Outcoupling efficiency in small-molecule OLEDs: from theory to experiment

The extraction of the luminous power internally generated by organic light emitting diodes (OLEDs) is still the most severe limitation in the overall efficiency of these devices. We present a joint theoretical and experimental study aimed to quantitatively evaluate the light outcoupling limitations of planar p-i-n type small-molecule OLEDs, both in bottom and top emitting configuration. We discuss the physical origin of these limitations by analyzing internal optical losses and overall light conversion efficiency in OLEDs.