Theoretical model for the external quantum efficiency of organic light-emitting diodes and its experimental validation

• An optical energy loss mechanism in OLEDs is introduced based on CPS theory.
• Theoretical calculations of both OCE and EQE in OLEDs are carried out.
• The simulation results are further validated experimentally.

An optical energy loss mechanism including the surface plasmon polariton (SPP) loss, wave guide (WG) mode and substrate mode in organic light-emitting diodes (OLEDs) is introduced based on CPS theory. The theoretical calculations of both the out-coupling efficiency (OCE) and the external quantum efficiency (EQE) of OLEDs are proposed. MATLAB tools are applied to simulate the optical model and provide the results of the two efficiencies. It is demonstrated that, the OCE and the EQE in a green phosphorescence OLED with optimized device structure can reach up to 20% and 27%, respectively (intrinsic quantum efficiency q = 90% assumed). The simulation results based on the theoretical model are further validated experimentally.

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