High thermoelectric performance of solid solutions CuGa _1-xIn _xTe ₂ (x = 0-1.0)

We synthesized the solid solutions CuGa _1-xIn _xTe ₂ (x 0-1.0) by isoelectronic substitution of element In (Ga) for Ga(In) in the CuMTe ₂ (M Ga, In) lattices and examined their thermoelectric properties. The structure upon substitution provides much high Seebeck coefficient (α), relatively low thermal (κ), and electrical conductivity (σ). AT 701 K, the α, σ, and κ are 283.15 V K ^-1, 1.15 × 10 ⁴ Ω ^-1 m ^-1, and 0.71 W m ^-1 K ^-1, respectively, for CuGa _0.36In _0.64Te ₂, which give the figure of merit (ZT) of 0.91, about two times those of the mother compounds CuGaTe ₂ and CuInTe ₂. This material holds great application perspectives at intermediate temperatures.