Oligothiophenes

End-capped oligothiophenes

Due to its remarkable electrical conductivity oligothiophenes were used as hole-transport  materials in several types of optical and microelectronic devices.
The oligothiophenes presented here form amorphous glasses with high stability.
Charge carriers were formed upon oxidation according to the following scheme.

For any application in devices it is very important to know the oxidation potentials of the oligomers. The formal potentials in dependence on the chain length are shown in the figure below.

From monocations and trications radicals were identified by electron spin resonance. It was found that the unpaired electron is delocalized in the conjugated system. The long-wave absorption maxima measured by in situ UV-Vis-NIR-ESR-spectroelectrochemistry (see below) were assigned to the open-shell monocations and trications.