Spectral control of organic light-emitting diodes with plasmonic nanostructures

The out-coupling efficiency of optical guided modes, including a surface plasmon mode, in organic light-emitting diodes (OLEDs) can be improved by the introduction of corrugations to the interface between the metal electrode and the adjacent organic layer. The relationship between the k-space spectra of the corrugations and the enhanced emission spectra of white OLEDs is experimentally investigated. The corrugations are fabricated with a novel colloidal lithography, in which colloidal particles with several different diameters are used as a mask in the following dryetching process. In this fabrication technique the k-space spectrum of the corrugations can be easily controlled by the combination of particle diameters and their mixing ratio. The obtained emission spectrum normalized to the emission spectrum of a flat OLED reflected the k-space spectrum of the corrugations with high fidelity. The design guide lines for the corrugations for the efficient out coupling in white OLEDs are also presented. (C) 2018 The Japan Society of Applied Physics