New Host Containing Bipolar Carrier Transport Moiety for High-Efficiency Electrophosphorescence at Low Voltages

A new host material for use in phosphorescent OLEDs with desirable electronic properties has been synthesized. The material exhibits superior carrier‐transport properties, a narrow optical band gap, relatively high triplet energy, and high thermal stability. It is synthesized by integrating hole‐transporting carbazole groups into an electron‐transporting phenanthroline core (see figure), and is demonstrated to be an excellent host for phosphorescent dopant emitters.