Sun Xiao-Qi, Qin Gui-Ya, Lin Pan-Pan, Wang Jin, Fan Jian-Xun, Li Hui-Yuan, Ren Ai-Min, Guo Jing-Fu
School of Physics, Northeast Normal University, Changchun, 130024, China.
Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, 130023, P. R. China.
Phys Chem Chem Phys. 2021 Jun 9;23(22):12679-12691. doi: 10.1039/d1cp00178g.
High-performance organic semiconductor materials based on the small aromatic anthracene-core and its derivatives develop comparatively slowly due to the lack of a profound understanding of the influence of chemical modifications on their charge-transfer properties. Herein, the electronic properties and the charge transport characteristics of several typical anthracene-based derivatives with aryl groups substituted at the 2,6-site are systematically investigated by multi-scale simulation methods including Molecular Dynamics (MD) simulation and the full quantum nuclear tunneling model in the framework of density functional theory (DFT). To elucidate the origin of different charge transport properties of these anthracene-based materials, analysis of the molecular stacking and noncovalent intermolecular interaction caused by different substituents was carried out. The results indicate that the electron and hole injection capabilities and the air oxidation stability of the anthracene derivatives are greatly improved when the size of the aryl substituent increases. In addition, the incorporation of 2,6-site aryl substituents can inhibit the stretching vibration of the anthracene-core during charge transport, and allow molecular packing along the long axis (a-axis of DPA and BDBFAnt, and c-axis of dNaAnt) with almost no slippage, and the main transport channels remain unchanged, exhibiting more isotropic 2D transport properties. It should be emphasized that the edge-to-face dimers with smallest dihedral angles are closest to the thermally stable dimer model, with relatively larger π-orbital distributions in transmission channels (dimer 1, 2) and the largest spatial overlap, resulting in the largest hole transfer integral in DPA (Vh1/h2 = 57 meV). Although the analysis of the thermal disorder effect shows a phonon scattering effect, the maximum hole mobility of the DPA molecule is still as high as 1.5 cm2 V-1 s-1.
基于小芳香族蒽核及其衍生物的高性能有机半导体材料由于对化学修饰对其电荷转移性质的影响缺乏深入了解，发展相对缓慢。在此，通过包括分子动力学（MD）模拟和密度泛函理论（DFT）框架下的全量子核隧穿模型在内的多尺度模拟方法，系统地研究了几种在2,6位被芳基取代的典型蒽基衍生物的电子性质和电荷传输特性。为了阐明这些蒽基材料不同电荷传输性质的起源，对不同取代基引起的分子堆积和非共价分子间相互作用进行了分析。结果表明，当芳基取代基的尺寸增加时，蒽衍生物的电子和空穴注入能力以及空气氧化稳定性得到显著提高。此外，2,6位芳基取代基的引入可以抑制电荷传输过程中蒽核的拉伸振动，并允许分子沿长轴（DPA和BDBFAnt的a轴以及dNaAnt的c轴）堆积，几乎没有滑移，且主要传输通道保持不变，表现出更各向同性的二维传输性质。应该强调的是，具有最小二面角的边对面二聚体最接近热稳定二聚体模型，在传输通道（二聚体1、2）中具有相对较大的π轨道分布和最大的空间重叠，导致DPA中空穴转移积分最大（Vh1/h2 = 57 meV）。尽管对热无序效应的分析显示出声子散射效应，但DPA分子的最大空穴迁移率仍高达1.5 cm2 V-1 s-1。
