Charge carrier solvation and large polaron formation on a polymer chain revealed in model ab initio computations

TL;DR

This study uses advanced ab initio computations to demonstrate that solvation in polar media induces large-radius polarons on polymer chains, significantly enhancing charge localization, which is relevant for 1D semiconductors in polar environments.

Contribution

It reveals a new solvation-induced mechanism for polaron formation on polymer chains using state-of-the-art ab initio methods.

Findings

Solvation causes more pronounced charge localization.

Large-radius polarons form on long carbon chains.

Mechanism is relevant for 1D semiconductors in polar media.

Abstract

When an excess charge carrier is added to a semiconducting polymer chain, it is well known that the carrier may self-trap into a polaronic state accompanied by a bond length adjustment pattern. A different mechanism of self-localization is the solvation of charge carriers expected to take place when the polymer chain is immersed in polar media such as common solvents. We use state-of-the-art ab initio computations in conjunction with the Polarizable Continuum Model to unequivocally demonstrate solvation-induced self-consistent charge localization into large-radius one-dimensional (1D) polarons on long $C_{N}H_{2}$ carbon chains with the polyynic structure. Within the framework used, the solvation results in a much more pronounced charge localization. We believe this mechanism of polaron formation to be of relevance for various 1D semiconductors in polar environments.