Improvement in the Thermoelectric Properties by Ag/Sb Co-Substitution in PbSe

Abstract:

The thermoelectric properties of Ag-doped and Ag/Sb codoped PbSe, prepared by furnace melting, quenching, ball milling and spark plasma sintering (SPS) techniques, were investigated. The X-ray diffraction (XRD) analysis indicated that all samples crystallize in the NaCl-type structure without noticeable secondary phase. The substitution of Ag¹⁺ ion for Pb²⁺ ion in PbSe caused the compound changed from n-type semiconductor to p-type semiconductor. The lower Ag doped sample Pb_1-xAg_xSe with x = 0.002 remains n-type conduction of PbSe, shows high electrical resistivity and thus low figure of merit (ZT). However, the higher Ag doped samples Pb_1-xAg_xSe with x = 0.004, 0.006, 0.008 exhibit n-type conduction, low electrical resistivity and thus leads to the higher ZT. The maximum ZT of the alloy Pb_0.996Ag_0.004Se reaches 0.66 at 673K, much higher than 0.24 of PbSe at the same temperature. A proper Sb doping in the n-type semiconductor Pb_0.998Ag_0.002Se can remain its n-type semiconductor, modify the carrier concentration, decrease the electrical resistivity and thus enhance the thermoelectric property. The alloy Sb0.002Pb0.998Ag0.002Se shows a ZT value of 0.59 at 573K, much higher than 0.26 of the sample Pb_0.998Ag_0.002Se at the same temperature.

• Periodical: Key Engineering Materials (Volume 519)
• Pages: 179-183
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.519.179
• Online since: July 2012
• Authors: Jun Qin Li, X.X. Li, S.P. Li, L. Wang, F.S. Liu, W.Q. Ao
• Keywords: Chemical Synthesis, Semiconductor, Thermoelectric Properties

References

[1] G. J. Snyder and E. S. Toberer, Complex thermoelectric materials, Nature Mater. 7 (2008) 105-114.

[2] B. C. Sales, Thermoelectric materials - Smaller is cooler, Science 295 (2002) 1248-1249.

[3] J. P. Heremans, V. Jovovic, E. S. Toberer, et al., Enhancement of thermoelectric efficiency in PbTe by distortion of the electronic density of states, Science 321 (2008) 554-557.

DOI: 10.1126/science.1159725

[4] G.T. Alekseeva, E.A. Gurieva, P.P. Konstantinov, et al., Thermoelectric figure of merit of hetero- and isovalently doped PbSe, Semicond. 30 (1996) 1125-1127.

[5] H. Unuma, N. Shigetsuka, M. Takahashi, Thermoelectric properties of pressureless-sintered PbSe ceramics, J. Mater. Sci. Lett. 17 (1998) 1055 – 1057.

[6] M. M. Ibrahim, S. A. Saleh, E. M. M. Ibrahim and A. M. Abdel Hakeem, Electrical and thermoelectric properties of PbSe doped with Sm, J. Alloys Compd. 452 (2008) 200-204.

DOI: 10.1016/j.jallcom.2006.11.049

[7] D. Parker and D. J. Singh, High-temperature thermoelectric performance of heavily doped PbSe, Phys., Rev. B 82 (2010) 035204.

DOI: 10.1103/physrevb.82.035204

[8] P. Villars, A. Prince, H. Okamoto and H. Okamoto, Handbook of Ternary Alloy Phase Diagrams, Asm Int, 1990.

[9] C. Lioutas, N. Frangis, I. Todorov, et al., Understanding Nanostructures in Thermoelectric Materials: An Electron Microscopy Study of AgPb18SbSe20, Crystals Chem. Mater. 22 (2010) 5630-5635.

DOI: 10.1021/cm102016j

[10] A.A. El-Sharkawy, A.M. Abou EI-Azm, et al., Thermophysical Properties of Polycrystalline PbS, PbSe, PbTe in the Temperature Range 300-700 K, Inter. J. Thermophys. (1983) 261-269.

DOI: 10.1007/bf00502357

[11] V. Jovovic, S. J. Thiagarajan, J.West, et al., Transport and magnetic properties of dilute rare-earth-PbSe alloys, J. Appl. Phys. 102 (2007) 43707.

DOI: 10.1063/1.2771048