Kim DanAh, Kim Il-Ho
Department of Materials Science and Engineering, College of Engineering, Korea National University of Transportation, Chungju 27469, Republic of Korea.
Materials (Basel). 2024 Sep 2;17(17):4345. doi: 10.3390/ma17174345.
Non-stoichiometric permingeatites CuSbSe (-0.04 ≤ m ≤ -0.02) were synthesized, and their thermoelectric properties were examined depending on the Cu deficiency. Phase analysis by X-ray diffraction revealed no detection of secondary phases. Due to Cu deficiency, the lattice parameters of tetragonal permingeatite decreased compared to the stoichiometric permingeatite, resulting in a = 0.5654-0.5654 nm and c = 1.1253-1.1254 nm, with a decrease in the c/a ratio in the range of 1.9901-1.9903. Electrical conductivity exhibited typical semiconductor behavior of increasing conductivity with temperature, and above 423 K, the electrical conductivity of all samples exceeded that of stoichiometric permingeatite; CuSbSe exhibited a maximum of 9.8 × 10 Sm at 623 K. The Seebeck coefficient decreased due to Cu deficiency, showing p-type semiconductor behavior similar to stoichiometric permingeatite, with majority carriers being holes. Thermal conductivity showed negative temperature dependence, and both electronic and lattice thermal conductivities increased due to Cu deficiency. Despite the decrease in the Seebeck coefficient due to Cu deficiency, the electrical conductivity increased, resulting in an increase in the power factor (especially a great increase at high temperatures), with CuSbSe exhibiting the highest value of 0.72 mWmK at 573 K. As the carrier concentration increased due to Cu deficiency, the thermal conductivity increased, but the increase in power factor was significant, with CuSbSe recording a maximum dimensionless figure-of-merit of 0.50 at 523 K. This value was approximately 28% higher than that (0.39) of stoichiometric CuSbSe.
合成了非化学计量比的亚硒酸铜锑矿CuSbSe（-0.04≤m≤-0.02），并根据铜的缺乏情况研究了它们的热电性能。通过X射线衍射进行的相分析表明未检测到次生相。由于铜的缺乏，四方亚硒酸铜锑矿的晶格参数与化学计量比的亚硒酸铜锑矿相比有所减小，得到a = 0.5654 - 0.5654 nm和c = 1.1253 - 1.1254 nm，c/a比在1.9901 - 1.9903范围内降低。电导率表现出典型的半导体行为，即电导率随温度升高而增加，并且在423 K以上，所有样品的电导率都超过了化学计量比的亚硒酸铜锑矿；CuSbSe在623 K时表现出最大值9.8×10 S/m。由于铜的缺乏，塞贝克系数降低，表现出与化学计量比的亚硒酸铜锑矿相似的p型半导体行为，多数载流子为空穴。热导率表现出负温度依赖性，并且由于铜的缺乏，电子热导率和晶格热导率均增加。尽管由于铜的缺乏塞贝克系数降低，但电导率增加，导致功率因数增加（特别是在高温下大幅增加），CuSbSe在573 K时表现出最高值0.72 mW/(m²K²)。随着由于铜的缺乏载流子浓度增加，热导率增加，但功率因数的增加很显著，CuSbSe在523 K时记录到最大无量纲品质因数为0.50。该值比化学计量比的CuSbSe（0.39）高出约28%。
