Luminescence properties of bipolar stylbeneamine–quinoxalines

Novel electroluminescent materials combining three functionalities were used as active layers in light-emitting diodes. These functionalities are brought about by the presence of three moieties: diphenylstylbeneamines, for hole transport, quinoxaline, for electron-transport, and a dehydroabietic acid methyl ester, to prevent crystallisation. The devices prepared with these materials and with magnesium cathodes show efficiencies up to 0.03 cd/A, which is about one order of magnitude higher than the efficiency obtained with the related diphenylstylbeneamines.