Effects of partial anion substitution on the thermoelectric properties of silver(I) chalcogenide halides in the system Ag{sub 5}Q{sub 2}X with Q=Te, Se and S and X=Br and Cl

Journal Article · Fri Apr 15 00:00:00 EDT 2011 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.01.031· OSTI ID:21504059

Eckstein, Nadine ^[1]; Nilges, Tom ^[1]; Decourt, Rodolphe; Bobet, Jean-Louis; Chevalier, Bernard ^[2]

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1. TU Muenchen, Lichtenbergstrasse 4, Garching (Germany)
2. CNRS, Universite de Bordeaux, ICMCB, Avenue du Docteur Schweitzer 87, 33608 PESSAC cedex (France)

A selection of mixed conducting silver chalcogenide halides of the general formula Ag{sub 5}Q{sub 2}X with Q=sulfur, selenium and tellurium and X=chlorine and bromine has been investigated due to their thermoelectric properties. Recently, the ternary counterpart Ag{sub 5}Te{sub 2}Cl showed a defined d{sup 10}-d{sup 10} interaction in the disordered cation substructure at elevated temperatures where Ag{sub 5}Te{sub 2}Cl is present in its high temperature {alpha}-phase. A significant drop of the thermal diffusivity has been observed during the {beta}-{alpha} phase transition reducing the values from 0.12 close to 0.08 mm{sup 2} s{sup -1}. At the same transition the thermopower reacts on the increasing silver mobility and jumps towards less negative values. Thermal conductivities, thermopower and thermal diffusivity of selected compounds with various grades of anion substitution in Ag{sub 5}Q{sub 2}X were determined around the silver-order/disorder {beta}-{alpha} phase transition. A formation of attractive interactions could be observed for selenium substituted phases while no effect was detected for bromide and sulfide samples. Depending on the grade and type of substitution the thermopower changes significantly at and after the {beta}-{alpha} phase transition. Thermal conductivities are low reaching values around 0.2-0.3 W m{sup -1} K{sup -1} at 299 K. Partial anion exchange can substantially tune the thermoelectric properties in Ag{sub 5}Q{sub 2}X phases. -- Graphical abstract: A structure section of the {alpha}-Ag{sub 5}Te{sub 2}Cl structure type and the thermopower evolution of Ag{sub 5}Te{sub 2}Cl{sub 0.4}Br{sub 0.6} undergoing a silver ion order/disorder phase transition. Display Omitted Research highlights: > We report on thermoelectric properties of silver(I) chalcogenide halides. > We examine thermopower, thermal diffusivity and thermal behavior. > Silver mobility, phase transitions and order/disorder phenomena are discussed. > Partial anion exchange can tune thermoelectric properties significantly.

• OSTI ID: 21504059
• Journal Information: Journal of Solid State Chemistry, Vol. 184, Issue 4; Other Information: DOI: 10.1016/j.jssc.2011.01.031; PII: S0022-4596(11)00042-9; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANIONS
BROMIDES
CHLORIDES
ION EXCHANGE
ORDER-DISORDER TRANSFORMATIONS
SELENIDES
SILVER COMPOUNDS
SILVER IONS
SULFIDES
TELLURIDES
THERMAL CONDUCTIVITY
THERMAL DIFFUSIVITY
THERMOELECTRIC PROPERTIES
BROMINE COMPOUNDS
CHALCOGENIDES
CHARGED PARTICLES
CHLORINE COMPOUNDS
ELECTRICAL PROPERTIES
HALIDES
HALOGEN COMPOUNDS
IONS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
SELENIUM COMPOUNDS
SULFUR COMPOUNDS
TELLURIUM COMPOUNDS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS