Red fluorescent materials based on naphthylamine for non-doping OLEDs

A novel family of red fluorescent materials for organic light emitting diodes (OLEDs), 4-(2-(3,3-dicyanomethylene-5,5-dimethyl-1-cyclohexylidene)vinyl) phenyldi(1-naphthyl)amine (DNP-2CN), 4-(2-(3,3-dicyanomethylene-5,5-dimethyl-1-cyclohexylidene)vinyl)phenyl(1-naphthyl)phenylamine (DPN-2CN), bis(4-(2-(3,3-dicyanomethylene-5,5-dimethyl-1-cyclohexylidene)vinyl)phenyl)(1-naphthyl)amine (DPN-4CN), were synthesized and characterized. These materials show red photoluminescence with a peak wavelength at 660–706 nm in the solid films. Two kinds of electroluminescent (EL) devices were fabricated: dye-doped OLED with a structure of ITO/NPB/red dopant (3 wt%): Alq3/PBD/LiF/Al and undoped OLED with a structure of ITO/NPB/red emitter/PBD/LiF/Al, where DNP-2CN and DPN-2CN were used as dopants and emitters. Both EL devices exhibit bright red emission centered at 640–670 nm.