Molecular Engineering of Blue Fluorescent Molecules Based on Silicon End-Capped Diphenylaminofluorene Derivatives for Efficient Organic Light-Emitting Materials

Blue fluorescent materials based on silicone end-capped 2-diphenylaminofluorene derivatives are synthesized and characterized. These materials are doped into a 2-methyl-9,10-di[2-naphthyl]anthracene host as blue dopant materials in the emitting layer of organic light-emitting diode devices bearing a structure of ITO/DNTPD (60 nm)/NPB (30 nm)/emitting layer (30 nm)/Alq(3) (20 nm)/LiF (1.0 nm)/Al (200 nm). All devices exhibit highly efficient blue electroluminescence with high external quantum efficiencies (3.47%-7.34% at 20 mA cm(-2)). The best luminous efficiency of 11.2 cd A(-1) and highest quantum efficiency of 7.34% at 20 mA cm(-2) are obtained in a device with CIE coordinates (0.15, 0.25). A deep-blue OLED with CIE coordinates (0.15, 0.14) exhibits a luminous efficiency of 3.70 cd A(-1) and quantum efficiency of 3.47% at 20 mA cm(-2).