White organic light-emitting devices with non-doped-type structure

A non-doped-type structure was proposed for obtaining organic light-emitting devices with high-efficiency and full-spectrum white light emission. The device structure included indium tin oxide glass substrate/450 Å 4,4′,4″-tris{N-(3-methylphenyl)-N-phenylamin}triphenylamine (m-MTDATA) hole injection layer/100 Å N,N′-bis-(1-naphthyl)-N,N′-diphenyl-1,1′-biph-enyl-4,4′-diamine (NPB) hole transport layer/150 Å 4,4′-bis(2,2′-diphenylvinyl)-1,1′-biphenyl (DPVBi) blue emitting layer/ultrathin [2-methyl-6-[2-(2,3,6,7-tetrahydro-1H, 5H-benzo[ij] quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene] propane-dinitrile (DCM2) yellow-emitting layer/ 80 Å 4,7-diphenyl-1,10-phenanthroline (BPhen) electron transporting layer and hole blocking layer/600 Å tris (8-hydroxyquinoline) aluminium (Alq3) electron-transporting layer /10 Å lithium fluoride (LiF)/aluminum (Al). A white emission (Commission Internationale de l’Eclairage 1931 chromaticity coordinate) (X = 0.3556, Y = 0.3117) at 5 V and (X = 0.282, Y = 0.2658) at 15 V was obtained. Its luminance was 11,497 cd/m2 at 15 V, and the maximum efficiency was 4.8 lm/W at 5 V.