High Quantum Efficiency Blue Phosphorescent Organic Light-Emitting Diodes Using 6‑Position-Modified Benzofuro[2,3-b]pyridine Derivatives

High quantum efficiency blue phosphorescent organic light-emitting diodes were developed using 6- position modified benzofuro[2,3-b]pyridine derivatives as host materials. Two high triplet energy host materials derived from benzofuro[2,3-b]pyridine modified with carbazole or 9-phenylcarbazole were synthesized and the device performances of the host materials were investigated. A high quantum efficiency of 24.3% was achieved using the benzofuro[2,3-b]pyridine host materials due to good charge balance and energy transfer.