DC Conduction in Electrochemically Synthesized Polypyrrole Films

摘要: DC conductivity measurements were performed by modified four-probe rig on electrochemically synthesized polypyrrole films at a temperature range of -30oC to 120oC. Conductivity increased with temperature. The dependence was very high for lightly doped polymers, decreasing as the doping level increased. model used describe conduction process originally developed amorphous silicon Mott and Davis. When applied conducting it assumes that electron transport originates from localized or fixed states within polymer chain. charge transfer between chains takes place hopping, referred phonon-assisted two states. Plots versus can be parametrized Mott's Variable Range Hopping model. light intermediate levels p-toluene sulphonic acid measured in 77K 300K. localization length electrons assumed 3\AA, which is approximately equal pyrrole monomer. parameters p-TS evaluated 300K 10K. Results found consistent requirement R >> 1. Theoretical values N(EF) have been determined 108 cm-1 1019-1020 cm-3 eV-1, respectively. Hence according experimental data samples, are seen better agreement those expected disordered systems, particularly indicating suitability these samples. average hopping distance decreased 16\AA 4.4\AA increase 0.006 M 0.03 300K, whereas 10K, 37\AA 10\AA over same dopant range.