Enhancing the solubility of Mn in AgSbSe2 for high thermoelectric performance through entropy engineering

Point defects play an important role in regulating the electrical and thermal transport properties of thermoelectric materials, but it is always restricted by the solubility of dopants in the matrix. Herein, we demonstrate an effective route to enhance the solubility of Mn from 8% up to 30% in AgSbSe2 through entropy-driven alloying with MnSe. It enables us to largely enhance the carrier concentration and electrical conductivity and also reduce the lattice thermal conductivity of AgSbSe2. As a consequence, (AgSbSe2)0.7(MnSe)0.3 has a high ZT of ∼0.96 at 750 K. Moreover, a further enhanced ZT of 1.18 was achieved in (AgSbSe2)0.7(Mn0.99Se)0.3 at 750 K by the introduced Mn vacancies.