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N-type thermoelectric materials PbTe doped with iodine (PbTe 1−x I x , x = 0.0001, 0.0003, 0.0007 and 0.001) were synthesized by high pressure and high temperature method (HPHT). Thermoelectric properties of PbTe 1−x I x are investigated in the range of 300–600 K. The carrier concentration of PbTe prepared by HPHT is more sensitive to I content compared to that of the PbTe 1−x I x sample prepared by other methods. The resistivities and the absolute values of Seebeck coefficients for PbTe 1−x I x increase while the thermal conductivities decrease with increasing temperature. A large power factor of 39.1 μW/(cmK 2 ) at room temperature is obtained with the carrier concentration of 9.7 × 10 18 cm −3 , which is much higher than that of Sb and Bi doped PbTe with the same synthesizing conditions. The high power factor is attributed to the high Hall mobility and large effective mass. The maximum figure-of-merit, ∼0.71 @ 600 K, is obtained for the samples with the carrier concentration of 9.7 × 10 18 cm −3 . [ABSTRACT FROM AUTHOR]

Abstract: Non-stoichiometric Ag1−x Pb18SbTe20 (x =0, 0.2, 0.5, 0.7, 0.85) thermoelectric materials were prepared by high pressure method. The composition-dependent transport properties were studied at room temperature. The measurement results show that the carrier concentration and hall mobility of AgPb18SbTe20 could be tuned effectively by adjusting the content of Ag. The Seebeck coefficient and resistivity decrease with an increase of x. The maximum power factor of 2.3×10−3 Wm−1 K−2 is obtained at x =0.7, which is about 76% higher than that of the sample with stoichiometric composition. [ABSTRACT FROM AUTHOR]

Besides inferior conversion efficiency, the widespread application of thermoelectric materials currently faces the challenges of the rare and high cost of constituent elements, complex and time-consuming synthesis. Therefore, it is urgent to develop facile synthesized methods and high-performance thermoelectric materials consisting of elements with earth-abundance and low cost. Meeting above partial requirement, lead sulfide (PbS) recently was identified as a potential thermoelectric material to substitute current commercial PbTe. In this paper, a one-step high-pressure method was employed to facile and fast synthesis of PbS. Trace Cl doping tunes the carrier concentration of PbS effectively, which optimizes the electrical transport properties. Further PbSe alloying sharply reduces the thermal conductivity of PbS. Therefore, an enhanced zT ∼1.0 @ 700 K was obtained for PbS doped with 0.3 at% Cl and alloyed with 25 at% PbSe, which is comparable to the commercially applied PbTe. These results indicate that high-pressure combing with Cl-doping and PbSe-alloying provide a facile method and strategy to fabricate high-performance PbS-based thermoelectric materials. • Earth-abundant and low-cost thermoelectric compound PbS was facile and fast synthesized by one-step high pressure method. • Cl doping modulates the carrier concentration of PbS and thus optimizes its electrical properties at high temperature. • The chemical bond of PbS was weaken by PbSe alloying, which induces an enhanced Hall mobility near room temperature. • The thermal conductivity of PbS was suppressed sharply by PbSe alloying. • The enhanced zT max and zT avg achieve to 1.0 and 0.67 for PbS 0.747 Cl 0.003 Se 0.25 and PbS 0.497 Cl 0.003 Se 0.5, respectively [ABSTRACT FROM AUTHOR]