It is generally believed that exciplex is formed at the interface between a acceptor and a donor, it is not a new species, and it has a transit excited state. Based on the concept, we discussed the formation process of exciplex in organic electroluminescent (OEL) device with rareearth complex and considered that exciplex is also formed in the mixinglayer and it′s formation is the result from the interaction of singlet state of ligand and the holetransport material. Therefore, exciplex emission and the central ions emission of rareearth complex is an energy competition process. Therefore, it was resonable to understand that elimination of exciplex emission means enhance of the central ion emission of the rareearth complex through adjusting molar ratio of the two molecules.
Organic electroluminescent device of europiumcomplex is fabricated with the structure of ITO/CuPc(4 nm)/TPD(20 nm)/TPD:(Eu0.5Gd0.5)(DBM)3bath(20 nm)(the weight ratio is 1∶3)/(Eu0.5Gd0.5)(DBM)3bath(30 nm)/LiF(2 nm)/Al. The device not only can luminesce pure sharpband light under different dias and keep good luminescent performance(5.2 lm/A at the current density of 05 mA·cm-2) and 405 cd·m-2 at 14 V), but also can show good photovoltaic effect. Under UV light with 4 mW·cm-2 opencircuit voltage(Voc) is 1.37 V, shortcurrent density(Isc) is 39 μA·cm-2, fill factor(FF) is 0.21 and the overall power conversion efficiency is 028%, respectively.
