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.