Enhancement of performance for blue organic light emitting devices based on double emission layers

Blue organic light emitting devices (OLEDs) with high efficiency were reported by the designing of double emission layers (DELs) and changing doping concentration of fluorescent material in DELs. The carrier injection in each emission layer was greatly improved with the aid of different doping concentration, which resulted in carriers’ recombination with a well balance. The maximum current efficiency and power efficiency of the OLEDs were 18.99 cd/A and 11.63 lm/W at 2.0 mA/cm2, respectively, and the maximum brightness of the optimum device was 40,040 cd/m2 at 14 V. Consequently, besides a better color and efficiency stabilization, these devices with the DELs presented a higher current efficiency and brightness than the conventional devices with single emission layer (SEL) by more than 70%.