Highly Efficiency Top-Emitting Organic Light-Emitting Diode with Double Capping Layers

In this work, we propose an outcoupling strategy to improve the efficiency of red OLEDs via adding double capping layers on top of the semitransparent cathode. The double capping layers consists of a low refractive layer as the light output of the normally directed mission, and a common high refractive capping layer upper to increase the optical interference and retribution. Red devices with double capping layers exhibited a 27% enhancement of efficiency compared with the one with single capping layer, which resulting in a maximum current efficiency of 64.12 cd/A.