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

Abstract— 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 × 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/m² and Panel 2 has 58‐lm/W efficacy, CRI = 82, CCT = 2640K, and lifetime to LT70 = 30,000 hours at 1000 cd/m². Operating at a 3000 cd/m² (7740 lm/m²), 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.