Nanoscale pores plus precipitates rendering high-performance thermoelectric SnTe1-xSex with refined band structures

Hong, Min ORCID: https://orcid.org/0000-0002-6469-9194 and Wang, Yuan and Xu, Shengduo and Shi, Xun and Chen, Lidong and Zou, Jin and Chen, Zhi-Gang ORCID: https://orcid.org/0000-0002-9309-7993 (2019) Nanoscale pores plus precipitates rendering high-performance thermoelectric SnTe1-xSex with refined band structures. Nano Energy, 60. pp. 1-7. ISSN 2211-2855


Abstract

Thermoelectric performance is proportional to the thermal conductivity reciprocal and power-factor, which are impacted by microstructures and electronic band structures, respectively. Herein, we study the effect of nanoscale pores on thermal conductivity. Within Cd-doped SnTe1-xSex, electron microscopy characterizations indicate the majority of pores are less than 200 nm, which is comparable to the phonon mean free path. Together with the point defects and nanoprecipitates, an ultra-low lattice thermal conductivity is obtained. Electrically, we find that the slight overdose of cation lone pair s2 character at L point of the first Brillion zone yields the energetically higher valence band edge at L point than at Σ point in rock-salt chalcogenides. As for SnTe1-xSex, Cd is a dopant free of lone pair s2 orbital. Cd doping decreases the energy offset of multivalence bands for SnTe1-xSex by partially reducing the cation lone pair s2 character. The refined band structures yield an enhanced power-factor. Combined with the decreased thermal conductivity, a figure-of-merit > 1.5 has been obtained. The demonstrated strategies of exploring nanoscale pores with size matching phonon mean free path to decrease lattice thermal conductivity and the computationally screening suitable dopants to modify band structures can enlighten the development of high-performance thermoelectric candidates in wide materials.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Files associated with this item cannot be displayed due to copyright restrictions.
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Future Materials (1 Jan 2017 -)
Faculty/School / Institute/Centre: Current - Institute for Advanced Engineering and Space Sciences - Centre for Future Materials (1 Jan 2017 -)
Date Deposited: 24 May 2022 02:57
Last Modified: 31 May 2022 03:09
Uncontrolled Keywords: Nanoscale poresl Phonon scatterings; Thermoelectrics; Molecular orbital theory; Density functional theory calculations
Fields of Research (2008): 10 Technology > 1007 Nanotechnology > 100708 Nanomaterials
09 Engineering > 0912 Materials Engineering > 091203 Compound Semiconductors
09 Engineering > 0912 Materials Engineering > 091205 Functional Materials
Fields of Research (2020): 40 ENGINEERING > 4016 Materials engineering > 401603 Compound semiconductors
40 ENGINEERING > 4016 Materials engineering > 401605 Functional materials
34 CHEMICAL SCIENCES > 3403 Macromolecular and materials chemistry > 340301 Inorganic materials (incl. nanomaterials)
40 ENGINEERING > 4018 Nanotechnology > 401807 Nanomaterials
Identification Number or DOI: https://doi.org/10.1016/j.nanoen.2019.03.031
URI: http://eprints.usq.edu.au/id/eprint/48503

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