Tetrahedrite (Cu12Sb4S13) composed of earth-abundant elements is a thermoelectric material capable of converting waste heat into electricity. Typically, it is produced by conventional solid-state methods requiring extended reaction times (weeks) at elevated temperatures (&gt;600° C). We developed a modified polyol synthesis that requires only one hour of heating at 220° C to produce high yields (2+ grams) of surfactant-free, nanostructured, and phase-pure tetrahedrite materials. Nanoparticles (50-200 nm) were characterized by powder x-ray diffractometry, scanning electron microscopy, and energy dispersive x-ray spectroscopy. Thermopower, electrical resistivity and thermal conductivity measurements were obtained to determine figure of merit (ZT) values, which describe the quality of thermoelectric performance. Our solution-phase synthesis outperforms tetrahedrite materials made by conventional methods, and has been shown to successfully incorporate dopants such as Fe, Zn, and Co on the copper-site. N-type behavior in tetrahedrites has not previously been observed. We report the first observation of negative Seebeck coefficient values over a temperature range of 80 K to 310 K for Fe-doped materials. Electrical and thermal transport properties on these samples are provided from 80 K to 673 K. Since thermoelectric devices require both n- and p-type legs, thermal expansion mismatch issues are eliminated by synthesizing tetrahedrite with each electrical behavior.

Solution-phase synthesis and thermoelectric characterization of n- and p-type tetrahedrite nanoparticles

2019 Spring National Meeting

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