Point defects, which scatter electronic carriers as well as phonons, play a vital role in the transport properties of thermoelectric materials. Therefore, defect engineering can be utilized for tuning thermoelectric… Click to show full abstract
Point defects, which scatter electronic carriers as well as phonons, play a vital role in the transport properties of thermoelectric materials. Therefore, defect engineering can be utilized for tuning thermoelectric properties. Mg vacancies, as the dominant defects in the n-type Mg3Sb2-based materials, can greatly impact the transport properties of this compound. Here we demonstrate that the Mg vacancies in the n-type Mg3Sb2-based materials can be successfully manipulated by simply tuning the preparation conditions. A substantial enhancement in the Hall mobility is obtained, from ∼39 to ∼128 cm2 V–1 s–2, an increase of ∼228%. The significantly improved Hall mobility noticeably boosts the power factor from ∼6 to ∼20 μW cm–1 K–2 and effectively enhances the thermoelectric figure of merit. Our results demonstrate that defect engineering could be very effective in improving the thermoelectric performance of n-type Mg3Sb2-based materials.
               
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