Elusive beta-Zn8Sb7: A New Zinc Antimonide Thermoelectric

作者：Wang Jian; Kovnir Kirill^*

来源：Journal of the American Chemical Society, 2015, 137(39): 12474-12477.

DOI：10.1021/jacs.5b08214

Zn8Sb7 was theoretically predicted to exhibit superior thermoelectric properties; however a crystalline phase with a similar composition was only stabilized in the form of nanoparticles. We report a new metastable compound, beta-Zn8Sb7, which was synthesized in the form of bulk polycrystalline powder via high-temperature solid-state annealing followed by quenching. Single crystal X-ray diffraction indicates that beta-Zn8Sb7 crystallizes in a new structure type (noncentrosymmetric orthorhombic space group Pmn2(1) (no. 31) with unit cell parameters of a = 15.029(1) angstrom, b = 7.7310(5) angstrom, c = 12.7431(9) angstrom, which is different from the nanoparticulate phase. According to differential scanning calorimetry, the beta-Zn8Sb7 phase melts incongruently at 825(5) K beta-Zn8Sb7 is a p-type semiconductor with high Seebeck thermopower and low thermal conductivity stemming from the complex crystal structure. beta-Zn8Sb7 exhibits a promising thermoelectric figure-of-merit, zT, of 0.33 at 400 K, which is comparable to the state-of-the-art thermoelectric materials based on binary zinc antimonides.

• 出版日期2015-10-7