Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA.
1] Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA [2] Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA.
Sci Rep. 2014 Jan 28;4:3909. doi: 10.1038/srep03909.
Graphene oxide is being used in energy, optical, electronic and sensor devices due to its unique properties. However, unlike its counterpart - graphene - the thermal transport properties of graphene oxide remain unknown. In this work, we use large-scale molecular dynamics simulations with reactive potentials to systematically study the role of oxygen adatoms on the thermal transport in graphene oxide. For pristine graphene, highly ballistic thermal transport is observed. As the oxygen coverage increases, the thermal conductivity is significantly reduced. An oxygen coverage of 5% can reduce the graphene thermal conductivity by 90% and a coverage of 20% lower it to ~8.8 W/mK. This value is even lower than the calculated amorphous limit (11.6 W/mK for graphene), which is usually regarded as the minimal possible thermal conductivity of a solid. Analyses show that the large reduction in thermal conductivity is due to the significantly enhanced phonon scattering induced by the oxygen defects which introduce dramatic structural deformations. These results provide important insight to the thermal transport physics in graphene oxide and offer valuable information for the design of graphene oxide-based materials and devices.
氧化石墨烯因其独特的性质而被应用于能源、光学、电子和传感器等领域。然而，与石墨烯不同，氧化石墨烯的热输运性质仍不清楚。在这项工作中，我们使用基于反应势的大规模分子动力学模拟，系统地研究了氧原子吸附物对氧化石墨烯热输运的作用。对于原始石墨烯，观察到了高度弹道热输运。随着氧覆盖率的增加，热导率显著降低。氧覆盖率为 5%时，可使石墨烯的热导率降低约 90%，覆盖率为 20%时，可降低至约 8.8 W/mK。这一数值甚至低于计算出的非晶极限值（约 11.6 W/mK，适用于石墨烯），通常被认为是固体可能达到的最小热导率。分析表明，热导率的大幅降低是由于氧缺陷引起的声子散射显著增强，这导致了剧烈的结构变形。这些结果为氧化石墨烯的热输运物理提供了重要的见解，并为基于氧化石墨烯的材料和器件的设计提供了有价值的信息。
