Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
ACS Nano. 2012 Oct 23;6(10):9050-7. doi: 10.1021/nn3031595. Epub 2012 Sep 20.
We investigate the effects of two-dimensional (2D) periodic patterns of functional groups on the thermal transport in a graphene monolayer by employing molecular and lattice dynamics simulations. Our calculations show that the use of patterned 2D shapes on graphene reduces the room temperature thermal conductivity, by as much as 40 times lower than that of the pristine monolayer, due to a combination of boundary and clamping effects. Lattice dynamics calculations elucidate the correlation between this large reduction in thermal conductivity and two dynamical properties of the main heat carrying phonon modes: (1) decreased phonon lifetimes by an order of magnitude due to scattering, and (2) direction-dependent group velocities arising from phonon confinement. Taken together, these results suggest that patterned graphene nanoroads provide a method for tuning the thermal conductivity of graphene without the introduction of defects in the lattice, opening an important possibility for thermoelectric applications.
我们通过分子动力学和晶格动力学模拟研究了功能基团二维（2D）周期性图案对单层石墨烯热输运性能的影响。我们的计算表明，在石墨烯上使用图案化的 2D 形状由于边界和夹持效应的结合，可将室温热导率降低多达 40 倍，比原始单层石墨烯的热导率低 40 倍。晶格动力学计算阐明了这种大幅降低热导率与主要热载声子模式的两个动力学特性之间的相关性：（1）由于散射，声子寿命减少了一个数量级；（2）由于声子限制，群速度具有方向依赖性。总的来说，这些结果表明，图案化的石墨烯纳米带为在不引入晶格缺陷的情况下调节石墨烯的热导率提供了一种方法，为热电应用开辟了重要的可能性。
