Non-doped red–green–blue electroluminescent devices based on fluorenyl and phenanthryl phenylamino derivatives

Abstract Red fluorescent dyes bis(4-( N -(9,9-diethyl-2-fluorenyl)phenylamino)phenyl)fumaronitrile (EFPAFN) and bis(4-( N -(9-phenanthryl)-3,5-dimethylphenylamino)phenyl)fumaronitrile (PhMPAFN), blue fluorescent dyes 2,7-bis( N -2-(9,9-diethylfluorenyl) phenylamino)-9,9-diethylfluorene (EFPAEF) and 2,7-bis( N -9-phenanthryl-3,5-dimethylphenylamino)-9,9-diethylfluorene (PhMPAEF) were prepared. The red dyes with donor–acceptor structure showed strong red photoluminescence at 676 and 650 nm in evaporated film. The five non-doped red devices showed emission at 680, 676, 680, 692 and 656 nm with efficiencies of 2.93, 1.33, 2.58, 2.96 and 1.04 cd/A. The three non-doped green and three blue devices emitted EL peaks at 516, 532, 420, 424, 457 and 520 nm with maximum efficiencies of 0.33, 0.55, 0.45, 1.25, 0.43, and 0.45 cd/A, respectively. The three blue devices exhibited narrower full width at half maximum of 42, 49 and 84 nm. EFPAFN, EFPAEF, PhMPAFN and PhMPAEF were multifunctional compounds as emitters and hole-transporting materials, device efficiencies kept relatively small decline within a wide range of current density. Fumaronitrile or fluorene bridge with the same non-planar fluorenyl or phenanthryl amino unit and the different device fabrications achieved non-doped red–green–blue (R–G–B) EL emissions.