Enhanced thermoelectric properties of Cu3SbSe4 via configurational entropy tuning

The ternary Cu3SbSe4 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 Cu3-xAgxSb1-yTeySe4 (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 Cu3SbSe4 were evaluated. It was found that the electrical conductivity of Cu2.9Ag0.1Sb0.95Te0.05Se4 was about 200% higher than that of pure sample due to the slightly configurational entropy tuning. Moreover, multiscale free path phonons of Cu2.9Ag0.1Sb0.95Te0.05Se4 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 Cu2.9Ag0.1Sb0.95Te0.05Se4 sample. These results displayed the multiple effects on thermoelectric transport during the formation of co-alloying solid solutions. [GRAPHICS] .