9,10-Diethyl-N,N-diphenyl-9H-fluoren-2-amine derivatives end-capped with various aromatics as blue emitters for OLEDs

To develop efficient blue emitters, we synthesized a series of 9,9-diethyl-N,N-diphenyl-9H-fluoren-2-amine derivatives end-capped with various aromatics using Suzuki coupling reaction and Buchwald-Hartwig amination. To investigate their electroluminescent properties, multilayer devices were fabricated in following structures: Indium-tin-oxide (ITO) (180 nm)/N, N'-diphenyl-N,N'-(1-napthyl)-(1,1'-phenyl)-4,4' -diamine (NPB) (50 nm)/blue emitters (30 nm)/bathophenanthroline (Bphen) (30 nm)/8-hydroxyquinolatolithium (Liq) (2 nm)/Al (100 nm). All devices showed the blue emissions. Particularly, a device using 9,9-diethyl-7-(10-(10-(naphthalen-2-yl) anthracen-9-yl) anthracen-9-yl)N, N-diphenyl-9H-fluoren-2-amine showed the efficient blue emission with 5.12 cd/A, 2.33 lm/W, and 3.94% of a luminous, power, and external quantum efficiency at 20 mA/cm(2), respectively and CIE (x,y) coordinates of (0.15, 0.15) at 6.0 V.