Electrical conductivity study on polythiophenes films

Mechanism of direct current electrical charge conduction in p-toluenesulfonate doped polypyrrole/carbon composites

“…The observed trend in r dc vs. 1000/T appears similar to those reported earlier for other conjugated polymers. 17,19,20,24,[27][28][29][30][31][32] The dc conductivity r dc (Fig. 7) can be given 13,45 by the following relation:…”

“…For this, the temperature dependence of conductivity can be given 13,[17][18][19]23,30,31 by the following relation:…”

“…15 The other two models, widely used to explain the dc conductivity of conjugated polymeric systems, are fluctuation induced tunneling (FIT) 16 and Mott's variable range hopping (VRH) conduction. [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] In FIT conduction model, 16 the tiny conducting domains, formed during doping in a granular system, participates in the delocalization of charge carriers by tunneling between conducting metallic islands. However, the macroscopic conductivity in most of the conjugated polymeric systems is assumed to result from the hopping conduction process.…”

“…However, when the carrier localization is not strong, the charge carriers jump to the sites for which the required activation energy is small and resides farther away, then the charge transport occurs by VRH. 13,23 It is worthwhile to mention here that the Mott's VRH conduction model has been applied to explain the dc conductivity of many conjugated polymeric systems such as doped polyacetylene, 25,26 polyanilines, 27,28 poly(2,5-dimethoxyaniline), 17 polypyrroles, 18,[21][22][23]33 poly(3-methylthiophene), [29][30][31]34 poly(3-hexylthiophene), 19 and poly(3-octylthiophene), 20,32 carbon-black/polypyrrole nanocomposites. 35 Several studies on dc conduction of different conducting polymers and their composite systems are available in literature.…”

“…35 Several studies on dc conduction of different conducting polymers and their composite systems are available in literature. [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] However, there is no report available on temperature dependence of dc electrical conductivity in pTS doped PPy/C composites.…”