39.2: Charge‐Transfer Exciton Manipulation Based on Hydrogen Bond of Iridium (III) Complexes for Highly Efficient Blue OLED

Phosphorescent iridium emitters have played the significant role in the development of organic light‐emitting diodes (OLEDs). In contrast to the green‐ and red‐emitting phosphors, the design and synthesis of high‐performance blue emitters remains as a major challenge, owing to the fact that the annihilation of long‐lived triplet excited states in the emissive layer, such as triplet‐triplet annihilation (TTA) and triplet‐polaron annihilation (TPA), could lead to the occurrence of chemical bond dissociation, which eventually caused the degradation of the OLEDs. In this work, blue‐emitting vacuum‐deposited OLEDs based on these iridium complexes have been realized, in which the devices retain a high EQE max and CE of 22.01 % and 56.54 cd A −1 , respectively, and their efficiency roll‐off value around 10 % at the high luminescence level of 1000 cd m −2 . To our knowledge, the max brightness value of the device is over 50000 cd m −2 , which is the brightness record in the blue phosphorescent OLED range.