Analysis of Out-Coupling Mechanism in Organic Light-Emitting Diodes

We investigated the quantitative mechanism of out-coupling enhancement in nanostructure-embedded organic light-emitting diodes (OLEDs). A numerical calculation was performed for a 2-D configuration with nanostructures, and power dissipation via various optical modes was achieved. The extraction of light loss from the surface plasmon mode was three times higher than that from the waveguide mode in nanostructure-embedded OLEDs. Thus, we conclude that out-coupling enhancement originates from the recovery of light losses related to the surface plasmon mode. Furthermore, we simulated the relation between out-coupling enhancement and the geometry of the nanostructure.