Abstract
Efficient sky‐blue organic light‐emitting diodes (OLEDs) employing thermally activated delayed fluorescence (TADF) display a three orders of magnitude increase in lifetime, which is superior to those of controlled phosphorescent OLEDs used in this study. The combination of electro‐oxidation and photo‐oxidation of the TADF emitters in their triplet excited‐states is suppressed through molecule design and device engineering.