A rapid and low energy synthesis for tetrahedrite (Cu12Sb4S13), a promising class of thermoelectric materials, has been developed utilizing the solution-phase polyol method. Characterization of the thermoelectric performance (thermopower, electrical resistivity, and thermal conductivity) determined maximum figure of merit (ZT) values at 723 K to be 0.66 and 1.09 for the undoped and zinc-doped tetrahedrite samples, respectively. These are comparable or greater than those obtained for the same compounds fabricated using time and energy intensive conventional solid-state methods. Our one-pot reaction required only 1 hour at 220°C producing 2+ grams of material, while the conventional means produce the same amount but require days to weeks at temperatures above 500°C. We produce pure-phase tetrahedrite nanomaterials on the 50-200 nm range without using ligands and surfactants. Enabled by our synthetic method, we investigate how tetrahedrite’s thermoelectric performance was affected by nanostructuring and doping the tetrahedrite. For both compounds, reduced thermal conductivity is observed (two to four times lower than that of the same compounds fabricated by conventional top-down methods) as well as increased thermopower (two times higher than that of the same material fabricated by conventional means). However, electrical resistivity was found to increase due to nanostructuring. Despite the losses for electrical resistivity, the gains in thermal conductivity and thermopower were sufficient to maintain the figure of merit for the undoped tetrahedrite and increase it for the zinc-doped tetrahedrite. Tetrahedrite is a thermoelectric material with an intrinsically low thermal conductivity, but it is shown here that lattice thermal conductivity is further decreased by nanostructuring and doping. Ongoing synthetic research continues to investigate additional dopants compatible with the synthetic methodology and subsequently to interrogate the thermoelectric performance.

Thermoelectric performance of tetrahedrite synthesized by a modified polyol process

254th National Meeting (2017)

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