High-Efficiency Nondoped Deep-Blue-Emitting Organic Electroluminescent Device

A new blue emitter, 9,9-bis-(3- (9-phenyl-carbazoyl))-2,7-dipyrenylfluorene (DCDPF), has been synthesized and characterized. Organic light-emitting devices (OLEDs) using DCDPF as a nondoped emitter exhibits deep-blue emission with a peak at 458 nm and CIE coordinates of (0.15, 0.15). The maximum efficiency of the device is 4.4 cd/A (3.1 lm/W). The results suggest that the introduction of carbazole units at the 9-position of fluorene provides an effective way to suppress molecular aggregation which would cause red shift in emission.