Ultrapure blue organic light-emitting diodes exhibiting 13 nm full width at half-maximum

Introducing two mesityl groups into the rigid and planar molecule dibenzo[2,3:5,6]pyrrolizino[1,7-bc]indolo[1,2,3-lm]carbazole successfully suppressed the aggregation-induced redshift and broadening in the emission spectra, enabling the new emitter mMes(2)DICz to be a promising electroluminescent material combining saturated blue emission, nearly 100% quantum efficiency, and a reduced blue-light hazard. The mMes(2)DICz-based organic light-emitting diode (OLED) exhibited an emission onset at 440 nm, but super-high color purity with a Commission Internationale de l'Eclairage y coordinate of 0.04, owing to the ultra-narrow full width at half-maximum of 13 nm, which is the best performance among reported bottom-emitting OLEDs.