Reduced efficiency roll-off in organic light-emitting diodes by a novel short-lived organoeuropium emitter.

In this paper, we report a novel organoeuropium complex [Eu(DPDBM)(3)DPPZ] based on a triphenylamine-derived beta-diketone ligand for short-lived emitter exploration. The (5)D(0) --> (7)F(2) ( approximately 610 nm) luminescence lifetime of Eu(DPDBM)(3)DPPZ is only 30 mus, which is 1 order of magnitude shorter than that of a typical Eu(3+) complex. The electroluminescence device using Eu(DPDBM)(3)DPPZ as the emitter achieves a maximum current efficiency of 3.0 cd/A, and the efficiency roll-off is largely reduced because of the emitter's short luminescence lifetime.