Models of Polymeric Mixed Ionic and Electronic Conductors

In organic polymeric materials with mixed ionic and electronic conduction (OMIEC), the excess charge in doped polymers is very mobile and the dynamics of the polymer chain cannot be accurately described with a model including only fixed point charges. Ions and polymer are comparatively slower and a methodology to capture the correlated motions of excess charge and ions is currently unavailable. Considering a prototypical interface encountered in this type of materials, we constructed a scheme based on the combination of MD and QM/MM to evaluate the classical dynamics of polymer, water and ions, while allowing the excess charge of the polymer chains to rearrange following the external electrostatic potential. We used this methodology to study the timescale for electronic charge rearrangement and the change in static and dynamic disorder as the doping level increase. We also propose a microscopic mechanism for reversible charging of OMIEC materials that can be used for designing new materials and rationalizing the current experimental observations.<br/><br/>Landi A et al.<i>, J. Mater. Chem. C</i>, 2023, https://doi.org/10.1039/D2TC05103F<br/>Keen S.T. et al<i>, J. Am. Chem. Soc</i>, 2022, https://doi.org/10.1021/jacs.2c02139<br/>Makki H. and Troisi A., 2022, <i>J. Mater. Chem. C</i>, 2022, https://doi.org.10.1039/d2tc03158b