Efficient blue phosphorescent host through nonbonded conformational locking interactions

We developed a new host material TCTEB with a conformationally homogeneous, sterically bulky structure due to nonbonded interactions between adjacent methylene groups. The host presented good thermal stability (T-g = 122 degrees C and T-d = 321 degrees C) and high triplet energy (3.0 eV). The Maximum quantum efficiency, current efficiency and power efficiency of the OLED device using the TCTEB host were 8.5%, 13.7 cd A(-1), and 11.3 lm W-1, respectively, when doped with 8 wt% FIrpic.