Fluorenobenzofuran as the core structure of high triplet energy host materials for green phosphorescent organic light-emitting diodes

Thermally stable high triplet energy host materials based on a fluorenobenzofuran (BFF) core were synthesized and the device performances of green phosphorescent organic light-emitting diodes were investigated. BFF was designed as the electron transport type core with improved thermal stability. Two host materials based on the BFF core showed a high glass transition temperature over 140 degrees C and high triplet energy above 2.70 eV. They were used as the host materials for green phosphorescent organic light-emitting diodes and a high quantum efficiency close to 20% was achieved.