Improvement of Thermoelectric Performance of SnTe by Energy Band Optimization and Carrier Regulation

doi:10.15541/jim20230316

Abstract

Abstract:

As group ⅣA tellurides, SnTe has the same crystal structure and similar bivalent band structure as PbTe, making it a promising thermoelectric material. However, the main concern of softening at elevated temperature and lower ZT at low temperatures has been hindering its application. Therefore, it is significant to expand the service temperature range of SnTe by improving its average ZT. It has been reported that the thermoelectric performance of SnTe is improved by regulating the power factor and lattice thermal conductivity based on band and lattice engineering. In this study, MgSe alloying strategy was used to prepare a series of Sn_1-_yPb_yTe-x%MgSe(0.01≤y≤0.05, 0≤x≤6) samples by combining melting and Spark Plasma Sintering (SPS) techniques. The results show that alloying MgSe leads to an increase in the band gap, effectively suppressing the bipolar effect of intrinsic SnTe, improving the Seebeck coefficient in the high-temperature range, and reducing lattice thermal conductivity through phonon scattering as well. As a result, ZT at 873 K is improved by 100%. The incorporation of Pb effectively modulates the carrier concentration, successfully suppressing electronic thermal conductivity, and thereby improving average thermoelectric performance of SnTe. Among them, Sn_0.96Pb_0.04Te-4%MgSe possesses a ZT value of 1.5 at 873 K and an average ZT value of 0.8 at 423-873 K, displaying superior performance compared to literature.

Key words: thermoelectric material, carrier modulation, alloying, band engineering, SnTe

CLC Number:

TB34

CHEN Hao, FAN Wenhao, AN Decheng, CHEN Shaoping. Improvement of Thermoelectric Performance of SnTe by Energy Band Optimization and Carrier Regulation[J]. Journal of Inorganic Materials, 2024, 39(3): 306-312.

Figures/Tables 8

Fig. 1 (a) XRD patterns and (b) lattice parameter for SnTe-x%MgSe (0≤x≤6) samples

Fig. 2 (a) Temperature dependent electrical conductivity, and (b) Houle carrier concentration and mobility for SnTe-x%MgSe (0≤x≤6) samples

Fig. 3 Band structures of (a) SnTe and (b) SnTe-4%MgSe, and (c) temperature dependent Seebeck coefficients of SnTe-x%MgSe (0≤x≤6) samples

Fig. 4 Temperature dependent thermoelectric properties of SnTe-x%MgSe (0≤x≤6) (a) Power factor; (b) Thermal conductivity and lattice thermal conductivity; (c) Thermoelectric figure of merit (ZT)

Fig. 5 (a) XRD patterns and (b) lattice parameter for Sn1-yPbyTe-4%MgSe (0.01≤y≤0.05) samples, and (c) EDS mappings for the sample Sn0.95Pb0.05Te-4%MgSe

Fig. 6 Thermoelectric properties of Sn1-yPbyTe-4%MgSe samples (0.01≤y≤0.05) (a) Houle carrier concentration and mobility; (b) Electrical conductivity; (c) Seebeck coefficient; (d) Power factor; (e) Average power factor; (f) Electronic thermal conductivity; (g) Total thermal conductivity; (h) Average ZT

Table 1 Thermoelectric properties of Sn1-yPbyTe-x%MgSe (0.01≤y≤0.05, 0≤x≤6) at room temperature in this study

Sn_1-_yPb_yTe-x%MgSe	S/(μV·K^-1)	σ/(×10³, S·cm^-1)	PF/(μW·cm^-1·K^-2)	n_H/(×10²⁰, cm^-3)	κ_tot/(W·m^-1·K^-1)	ZT
x=0, y=0	24	7.28	4.2	4.3	8.62	0.015
x=2, y=0	15	6.75	1.52	4.21	8.06	0.006
x=4, y=0	17	6.2	1.79	4.31	7.68	0.007
x=6, y=0	18	6.03	1.95	4.02	7.67	0.008
x=4, y=0.01	18	6.87	2.23	3.84	3.74	0.018
x=4, y=0.02	23	5.89	3.12	3.56	3.44	0.027
x=4, y=0.03	30	5.4	4.86	3.42	3.36	0.043
x=4, y=0.04	32	5.2	5.32	3.2	3.27	0.049
x=4, y=0.05	39	4.45	6.77	2.8	3.25	0.062

