White OLEDs for Displays and General Lighting

Abstract

Junji Kido presents a talk on the recent progress in white OLEDs. In 1993, white-light-emitting OLEDs were developed for the first time. Since then, the performance of white OLEDs has steadily improved and, today, they are considered to be the light source of the next generation. OLED displays based on white OLEDs have also been developed and large-size displays have been commercialized. Recently, high quantum efficiencies (QEs) are obtained by using phosphorescent emitters such as iridium complexes. External QE of 25-30% was achieved for blue, green and red OLEDs, which correspond to the internal QE of nearly 100%. Device lifetime at high luminance levels, which is required for general lighting, is significantly improved by using the multiphoton structure. By combining the above techniques, OLEDs can be extremely efficient and possess an extremely long life, even at high luminance level. In 2010, Lumiotec Inc. started a small-scale production of white OLED panels in Yonezawa, and luminaires using their panels have been commercialized.