Electrical Transport Over Wide Temperature Range In Doped And Undoped Polypyrrole

Polypyrrole was synthesized by chemical oxidation method by varying oxidant to monomer molar ratio for the optimization of electrical conductivity without using any external dopant. The conductivity in doped polypyrrole reached up to a maximum value of 7.2S/cm. Neutralization of doped polypyrrole was done with aqueous ammonium hydroxide and three orders of reduced conductivity was obtained in neutral polypyrrole. Doping and neutralization of polypyrrole samples was supported by FTIR spectroscopy. Doped and undoped samples of polypyrrole were then electrically characterized over wide temperature range of 10-300K. Stronger and weak temperature dependence of conductivity was revealed by undoped and doped polypyrrole samples respectively. An effort has been made to explore the electrical transport in doped and undoped polypyrrole by charge transport models. The experimental data obeys Kivelson's hopping model in temperature range of 60-300K and fluctuation assisted tunneling was dominant conduction mechanism below 80K.