Red non-doped electroluminescent dyes based on arylamino fumaronitrile derivatives

A diarylamine, 2-(phenylamino)-9,9-diethylfluorene and three red fluorescent dyes based on arylamino fumaronitrile derivatives, bis(4-(N-(1-naphthyl)phenylamino)-phenyl)fumaronitrile (1-NPAFN, 5a), bis(4-(N-(2-naphthyl)phenylamino)phenyl)-fumaronitrile (2-NPAFN, 5b) and bis(4-(N-(9,9-diethyl-2-fluorenyl)phenylamino)-phenyl)fumaronitrile (EFPAFN, 5c), were prepared. The red dyes showed strong red photoluminescence upon excitation which centered at around 635, 650, 658 nm for 1-NPAFN, 2-NPAFN and EFPAFN in solid film respectively. Fluorescence concentration quenching of red dyes was suppressed. Thermal stability and energy levels were also measured. Multilayer non-doped electroluminescent devices were fabricated using the red dyes (5b, 5c) as red emitters. Device performance kept relatively constant at a wide current density level in the range of 20–150 mA/cm2.