Efficient white organic light emission by single emitting layer

Stable organic white light-emitting diodes are successfully fabricated by a single organic white emitting layer, which is Bis (2-methyl-8-quinolinato) (triphenylsiloxy) aluminum (111) (SAlq) doped red fluorescent dye of 4-(dicyanomethylene)-2-tert-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB). The incomplete energy transfer from blue-emitting SAlq to red-emitting DCJTB enables to obtain a stable white balanced light-emission by the DCJTB doping concentration of 0.5%. A device with the structure of ITO/TPD (50 nm)/SAlq:DCJTB (30 nm, 0.5%)/Alq(3) (20 nm)/LiF (0.5 nm)/Al (110 nm) shows maximum luminance of 20 400 cd/m(2) at 810 mA/cm(2), external quantum efficiency of 2% at 200 cd/m(2) (similar to 3 mA/cm(2)), power efficiency of 2.3 lm/W at 67 cd/m(2) (similar to 1 mA/cm(2)), and a Commission Internationale de l'Eclairage chromaticity coordinates of (0.34, 0.39) at 1.8 mA/cm(2) to (0.31, 0.38) at 36 mA/cm(2). (C) 2003 Elsevier Science B.V. All rights reserved.