TAGS-related indium compounds and their thermoelectric properties – the solid solution series (GeTe)xAgInySb1−yTe2 (x = 1–12; y = 0.5 and 1)
TAGS-related indium compounds and their thermoelectric properties – the solid solution series (GeTe)xAgInySb1−yTe2 (x = 1–12; y = 0.5 and 1)
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DOI：
10.1039/c4ta00072b
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发表时间：
2014-04
影响因子：
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通讯作者：
T. Schröder;T. Rosenthal;Nadja Giesbrecht;Stefan A. Maier;E. Scheidt;W. Scherer;G. J. Snyder;W. Schnick;O. Oeckler
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文献类型：
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作者：
T. Schröder;T. Rosenthal;Nadja Giesbrecht;Stefan A. Maier;E. Scheidt;W. Scherer;G. J. Snyder;W. Schnick;O. Oeckler
固溶体系列（GeTe）xAgInySb 1 − yTe 2的各种成员可以通过淬火高温相（x = 12，y = 1; x > 5，y = 0.5）获得。相比之下，In含量>3.6原子%的成员（如x5采用α-GeTe结构类型（3 + 3配位））的合成需要高温高压条件（2.5 GPa，350 ℃）。因此，在所研究的所有样品中，3或4个阳离子在一个维科夫位置上无序。淬火的高温或高压相分别几乎是均匀的。它们的粉末X射线衍射图案表明纯相;然而，高分辨率电子显微镜偶尔会发现非常小程度的纳米级沉淀物以及位错和孪晶。（GeTe）5.5AgIn0.5Sb0.5Te2显示出0.75的最大ZT值，即使在300 °C下（部分）分解成TAGS材料（GeTe）11 AgSbTe 2和黄铜矿型AgInTe 2时也是如此。在高压条件下制备的（GeTe）5.5AgInTe2在125 °C下表现出0.6的ZT值，即远低于分解温度，因此是一种令人感兴趣的新型低温热电材料。
Various members of the solid solution series (GeTe)xAgInySb1−yTe2 can be obtained by quenching high-temperature phases (x = 12 for y = 1 and x > 5 for y = 0.5). In contrast, high-temperature and high-pressure conditions (2.5 GPa, 350 °C) are required for the synthesis of members with In contents >3.6 atom% (such as x 5 adopt the α-GeTe structure type (3 + 3 coordination). Thus, in all samples investigated, 3 or 4 cations are disordered at one Wyckoff position. The quenched high-temperature or high-pressure phases, respectively, are almost homogeneous. Their powder X-ray diffraction patterns suggest pure phases; yet, high-resolution electron microscopy occasionally reveals a very small extent of nanoscopic precipitates as well as dislocations and twinning. (GeTe)5.5AgIn0.5Sb0.5Te2 shows a maximal ZT value of 0.75 even when (partial) decomposition into the TAGS material (GeTe)11AgSbTe2 and chalcopyrite-type AgInTe2 has occurred at 300 °C. (GeTe)5.5AgInTe2 prepared under high-pressure conditions exhibits a ZT value of 0.6 at 125 °C, i.e. far below the decomposition temperature and thus is an interesting new low-temperature thermoelectric material.