Second Phases\nand Dislocations to Boost the Thermoelectric\nProperties of CuInTe<sub>2</sub> by Sb Doping at In Site

Facing the severe energy crisis and environmental pollution,\nthermoelectric\nmaterials make full use of converting waste heat into electrical energy\nand have attracted considerable attention. Among these materials,\nCuInTe<sub>2</sub> stands out as a potential thermoelectric material\nfor application due to its low thermal conductivity. A series of Sb-doped\nCuInTe<sub>2</sub> compounds are prepared successfully by vacuum melting,\nannealing, and hot-pressure sintering techniques. The Seebeck coefficient\nof CuIn<sub>0.90</sub>Sb<sub>0.10</sub>Te<sub>2</sub> is enhanced,\nnotably benefiting from an increased DOS effective mass and a trade-off\nbetween carrier concentration and mobility. Sb doping contributes\nto the formation of Sb-rich phases and dislocations, which effectively\nscatter phonons, resulting in a reduced lattice thermal conductivity.\nDue to the significantly increased Seebeck coefficient, a maximum\npower factor of 0.81 mW·m<sup>–1</sup>·K<sup>–2</sup> is achieved at 823 K for CuIn<sub>0.90</sub>Sb<sub>0.10</sub>Te<sub>2</sub>, increased by 47% compared to pristine CuInTe<sub>2</sub>. The combination of the increased power factor and reduced thermal\nconductivity results in a maximum figure of merit (ZT) of 0.95 at\n823 K for CuIn<sub>0.90</sub>Sb<sub>0.10</sub>Te<sub>2</sub>. The\naverage ZT values from 323 to 823 K and from 523 to 823 K reach 0.38\nand 0.59, respectively, enhanced by 66.7 and 64.7%, compared to that\nof pristine CuInTe<sub>2</sub>. Meanwhile, a calculated maximum energy\nconversion efficiency of ∼9.6% is achieved at Δ<i>T</i> = 500 K for CuIn<sub>0.90</sub>Sb<sub>0.10</sub>Te<sub>2</sub>. This work testifies to the effective utilization of doping\nengineering to enhance the thermoelectric properties of CuInTe<sub>2</sub>-based materials.