Synthesis and Thermoelectric Properties of Ag-doped SnSe

doi:10.15541/jim20150599

Abstract

Abstract:

SnSe material is one of the most promising state-of-art thermoelectric materials. The polycrystalline Ag-doped Sn_1-_xAg_xSe (0.005≤x≤0.03) bulks were prepared by mechanical alloying and spark plasma sintering technique, and the composition, microstructure and thermoelectric properties were systematically studied by XRD, SEM and thermoelectric performance measurement. XRD results show that single-phase orthorhombic SnSe-based compounds can be prepared with small amount of Ag-doping (0.005≤x≤0.01), but with Ag doping amount increasing, small quantity of secondary phase, SnAgSe₂, can be detected in the matrix. The carrier concentration and overall electrical properties (power factor) are significantly enhanced as a result of Ag doping. The power factor of Sn_0.98Ag_0.02Se increases up to 0.495×10^-3W/(m·K²), which is about 36% higher than that of SnSe material. Although the thermal conductivity increases slightly, the dimensionless figure of merit, ZT is still optimized for the Ag-doped samples. Sn_0.98Ag_0.02Se bulk shows optimal ZT value and the highest ZT of 0.82 is obtained at 823 K, which is the highest value reported for the polycrystalline SnSe-based thermoelectric materials.

Key words: SnSe, Ag-doped, Spark plasma sintering, thermoelectric property

CLC Number:

TB34

LI Song-Hao, ZHANG Xin, LIU Hong-Liang, ZHENG Liang, ZHANG Jiu-Xing. Synthesis and Thermoelectric Properties of Ag-doped SnSe[J]. Journal of Inorganic Materials, 2016, 31(7): 751-755.

Figures/Tables 4

Fig. 1 XRD patterns of the sintered Sn1-xAgxSe alloys bulks

Fig. 2 Fractured surface images of (a) SnSe and (b) Sn0.98Ag0.02Se

Fig. 3 Temperature dependence of thermoelectric properties for Sn1-xAgxSe alloys (a) Electrical resistivity; (b) Seebeck coefficient; (c) Power factor; (d) Thermal conductivity; (e) Lattice thermal conductivity; (f) Figure of merit ZT

Table 1 Some physical properties of the samples prepared

Component		Carrier concentration, n/cm³	Mobility, μ_h/(cm²·V^-1·s^-1)
SnSe	14,.95	4.185×10¹⁷	1.370
Sn_0.995Ag_0.005Se	3.02	2.065×10¹⁸	0.827
Sn_0.99Ag_0.01Se	2.21	2.972×10¹⁸	1.121
Sn_0.985Ag_0.015Se	1.65	3.793×10¹⁸	1.194
Sn_0.98Ag_0.02Se	1.19	4.566×10¹⁸	1.251
Sn_0.97Ag_0.03Se	0.88	5.854×10¹⁸	1.376

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