Highly Efficient and Stable Narrow‐Band Phosphorescent Emitters for OLED Applications

In order to develop organic light‐emitting diodes with improved optical properties, a series of phosphorescent complexes exhibiting narrow‐band emission spectra are prepared and color tuned to emit efficiently across the whole visible spectrum through a judicious molecular design. Devices employing a green narrow‐band phosphorescent emitter are fabricated and demonstrate an internal quantum efficiency of close to unity and impressive device operational lifetimes, estimate at over 70 000 h at a practical luminance of 100 cd m ‐2 . Additionally, a deep blue narrow‐band emitter is incorporated into a device setting that demonstrates a peak external quantum efficiency of 17.6% and CIE coordinates of (0.14, 0.09).