Organic electroluminescence of silole-incorporated polysilane

We have examined the electroluminescent (EL) device utilizing a new type of polysilane that incorporates siloles with a high electron affinity, poly(2',3',4',5'-tetraphenyl-1'-silacyclopenta-2',4'-diene-1',1'-ylidene-1,1,2,2,3,3,4,4-octamethyl-terrasilanylene) (PDMS-S). PDMS-S based single-layer EL device exhibited blue emission with a peak at 488 nm and better electrical properties compared to the device using poly(methylphenylsilane) (PMPS) without silole rings. The maximum external quantum efficiency of the device with PDMS-S was 0.001% and the: maximum luminance reached was 5 cd/m(2) at 22 V. The hole-transporting properties of PDMS-S were almost equal to that of PMPS from the hole-mobility with the standard time-of-flight technique and the current-voltage characteristics of double-layer EL device which comprised of PDMS-S as a hole-transporting layer and tris (8-quinolinolato) aluminum (III) complex as an electron-transporting emitting layer. It is clear from these results of the improvement in the single-layer device with PDMS-S and the hole-transporting properties that the electron-transporting property of PDMS-S with silole rings is higher than that of PMPS. (C) 2000 Published by Elsevier Science B.V. All rights reserved.