cz4F, doped with PVK, in a double-layer device exhibited a rather broad emission spectrum with a maximum brightness of 926.6 cd m -2 at 17.0 V, which indicated that it might have potential use in white organic light-emitting diodes (WOLEDs). Moreover, Cz6F exhibited a bifunctional property, blue- or white-light-emitting property, and hole-transport ability, which qualified it as a light-emitter as well as hole-transport material.