High-efficiency top-emitting organic light-emitting devices

Based on theoretical arguments that top-emitting organic light-emitting devices (TOLEDs) can be more efficient than equivalent bottom-emitting devices, we fabricated TOLEDs comprising reflective anodes and transparent compound cathodes that emit 20.8% more photons in the forward 120degrees cone than equivalent bottom-emitting OLEDs. Device optimization by tuning the thickness of the top indium-tin-oxide layer according to a microcavity model is also reported. (C) 2002 American Institute of Physics.