Semiconductor-metal transition powers high-efficiency MgAgSb thermoelectrics.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40614184.
- Also identified by DOI 10.1126/sciadv.adx7115 and PMC identifier 12227046.
- Licence recorded as CC BY-NC.
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Abstract
Because of the inferior thermoelectric performance of metals, the semiconductor-to-metal transition in thermoelectric materials is always avoided. Here, we demonstrate that α-to-β semiconductor-metal transition in MgAgSb is actually not detrimental but can be strategically exploited to create α/β-MgAgSb junction, enabling 150% enhancement in output power while maintaining high conversion efficiency. This power enhancement lies in the notably reduced internal resistance induced by semiconductor-to-metal transition, which is independent of dimensional changes. Consequently, α/β-MgAgSb can simultaneously achieve high maximum conversion efficiency exceeding 10% (9%) and maximum power density above 1 (0.9) W cm<sup>-2</sup> by simulation (experiment), outperforming most p-type materials under identical conditions. In addition, a two-pair thermoelectric module combining α/β-MgAgSb with n-type Mg<sub>3</sub>Sb<sub>0.6</sub>Bi<sub>1.4</sub> achieves an unprecedented power density, representing notable advancements over existing Mg<sub>3</sub>(Sb,Bi)<sub>2</sub>/MgAgSb two-pair system. These findings highlight the immense potential of α/β-MgAgSb for thermoelectric applications and provide insights into the design of high-power thermoelectrics.