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-diphenyldisilanylene)-phenylylene], poly[4,4'-(1,2-dimethyl-1,2-diphenyldisilanylene)-biphenylylene], poly[(1.2-dimethyl-1,2-diphenyl-1,2-disilanylene)-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 pi-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. (C) 1997 Elsevier Science S.A.