Transport in $\alpha$-Sexithiophene Films

TL;DR

This paper analyzes hole polaron transport in $$-sexithiophene films, demonstrating that a modified polaron theory accurately describes mobility in thin film transistors, improving understanding of charge transport in organic semiconductors.

Contribution

It introduces a successful application of a polaron transport theory, originally used for naphthalene crystals, to $$-sexithiophene films, addressing limitations of Holstein's small polaron model.

Findings

Mobility data fit well with the polaron transport theory.

Holstein's small polaron theory does not converge for this system.

The alternative polaron model explains charge transport in the material.

Abstract

The field-effect mobility of hole polarons in $\alpha$-sexithiophene, measured in thin film transistors, was shown to be well fitted by Holstein's small polaron theory. Unfortunately, Holstein's formulation is based on an integral that does not converge. We show that the data are well fitted by a theory of polaron transport that was successful in accounting for mobility in molecular crystals of naphthalene.