Dimethylacridine based emitters for non‐doped organic light‐emitting diodes with improved efficiency

Organic light‐emitting diodes (OLEDs) has been attracting much extensive interest owing to their advantages of high‐definition and flexible displays. Many advances have been focused on boosting the efficiency and stability. Two innovative dimethylacridine‐based emitters,1,1,2,2‐tetrakis(4‐ (2,7‐di‐tert‐butyl‐9,9‐dimethylacridin‐10(9H)‐yl)phenyl ethene (AcTPE), and bis(4‐(2,7‐di‐tert‐butyl‐9,9‐dimethylacridin‐10(9H)‐yl)phenyl)methanone (Ac2BP) were designed and synthesized, in which TPE‐baesed AcTPE presents AIE properties, and with the phenyl as spacer between the DMAC and carbony, aryl‐ketone‐based Ac2BP doesn’t show AIE properties due to the absence of restriction of intramolecular rotations. As the electron‐withdrawing ability of carbonyl, well‐matched energy levels of the Ac2BP improve carriers transfer and hole injecting process in devices, resulting an efficient green emission with a maximum PE of of 5.64 lm W‐1, a EQE of 10.56% and a maximum CE of 18.27 cd A‐1. They are much higher than that of AcTPE‐based devices (3.45 cd A‐1, 1.18 lm W‐1, and 1.46%). This study provides a promising design strategy for efficient OLED emitters of aryl‐ketone‐architecture.