Insulator-metal transition of Li salts doped polyaniline

The results of de conductivity (sigma (dc)), X-ray photoelectron spectrosco py (XPS), and electron paramagnetic resonance (EPR) for Li salts (LiPF6, Li BF4) doped polyaniline (PAN) are reported. Temperature (T) dependence of si gma (dc) of LiPF6 or LiBF4 doped PAN samples shows ln sigma (dc) proportion al to T-1/2 arising from a quasi-one-dimensional (1D) variable range hoppin g (VRH) model. As molar concentration increases, the insulator-metal transi tion is observed in the results of sigma (dc) and the density of states obt ained from EPR experiments. The doping levels of the systems are obtained f rom XPS nitrogen (N) 1s peak analysis. The doping process and the insulator -metal transition of Li salts doped PAN samples are compared with those of HCl doped PAN samples.