Thermoelectric properties of lanthanum sulfide

Wood, C.; Lockwood, A.; Parker, J. Brandon; Zoltan, A.; Zoltan, D.; Danielson, L. R.; Raag, V.

doi:10.1063/1.336088

Cited by 77 publications

(46 citation statements)

References 10 publications

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“…1) High thermoelectric performances were observed in -La 2 S 3 phase with high sulfur content. 1,2,9) The lanthanumrich sample promotes the formation of -La 2 S 3 , whose composition is nearly identical to that of La 3 S 4 .…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of La2S3 Thin Films by Sulfurization of LaCl3 and CS(NH2)2

et al. 2006

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La 2 S 3 thin films were prepared by dipping the substrates in methanol solutions of LaCl 3 Á7H 2 O and CS(NH 2 ) 2 , followed by sulfurization with CS 2 gas in the temperature range of 773-1073 K. The effects of the substrate and the mole ratio of LaCl 3 Á7H 2 O to CS(NH 2 ) 2 on the phase formation after sulfurization were investigated. When the mole ratio of LaCl 3 Á7H 2 O to CS(NH 2 ) 2 was 2:3, the tetragonal -La 2 S 3 coatings were obtained on silica glass and Mo substrates for sulfurization at 1073 K. On the other hand, the cubic -La 2 S 3 coating was obtained on a soda-lime glass substrate for sulfurization at 973 K. The thin films on Ta and Ti substrates were comprised of -La 2 S 3 and -La 2 S 3 phases for sulfurization at 1073 K. The LaS 2 phase was identified as an intermediate product of sulfurization at about 873 K. When the mole ratio of LaCl 3 Á7H 2 O to CS(NH 2 ) 2 was 1:1, the -La 2 S 3 coating was also obtained on silica glass substrate for sulfurization at 1073 K. Since the gaseous phases formed during sulfurization pass through the La 2 S 3 layer, the thin films obtained were porous.

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Section: Introductionmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11] However, in order to apply these materials to thermoelectric devices for smallscale refrigeration and power generation, it is required to prepare thin films. A majority of the previous studies have been confined to the investigation of bulk materials.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of La2S3 Thin Films by Sulfurization of LaCl3 and CS(NH2)2

et al. 2006

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“…The begirming of life subhmation rates of nSio8Geo2, lanthanum telluride, and the high temperature p-type Yb^MnSbn Zintl are compared in Table 1. The target long-term sublimation rate is 5x10"' g/cm^/hr, which is achieved using thin coatings of Si3N4/Si02 on Sio SGQQ 2 (Wood, 1985).…”

Section: Thermal and Mechanical Propertiesmentioning

confidence: 99%

Lanthanum Telluride: Mechanochemical Synthesis of a Refractory Thermoelectric Material

May

Snyder

Fleurial

2008

AIP Conference Proceedings

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Abstract. Recent experimental work on lanthanum telluride has confirmed its significant potential as an n-type material for high temperature thermoelectric (TE) power generation application. The phase of interest, La3.xTe4, has a Th3P4 defect structure where x is the lanthanum vacancy with values ranging between 0 and 1/3. Thermoelectric properties change rapidly with x since the carrier concentration, «, is proportional to the (l-3x) parameter. Controlling the Te to La stoichiometry in lanthanum telluride is thus vital to achieving the optimum self-doping level for the highest dimensionless figure of merit ZT value. We report on a significant improvement in reproducibly preparing this refractory compound over prior lengthy and unwieldy high temperature experimental techniques developed in the 1980's. Mechanochemical processes are utilized to synthesize precise stoichiometries of lanthanum telluride at room temperature, enabling improved characterization, analysis and modeling of its transport properties as a function of the number of La vacancies. We report TE properties for a large range of the allowed compositions, with ZT values greater than 1.0 obtained at 1275 K for several compositions. In addition to stoichiometric optimization within the pure compound, chemical substitutions can enhance performance by decreasing the lattice thermal conductivity and tuning the electrical properties for maximum ZT values at lower temperatures; preliminary studies indicate that the addition of ytterbium increases ZT. Some properties pertaining to device development are discussed. Specifically, lanthanum telluride has a low sublimation rate, and a coefficient of thermal expansion that closely matches a p-type rare earth compound analog (the Yb^MnSbn Zintl compound).

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“…4 The highest figure of merit ZT ͑=S 2 T / , where S is the thermopower, T the absolute temperature, the electrical resistivity, the thermal conductivity͒ has been found in the ␥ phase with high sulfur content. Wood et al 2 and Gadzhiev et al 3 have reported the ZT values of 0.5-0.6 for La 2 S 2.96 at 1000 K.…”

mentioning

confidence: 99%

“…[1][2][3] The ␥ phase crystallizes in the cubic Th 3 P 4 structure over the compositional range La 2 S 2.67 -La 2 S 3 . 4 The highest figure of merit ZT ͑=S 2 T / , where S is the thermopower, T the absolute temperature, the electrical resistivity, the thermal conductivity͒ has been found in the ␥ phase with high sulfur content.…”

mentioning

confidence: 99%

Thermoelectric properties of lanthanum sesquisulfide with Ti additive

Ohta

Hirai

Kato

et al. 2005

Applied Physics Letters

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The electrical resistivity, thermopower, and thermal conductivity have been measured for the lanthanum sesquisulfide ͑La 2 S 3 ͒ of which the crystal phase is controlled by the Ti additive. In all the samples, the thermopower is negative between 300 and 1000 K. The sample with 8 wt % Ti, which consists almost of the cubic ␥ phase, behaves as a degenerate semiconductor. The thermoelectric figure of merit ZT increases with increasing temperature, reaching a value of 0.21 at 1000 K. In contrast, the sample with 2 wt % Ti consists almost of the tetragonal ␤ phase. The transport mechanism can be well explained by the model of the Anderson localization. The ZT value increases abruptly with increasing temperature. At 1000 K, this ZT value is comparable with that of the sample with 8 wt % Ti.

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Thermoelectric properties of lanthanum sulfide

Abstract: The Seebeck coefficient, electrical resistivity, thermal conductivity, and Hall effect have been studied in r-phase La3 _ x S4 (LaS y ) in the composition range 0.04 Show more

Cited by 77 publications

References 10 publications

Synthesis of La<SUB>2</SUB>S<SUB>3</SUB> Thin Films by Sulfurization of LaCl<SUB>3</SUB> and CS(NH<SUB>2</SUB>)<SUB>2</SUB>

Synthesis of La<SUB>2</SUB>S<SUB>3</SUB> Thin Films by Sulfurization of LaCl<SUB>3</SUB> and CS(NH<SUB>2</SUB>)<SUB>2</SUB>

Lanthanum Telluride: Mechanochemical Synthesis of a Refractory Thermoelectric Material

Thermoelectric properties of lanthanum sesquisulfide with Ti additive

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