One-dimensionality of thermoelectric properties of semiconducting nanomaterials
One-dimensionality of thermoelectric properties of semiconducting nanomaterials
复制标题
DOI：
10.1103/physrevmaterials.5.025404
复制
发表时间：
2021-02-26
影响因子：
3.4
通讯作者：
Yanagi, Kazuhiro
中科院分区：
文献类型：
--
作者：
Ichinose, Yota;Matsubara, Manaho;Yanagi, Kazuhiro
热电转换，即利用废热发电，可以在可再生能源的利用中发挥重要作用。降低半导体热电材料的维数是提高热电性能的一种有前途的方法，并且最终一维（1D）半导体材料有可能表现出最大化的性能，因为一维电子结构的存在，例如态密度中的范霍夫奇点（vHs）。然而，通过实验验证半导体纳米材料的一维性质对热电性能的影响一直很困难，因为我们无法在常规热电参数（例如塞贝克系数或功率因数）方面观察到一维电子结构的任何痕迹。在这里，我们证明热电参数热电导率 (L-12) 与电子结构密切相关，并且在单壁碳纳米管 (SWCNT) 中表现出独特的一维迹线。我们通过实验阐明，高纯度半导体 SWCNT 的 L-12 具有化学势位于 vH 附近的峰结构。为了进行比较，选择单层二硫化钼和石墨烯作为二维模型的 L-12 显示出不同的行为，仅表现出恒定值。此外，我们发现理论计算支持这些 L-12 行为，这与一维和二维电子结构的预期行为一致。我们的结果表明，L-12 是评估维数痕迹的一个非常好的参数，从而促进了低维材料开发所需的基本热电性质的阐明。
Thermoelectric conversion, which is the generation of electricity from waste heat, can play an important role in renewable energy use. Lowering the dimensionality of semiconductor thermoelectric materials is a promising approach for improving thermoelectric performance, and ultimately one-dimensional (1D) semiconductor materials have the potential to exhibit maximized performance because of the presence of a 1D electronic structure, such as the van Hove singularity (vHs) in the density of states. However, experimentally verifying the effect of the 1D nature on the thermoelectric performance in semiconductor nanomaterials has been difficult because we cannot observe any traces of the 1D electronic structure in terms of conventional thermoelectric parameters, such as the Seebeck coefficient or power factor. Here, we show that a thermoelectric parameter, the thermoelectrical conductivity (L-12), is strongly correlated with the electronic structure and exhibits a unique 1D trace with single-walled carbon nanotubes (SWCNTs). We experimentally clarify that the L-12 of high-purity semi-conducting SWCNTs has a peak structure with a chemical potential in the vicinity of the vHs. For comparison, the L-12 of monolayer molybdenum disulfides and graphene, which are chosen as 2D models, shows a different behavior, simply exhibiting constant values. Furthermore, we find that theoretical calculations support these L-12 behaviors, which are consistent with the expected behaviors of 1D and 2D electronic structures. Our results demonstrate that L-12 is a very good parameter for evaluating the traces of dimensionalities, thereby advancing the elucidation of the fundamental thermoelectric properties necessary for the development of low-dimensional materials.