Combinatorial fabrication and studies of bright white organic light-emitting devices based on emission from rubrene-doped 4,4′-bis(2,2′-diphenylvinyl)-1,1′-biphenyl

Very bright and efficient white multilayer organic light-emitting devices based on orange-emitting 2–10-nm-thick layers of 0.25 and 0.5 wt % rubrene-doped 4,4′-bis(2,2′-diphenylvinyl)-1,1′biphenyl are described. The color coordinates of all but one of the devices are well within the white region at 6–12 V, corresponding to a dynamic white brightness range of 30 dB. Their highest brightness Lmax was over 74 000 Cd/m2; in all devices Lmax exceeded 50 000 Cd/m2. The maximum efficiencies were 11.0 Cd/A, 6.0 lm/W, and 4.6% at 5.8 V, 0.6 mA/cm2, and 68 Cd/m2 in the 0.25 wt %, 2-nm-thick doped layer device. The color variation is attributed to either emission from different zones in devices with a thin doped layer, or saturation of emission sites due to relatively light doping.