Burke Colm, Landi Alessandro, Troisi Alessandro
Department of Chemistry, University of Liverpool, Liverpool, L69 3BX, UK.
Dipartimento di Chimica e Biologia "Adolfo Zambelli", Università di Salerno, Via Giovanni Paolo II, I-84084 Fisciano, Salerno, Italy.
Mater Horiz. 2024 Oct 28;11(21):5313-5319. doi: 10.1039/d4mh00706a.
Charge dynamics in disordered media is described invariably assuming that the energy landscape for hopping site energy is stationary. Within the same framework, the correlation between low electronic disorder and high charge mobility is considered extremely robust, despite the emergence of materials with mixed ionic and electronic conductivity (OMIECs) that display high mobility coexisting with large disorder. We show in this work that the disorder of OMIEC polymers is highly dynamical, the on-site energy for charge transport fluctuates with a characteristic time comparable with that of electron transport. Under these conditions, the disorder of the "frozen" system is not relevant for the charge carrier, whose dynamics are instead controlled by the underlying dynamics of the material. Deep traps exist but have a finite lifetime. The combination of classical simulations and quantum chemical calculations on the nanosecond timescale seems ideal to disclose and characterise the phenomenon.
无序介质中的电荷动力学总是在假设跳跃位点能量的能量景观是静止的情况下进行描述。在同一框架内，尽管出现了具有混合离子和电子导电性的材料（离子电子混合导体，OMIECs），其显示出高迁移率与大无序共存，但低电子无序与高电荷迁移率之间的相关性仍被认为极其稳固。我们在这项工作中表明，OMIEC聚合物中的无序是高度动态的，电荷传输的在位能量以与电子传输相当的特征时间波动。在这些条件下，“冻结”系统的无序与电荷载流子无关，电荷载流子的动力学反而由材料的潜在动力学控制。深陷阱存在但具有有限的寿命。在纳秒时间尺度上结合经典模拟和量子化学计算似乎是揭示和表征该现象的理想方法。
