Ultralow Lattice Thermal Conductivity and Enhanced Thermoelectric Performance in SnTe:Ga Materials

Orabi, Rabih Al Rahal Al; Hwang, Junphil; Lin, Chan Chieh; Gautier, Régis; Fontaine, Bruno La; Kim, Woochul; Rhyee, Jong‐Soo; Wee, Daehyun; Fornari, Marco

doi:10.1021/acs.chemmater.6b04076

Cited by 90 publications

(57 citation statements)

References 63 publications

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“…This implies a strategy for reducing (means optimization here) the carrier concentration in GeTe, by increasing the mean size of cations and vice‐versa decreasing the average size of anions through isovalent substitutions. Such an effect can be seen in SnTe, where an isovalent substitution of Sn by smaller Mn, Mg, and Ga increases the carrier concentration while a bigger cation substitution by Cd decreases. Similarly in PbTe, cation substitution by a smaller sized Sn leads to an increase in carrier concentration .…”

Section: Introductionmentioning

confidence: 94%

Simultaneous Optimization of Carrier Concentration and Alloy Scattering for Ultrahigh Performance GeTe Thermoelectrics

et al. 2017

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In order to locate the optimal carrier concentrations for peaking the thermoelectric performance in p‐type group IV monotellurides, existing efforts focus on aliovalent doping, either to increase (in PbTe) or to decrease (in SnTe and GeTe) the hole concentration. The limited solubility of aliovalent dopants usually introduces insufficient phonon scattering for thermoelectric performance maximization. With a decrease in the size of cation, the concentration of holes, induced by cation vacancies in intrinsic compounds, increases rapidly from ≈1018 cm−3 in PbTe to ≈1020 cm−3 in SnTe and then to ≈1021 cm−3 in GeTe. This motivates a strategy here for reducing the carrier concentration in GeTe, by increasing the mean size of cations and vice‐versa decreasing the average size of anions through isovalent substitutions for increased formation energy of cation vacancy. A combination of the simultaneously resulting strong phonon scattering due to the high solubility of isovalent impurities, an ultrahigh thermoelectric figure of merit, zT of 2.2 is achieved in GeTe–PbSe alloys. This corresponds to a 300% enhancement in average zT as compared to pristine GeTe. This work not only demonstrates GeTe as a promising thermoelectric material but also paves the way for enhancing the thermoelectric performance in similar materials.

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Section: Introductionmentioning

confidence: 94%

Simultaneous Optimization of Carrier Concentration and Alloy Scattering for Ultrahigh Performance GeTe Thermoelectrics

et al. 2017

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“…Both strategies allowed for higher Seebeck coefficients. Further strategies to reduce the lattice thermal conductivity are based on the introduction of nanoscale secondary phases such as SrTe, 30 AgBiTe 2 , 41 AgInTe 2 , 42 In 2 Te 3 , 43 GaTe, 44 CdS, 31 and ZnS 31 within the SnTe matrix via solid state precipitation.…”

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confidence: 99%

Ligand-Mediated Band Engineering in Bottom-Up Assembled SnTe Nanocomposites for Thermoelectric Energy Conversion

et al. 2019

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The bottom-up assembly of colloidal nanocrystals is a versatile methodology to produce composite nanomaterials with precisely tuned electronic properties. Beyond the synthetic control over crystal domain size, shape, crystal phase, and composition, solution-processed nanocrystals allow exquisite surface engineering. This provides additional means to modulate the nanomaterial characteristics and particularly its electronic transport properties. For instance, inorganic surface ligands can be used to tune the type and concentration of majority carriers or to modify the electronic band structure. Herein, we report the thermoelectric properties of SnTe nanocomposites obtained from the consolidation of surface-engineered SnTe nanocrystals into macroscopic pellets. A CdSe-based ligand is selected to (i) converge the light and heavy bands through partial Cd alloying and (ii) generate CdSe nanoinclusions as a secondary phase within the SnTe matrix, thereby reducing the thermal conductivity. These SnTe-CdSe nanocomposites possess thermoelectric figures of merit of up to 1.3 at 850 K, which is, to the best of our knowledge, the highest thermoelectric figure of merit reported for solution-processed SnTe.

