Modified Julolidine-Containing Emitters for Red Organic Light-Emitting Diodes

Abstract

The compounds 2 1 1-(2-(4-pentylbicyclo[2 2 2]octan-1-yl)-6-(2-(1,1,7,7-tetramethyl-1,2,3,5,6,7-hexahydropyrido[3,2,1-ij]quinolin-9-yl)vinyl)-4H-pyran-4-ylidene)malononitrile (Red 1) and 2-(2-(2-(1,1-dimethyl-7,7-bis((trimethylsilylmethyl)-1,2,3.5,6,7-hexahydropyndo[3.2,1-ij]quinolin-9-yl)vinyl)-6-(4-pentylbicyclo[2 2 2]octan-1-yl)-4H-pyran-4-ylidene)malononitrile (Red 2) with modified julolidine moieties were developed and synthesized To determine the electroluminescence properties of these materials, multilayered organic light-emitting diodes (OLEDs) were fabricated with a device structure of indium tin oxide (ITO)/N, N'-diphenyl-N. N'-(1-napthyl)-(1,1'-phenyl)-4,4'-diamine (50 nm)/tris(8-quinolinolato)-aluminum (Alq(3)) dopants Red 1 and Red 2 (30 nm, 1 5%)/Alq(3) (50 nm)/8-hydroxyquinolatolithium (2 nm)/Al All devices exhibited efficient red emission In particular, a device using Red 2 as the dopant material showed a maximum luminance of 1455 cd/m(2) at 12 0 V, and maximum luminous and power efficiencies of 1 71 cd/A and 1 32 lm/W, respectively The Commission Internationale de l'Eclairage coordinates of this device were (0 64, 0 36) at 7 0 V, which indicated stable color chromaticity at various voltages (C) 2010 The Japan Society of Applied Physics