Substrate-Induced Variations of Molecular Packing, Dynamics, and Intermolecular Electronic Couplings in Pentacene Monolayers on the Amorphous Silica Dielectric
Substrate-Induced Variations of Molecular Packing, Dynamics, and Intermolecular Electronic Couplings in Pentacene Monolayers on the Amorphous Silica Dielectric
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DOI：
10.1021/nn405399n
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发表时间：
2014-01-01
期刊：
影响因子：
17.1
通讯作者：
Bredas, Jean-Luc
中科院分区：
文献类型：
--
作者：
Viani, Lucas;Risko, Chad;Bredas, Jean-Luc
薄膜有机场效应晶体管中的电荷载流子传输发生在与栅极电介质接触的活性有机材料的第一（几个）分子层内。在这里，我们使用原子分子动力学模拟来评估与表面电位变化的裸露无定形二氧化硅表面的相互作用如何影响单层并五苯薄膜的分子堆积和动力学。结果表明，并五苯分子的长轴与表面法线的倾斜角不可忽略。计算了这些模型的掠入射 X 射线衍射图，并且我们讨论了布拉格棒形状作为分子堆积函数的显着差异，也与之前发表的实验报告相关。与块状晶体计算相比，对单层分子间电子耦合（转移积分）的评估显示出显着差异，这一结果表明在有机电子材料的电荷载流子迁移率模型中充分考虑分子堆积环境的重要性。
Charge-carrier transport in thin-film organic field-effect transistors takes place within the first (few) molecular layer(s) of the active organic material in contact with the gate dielectric. Here, we use atomistic molecular dynamics simulations to evaluate how interactions with bare amorphous silica surfaces that vary in terms of surface potential influence the molecular packing and dynamics of a monolayer pentacene film. The results indicate that the long axis of the pentacene molecules has a non-negligible tilt angle away from the surface normal. Grazing-incidence X-ray diffraction patterns for these models are calculated, and we discuss notable differences in the shapes of the Bragg rods as a function of the molecular packing, also in relation to previously published experimental reports. Intermolecular electronic couplings (transfer integrals) evaluated for the monolayers show marked differences compared to bulk crystal calculations, a result that points to the importance of fully considering the molecular packing environment in charge-carrier mobility models for organic electronic materials.