Enhanced thermoelectric performance of CuGaTe2 by Gd-doping and Te incorporation

•The effect of Gd-doping and Te incorporation on the thermoelectric performance of CuGaTe2 is studied.•The thermal conductivity κ is reduced by Gd-doping and Te incorporation.•The maximum ZT = 0.75 at 737 K is obtained for the specimen CuGa0.99Gd0.01Te2/0.7 vol.%Te.

Gd-doped compounds CuGa1−xGdxTe2 (0 ≤ x ≤ 0.02) incorporated with tellurium nanoparticles are synthesized by fusion method. Their thermoelectric properties are investigated in the temperature range of 300–800 K. The results indicate that the synergistic effect of Gd-doping and Te incorporation remarkably enhances the thermoelectric performance of CuGaTe2. Specially, the thermal conductivity κ of the specimen CuGa0.98Gd0.02Te2/0.7 vol.%Te reduces to 0.45 Wm−1 K−1 at 684 K, which is ∼74% smaller than that of pure CuGaTe2 (κ = 1.76 W m−1 K−1 at 684 K) due to the incorporation of nanostructure Te. The thermoelectric figure of merit value (ZT) reaches 0.75 at 737 K for the specimen CuGa0.99Gd0.01Te2/0.7 vol.%Te, which is ∼115% larger than that of pure CuGaTe2.