at CIE coordinates of (0.173, 0.055) was achieved. The EQEmax could be enhanced to 11.3% at a higher emitter doping of 3 wt%, with only a small loss in the color purity, reflected in CIE coordinates of (0.176, 0.068). The EQEmax values reported here are among the highest reported for deep-blue OLED devices where the lEL < 420 nm.