期刊
NANOTECHNOLOGY
卷 25, 期 24, 页码 -出版社
IOP Publishing Ltd
DOI: 10.1088/0957-4484/25/24/245401
关键词
graphyne; thermal transport; thermoelectrics; nonequilibrium Green's function; energy conversion
资金
- Julich Aachen Research Alliance-High Performance Computing (JARA-HPC) from RWTH Aachen University [jara0073]
- National Natural Science Foundation of China [11304262]
- Hunan Provincial Natural Science Foundation of China [14JJ3074]
- Scientific Research Fund of Hunan Provincial Education Department [13C927]
Graphyne, an allotrope of graphene, is currently a hot topic in the carbon-based nanomaterials research community. Taking beta-graphyne as an example, we performed a comprehensive study of thermal transport and related thermoelectric properties by means of nonequilibrium Green's function (NEGF). Our simulation demonstrated that thermal conductance of beta-graphyne is only approximately 26% of that of the graphene counterpart and also shows evident anisotropy. Meanwhile, thermal conductance of armchair beta-graphyne nanoribbons (A-BGYNRs) presents abnormal stepwise width dependence. As for the thermoelectric property, we found that zigzag beta-graphyne nanoribbons (Z-BGYNRs) possess superior thermoelectric performance with figure of merit value achieving 0.5 at room temperature, as compared with graphene nanoribbons (similar to 0.05). Aiming at obtaining a better thermoelectric coefficient, we also investigated Z-BGYNRs with geometric modulations. The results show that the thermoelectric performance can be enhanced dramatically (figure of merit exceeding 1.5 at room temperature), and such enhancement strongly depends on the width of the nanoribbons and location and quantity of geometric modulation. Our findings shed light on transport properties of beta-graphyne as high efficiency thermoelectrics. We anticipate that our simulation results could offer useful guidance for the design and fabrication of future thermoelectric devices.
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