Akande Akinlolu, Bhattacharya Sandip, Cathcart Thomas, Sanvito Stefano
School of Physics, AMBER and CRANN Institute, Trinity College Dublin, Dublin 2, Ireland.
J Chem Phys. 2014 Feb 21;140(7):074301. doi: 10.1063/1.4864754.
We investigate with state of the art density functional theory the structural, electronic, and transport properties of a class of recently synthesized nanostructures based on triarylamine derivatives. First, we consider the single molecule precursors in the gas phase and calculate their static properties, namely (i) the geometrical structure of the neutral and cationic ions, (ii) the electronic structure of the frontier molecular orbitals, and (iii) the ionization potential, hole extraction potential, and internal reorganization energy. This initial study does not evidence any direct correlation between the properties of the individual molecules and their tendency to self-assembly. Subsequently, we investigate the charge transport characteristics of the triarylamine derivatives nanowires, by using Marcus theory. For one derivative we further construct an effective Hamiltonian including intermolecular vibrations and evaluate the mobility from the Kubo formula implemented with Monte Carlo sampling. These two methods, valid respectively in the sequential hopping and polaronic band limit, give us values for the room-temperature mobility in the range 0.1-12 cm(2)/Vs. Such estimate confirms the superior transport properties of triarylamine-based nanowires, and make them an attracting materials platform for organic electronics.
我们运用最先进的密度泛函理论，研究了一类基于三芳基胺衍生物的近期合成纳米结构的结构、电子和输运性质。首先，我们考虑气相中的单分子前驱体，并计算它们的静态性质，即（i）中性和阳离子离子的几何结构，（ii）前沿分子轨道的电子结构，以及（iii）电离势、空穴提取势和内部重组能。这项初步研究并未证明单个分子的性质与其自组装倾向之间存在任何直接关联。随后，我们运用马库斯理论研究了三芳基胺衍生物纳米线的电荷输运特性。对于一种衍生物，我们进一步构建了一个包含分子间振动的有效哈密顿量，并通过蒙特卡罗采样实现的久保公式评估迁移率。这两种方法分别在顺序跳跃和极化子能带极限下有效，为我们提供了室温迁移率在0.1 - 12 cm²/Vs范围内的值。这样的估计证实了基于三芳基胺的纳米线具有优异的输运性质，并使其成为有机电子学中一个有吸引力的材料平台。
