Isotropic Seebeck coefficient of aligned single-wall carbon nanotube films
Isotropic Seebeck coefficient of aligned single-wall carbon nanotube films
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DOI：
10.1063/1.5066021
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发表时间：
2018-12-10
影响因子：
4
通讯作者：
Yanagi, Kazuhiro
中科院分区：
文献类型：
--
作者：
Fukuhara, Kengo;Ichinose, Yota;Yanagi, Kazuhiro
纳米物体宏观组装体的形态如何影响其性质是纳米材料科学与工程中一个长期存在的问题。在这里，我们研究了碳纳米管的柔性薄膜的热电性能如何取决于宏观纳米管排列。具体来说，我们已经调查了对齐和门控单壁碳纳米管薄膜的塞贝克系数的各向异性。我们在很宽的范围内改变费米能级，包括p型和n型制度，使用电解质门控。虽然我们发现的电导率沿着的纳米管排列方向是在垂直方向上的几倍大，塞贝克系数被发现是完全各向同性的，无论费米能级的位置。我们提供了一个解释这种显着的差异之间的各向异性的电导率和塞贝克系数使用莫特的跳跃传导理论。我们的实验证据的各向同性塞贝克系数在各向异性的纳米管组件表明，通过形态控制的碳纳米管薄膜的热电性能控制的路线。出版社：AIP Publishing
How the morphology of a macroscopic assembly of nanoobjects affects its properties is a long-standing question in nanomaterials science and engineering. Here, we examine how the thermoelectric properties of a flexible thin film of carbon nanotubes depend on macroscopic nanotube alignment. Specifically, we have investigated the anisotropy of the Seebeck coefficient of aligned and gated single-wall carbon nanotube thin films. We varied the Fermi level in a wide range, covering both the p-type and n-type regimes, using electrolyte gating. While we found the electrical conductivity along the nanotube alignment direction to be several times larger than that in the perpendicular direction, the Seebeck coefficient was found to be fully isotropic, irrespective of the Fermi level position. We provide an explanation for this striking difference in anisotropy between the conductivity and the Seebeck coefficient using Mott's theory of hopping conduction. Our experimental evidence for an isotropic Seebeck coefficient in an anisotropic nanotube assembly suggests a route toward controlling the thermoelectric performance of carbon nanotube thin films through morphology control. Published by AIP Publishing.