Electrical Conductivity and Charges on Conjugated Chains

The electrical conductivity of a material is a macroscopic solid-state property since even in high molecular-weight polymers there is not just one conjugated chain which spans the distance between two electrodes. Then it is not valid to describe the conductivity by the electronic structure of a single chain only, because intra- and interchain charge transport are important. As with crystalline materials, some basic features of the microscopic charge-transport mechanism can be inferred from conductivity measurements [83]. The specific conductivity a can be measured as the resistance R of a piece of material with length d and cross section F within a closed electrical circuit, 

Where n is the charge-carrier concentration and e the elementary charge. The electrons do not move undisturbed, but are scattered by collision with other carriers and thermal lattice vibrations, so-called phonons, and structural defects. Upon lowering the temperature, collision probability and thermal lattice vibrations are reduced, and the mobility of the electron increases, while n is constant. This leads to a large increase of conductivity with decreasing temperature. 

The sohton concept has been developed to explain charge transport in trans-PAc 6 [90], where the neutral radical centers are already created upon thermal, chemical, or electrochemical treatment of the synthetically produced cis form [29]. Within the charge-transfer description, 6 is unique in that it is the only 

In an attempt to combine the description of the charge-carrier formation within the language of condensed-matter physics and of physical organic chemistry, the exposure of a mono-charged 7t-chain to additional doping 

1) Radical anions are characterized by three and the dianions by two bands. 

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