Investigation of light out-coupling efficiency of blue OLED using microcavity effects

Microcavity effect plays an important role inside organic light-emitting diodes (OLEDs) due to a strong influence on the extraction of the light of the devices. In this work, the performance of blue fluorescent OLEDs (FLOLEDs) by constructing an epsilon negative tri-metal layer (ENTML) electrode is investigated. The function of the ENTML electrode is modulating the optical properties of the device under microcavity effects. The theoretical studies and experiments to evaluate the influence of the thicknesses of ENTML electrode and organic layers on the performance of blue FLOLED are presented. It is observed that the overall tendencies of both theory and experiment show good agreement. The measured results show 3.34% in maximum external quantum efficiency and 4.21 cd/A in luminous efficiency. The efficiencies of the FLOLEDs is optimized using the thin organic layer thickness of 90 nm with the Ni/Ag/Ni 2/8/2-nm thick ENTML anode.