Evolution of the bipolaron structure in oligo-diacetylene films: a semiempirical study

The formation of polaron and/or bipolaron species upon chemical doping and photo- or electro-chemical generation is a scientific and technological problem which is still object of discussion. Here we use a simple electrostatic model to study the role of the interchain interaction in stabilizing or destabilizing the bipolaronic structure, which is usually neglected in theoretical studies. The results show that, as a consequence of the interchain interactions in the bulk system, a bipolaron generated on a single oligomer chain more than 12 units long will soon split into two polarons on adjacent chains, this process being maximized for specific interchain distances.