Benzo[4,5]thieno[2,3-b]pyridine derivatives as host materials for high efficiency green and blue phosphorescent organic light-emitting diodes

Benzo[4,5]thieno[2,3-b]pyridine (BTP) was newly developed as an electron deficient moiety for high triplet energy materials and two BTP derivatives with the BTP and carbazole groups were synthesized as high triplet energy bipolar host materials. The BTP derivatives were effective as the host materials for green and blue phosphorescent organic light-emitting diodes and a high quantum efficiency above 20% was achieved both in green and blue devices.