CoSb3-based mark mid-temperature skutterudites have been a benchthermoelectric material under intensive experimental and theoretical studies for decades. Doping and filling, to the first order, alter the crystal latti...CoSb3-based mark mid-temperature skutterudites have been a benchthermoelectric material under intensive experimental and theoretical studies for decades. Doping and filling, to the first order, alter the crystal lattice constant of CoSb3 in the context of ＂chemical pressure.＂ In this work, we employed ab initio density functional theory in conjunction with semiclassical Boltzmann transport theory to investigate the mechanical properties and especially how hydrostatic loadings, i.e., ＂physical pressure,＂ impact the electronic band structure, Seebeck coefficient, and power factor of pristine CoSb3. It is found that hydrostatic pressure enlarges the band gap, suppresses the density of states （DOS） near the valence band edge, and fosters the band convergence between the valley bands and the conduction band minimum （CBM）. By contrast, hydrostatic tensile reduces the band gap, increases the DOS near the valence band edge, and diminishes the valley bands near the CBM. Therefore, applying hydrostatic pressure provides an alternative avenue for achieving band convergence to improve thermoelectric properties of N-type CoSb3, which is further supported by our carrier concentration studies. These results provide valuable insight into the further improvement of thermoelectric performance of CoSb3-based skutterudites via a synergy of physical and chemical pressures.展开更多
CoSb3 nanowire arrays, preferred orientation of [510], were fabricated by electrodeposition of Co2+ and Sb3+ into anodic aluminum oxide (AAO) templates. The morphologies, structure, and composition of the as-synthesiz...CoSb3 nanowire arrays, preferred orientation of [510], were fabricated by electrodeposition of Co2+ and Sb3+ into anodic aluminum oxide (AAO) templates. The morphologies, structure, and composition of the as-synthesized sample have been performed using X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and energy-dispersive X-ray spectroscopy (EDS). Based on the previous investigation on CoSb3 nanowire arrays orientated along [420], the formation mechanism for different preferential orientation nanowire arrays was discussed.展开更多
基金Guizhou Provincial Department of Education Foundation(Qianjiaohe KYzi[2016]102)National Natural Science Foundation of China(51764005)Liupanshui Science and Technology Foundation(52020-2018-04-05)
基金supported by the Office of Science of the US Department of Energy (Nos. DEAC05-00OR22750 and DE-AC02-05-CH11231)the support of National Science Foundation (No. DMR-1307740)
文摘CoSb3-based mark mid-temperature skutterudites have been a benchthermoelectric material under intensive experimental and theoretical studies for decades. Doping and filling, to the first order, alter the crystal lattice constant of CoSb3 in the context of ＂chemical pressure.＂ In this work, we employed ab initio density functional theory in conjunction with semiclassical Boltzmann transport theory to investigate the mechanical properties and especially how hydrostatic loadings, i.e., ＂physical pressure,＂ impact the electronic band structure, Seebeck coefficient, and power factor of pristine CoSb3. It is found that hydrostatic pressure enlarges the band gap, suppresses the density of states （DOS） near the valence band edge, and fosters the band convergence between the valley bands and the conduction band minimum （CBM）. By contrast, hydrostatic tensile reduces the band gap, increases the DOS near the valence band edge, and diminishes the valley bands near the CBM. Therefore, applying hydrostatic pressure provides an alternative avenue for achieving band convergence to improve thermoelectric properties of N-type CoSb3, which is further supported by our carrier concentration studies. These results provide valuable insight into the further improvement of thermoelectric performance of CoSb3-based skutterudites via a synergy of physical and chemical pressures.
文摘CoSb3 nanowire arrays, preferred orientation of [510], were fabricated by electrodeposition of Co2+ and Sb3+ into anodic aluminum oxide (AAO) templates. The morphologies, structure, and composition of the as-synthesized sample have been performed using X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and energy-dispersive X-ray spectroscopy (EDS). Based on the previous investigation on CoSb3 nanowire arrays orientated along [420], the formation mechanism for different preferential orientation nanowire arrays was discussed.
