Color-tunable electroluminescence from white organic light-emitting devices through coupled surface plasmons

The authors report color-tunable electroluminescence from white organic light-emitting devices (WOLEDs) through coupling of surface plasmons in a metal/insulator/metal (MIM) structure. The MIM structure was fabricated by depositing Ag and 2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline (BCP) films on the Ag cathode of a WOLED. The transmission wavelength through the MIM structure depends on the thickness of the middle BCP layer and can be tuned in the visible range. Therefore, the broadband emission from WOLEDs is selectively transmitted, and color-tunable EL emission was obtained. Blue, green, and red light emissions were observed when the BCP layer thicknesses are 70, 100, and 130 nm, respectively. (c) 2007 American Institute of Physics.