G. Greczynski et al., An experimental study of poly(9,9-dioctyl-fluorene) and its interfaces with Li, Al, and LiF, J CHEM PHYS, 113(6), 2000, pp. 2407-2412
The chemical and electronic structure of a new conjugated polymer, poly(9,9
-dioctyl-fluorene), has been studied by photoelectron spectroscopy. The pol
ymer films were free of oxygen contamination (within the detection limits o
f photoelectron spectroscopy). X-ray and ultraviolet photoelectron spectros
copy was carried out on Li- and LiF-deposition on poly(9,9-dioctyl-fluorene
), as well as, on LiF deposition on aluminum. In the case of Li-deposition
on poly(9,9-dioctyl-fluorene) films, doping occurred resulting in the forma
tion of polaronic charge carriers at low doping levels and bipolaronic char
ge carriers at high doping levels. LiF-deposition on poly(9,9-dioctyl-fluor
ene) did not cause doping of the polymer films, nor did the LiF dissociate
at the interface. No significant shifts in a binding energy of the core lev
els nor any changes in the work function occurred. LiF-deposition on sputte
r-cleaned aluminum may cause the surface dipole formation, though LiF disso
ciation was not detected. Al-deposition on LiF/PFO films did not cause diss
ociation of LiF, unlike the case in Alq(3). (C) 2000 American Institute of
Physics. [S0021-9606(00)70230-3].