High-color rendering index white organic light-emitting diodes based on exciplex forming blue emitters

[Display omitted] A novel emitting layer structure of white organic light-emitting diodes (WOLED) was developed using exciplex-forming two blue emitters, 2,3,4,5,6-penta(9H-carbazol-9-yl)benzonitrile (5CzCN) and tris(2-(1-(2,4-diisopropyldibenzo[b,d]furan-3-yl)-1H-imidazol-2-yl)phenyl)iridium (Ir(dbi)3). The 5CzCN blue delayed fluorescence material and Ir(dbi)3 phosphorescent emitter partially formed a red exciplex in the mixed film. Combination of blue emission from the blue emitters and red emission from the exciplex provided white emission in the blue emitting 5CzCN and Ir(dbi)3 co-doped device. The WOLED fabricated using the blue emitting 5CzCN and Ir(dbi)3 emitters achieved high color rendering index of 90.8 at 100cd/m2.