2018-Sustainable Industrial Processing Summit
SIPS2018
Volume 6. New and Advanced Materials and Technologies
| Editors: | F. Kongoli, F. Marquis, P. Chen, T. Prikhna, N. Chikhradze |
| Publisher: | Flogen Star OUTREACH |
| Publication Year: | 2018 |
| Pages: | 392 pages |
| ISBN: | 978-1-987820-92-8 |
| ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
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Ab-initio Calculations of the Thermoelectric Properties of MXenes
Udo Schwingenschlogl1;1KING ABDULLAH UNIVERSITY OF SCIENCE AND TECHNOLOGY (KAUST), Thuwal, Saudi Arabia;
Type of Paper: Keynote
Id Paper: 285
Topic: 43
Abstract:
This presentation gives an overview of ab-initio calculations [1-3] addressing the thermoelectric performance of MXenes. Specific examples include a comparison of Ti<sub>2</sub>CO<sub>2</sub>, Zr<sub>2</sub>CO<sub>2</sub>, and Hf<sub>2</sub>CO<sub>2</sub> in order to evaluate the role of the metal atom. The lattice thermal conductivity is demonstrated to grow along the series Ti-Zr-Hf in the temperature range 300-700 K, resulting in the highest figure of merit in the case of Ti<sub>2</sub>CO<sub>2</sub>. Flat conduction bands promote the thermopower in the case of n-doping. Functionalization effects are studied for Sc<sub>2</sub>C, which is semiconducting for various functional groups, including O, F, and OH. The lowest lattice thermal conductivity is found for OH functionalization. Therefore, despite a relatively low thermopower, Sc<sub>2</sub>C(OH)<sub>2</sub> may be interesting for intermediate-temperature thermoelectric applications due to a high electrical conductivity. We also discuss results on heterostructures built from MXenes and transition metal dichalcogenide monolayers. Low frequency optical phonons are found to occur as a consequence of the van der Waals bonding. They contribute significantly to thermal transport and compensate for reduced contributions of the acoustic phonons (strong scattering in heterostructures), such that the thermal conductivities become similar to those of the constituent MXenes.
Keywords:
Alternative energy sources; Energy; Nanomaterials; New and advanced materials; Renewable energy;References:
[1] A. N. Gandi, H. N. Alshareef, and U. Schwingenschlogl, Chem. Mater. 28 (2016), 1647-1652.[2] S. Kumar and U. Schwingenschlogl, Phys. Rev. B 94 (2016), 035405.
[3] A. N. Gandi, H. N. Alshareef, and U. Schwingenschlogl, J. Phys.: Condens. Matter 29 (2017), 035504.