Phosphorescent OLEDs: Enabling energy-efficient lighting with improved uniformity and longer lifetime

In this paper, the design criteria for scaling up from small-area organic light-emitting-diode (OLED) pixels to large-area OLED light panels is described. Particular focus is placed on using phosphorescent OLEDs (PHOLEDs) to maximize panel efficacy and uniformity and minimize operating temperature. Data for a pair of all-phosphorescent 15 x 15 cm OLED light panels are also presented: Panel 1 has 62-lm/W efficacy, CRI = 81, CCT = 3180K, and lifetime to LT70 = 18,000 hours at 1000 cd/m(2) and Panel 2 has 58-lm/W efficacy, CRI = 82, CCT = 2640K, and lifetime to LT70 = 30,000 hours at 1000 cd/m(2). Operating at a 3000 cd/m(2) (7740 lm/m(2)), Panel 2 has 49-lm/W efficacy with lifetime to LT70 = 4000 hours. Excellent panel lifetime is enabled by a stable light-blue phosphorescent materials system and by the use of efficient phosphorescent emitters that ensure very low panel temperature without any additional thermal management.