A Cubic CuInTe₂-Based Material Modulated by Entropy Engineering

CuInTe2 is considered a promising thermoelectric material due to its intrinsic high Seebeck coefficient and relatively low thermal conductivity. However, due to its low carrier concentration, despite elaborate strategies such as doping, composites, and second-phase engineering having been developed, enhancement in its thermoelectric performance remains limited. In this work, a cubic medium-entropy CuInTe2-based thermoelectric material (CuZnxInTe2+x) was prepared by incorporating binary ZnTe into ternary CuInTe2 based on structure modulation and the impact of the ZnTe alloying on the nanoscale microstructure and thermal conductivity was explored. It is illustrated that alloying ZnTe into CuInTe2 can introduce elemental enrichment nanodomains and a medium entropy effect, which leads to numerous dislocations, strain fluctuations, and point defects, thus effectively enhancing phonon scattering and reducing the lattice thermal conductivity κL of the medium-entropy cubic CuZnxInTe2+x. Consequently, a κL of 2.80 W·m–1·K–1 at 303 K was achieved for the x = 1 sample, representing a 42% reduction compared to that of pristine CuInTe2. This work provides novel insights into structural modulation in designing thermoelectric materials with low thermal conductivity and a potential applicability to other thermoelectric families.