Electrical, magnetic, and structural properties of lithium salt doped polyaniline

We report the results of temperature dependence of dc conductivity σdc(T), electron paramagnetic resonance (EPR), and X-ray photoelectron spectroscopy (XPS) experiments for the polyaniline (PAN) doped with various lithium (Li) salts such as LiPF6, LiBF4, LiClO4, LiAsF6, and LiCF3SO3. A quasi one-dimensional (1D) variable range hopping (VRH) model provide the best fitting for σdc(T) the Li salt doped PAN samples, which is similar to that of protonic acid (HCl) doped polyaniline samples. The σdc and its temperature dependence vary with the kind of Li salts used. Temperature dependence of thermoelectric power of PAN doped with LiPF6 shows the metallic behavior. From EPR experiments, we obtain that χP depends on the kind of Li salts. The results of XPS experiments are discussed to account for the doping procedure with Li salts. Temperature dependence of EPR linewidths and X-ray diffraction patterns are compared for the various Li salt doped PAN samples. The insulator–metal transition of PAN-LiPF6 samples is also discussed.