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arXiv 1503.07239cond-mat.mtrl-scicond-mat.mes-hall
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氧化石墨烯自支撑薄膜高温退火后热导率的各向异性

Anisotropy of Thermal Conductivity of Free-Standing Reduced Graphene Oxide Films Annealed at High Temperature

J. D. Renteria, S. Ramirez, H. Malekpour, B. Alonso, A. Centeno, A. Zurutuza, A. I. Cocemasov, D. L. Nika, A. A. Balandin

摘要:

我们研究了经受高达1000 C的高温处理的独立式还原氧化石墨烯膜的热导率。结果发现,高温退火显着增加的面内热导率,K,在室温下从3 W/mK到61 W/mK的膜。在1000 ℃下退火的还原氧化石墨烯膜中,交叉平面热导率Kc显示出有趣的相反趋势,即降低至0.09 W/mK的非常小的值。所得到的薄膜表现出非常强的各向异性的热导率,K/Kc ~ 675,这是大大大于甚至在高品质的石墨。退火膜的电阻率降低到1 - 19欧姆/平方。从理论上解释了所观察到的面内和跨面热导率分量的修改导致不寻常的K/Kc各向异性。理论分析表明,随着sp2畴尺寸的增加和氧含量的进一步降低,K可以达到高达~500 W/mK。这些膜的强各向异性热传导性质可用于热管理中的应用。

英文摘要:

We investigated thermal conductivity of free-standing reduced graphene oxide films subjected to a high-temperature treatment of up to 1000 C. It was found that the high-temperature annealing dramatically increased the in-plane thermal conductivity, K, of the films from 3 W/mK to 61 W/mK at room temperature. The cross-plane thermal conductivity, Kc, revealed an interesting opposite trend of decreasing to a very small value of 0.09 W/mK in the reduced graphene oxide films annealed at 1000 C. The obtained films demonstrated an exceptionally strong anisotropy of the thermal conductivity, K/Kc ~ 675, which is substantially larger even than in the high-quality graphite. The electrical resistivity of the annealed films reduced to 1 - 19 Ohms/sq. The observed modifications of the in-plane and cross-plane thermal conductivity components resulting in an unusual K/Kc anisotropy were explained theoretically. The theoretical analysis suggests that K can reach as high as ~500 W/mK with the increase in the sp2 domain size and further reduction of the oxygen content. The strongly anisotropic heat conduction properties of these films can be useful for applications in thermal management.

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