Kwon Hyeokmin, Kim Il-Ho
Department of Materials Science and Engineering, College of Engineering, Korea National University of Transportation, Chungju 27469, Republic of Korea.
Materials (Basel). 2025 Jun 11;18(12):2738. doi: 10.3390/ma18122738.
Chalcopyrite (CuFeS) has attracted interest as a thermoelectric material due to its narrow bandgap and its ability to tailor its carrier concentration through doping. In this study, we investigated the effects of Ni substitution at Cu sites in chalcopyrite (CuNiFeS) on its structural, microstructural, and thermoelectric properties. Samples were synthesized using mechanical alloying followed by hot pressing to ensure high-density compaction. X-ray diffraction analysis confirmed the formation of the tetragonal chalcopyrite phase without detectable secondary phases. The observed reduction in lattice parameters with increasing Ni content provided evidence of successful Ni incorporation at Cu sites within the chalcopyrite structure. Microstructural analysis and elemental mapping further supported the uniform distribution of Ni within the chalcopyrite matrix. Thermoelectric property measurements revealed that Ni-doped chalcopyrite exhibited n-type conduction. As the Ni concentration increased, the carrier concentration and electrical conductivity increased significantly, with CuNiFeS achieving the highest electrical conductivity of 2.5 × 10 Sm at 723 K. However, the absolute value of the Seebeck coefficient decreased with increasing Ni doping, following the expected trade-off between electrical conductivity and thermopower. The optimized composition, CuNiFeS, exhibited the highest thermoelectric performance, with a power factor of 0.50 mWmK and a maximum dimensionless figure of merit (ZT) of 0.18 at 623 K. Compared to undoped chalcopyrite, these enhancements represent a 43% increase in power factor and a 50% improvement in ZT.
黄铜矿（CuFeS₂）因其窄带隙以及通过掺杂来调节其载流子浓度的能力，而作为一种热电材料受到关注。在本研究中，我们研究了在黄铜矿（CuNiFeS₂）中Cu位点上Ni替代对其结构、微观结构和热电性能的影响。样品通过机械合金化然后热压合成，以确保高密度压实。X射线衍射分析证实形成了四方黄铜矿相，未检测到次生相。随着Ni含量增加观察到的晶格参数减小，为Ni成功掺入黄铜矿结构内的Cu位点提供了证据。微观结构分析和元素映射进一步支持了Ni在黄铜矿基体中的均匀分布。热电性能测量表明，Ni掺杂的黄铜矿表现出n型传导。随着Ni浓度增加，载流子浓度和电导率显著增加，CuNiFeS₂在723 K时实现了2.5×10⁻² S/m的最高电导率。然而，随着Ni掺杂增加，塞贝克系数的绝对值降低，这符合电导率和热功率之间预期的权衡。优化后的成分CuNiFeS₂表现出最高的热电性能，在623 K时功率因子为0.50 mW/(m·K²)，最大无量纲品质因数（ZT）为0.18。与未掺杂的黄铜矿相比，这些增强代表功率因子提高了43%，ZT提高了50%。
