Chemical Bond Stabilization and Exciton Management by CN Modified Host Material for Improved Efficiency and Lifetime in Blue Phosphorescent Organic Light‐Emitting Diodes

A high triplet energy host material for improved efficiency and elongated lifetime is developed by modifying carbazole linked terphenyl with a CN substituent. The CN modification strengthens electron injection and transport of the host material, which reduces the driving voltage, improved quantum efficiency, and power efficiency of blue phosphorescent organic light‐emitting diodes. Furthermore, the CN modification also extends the lifetime of the blue device due to the chemical bond stabilizing effect of the CN moiety in radical, anion, and cation states. Therefore, the molecular design modifying the backbone structure with CN is an efficient approach for high efficiency and long lifetime.