An experimental study of poly(9,9-dioctyl-fluorene) and its interfaces with Al, LIF and CsF

Sandwich-style interfaces of Al/LiF/poly(9,9-dioctyl-fluorene) and AVCsF/po ly(9.9-dioctyl-fluorene) have been studied using X-ray and ultraviolet phot oelectron spectroscopy. The polymer films were free of oxygen contamination (within the detection limits of photoelectron spectroscopy). In the case o f LiF-deposition on poly(9,9-dioctyl-fluorene) films, doping did not occur, nor did the LiF dissociate upon Al-deposition. No significant shifts in a binding energy of the core levels, nor any changes in the work function wer e detected. However, for the Al/LiF/poly(9.9-dioctyl-fluorene) interface, t here was no degradation of the re-electronic structure, unlike the case for Al deposited directly unto poly(9.9-dioctyl-fluorene). For the All CsF/pol y(9,9-dioctyl-fluorene) interface, the CsF dissociated upon Al-deposition, with the Ca likely n-doping, the polymer at the interface. When deposited o nto an Al surface. CsF also were found to dissociate at the interface but r emaining in the CsF form away from the Al surface. (C) 2001 Elsevier Scienc e B.V. All rights reserved.