66.2: Efficiency Enhancement in White PIN OLEDs by Simple Internal Outcoupling Methods

Highly efficient white PIN OLED structures based on internal outcoupling approaches using vacuum processable materials have been developed. In combination with external MLA outcoupling films an efficiency enhancement of 1.8 can be achieved resulting in a power efficiency of 50 lm/W at color coordinates x,y = 0.46/0.41 for a tandem OLED using fluorescent blue and phosphorescent green and red emitter systems. In a single unit 2‐color fluorescent white system with the same combination of internal and external outcoupling methods an efficiency of 37 lm/W at a color x,y = 0.48/0.42 is reached. This is to our knowledge the highest power efficiency reported for a fluorescent white OLED with a flat light extraction method. A similar approach using a vacuum processable scattering material in top emission OLED architectures on metal substrates allows to reach efficiencies of 36.5 lm/W with a CRI of 75 at a color x,y = 0.45/0.41.