LAUSR

Abstract We designed and synthesized a novel sky-blue fluorescent dye, 7,7,13,13-tetramethyl- N 5 ,N 5 ,N 11 ,N 11 -tetra- p -tolyl-7,13-dihydrobenzo[ g ]indeno[1,2- b ]fluorene-5,11-diamine (DANIF), which contains a naphthalene indenofluorene (NIF) core and two diphenylamine end-capped groups. Because of the presence of steric diphenylamine terminal groups, DANIF showed a high glass transition temperature ( T g ) of 161 °C and decomposition temperature (5% weight loss temperature) of 390 °C, which is suitable for the evaporation process. With 9,10-di(2-naphthyl)anthracene as the host and DANIF as the emitter, the fabricated vacuum-deposited organic light-emitting diodes exhibited a relatively low turn-on voltage of 2.8 V and a maximum luminous efficiency of 11.0 cd A −1 . The Commission Internationale de l’Eclairage coordinates of (0.15, 0.22) were achieved with a DANIF weight ratio of 7%. The combination of low driving voltage and high efficiency of the device gave rise to an impressive operational lifetime of 160 h (initial at 1000 cd m −2 , decay to 85% of the initial luminance). These results indicate that DANIF is a promising candidate for the development of highly efficient blue organic light-emitting diodes.