Thermal Transport is Influenced by Nanoparticle Morphology: A Molecular Dynamics Study
Thermal Transport is Influenced by Nanoparticle Morphology: A Molecular Dynamics Study
复制标题
热传输受纳米颗粒形态的影响：分子动力学研究
DOI：
10.1021/acs.jpcc.7b12362
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Gezelter, J. Daniel
中科院分区：
文献类型：
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作者：
Neidhart, Suzanne M.;Gezelter, J. Daniel
采用分子动力学模拟方法研究了裸金纳米粒子（二十面体、立方八面体和球形）与正己烷溶剂的界面热导率。计算的电导被发现不仅取决于颗粒的形状，但也对纳米颗粒的大小，特别是对于纳米球。将这些结果与平面小面的电导进行比较：（111），（100）和（110）;所有这些都通常表现在球形颗粒上的小块中。表面原子的配位不足和二十面体中的振动态密度解释了其中的一些观察结果。二十面体颗粒的暴露表面主要由具有9配位的金原子的（111）小面构成。立方八面体颗粒主要是由（100）和（111）面，分别与8和9配位的表面原子。纳米球在大颗粒尺寸下接近6 - 9个配位位点的恒定表面密度，并且这些表面原子在溶剂的电导中起很大作用。表面正常的振动态密度被用来解释一个简单的表面欠配位模型，恢复了大部分的贡献大小依赖的电导。
Molecular dynamics simulations were performed to model the interfacial thermal conductance (G) from bare gold nanoparticles (icosahedral, cuboctahedral, and spherical) to a hexane solvent. The computed conductance was found to depend not only on particle shape, but also on the size of the nanoparticles, particularly for nanospheres. These results are compared with conductance out of the planar facets: (111), (100), and (110); all commonly exhibited in small patches on the spherical particles. Undercoordination of the surface atoms and the vibrational density of states in the icosahedra explain some of these observations. The exposed surfaces of icosahedral particles are dominated by (111) facets with 9-coordinated gold atoms. Cuboctahedral particles are dominated by the (100) and (111) facets with 8- and 9-coordinated surface atoms, respectively. The nanospheres approach a constant surface density of 6–9 coordinated sites at large particle sizes, and these surface atoms play a large role in the conductance to the solvent. The surface-normal vibrational densities of states were used to explain a simple surface undercoordination model, which recovers most of the contributions to the size-dependent conductance.