Thermoelectric Properties of Nickel and Selenium Co-Doped Tetrahedrite

Abstract

As the search continues for novel, cheaper, more sustainable, and environmentally friendly thermoelectric materials in order to expand the range of applications of thermoelectric devices, the tetrahedrite mineral (Cu12Sb4S13) stands out as a potential candidate due to its high abundance, low toxicity, and good thermoelectric performance. Unfortunately, as most current thermoelectric materials achieve zTs above 1.0, ternary tetrahedrite is not a suitable alternative. Still, improvement of its thermoelectric performance has been achieved to zTs ≈ 1 via isovalent doping and composition tuning, but most studies were limited to a single doping element. This project explores the effects of simultaneous doping with nickel and selenium in the thermoelectric properties of tetrahedrite. Simulated properties for different stoichiometric contents of these dopants, as well as the measured thermoelectric properties of the correspondent materials, are reported. One of the samples, Cu11.5Ni0.5Sb4S12.5Se0.5, stands out with a high power factor = 1279.99 µW/m·K2 at 300 K. After estimating the thermal conductivity, a zT = 0.325 at 300 K was obtained for this composition, which is the highest for tetrahedrites for this temperature. However, analysis of the weighted mobility shows the presence of detrimental factors, such as grain boundaries, disorder, or ionized impurity scattering, pointing to the possibility of further improvements.

Multinary Tetrahedrite (Cu12–x–yMxNySb4S13) Nanoparticles: Tailoring Thermal and Optical Properties with Copper-Site Dopants

“…Therefore, the synthesis of quintenary, codoped tetrahedrite nanoparticles is pursued as a method to further increase the thermal stability of tetrahedrite material. Codoping involves introducing two coexisting dopants into the tetrahedrite crystal lattice, but studies thus far only evaluated the impact of codoping on thermoelectric properties. − A quintenary tetrahedrite with Zn and Ni as Cu-site codopants displayed improved thermoelectric properties compared to ternary and quaternary tetrahedrites produced with the same method, while tetrahedrites codoped with Ni, Zn, or cobalt on the Cu-site and Se or Te on the sulfur-site have also had their thermoelectric properties studied. − Additionally, the modified polyol process was previously used to synthesize phase-pure tetrahedrite nanoparticles codoped with Zn on the Cu-site and Se on the sulfur-site, but Cu-site codoped nanomaterials were not synthesized . None of the aforementioned studies discussed the thermal stability or optical band gaps of codoped tetrahedrite materials, both of which are important material properties for thermoelectric and photovoltaic applications.…”