Highly directional emission via coupled surface-plasmon tunneling from electroluminescence in organic light-emitting devices

We report that highly directional electroluminescence from top-emitting organic light-emitting devices (TEOLEDs) can be achieved by using a two-dimensionally periodically corrugated silver film as a cathode and an organic dye with a narrow bandwidth of emission spectrum as an emitting material. The resonant excitation of surface plasmons on the silver film interfaces contributes to the light transmission through the silver cathode and to the directional emission. The TEOLEDs with a europium complex as an emissive layer show beam divergence of less than 4 degrees and the beam direction is controlled by periodicity of the corrugation. (c) 2005 American Institute of Physics.