The Effect of Nb Doping on the Thermoelectric Properties of Indium Oxide

作者：Tongqiang Xiong, Bo Feng, Haitao Zhang, Wenzheng Li, Tong B. Tang, Ruolin Ruan, Jin Peng, Guopeng Zhou, Heng Zhao · 发表于：Inorganics · 年份：2025 · DOI：10.3390/inorganics13110356 · 被引用次数：2 · 研究领域：Advanced Thermoelectric Materials and Devices、Advanced Sensor and Energy Harvesting Materials、Nanowire Synthesis and Applications

To optimize the performance of indium oxide (In2O3)-based thermoelectric materials, this study prepared Nb-doped In2O3 via mechanical alloying and spark plasma sintering (SPS), investigating its regulatory mechanism on the crystal structure, as well as on thermoelectric and mechanical properties. X-ray diffraction (XRD) showed that Nb was incorporated into the In2O3 lattice; with increasing Nb doping, the lattice constant decreased due to the ionic radius difference between Nb (64 pm) and In3+ (80 pm) plus Nb’s strong polarization effect. In electrical properties, Nb doping significantly improved conductivity: pure In2O3 had ~53.42 S/cm, reaching 272.07 S/cm (over 5x increase) at x = 0.005, which is attributed to Nb releasing free electrons and increasing the carrier concentration; though carrier mobility slightly decreased, carrier concentration growth dominated conductivity improvement. The absolute Seebeck coefficient decreased (from −185.24 μV/K to −120.12 μV/K at x = 0.005), but electrical conductivity increased and far exceeded the decrease in the square of the Seebeck coefficient, leading to a high-temperature power factor of 5.10 μW/(cm·K2). In terms of thermal properties, Nb doping reduced thermal conductivity and lattice thermal conductivity. Collectively, the x = 0.004 sample achieved a ZT value of 0.302 at 800 K, which is over 5 times higher than that of pure In2O3 (0.055 at 973 K); meanwhile, Nb doping enhanced the Vickers hardness, realizing the optimization of ...