Department of Physics and Materials Science, City University of Hong Kong, Hong Kong SAR, People's Republic of China.
J Chem Phys. 2009 Nov 21;131(19):194702. doi: 10.1063/1.3251785.
The interlayer pi-pi interaction between finite-size models of graphene sheets was investigated by using a density functional theory method, augmented with an empirical R(-6) term for the description of long-range dispersive interaction; these were calibrated by studying the pi-pi interaction between various benzene dimer configurations and comparing the results with previous calculations. For stacked bilayers (dimers) and multilayers of polyaromatic hydrocarbons, which serve as molecular models of graphene sheets, we found that binding energies and energy gaps are strongly dependent on their sizes, while the stacking order and the number of stacked layers have a minor influence. The remarkably broad variation of the energy gap, ranging from 1.0 to 2.5 eV, due mainly to variation of the model size, suggests the potential of broadband luminescence in the visible range for carbon-based nanomaterials that have pi-pi interacting.
采用密度泛函理论方法，结合经验 R(-6) 项来描述长程色散相互作用，研究了有限尺寸石墨烯片层间的层间π-π相互作用；通过研究各种苯二聚体构型之间的π-π相互作用，并与之前的计算结果进行比较，对该方法进行了校准。对于作为石墨烯片层分子模型的堆积双层（二聚体）和多芳香族碳氢化合物的多层，我们发现结合能和能隙强烈依赖于它们的尺寸，而堆积顺序和堆积层数的影响较小。由于模型尺寸的变化，能隙的显著变化范围为 1.0 至 2.5 eV，这表明具有π-π相互作用的基于碳的纳米材料在可见光范围内具有宽带发光的潜力。