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“…Interest in thermoelectric (TE) technology has been continuously growing in the last decade due to the need to produce ecofriendly materials at low cost for the conversion of waste heat into electricity.Ahost of materials has been investigated in the past, [1][2][3] often neglecting the need to reconcile efficiencyw ith environment and cost constraints, both from acomposition and/or aprocessing perspective.F or instance,t elluride-based materials exhibit good performances, [4][5][6][7][8][9][10][11][12] but are of value only for niche applications due to the escalating price of tellurium. Therefore,o ther less costly compositions are more attractive,provided that the synthesis approaches are scalable to industrial settings.…”

Section: Introductionmentioning

confidence: 99%

Copper‐Rich Thermoelectric Sulfides: Size‐Mismatch Effect and Chemical Disorder in the [TS₄]Cu₆ Complexes of Cu₂₆T₂Ge₆S₃₂ (T=Cr, Mo, W) Colusites

et al. 2019

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In the present study, we investigate the Mo and W for Cr substitution in the synthetic mineral colusite, Cu26Cr2Ge6S32. Primarily, we elucidate the origin of extremely low electrical resistivity which does not compromise the Seebeck coefficient and leads to outstanding power factors of 1.94 mW m -1 K -2 at 700 K in Cu26Cr2Ge6S32. We demonstrate that the abnormally long iono-covalent T-S bonds competing with short metallic Cu-T interactions govern the electronic transport properties of the conductive "Cu26S32" framework. Additionally, we address the key role of the cationic size-mismatch at the core of the mixed tetrahedraloctahedral complex, illustrated by the cation-size variance, σ 2 , over the transport properties.Using a combination of experimental and theoretical tools, the explanation for the remarkable electrical and thermal transport properties of the Cu26Cr2-xMoxGe6S32 and Cu26Cr2-xWxGe6S32 solid solutions is discussed. In-depth structural analysis using Rietveld refinements of XRPD data reveals two essential effects caused by the substitution of Cr in the solid solutions: (1) Only the tetrahedra that are directly bonded to the [TS4]Cu6 complex are significantly distorted upon substitution and (2) the major contribution to the disorder is localized at the central position of the mixed tetrahedral-octahedral complex, and is maximized for x = 1, i.e. for the highest cationic size-variance, σ 2 . We investigated the low-(5 ≤ T / K ≤ 300) and high-(300 ≤ T / K ≤ 700) temperature electrical and thermal transport properties, including electrical resistivity, Seebeck coefficient, thermal conductivity, and Hall effect (low temperature only) measurements and linked the structural/chemical disorder to the radically different conduction mechanisms in the Cu26Cr2-xMoxGe6S32 and Cu26Cr2-xWxGe6S32 solid solutions.

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Ultralow Lattice Thermal Conductivity and Enhanced Thermoelectric Performance in SnTe:Ga Materials

Cited by 90 publications

References 63 publications

Simultaneous Optimization of Carrier Concentration and Alloy Scattering for Ultrahigh Performance GeTe Thermoelectrics

Simultaneous Optimization of Carrier Concentration and Alloy Scattering for Ultrahigh Performance GeTe Thermoelectrics

Ligand-Mediated Band Engineering in Bottom-Up Assembled SnTe Nanocomposites for Thermoelectric Energy Conversion

Copper‐Rich Thermoelectric Sulfides: Size‐Mismatch Effect and Chemical Disorder in the [TS₄]Cu₆ Complexes of Cu₂₆T₂Ge₆S₃₂ (T=Cr, Mo, W) Colusites

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Ultralow Lattice Thermal Conductivity and Enhanced Thermoelectric Performance in SnTe:Ga Materials

Cited by 90 publications

References 63 publications

Simultaneous Optimization of Carrier Concentration and Alloy Scattering for Ultrahigh Performance GeTe Thermoelectrics

Simultaneous Optimization of Carrier Concentration and Alloy Scattering for Ultrahigh Performance GeTe Thermoelectrics

Ligand-Mediated Band Engineering in Bottom-Up Assembled SnTe Nanocomposites for Thermoelectric Energy Conversion

Copper‐Rich Thermoelectric Sulfides: Size‐Mismatch Effect and Chemical Disorder in the [TS4]Cu6 Complexes of Cu26T2Ge6S32 (T=Cr, Mo, W) Colusites

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Copper‐Rich Thermoelectric Sulfides: Size‐Mismatch Effect and Chemical Disorder in the [TS₄]Cu₆ Complexes of Cu₂₆T₂Ge₆S₃₂ (T=Cr, Mo, W) Colusites