Enhanced thermoelectric properties of Cu3SbSe4 via configurational entropy tuning

The ternary Cu 3 SbSe 4 thermoelectric material with diamond-like structure exhibit good electrical properties in the middle-temperature region. Forming co-alloying solid solutions has long been considered as an effective strategy for decoupling electrical conductivity and Seebeck coefficient. In this study, the Cu 3- x Ag x Sb 1- y Te y Se 4 ( x  = 0–0.1; y  = 0–0.05) materials were fabricated by melting-ball milling-hot pressing process. The influences of configurational entropy on the microstructure and thermoelectric properties of Cu 3 SbSe 4 were evaluated. It was found that the electrical conductivity of Cu 2.9 Ag 0.1 Sb 0.95 Te 0.05 Se 4 was about 200% higher than that of pure sample due to the slightly configurational entropy tuning. Moreover, multiscale free path phonons of Cu 2.9 Ag 0.1 Sb 0.95 Te 0.05 Se 4 can be greatly scattered and the lattice thermal conductivity decreased from 3.0 to 2.1 Wm −1  K −1 at 300 K via lattice-distortion effect. The maximum zT value of 0.84 was obtained at 650 K for the Cu 2.9 Ag 0.1 Sb 0.95 Te 0.05 Se 4 sample. These results displayed the multiple effects on thermoelectric transport during the formation of co-alloying solid solutions. Graphical abstract