White top-emitting organic light-emitting diodes using one-emissive layer of the DCJTB doped DPVBi layer

White top-emitting organic light-emitting diodes (TEOLEDs) composed of one doped emissive layer which emits two-wavelength light though the radiative recombination were fabricated. As the emissive layer, 4,4-bis(2,2-diphenylethen-1-yl)biphenyl (DPVBi) was used as the host material and 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) was added as the dopant material. By optimizing the DCJTB concentration (1.2%) and the thickness of the DPVBi layer (30 nm), the intensity ratio of the two wavelengths could be adjusted for balanced white light emission. By using the device composed of glass/Ag (100 nm)/ITO (90 nm)/2-TNATA (60 nm)NPB (15 nm)/ DPVBi:DCJTB (1.2%, 30 nm)/Alq(3) (20 nm)Li (1.0 nm)/Al (2.0 nm)/Ag (20 =)/ITO (63 nm)/SiO2 (42 nm), the Commission Internationale d'Eclairage (CIE) chromaticity coordinate of (0.32, 0.34) close to the ideal white color CIE coordinate could be obtained at 100 cd/m(2). (c) 2007 Elsevier B.V. All rights reserved.