Blue thermally activated delayed fluorescence based on tristriazolotriazine core: Synthesis, property and the application for solution-processed OLEDs

Blue emitters with thermally activated delayed fluorescence (TADF) characteristics have attracted much attention from both academic and industrial researchers in organic light-emitting diodes (OLEDs). In this contribution, three blue molecules of TTT-Ph-Cz, TTT-Ph-Ac and TTT-Ph-BAc in which the tristriazolotriazine (TTT) was employed as the electron acceptor and arylamine (carbazole and acridine derivatives) as the electron donor were prepared and characterized. Both the acridine-substituted compounds (TTT-Ph-Ac and TTT-Ph-BAc) displayed the blue TADF emission between 460 and 470 nm in film state. Additionally, the TTT-Ph-BAc showed clear aggregation-induced emission character. The solution processed OLEDs based on these three molecules were fabricated, and the TTT-Ph-Ac based device displayed a maximum external quantum efficiency of ～10% and peak wavelength of 480 nm. This research demonstrates that this novel TTT core can be a promising electron accepting unit for the design of TADF materials.