Effect of Sb-Doping on the thermoelectric Performance of CuInTe₂

CuInTe₂is a material of interest for thermoelectric power generation and photovoltaic energy harvesting. We present a detailed experiment-theory study of all intrinsic defect species, followed by extrinsic doping by antimony (Sb), to investigate the optimal conditions for performance. Hybrid-density functional theory (DFT) with spin-orbit coupling (SOC) was used to accurately model the electronic behaviour of CuInTe₂. Antimony was the chosen dopant as experimental studies observed an improvement in the power factor and transport properties required for a desirable thermoelectric figure of merit (ZT).¹<br/>The formation of energies of Cu_1-xSb_xInTe₂, CuIn_1-xSb_xTe₂ and CuInTe_2-xSb_x systems were calculated to determine the lowest energy defective composition, employing the ShakeNBreak approach to identify the ground-state defect structures.² In addition, a ternary competing phase was included to give new insights on the true phase space of the system.<br/>The effect of Sb-doping on the transport properties of CuInTe₂ was then calculated by applying the momentum relaxation time as implemented by the AMSET³ code. Combining the theoretical and experimental results, we rationalise the effect of Sb-doping on the power factor and electrical thermal conductivity, yielding insights and design principles that can be applied to optimise performance in this and other emerging thermoelectric materials.<br/>1. D.V.M. Repaka, Z. Wenhao (in progress)<br/>2. I. Mosquera-Lois, S. R. Kavanagh, A. Walsh and D. O. Scanlon, 2022.<br/>3. A. M. Ganose, J. Park, A. Faghaninia, R. Woods-Robinson, K. A. Persson and A. Jain, <i>Nat. Commun.</i>, 2021, <b>12</b>, 2222.