[The emission of rare earth complex Eu(asprin)3phen]

Two kinds of electroluminescent devices were fabricated by doping the rare earth complex Eu(asprin)3phen into polymer PVK: (1) ITO/PVK:RE/LiF/Al; (2) ITO/PVK:RE/PBD/LiF/Al. A great difference in the EL spectrum was found between the two kinds of devices. In device (2) the intensity of 594 nm was rather weak compared with that of 614 nm. The spectrum was consistent with the photoluminescence (PL) spectrum under the state of thin film. But in device (1), the peak emission of 594 nm was comparable to that of 614 nm. Preliminary discuss on this phenomenon was made; in device (1), the recombination region was close to the metal cathode, effect of metal cathode on the electroluminescence of the rare earth complex caused the changes of the EL emission which was quite different from the TL emission. The phenomenon was not observed in device (2) whose recombination region was far from the cathode because an electron-transport layer was inserted.