Herzhoff Robert, Plein Laura, Troisi Alessandro, Meerholz Klaus, Fazzi Daniele
Institut für Licht und Materialien, Department für Chemie, Universität zu Köln, Greinstr. 4-6, 50939 Köln, Germany.
University of Liverpool, Department of Chemistry, Liverpool, L69 3BX, UK.
Mater Horiz. 2025 Jul 17. doi: 10.1039/d5mh00610d.
The coupled electronic and ionic transport mechanisms in organic mixed ionic-electronic conductors (OMIECs) remain elusive to rationalize. We introduce here an approach to model the entangled hole and ion transport in linear and cross-linked triphenylamine-based (TPA) non-conjugated polymers, studied as redox active materials for organic electrodes. The polymers are created a heuristic method based on molecular dynamics (MD) simulations. Remarkable energetic disorder effects (up to 1.6 eV) are computed in the static limit, for both pristine and doped polymer films, seemingly hindering hole transport. The explicit inclusion of dynamic effects in modelling the energetic disorder leads instead to strong and rapid oscillations of the site-energies, thus enabling a dynamic opening of hole transport channels. To go beyond the static limit for the calculation of the hole transfer rates, encompassing the time-dependence of disorder effects, effective Marcus residence times are introduced for the first time. Distributions of charge escape times are derived for both linear and cross-linked polymers, in their pristine and doped states. Linear polymers show hole escape networks denser than cross-linked ones, suggesting a more efficient hole de-trapping developing as a function of time and disorder effects. Our approach shows that electronic transport in non-conjugated organic electrodes is a highly interdependent phenomenon connected to the bulk morphologies, polymer chain mobility and ion dynamics. A multiscale modelling that captures the dynamics of disorder is therefore indispensable.
有机混合离子-电子导体（OMIECs）中耦合的电子和离子传输机制仍难以合理解释。我们在此介绍一种方法，用于模拟线性和交联的三苯胺基（TPA）非共轭聚合物中纠缠的空穴和离子传输，这些聚合物被研究用作有机电极的氧化还原活性材料。这些聚合物是基于分子动力学（MD）模拟通过启发式方法生成的。在静态极限下，对于原始和掺杂的聚合物薄膜，计算出了显著的能量无序效应（高达1.6 eV），这似乎阻碍了空穴传输。相反，在对能量无序进行建模时明确纳入动态效应会导致位点能量出现强烈且快速的振荡，从而使空穴传输通道能够动态打开。为了超越计算空穴转移速率的静态极限，考虑无序效应的时间依赖性，首次引入了有效的马库斯停留时间。推导了线性和交联聚合物在原始和掺杂状态下的电荷逃逸时间分布。线性聚合物显示出比交联聚合物更密集的空穴逃逸网络，这表明随着时间和无序效应的发展，空穴脱陷效率更高。我们的方法表明，非共轭有机电极中的电子传输是一种与本体形态、聚合物链迁移率和离子动力学高度相关的现象。因此，捕捉无序动态的多尺度建模是必不可少的。
