The Bi2Te3 family has been considered a state-of-the-art thermoelectric material for room-temperature applications for over half a century. However, scarcity of the material Te has been a persistent issue. Recently, the discovery of n-type Mg3(Bi, Sb)2-based materials provides new hope for replacing traditional Bi2Te3, but their thermoelectric properties near room temperature still need improvement for application to practical devices. Herein, a competitive figure of merit of ≈0.8 at 300 K and a high power factor greater than 30 µW cm−1 K−2 at 300 K in n-type Mg3.14Mn0.06Bi1.4Sb0.59Se0.01 is reported, benefiting from the rationally tuned carrier concentration of 2.29×1019 cm−3 at room temperature. Substituting the Mg site with Mn in Mg3.2Bi1.4Sb0.59Se0.01 changes the dominant carrier scattering mechanism from a mixed scattering of acoustic phonons and ionized impurities to acoustic phonon scattering. Mn doping in Mg3.2Bi1.4Sb0.59Se0.01 also enhances the mobility to 180 cm2 V−1 s−1, reduces the thermal conductivity, and significantly increases the quality factor β of the material. The high room temperature thermoelectric performance of n-type Mn&Se co-doped Mg3(Bi, Sb)2-based materials makes them a highly competitive substitute for commercialized n-type Bi2Te3.
- Mg(Bi, Sb)-based materials
- Mn doping
- room-temperature thermoelectric properties
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- Environmental Science(all)