OLED device having enhancement layer(s)

An organic electroluminescent device comprising:

• a substrate;
• a first electrode disposed over the substrate;
• an organic emissive layer disposed over the first electrode, the organic emissive layer comprising an organic emissive material, wherein the organic emissive material has a total non-radiative decay rate constant knon-rad0, a total radiative decay rate constant krad0, a total non-radiative decay rate constant due to the enhancement layer knon-radplasmon, and a total radiative decay rate constant due to the enhancement layer kradplasmon;
• an enhancement layer comprising a plasmonic material exhibiting surface plasmon resonance that non-radiatively couples to the organic emissive material and transfers excited state energy from the organic emissive material to non-radiative modes of surface plasmon polaritons, the enhancement layer being disposed not more than a threshold distance from the organic emissive layer;
• wherein the threshold distance is a distance at which
• k
• rad
• plasmon
• k
• non
• -
• rad
• plasmon
• =
• k
• rad
• 0
• k
• non
• -
• rad
• 0
• .