Hira Uzma, Bos Jan-Willem G, Missyul Alexander, Fauth François, Pryds Nini, Sher Falak
Department of Chemistry and Chemical Engineering, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, 54792 Lahore, Pakistan.
School of Physical Sciences, University of the Punjab, New Campus, 54590 Lahore, Pakistan.
Inorg Chem. 2021 Dec 6;60(23):17824-17836. doi: 10.1021/acs.inorgchem.1c02442. Epub 2021 Nov 7.
A new series of BaBiCoRuO (0.0 ≤ ≤ 0.6) hexagonal double perovskite oxides have been synthesized by a solid-state reaction method by substituting Ba with Bi. The polycrystalline materials are structurally characterized by the laboratory X-ray diffraction, synchrotron X-ray, and neutron powder diffraction. The lattice parameters are found to increase with increasing Bi doping despite the smaller ionic radius of Bi compared to Ba. The expansion is attributed to the reduction of Co/Ru-site cations. Scanning electron microscopy further shows that the grain size increases with the Bi content. All BaBiCoRuO (0.0 ≤ ≤ 0.6) samples exhibit p-type behavior, and the electrical resistivity (ρ) is consistent with a small polaron hopping model. The Seebeck coefficient () and thermal conductivity (κ) are improved significantly with Bi doping. High values of the power factor (PF ∼ 6.64 × 10 W/m·K) and figure of merit ( ∼ 0.23) are obtained at 618 K for the = 0.6 sample. These results show that Bi doping is an effective approach for enhancing the thermoelectric properties of hexagonal BaBiCoRuO perovskite oxides.
通过用铋替代钡，采用固态反应法合成了一系列新的BaBiCoRuO（0.0≤≤0.6）六方双钙钛矿氧化物。通过实验室X射线衍射、同步辐射X射线和中子粉末衍射对多晶材料进行结构表征。尽管铋的离子半径比钡小，但发现晶格参数随着铋掺杂量的增加而增大。这种膨胀归因于Co/Ru位阳离子的减少。扫描电子显微镜进一步表明，晶粒尺寸随铋含量的增加而增大。所有BaBiCoRuO（0.0≤≤0.6）样品均表现出p型行为，且电阻率（ρ）符合小极化子跳跃模型。随着铋掺杂，塞贝克系数（）和热导率（κ）显著提高。对于=0.6的样品，在618K时获得了高功率因子（PF∼6.64×10W/m·K）和优值（∼=0.23）。这些结果表明，铋掺杂是提高六方BaBiCoRuO钙钛矿氧化物热电性能的有效方法。
