Multilayer electroluminescent device using organosilicon polymer as hole transport layer

Double-layer-type organic electroluminescent devices using organosilicon polymers, such as poly [4,4′-(1,2-dimethyl-1, 2-diphenyldisilan-ylene)-phenylylene], poly [4,4′-(1,2-dimethyl-1,2-diphenyldisilanylene) -biphenylylene], poly[(1,2-dimethyl-1,2-diphenyl-1, 2-disilany-lene)-1,5-naphthylene] and poly [(1,2-tetraethyldisilanylene)-9,10-anthracene] (PDEDS-AN), as hole transport layers were fabricated. In these devices, tris(8-quinolinolato) aluminum(III) complex (Alq) was used as an electron-transporting emitter layer and the effect of the π-electron system of the polymers on device performance was investigated. Among the devices, the PDEDS-AN-based device exhibited the highest external quantum efficiency (QE) of about 0.2%. The low QE values of the organosilicon-based devices compared with that (0.8%) of the double-layer-type device having poly(N-vinylcarbazole) as a typical hole transport layer may be attributed to the poor electron-blocking properties of the organosilicon polymers.