High thermoelectric performance in low-cost SnS<sub>0.91</sub>Se<sub>0.09</sub> crystals.
basic_science · Level V
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- Record sourced from PubMed, PMID 31604269.
- Also identified by DOI 10.1126/science.aax5123.
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Abstract
Thermoelectric technology allows conversion between heat and electricity. Many good thermoelectric materials contain rare or toxic elements, so developing low-cost and high-performance thermoelectric materials is warranted. Here, we report the temperature-dependent interplay of three separate electronic bands in hole-doped tin sulfide (SnS) crystals. This behavior leads to synergistic optimization between effective mass (<i>m</i>*) and carrier mobility (μ) and can be boosted through introducing selenium (Se). This enhanced the power factor from ~30 to ~53 microwatts per centimeter per square kelvin (μW cm<sup>-1</sup> K<sup>-2</sup> at 300 K), while lowering the thermal conductivity after Se alloying. As a result, we obtained a maximum figure of merit <i>ZT</i> (<i>ZT</i> <sub>max</sub>) of ~1.6 at 873 K and an average <i>ZT</i> (<i>ZT</i> <sub>ave</sub>) of ~1.25 at 300 to 873 K in SnS<sub>0.91</sub>Se<sub>0.09</sub> crystals. Our strategy for band manipulation offers a different route for optimizing thermoelectric performance. The high-performance SnS crystals represent an important step toward low-cost, Earth-abundant, and environmentally friendly thermoelectrics.