ChemInform Abstract: Enhanced High‐Temperature Thermoelectric Performance of Yb_14‐xCa_xMnSb₁₁.

Abstract

Crystals of Yb14‐xCaxMnSb11 (x = 2, 4, 6, 8) solid solutions are prepared by reaction of the elements in a Sn flux (excess Mn, alumina crucible sealed in a quartz tube, 1000 °C).

Evolution of Thermoelectric Properties in the Triple Cation Zintl Phase: Yb13–xCaxBaMgSb11 (x = 1–6)

“…At room temperature, Ca has the effect of decreasing the overall magnitude of a sample's carrier concentration (Figure S5), previously documented in Yb 14−x Ca x MnSb 11 . 42 This effect is observed in other Zintl phases as well and has been attributed to either reduction of cation defects with the substitution of Ca or to changes in bonding as the polar covalent Yb−Sb bond is replaced by the ionic Ca−Sb bond. 19,44 A unique feature of Ca substitution for this solid solution series is that at temperatures > 600 K the relative order of carrier concentration changes, with increased Ca concentration resulting in higher carrier concentration and a steeper increase, most notable for x = 4−6.…”

“…29 In Yb 14−x Ca x MnSb 11 , lengthening in A-Sb is observed and attributed to Ca ionizing more completely compared to Yb causing bond elongation and decreasing carrier concentration. 42 While A-Sb elongation is seen, contraction in distance in the Sb(1)−Sb(4) linear unit's distance is not seen showing the differences between the Mg/Mn system and with the additional Ba incorporation. The angles of the MgSb 4 tetrahedron are also about the same as those for in Yb 14 MgSb 11 .…”