Abstract

A series of distyrylbenzene (DSB) derivatives, as the oligomeric analogue of poly-p-phenylenevinylene (PPV), were synthesized and assessed as the emitter in organic light emitting diode (OLED) fabrication. The presence of an electron-withdrawing cyano group and an electron-donating methoxy group was studied at various positions in the molecule to evaluate their influence on the photophysical properties and the electroluminescent behavior of these derivatives in OLED. Bright blue emissions were achieved with these materials, as dopant, in a device of structure ITO/NPB/CBP/TPBI ∶ DSB/TPBI/Mg ∶ Ag, where NPB, CBP, and TPBI stand for 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl, 4,4′-dicarbazolyl-1,1′-biphenyl and 2,2′,2″-(benzene-1,3,5-triyl)tris-[1-phenyl-1H-benzimidazole], respectively. There was not much difference in the absorption and emission spectra of the compounds containing n-hexyloxy and 2-ethylhexyloxy groups. However, 2-ethylhexyloxy groups produce a more saturated blue color in their EL. The compounds 1–6 with higher fluorescence quantum yield did not result in higher EL quantum efficiency in this multilayer OLED fabrication as that of 7–9 with lower fluorescence quantum yield.