Thermoelectric Properties of Hexagonal M2C3 (M = As, Sb, and Bi) Monolayers from First-Principles Calculations
Xue-Liang Zhu 1, Peng-Fei Liu 2
, Guofeng Xie 1,3,4,*, Wu-Xing Zhou 3,4, Bao-Tian Wang 2 and Gang Zhang 5,*
, Guofeng Xie 1,3,4,*, Wu-Xing Zhou 3,4, Bao-Tian Wang 2 and Gang Zhang 5,*
1
School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, China
2
Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China
3
School of Materials Science and Engineering, Hunan University of Science and Technology, Xiangtan 411201, China
4
Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and Conversion, Xiangtan 411201, China
5
Institute of High Performance Computing, Singapore 138632, Singapore
*
Authors to whom correspondence should be addressed.
Nanomaterials 2019, 9(4), 597; https://doi.org/10.3390/nano9040597
Received: 20 March 2019 / Revised: 1 April 2019 / Accepted: 5 April 2019 / Published: 11 April 2019
(This article belongs to the Special Issue Nanostructured Materials for Thermoelectrics)
Abstract
Hexagonal M2C3 compound is a new predicted functional material with desirable band gaps, a large optical absorption coefficient, and ultrahigh carrier mobility, implying its potential applications in photoelectricity and thermoelectric (TE) devices. Based on density-functional theory and Boltzmann transport equation, we systematically research the TE properties of M2C3. Results indicate that the Bi2C3 possesses low phonon group velocity (~2.07 km/s), low optical modes (~2.12 THz), large Grüneisen parameters (~4.46), and short phonon relaxation time. Based on these intrinsic properties, heat transport ability will be immensely restrained and therefore lead to a low thermal conductivity (~4.31 W/mK) for the Bi2C3 at 300 K. A twofold degeneracy is observed at conduction bands along Γ-M direction, which gives a high n-type electrical conductivity. Its low thermal conductivity and high Seebeck coefficient lead to an excellent TE response. The maximum thermoelectric figure of merit (ZT) of n-type can approach 1.41 for Bi2C3. This work shows a perspective for applications of TE and stimulate further experimental synthesis. View Full-Text
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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
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Zhu, X.-L.; Liu, P.-F.; Xie, G.; Zhou, W.-X.; Wang, B.-T.; Zhang, G. Thermoelectric Properties of Hexagonal M2C3 (M = As, Sb, and Bi) Monolayers from First-Principles Calculations. Nanomaterials 2019, 9, 597.
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