Improving the Electroluminescence Properties of New Chrysene Derivatives with High Color Purity for Deep-Blue OLEDs

Two blue-emitting materials, 4-(12-([1,1':3',1″-terphenyl]-5'-yl)chrysen-6-yl)-N,N-diphenylaniline (TPA-C-TP) and 6-([1,1':3',1″-terphenyl]-5'-yl)-12-(4-(1,2,2-triphenylvinyl)phenyl)chrysene (TPE-C-TP), were prepared with the composition of a chrysene core moiety and terphenyl (TP), triphenyl amine (TPA), and tetraphenylethylene (TPE) moieties as side groups. The maximum photoluminescence (PL) emission wavelengths of TPA-C-TP and TPE-C-TP were 435 and 369 nm in the solution state and 444 and 471 nm in the film state. TPA-C-TP effectively prevented intermolecular packing through the introduction of TPA, a bulky aromatic amine group, and it showed an excellent photoluminescence quantum yield (PLQY) of 86% in the film state. TPE-C-TP exhibited aggregation-induced emission; the PLQY increased dramatically from 0.1% to 78% from the solution state to the film state. The two synthesized materials had excellent thermal stability, with a high decomposition temperature exceeding 460 °C. The two compounds were used as emitting layers in a non-doped device. The TPA-C-TP device achieved excellent electroluminescence (EL) performance, with Commission Internationale de L'Eclairage co-ordinates of (0.15, 0.07) and an external quantum efficiency of 4.13%, corresponding to an EL peak wavelength of 439 nm.