Charge Storage Configurations in Solids and their Anisotropic Properties

1 Charge storage configurations in solids and their anisotropic properties 

In this subsection, we deal with the charge storage configurations on the polythiophenes in the sohds and their anisotropic features. These investigations also serve the purpose of examining whether the charged states share the nature of the charge excitations predicted by theories. 

Although the above-mentioned charged species carrying a spin may well be associated with a polaron, Colaneri et al. [67] referred the origin of these charged species to defect states in the energy gap localized by disorder. Furthermore, they remarked that the nature of these species is pretty different from that of the self-localized polarons characteristic of a charge added to a polymer chain without the disorder. 

The sudden change of the susceptibility near 3.4 V vs Li (corresponding to a doping level of a few mol% per thiophene ring) is apparently related to a bend noted in the relationship between conductivity and dopant concentration for the same material [37] this bend also occurs at a doping level of a few mol% per ring [89]. This is suggestive of the transition associated with the formation of bipolaron lattices in PMT [155]. 

It will be interesting to compare on the same material PHT the results of Ziemehs et al. [74] with those of Kim et al. [158], the latter being obtained by the conventional method of chemical doping. Since in the former case the counterions (dopants) are absent in the system, in Eq. (4) should be zero. Here we make a premise that in Eq. (4) of PHT is identical to that of PMT, viz. 2.2 eV [67]. This may be justified 

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