Pi-stacking in charged thiophene oligomers

TL;DR

This study uses ab-initio methods to explore pi-stacking in charged thiophene oligomers, emphasizing environmental effects like solvation in stabilizing dimer formations crucial for organic electronic applications.

Contribution

It provides detailed insights into the stabilization mechanisms of charged thiophene stacks, highlighting the importance of solvation and electronic correlation effects.

Findings

Singly-charged oligothiophene dimers are unstable in gas phase.

Polar solvents can stabilize these dimers as bound dications.

Accurate electronic and solvation models are essential for realistic descriptions.

Abstract

The pi-stacking of oxidized thiophene oligomers is investigated using ab-initio quantum chemistry methods. Dimers of singly-charged oligothiophenes are found to be unstable in the gas phase, but can be stabilized as bound dications in the singlet state by a polarizable solvent such as acetonitrile. Our calculations provide a detailed description of the mechanisms and the energetics involved in the dimerization phenomenon, and highlight the role and importance of the environment in the stabilization of the stacks. The need for accurate treatments of electronic correlations and of solvation effects for a realistic description of these materials is underscored.