Effect of lithium doping on the conductivity of poly(p-phenylene vinylene)

The effect of lithium doping on the conductivity (σ) of poly(p-phenylene vinylene) (ppv) has been studied via a.c. impedance measurements. Ppv has been synthesized via a water-soluble polymer electrolyte precursor. Its conductivity in both undoped and doped forms has been measured as a function of temperature. While doping with LiCl has not resulted in reliable data, doping with lithium triflate (LiCF3SO3) has improved the conductivity of ppv by more than two orders of magnitude. Plots of log(σ) versus 1/T show that the conductivities of undoped and doped ppv follow Arrhenius behavior with equal activation energies (Ea ≈ 0.37 eV). The increase in conductivity without a change in activation energy is attributed to the increase in the electronic density of ppv.