Model and simulation on the efficiencies of microcavity OLEDs

This paper presents simple calculation models of the external quantum efficiency and power efficiency for the microcavity OLEDs. The models take into account the energy spatial distribution of the device and provide a rough estimate of the efficiencies for the planar surface emitting devices, by which the integrating sphere and monochrometer were saved. The external quantum efficiency and luminous current efficiency from the structures of glass/DBR/ITO/NPB/Alq: C545T/Alq/LiF/Al and glass/ITO/NPB/Alq: C545T/Alq/LiF/Al were calculated based on these models and the measured data. Comparing with conventional OLED, the external quantum efficiency and luminous current efficiency of the MOLED were improved 3.1% and 8% at low current density (<10mA/cm2, corresponding to the display brightness range), respectively.