Surface plasmon-polariton mediated emission of light from top-emitting organic light-emitting diode type structures

Surface plasmon polariton (SPP) modes may act as significant loss channels in organic light-emitting diode devices. We present experimental data illustrating that by the introduction of an appropriately scaled microstructure into a device, some of this lost power may be recovered as light. It is shown that in order to maximize this SPP-mediated light emission in a top-emitting light-emitting diode (TOLED) the plasmon modes associated with the two metal surfaces of the cathode must be coupled together. Data from grating-coupled and index-coupled SPP schemes are presented, and we show that photoluminescence emission from a structure containing a microstructured thin metal film that supports coupled SPPs is at least 50 times more effective than a similar planar structure. Experimental data is also presented from a structure containing a thin metal film whose profile contains a wavelength scale microstructure on a single interface. These data suggest that such a device geometry has the potential to increase the efficiency of top-emitting organic light-emitting devices. (c) 2006 Elsevier B.V. All rights reserved.