Reduction of guided waves in ITO/glass interface of white organic light emitting diodes (WOLEDs): Layer optimization

In this paper, our main purpose is to reduce Total Internal Reflection (TIR) phenomenon that is happening at Indium Tin Oxide (ITO, n_ito = 1.8 + 0.01i) and Glass (n_glass = 1.51) interface in WOLED to achieve higher output power. In normal WOLED because of higher refractive index contrast between ITO and Glass, guided waves usually limited into ITO layer and approximately 50% of generated light is trapped into ITO layer. Here, we tried to reduce this portion of trapped light by using 12-fold quasi-photonic crystal in mentioned interface. With some gentle changes in 12-folds structure, we could reduce TIR in this interface to less than 9%. Also, far field results before and after adding the structure were studied, which represents success of this idea and will open a new insight to lightning applications.