Planarized SiNx/spin-on-glass photonic crystal organic light-emitting diodes

The light extraction characteristics of low-index spin-on-glass (SOG)-assisted, planarized photonic crystal organic light-emitting diodes (PC OLEDs) are reported. The light extraction efficiencies of planarized two-dimensional (2D) SiNx/SOG PC OLEDs (type II) and 2D SiNx/SOG PC OLEDs with an additional high-index SiNx layer (type III) are significantly better under typical operating conditions than those of the first generation of 2D SiO2/SiNx PC OLEDs (type I). The enhancements in the extraction efficiencies of type-II and type-III PC OLEDs are about 63% and 85%, respectively, with respect to those of conventional OLEDs with indium tin oxide layers of identical thicknesses. These improvements in extraction efficiencies are attributed not only to the liberation of the photons trapped in the high-index guiding layer but also to a reduction in the surface plasmon contribution. (c) 2006 American Institute of Physics.