High quantum efficiency and color stability in white phosphorescent organic light emitting diodes using a pyridine modified carbazole derivative

• High triplet energy host material derived from carbazole and pyridine.
• High quantum efficiency in blue and white phosphorescent organic light-emitting diodes.
• Color stability in white phosphorescent organic light-emitting diodes.

A high triplet energy material derived from carbazole and pyridine, 9,9′-(5-(2-methylpyridin-3-yl)-1,3-phenylene)bis(9H-carbazole), was synthesized as the host material for blue and white phosphorescent organic light-emitting diodes. The 9,9′-(5-(2-methylpyridin-3-yl)-1,3-phenylene)bis(9H-carbazole) host showed a high triplet energy of 2.99 eV for efficient energy transfer to blue triplet emitter. High quantum efficiencies of 19.8% and 17.1% were achieved in blue and white phosphorescent organic light-emitting diodes using the 9,9′-(5-(2-methylpyridin-3-yl)-1,3-phenylene)bis(9H-carbazole) host material. In addition, the 9,9′-(5-(2-methylpyridin-3-yl)-1,3-phenylene)bis(9H-carbazole) based white phosphorescent organic light-emitting diodes showed good color stability.