Fig. 7 Thermoelectric property comparison of Sn0.96Pb0.04Te- 4%MgSe in this work with corresponding materials in literature[3,10,12,17,26,32,35⇓⇓⇓ -39]

References 39

[1]	SNYDER G J, TOBERER E S. Complex thermoelectric materials. Nature Materials, 2008, 7(2): 105. DOI PMID
[2]	陈立东, 王群, 李小亚. 环境友好型能源技术—热电转换技术. 中国科技成果, 2005, (13): 34.
[3]	AN D, WANG J, ZHANG J, et al. Retarding Ostwald ripening through Gibbs adsorption and interfacial complexions leads to high-performance SnTe thermoelectrics. Energy & Environmental Science, 2021, 14(10): 5469.
[4]	LIU W, JIE Q, KIM H S, et al. Current progress and future challenges in thermoelectric power generation: from materials to devices. Acta Materialia, 2015, 87: 357. DOI URL
[5]	YOON J S, SONG J M, RAHMAN J U, et al. High thermoelectric performance of melt-spun Cu_xBi_0.5Sb_1.5Te₃ by synergetic effect of carrier tuning and phonon engineering. Acta Materialia, 2018, 158: 289. DOI URL
[6]	LU W, HE T, LI S, et al. Thermoelectric performance of nanostructured In/Pb codoped SnTe with band convergence and resonant level prepared via a green and facile hydrothermal method. Nanoscale, 2020, 12(10): 5857. DOI URL
[7]	PEI Y, WANG H, SNYDER G J. Band engineering of thermoelectric materials. Advanced Materials, 2012, 24(46): 6125. DOI URL
[8]	SUN P, KUMAR K R, LYU M, et al. Generic Seebeck effect from spin entropy. The Innovation, 2021, 2(2): 100101. DOI URL
[9]	ZOU T, QIN X, ZHANG Y, et al. Enhanced thermoelectric performance of beta-Zn₄Sb₃ based nanocomposites through combined effects of density of states resonance and carrier energy filtering. Scientific Reports, 2015, 5: 17803. DOI
[10]	XIE G, LI Z, LUO T, et al. Band inversion induced multiple electronic valleys for high thermoelectric performance of SnTe with strong lattice softening. Nano Energy, 2020, 69: 104395. DOI URL
[11]	CHEN L, SHI X, QIU P, et al. Application of entropy engineering in thermoelectrics. Journal of Inorganic Materials, 2021, 36(4): 347. DOI
[12]	ZHANG Q, GUO Z, WANG R, et al. High-performance thermoelectric material and module driven by medium-entropy engineering in SnTe. Advanced Functional Materials, 2022, 32(35): 2205458. DOI URL
[13]	TAN G, SHI F, SUN H, et al. SnTe-AgBiTe₂ as an efficient thermoelectric material with low thermal conductivity. Journal of Materials Chemistry A, 2014, 2(48): 20849. DOI URL
[14]	HE W, LI N, WANG H, et al. Multiple effects promoting the thermoelectric performance of SnTe by alloying with CuSbTe₂ and CuBiTe₂. ACS Applied Materials & Interfaces, 2021, 13(44): 52775.
[15]	TAN G, SHI F, HAO S, et al. Valence band modification and high thermoelectric performance in SnTe heavily alloyed with MnTe. Journal of the American Chemical Society, 2015, 137(35): 11507. DOI PMID
[16]	WU G, GUO Z, ZHANG Q, et al. Refined band structure plus enhanced phonon scattering realizes thermoelectric performance optimization in CuI-Mn codoped SnTe. Journal of Materials Chemistry A, 2021, 9(22): 13065. DOI URL
[17]	BANIK A, SHENOY U S, ANAND S, et al. Mg alloying in SnTe facilitates valence band convergence and optimizes thermoelectric properties. Chemistry of Materials, 2015, 27(2): 581. DOI URL
[18]	TAN G, ZHAO L D, SHI F, et al. High thermoelectric performance of p-type SnTe via a synergistic band engineering and nanostructuring approach. Journal of the American Chemical Society, 2014, 136(19): 7006. DOI URL
[19]	AL RAHAL AL ORABI R, MECHOLSKY N A, HWANG J, et al. Band degeneracy, low thermal conductivity, and high thermoelectric figure of merit in SnTe-CaTe alloys. Chemistry of Materials, 2015, 28(1): 376. DOI URL
