High power efficiency in blue phosphorescent organic light-emitting diodes using 2,4-substituted dibenzofuran with a carbazole and a diphenylphosphine oxide

A dibenzofuran derivative with a carbazole and a diphenylphosphine oxide at 2,4-positions of dibenzofuran was synthesized as the high triplet energy bipolar host material for high power efficiency in blue phosphorescent organic light-emitting diodes. The device performances of 2,4-substituted dibenzofuran compound were compared with those of 2,8-substituted dibenzofuran. The 2,4 substitution was better than common 2,8-substitution in terms of driving voltage and power efficiency.