Simple aggregation–induced delayed fluorescence materials based on anthraquinone derivatives for highly efficient solution–processed red OLEDs

Two simple red–emitting compounds, 2–carbazol–9–yl–anthraquinone (Cz–AQ) and 2–(4–diphenylamino–phenyl)–anthraquinone (TPA–AQ) have been synthesized. The optical, electrochemical and thermal properties of anthraquinone derivatives were systematically characterized. These materials simultaneously exhibit aggregation–induced emission (AIE) and thermally activated delayed fluorescence (TADF). The solution–processed devices using Cz–AQ and TPA–AQ as the dopants exhibit orange and red emission color with peaks at 572 and 612 nm, low turn–on voltage of 3.5 and 3.8 V, maximum current efficiency of 10.8 and 10.6 cd A^–1, high external quantum efficiency of 5.8% and 7.8%, maximum luminance of 3200 and 2200 cd m^–2, and the Commission Internationale del'Eclairage (CIE) coordinates of (0.50, 0.49) and (0.60, 0.40), respectively. The results may help the design and development of AIE–TADF emitters for high–performance solution–processed OLEDs. - Highlights: • Anthraquinone derivatives have been synthesized via one–step reactions. • These materials simultaneously exhibit AIE and TADF. • The solution–processed red OLEDs exhibited a high EQE of 7.8%.