[20]	TAN X F, DUAN S C, WANG H X, et al. Multi-doping in SnTe: improvement of thermoelectric performance due to lower thermal conductivity and enhanced power factor. Journal of Inorganic Materials, 2019, 34(3): 335. DOI URL
[21]	TAN G, ZEIER W G, SHI F, et al. High thermoelectric performance SnTe-In₂Te₃ solid solutions enabled by resonant levels and strong vacancy phonon scattering. Chemistry of Materials, 2015, 27(22): 7801. DOI URL
[22]	ZHOU M, GIBBS Z M, WANG H, et al. Optimization of thermoelectric efficiency in SnTe: the case for the light band. Physical Chemistry Chemical Physics, 2014, 16(38): 20741. DOI PMID
[23]	BANIK A, VISHAL B, PERUMAL S, et al. The origin of low thermal conductivity in Sn_1-_xSb_xTe: phonon scattering via layered intergrowth nanostructures. Energy & Environmental Science, 2016, 9(6): 2011.
[24]	SHENOY U S, BHAT D K. Bi and Zn co-doped SnTe thermoelectrics: interplay of resonance levels and heavy hole band dominance leading to enhanced performance and a record high room temperature ZT. Journal of Materials Chemistry C, 2020, 8(6): 2036. DOI URL
[25]	ALLAOUI I, BENYOUSSEF A, EL KENZ A. Two-dimensional SnTe/Sb van der Waals heterostructure for photovoltaic application. Solid State Sciences, 2021, 121: 106736. DOI URL
[26]	WANG D, ZHANG X, YU Y, et al. Enhancing thermoelectric performance of SnTe via stepwisely optimizing electrical and thermal transport properties. Journal of Alloys and Compounds, 2019, 773: 571. DOI URL
[27]	GUO C, WANG D, ZHANG X, et al. One-one correspondence between n-type SnTe thermoelectric and topological phase transition. Chemistry of Materials, 2022, 34(7): 3423. DOI URL
[28]	TANG J, GAO B, LIN S, et al. Manipulation of band structure and interstitial defects for improving thermoelectric SnTe. Advanced Functional Materials, 2018, 28(34): 1803586. DOI URL
[29]	KRESSE G, FURTHMÜLLER J. Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane- wave basis set. Computational Materials Science, 1996, 6(1): 15. DOI URL
[30]	PERDEW J P, BURKE K, E M. Generalized gradient approximation made simple. Physical Review Letters, 1996, 77(18): 3865. DOI PMID
[31]	BLÖCHL P E. Projector augmented-wave method. Physical Review B, 1994, 50(24): 17953. DOI PMID
[32]	TANG J, YAO Z, CHEN Z, et al. Maximization of transporting bands for high-performance SnTe alloy thermoelectrics. Materials Today Physics, 2019, 9: 100091. DOI URL
[33]	LITTLEWOOD P B, MIHAILA B, SCHULZE R K, et al. Band structure of SnTe studied by photoemission spectroscopy. Physical Review Letters, 2010, 105(8): 086404. DOI URL
[34]	MUTHAIAH R, GARG J. Thermal conductivity of magnesium selenide (MgSe)-a first principles study. Computational Materials Science, 2021, 198: 110679. DOI URL
[35]	ROYCHOWDHURY S, SHENOY U S, WAGHMARE U V, et al. An enhanced seebeck coefficient and high thermoelectric performance in p-type In and Mg co-doped Sn_1-_xPb_xTe via the co-adjuvant effect of the resonance level and heavy hole valence band. Journal of Materials Chemistry C, 2017, 5(23): 5737. DOI URL
[36]	BANIK A, BISWAS K. Lead-free thermoelectrics: promising thermoelectric performance in p-type SnTe_1-_xSe_x system. Journal of Materials Chemistry A, 2014, 2(25): 9620. DOI URL
[37]	FU T, XIN J, ZHU T, et al. Approaching the minimum lattice thermal conductivity of p-type SnTe thermoelectric materials by Sb and Mg alloying. Science Bulletin, 2019, 64(14): 1024. DOI PMID
[38]	LIU X, ZHANG B, CHEN Y, et al. Achieving enhanced thermoelectric performance in (SnTe)_1-_x(Sb₂Te₃)_x and (SnTe)_1-_y (Sb₂Se₃)_y synthesized via solvothermal reaction and sintering. ACS Applied Materials & Interfaces, 2020, 12(40): 44805.
[39]	BHAT D K, SHENOY U S. SnTe thermoelectrics: dual step approach for enhanced performance. Journal of Alloys and Compounds, 2020, 834: 155181. DOI URL