Structural and dynamic disorder, not ionic trapping, controls charge transport in highly doped conducting polymers
Abstract
Doped organic semiconductors are critical to emerging device applications, including thermoelectrics, bioelectronics, and neuromorphic computing devices. It is commonly assumed that low conductivities in these materials result primarily from charge trapping by the Coulomb potentials of the dopant counter-ions. Here, we present a combined experimental and theoretical study rebutting this belief. Using a newly developed doping technique, we find the conductivity of several classes of high-mobility conjugated polymers to be strongly correlated with paracrystalline disorder but poorly correlated with ionic size, suggesting that Coulomb traps do not limit transport. A general model for interacting electrons in highly doped polymers is proposed and carefully parameterized against atomistic calculations, enabling the calculation of electrical conductivity within the framework of transient localisation theory. Theoretical calculations are in excellent agreement with experimental data, providing insights into the disordered-limited nature of charge transport and suggesting new strategies to further improve conductivities.
Cite
@article{arxiv.2101.01714,
title = {Structural and dynamic disorder, not ionic trapping, controls charge transport in highly doped conducting polymers},
author = {Ian E. Jacobs and Gabriele D'Avino and Vincent Lemaur and Yue Lin and Yuxuan Huang and Chen Chen and Thomas Harrelson and William Wood and Leszek J. Spalek and Tarig Mustafa and Christopher A. O'Keefe and Xinglong Ren and Dimitrios Simatos and Dion Tjhe and Martin Statz and Joseph Strzalka and Jin-Kyun Lee and Iain McCulloch and Simone Fratini and David Beljonne and Henning Sirringhaus},
journal= {arXiv preprint arXiv:2101.01714},
year = {2022}
}