Two-Dimensional WSe2/SnSe p-n Junctions Secure Ultrahigh Thermoelectric Performance in n-type Pb/I Co-doped Polycrystalline SnSe

Chen, Yue-Xing and Shi, Xiao-Lei ORCID: https://orcid.org/0000-0003-0905-2547 and Zheng, Zhuang-Hao and Li, Fu and Liu, Wei-Di and Chen, Wen-Yi and Li, Xin-Ru and Liang, Guang-Xing and Luo, Jing-Ting and Fan, Ping and Chen, Zhi-Gang ORCID: https://orcid.org/0000-0002-9309-7993 (2020) Two-Dimensional WSe2/SnSe p-n Junctions Secure Ultrahigh Thermoelectric Performance in n-type Pb/I Co-doped Polycrystalline SnSe. Materials Today Physics:100306. pp. 1-29.

Text (Accepted Version) MTP-D-20-00399_R1.pdf Restricted - Available after 20 October 2022. Available under License Creative Commons Attribution Non-commercial No Derivatives 4.0.

Abstract

In this study, we, for the first time, introduce p-type two-dimensional (2D) WSe2 nanoinclusions in n-type Pb/I co-doped SnSe matrix to form WSe2/SnSe p-n junctions. These p-n junctions act as energy barriers and effective phonon scattering sources, leading to a high figure-of-merit (ZT) of ∼1.35 at ∼790 K in n-type polycrystalline SnSe. First-principles density functional theory calculation results indicates that I-doping shifts Fermi level up into conduction bands of SnSe, making the system n-type behavior, while both Pb and I dopants act as point-defect-based short-wavelength phonon scattering centers. The introduced p-type 2D WSe2 nanoinclusions induce high-density WSe2/SnSe interfaces that act as p-n junctions, which block the electron carriers and rationally tune the carrier density, contributing to a high absolute Seebeck coefficient of ∼470.7 μV K-1 and a high power factor of ∼5.9 μW cm-1 K-2. Meanwhile, the dense phase boundaries and considerable lattice strains by the introduced 2D WSe2 nanoinclusions significantly strengthen the mid- and long-wavelength phonon scattering, giving rise to a much low thermal conductivity of 0.35 W m-1 K-1 and in turn a high ZT of ∼1.35. This study provides a new strategy to achieve high thermoelectric performance in n-type polycrystalline SnSe.

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Item Type:	Article (Commonwealth Reporting Category C)
Refereed:	Yes
Item Status:	Live Archive
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:	21 Oct 2020 00:00
Last Modified:	27 Oct 2020 05:55
Uncontrolled Keywords:	thermoelectric; SnSe; n-type; p-n junction; doping
Fields of Research (2008):	09 Engineering > 0912 Materials Engineering > 091205 Functional Materials
Identification Number or DOI:	https://doi.org/10.1016/j.mtphys.2020.100306
URI:	http://eprints.usq.edu.au/id/eprint/39950

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