Suppressing surface plasmon losses to improve the efficiency of blue organic light-emitting diodes using the plasmonic quasi-bandgap phenomenon

Abstract

It is a persistent problem in organic light-emitting diode (OLED) display devices that the efficiency of blue-light source materials is lower than that of green- or red-light source materials. To address this problem, numerous studies have investigated blue-light-emitting materials. However, ensuring the reliability of the blue-light-emitting materials has been difficult in most studies. In this study, electrodes using asymmetric dielectric/metal/dielectric structures with plasmonic quasi-bandgap characteristics were developed to achieve a highly efficient blue fluorescent OLED. The electrodes were applied in a microcavity OLED and a transparent OLED. Using the developed electrode in fabricated OLED devices not only maximized the cavity resonance effect and transparency, but also preserved the advantage of the work function of the metal in terms of electrical properties, with high device stability. The approach also minimized losses caused by surface plasmon polaritons, which is a blind spot in the optical aspect of metal electrodes, resulting in improved light extraction efficiency.