Enhanced thermoelectric properties of Ag-doped compounds CuAgxGa1-xTe2 (0 <= x <= 0.05)

Abstract Ag-doped compounds CuAg x Ga 1 − x Te 2 (0 ⩽  x  ⩽ 0.05) have been synthesized, and their TE properties have been investigated in the temperature range of 300–610 K. The results indicated that Ag doping remarkably enhanced the TE performance of CuGaTe 2 , its ZT value reached 0.31 at 590 K, which is 82% larger than that of pure CuGaTe 2 . The enhancement of TE performance owes much to its lower thermal conductivity. Specially, the thermal conductivity of the specimen CuAg 0.05 Ga 0.95 Te 2 decreased to 0.6 W m −1  K −1 at 610 K, ∼67% smaller than that of pure CuGaTe 2 ( κ  = 1.8 W m −1  K −1 at 610 K), which ascribed to the remarkable decrease in holes (and lattice) thermal conductivity κ h (and κ L ) after Ag doping at high temperature region. Furthermore, both the electrical resistivity and thermopower decreased with Ag doping, as a result, the power factor of doped compounds is slightly smaller than that of pure CuGaTe 2 . All the results can indicate that Ag doping is an effective method to enhance the thermoelectric performance of CuGaTe 2 as a potential TE material.