Synthesis, Crystal and Electronic Structures, and Thermoelectric Properties of the Novel Cluster Compound Ag3In2Mo15Se19

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• 作者：Patrick Gougeon ; Philippe Gall ; Rabih Al Rahal Al Orabi ; Bruno Fontaine ; R茅gis Gautier ; Michel Potel ; Tong Zhou ; Bertrand Lenoir ; Malika Colin ; Christophe Candolfi ; Anne Dauscher
• 刊名：Chemistry of Materials
• 出版年：2012
• 出版时间：August 14, 2012
• 年：2012
• 卷：24
• 期：15
• 页码：2899-2908
• 全文大小：537K
• 年卷期：v.24,no.15(August 14, 2012)
• ISSN：1520-5002

文摘

Polycrystalline samples and single crystals of the new compound Ag₃In₂Mo₁₅Se₁₉ were synthesized by solid-state reaction in a sealed molybdenum crucible at 1300 掳C. Its crystal structure (space group R3̅c, a = 9.9755(1) 脜, c = 57.2943(9) 脜, and Z = 6) was determined from single-crystal X-ray diffraction data and constitutes an Ag-filled variant of the In₂Mo₁₅Se₁₉ structure-type containing octahedral Mo₆ and bioctahedral Mo₉ clusters in a 1:1 ratio. The increase of the cationic charge transfer due to the Ag insertion induces a modification of the Mo鈥揗o distances within the Mo clusters that is discussed with regard to the electronic structure. Transport properties were measured in a broad temperature range (2鈥?000 K) to assess the thermoelectric potential of this compound. The transport data indicate an electrical conduction dominated by electrons below 25 K and by holes above this temperature. The metallic character of the transport properties in this material is consistent with electronic band structure calculations carried out using the linear muffin-tin orbital (LMTO) method. The complex unit cell, together with the cagelike structure of this material, results in very low thermal conductivity values (0.9 W m^鈥? K^鈥? at 300 K), leading to a maximum estimated thermoelectric figure of merit (ZT) of 0.45 at 1100 K.

Keywords:

cluster compound; single crystal X-ray diffraction; electronic structure; thermoelectric properties