Grain boundary dominated charge transport in Mg<sub>3</sub>Sb<sub>2</sub>-based compounds

Kuo, Jimmy Jiahong; Kang, Stephen Dongmin; Imasato, Kazuki; Tamaki, Haruo; Ohno, Saneyuki; Kanno, Tsutomu; Snyder, G. Jeffrey

doi:10.1039/c7ee03326e

Cited by 287 publications

(289 citation statements)

References 38 publications

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“…The signature of the grain boundary effect in these materials is electrical conductivity that is activated with temperature (Figure 3a), and a Seebeck coefficient (the absolute value) that increases gradually with temperature (Figure 3b). Essentially, the conductivity is affected by grain boundaries, while the Seebeck coefficient is not. The relative weighted mobility between polycrystalline samples and single crystal samples indicates the strength of the grain boundary effect.…”

Section: Resultsmentioning

confidence: 99%

Graphene/Strontium Titanate: Approaching Single Crystal–Like Charge Transport in Polycrystalline Oxide Perovskite Nanocomposites through Grain Boundary Engineering

Lin

Dylla

Kuo

et al. 2020

Adv Funct Materials

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Grain boundaries critically limit the electronic performance of oxide perovskites. These interfaces lower the carrier mobilities of polycrystalline materials by several orders of magnitude compared to single crystals. Despite extensive effort, improving the mobility of polycrystalline materials (to meet the performance of single crystals) is still a severe challenge. In this work, the grain boundary effect is eliminated in perovskite strontium titanate (STO) by incorporating graphene into the polycrystalline microstructure. An effective mass model provides strong evidence that polycrystalline graphene/strontium titanate (G/STO) nanocomposites approach single crystal‐like charge transport. This phenomenological model reduces the complexity of analyzing charge transport properties so that a quantitative comparison can be made between the nanocomposites and STO single crystals. In other related works, graphene composites also optimize the thermal transport properties of thermoelectric materials. Therefore, decorating grain boundaries with graphene appears to be a robust strategy to achieve “phonon glass–electron crystal” behavior in oxide perovskites.

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Section: Resultsmentioning

confidence: 99%

Graphene/Strontium Titanate: Approaching Single Crystal–Like Charge Transport in Polycrystalline Oxide Perovskite Nanocomposites through Grain Boundary Engineering

Lin

Dylla

Kuo

et al. 2020

Adv Funct Materials

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“…[33] In the place of ionized impurity scattering, they proposed a model of grain boundary (GB) dominated electrical transport that provides a good theoretical prediction of both the electrical conductivities and Seebeck coefficients. [33] In the place of ionized impurity scattering, they proposed a model of grain boundary (GB) dominated electrical transport that provides a good theoretical prediction of both the electrical conductivities and Seebeck coefficients.…”

Section: Unorthodox Charge Transport Below 500 K and Future Directionsmentioning

confidence: 99%

“…[33] Future work dedicated to the understanding and mitigation of this undesired effect will be thus expected to provide an additional boost to the thermoelectric performance. Because the GB scattering significantly degrades the charge carrier mobility, while providing no competing beneficial effects, it is an undesirable feature in thermoelectric materials and should be eliminated if possible.…”

Section: Unorthodox Charge Transport Below 500 K and Future Directionsmentioning

confidence: 99%

“…[31][32][33] Elimination of this effect may represent a future path toward further improving the thermoelectric performance of NaPb m SbSe m+2 . As a result, properly doped NaPb m SbSe m+2 achieves maximum ZT of 1.4 near 900 K and critically, a record estimated ZT avg for p-type PbSe of 0.64 over 400-873 K, marking a significant improvement on existing tellurium free p-type PbSe-based thermoelectrics.…”

Section: Introductionmentioning

confidence: 99%

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High Thermoelectric Performance in PbSe–NaSbSe₂ Alloys from Valence Band Convergence and Low Thermal Conductivity

Slade

Bailey

Grovogui

et al. 2019

Advanced Energy Materials

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PbSe is an attractive thermoelectric material due to its favorable electronic structure, high melting point, and lower cost compared to PbTe. Herein, the hitherto unexplored alloys of PbSe with NaSbSe 2 (NaPb m SbSe m+2 ) are described and the most promising p-type PbSe-based thermoelectrics are found among them. Surprisingly, it is observed that below 500 K, NaPb m SbSe m+2 exhibits unorthodox semiconducting-like electrical conductivity, despite possessing degenerate carrier densities of ≈10 20 cm −3 . It is shown that the peculiar behavior derives from carrier scattering by the grain boundaries. It is further demonstrated that the high solubility of NaSbSe 2 in PbSe augments both the thermoelectric properties while maintaining a rock salt structure. Namely, density functional theory calculations and photoemission spectroscopy demonstrate that introduction of NaSbSe 2 lowers the energy separation between the L-and Σ-valence bands and enhances the power factors under 700 K. The crystallographic disorder of Na + , Pb 2+ , and Sb 3+ moreover provides exceptionally strong point defect phonon scattering yielding low lattice thermal conductivities of 1-0.55 W m −1 K −1 between 400 and 873 K without nanostructures. As a consequence, NaPb 10 SbSe 12 achieves maximum ZT ≈1.4 near 900 K when optimally doped. More importantly, NaPb 10 SbSe 12 maintains high ZT across a broad temperature range, giving an estimated record ZT avg of ≈0.64 between 400 and 873 K, a significant improvement over existing p-type PbSe thermoelectrics.

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“…However, n‐type Mg 3 Sb 2 was recently prepared by adding excess Mg in order to suppress the Mg vacancies 10–14. This has inspired the further enhancement of electron concentration by extrinsic doping, typically by a chalcogen 9–12,15–17. Combined with the alloying of Mg 3 Bi 2 to decrease the lattice thermal conductivity, ZT values higher than 1.5 have been widely achieved 9,11,13,14,16,18–21.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Thermoelectric Performance in N‐Type Mg_3.2Sb_1.5Bi_0.5 by La or Ce Doping into Mg

Zhang

Chen

et al. 2020

Adv Elect Materials

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N‐type Mg3.2Sb1.5Bi0.5 materials are prepared by cation‐site doping with lanthanides (La, Ce). Both La‐ and Ce‐doped samples exhibit a higher doping limit and greater efficiency than those of chalcogen (Te, Se, S)‐doped n‐type Mg3.2Sb1.5Bi0.5 samples. High electron carrier concentration ≈9 × 1019 cm−3 is obtained in Mg3.18La0.02Sb1.5Bi0.5 and Mg3.185Ce0.015Sb1.5Bi0.5, which is close to the theoretical doping‐concentration limit and induces contributions from more electron bands. A higher electrical conductivity was thus obtained and is beneficial to the enhanced ZT values for lanthanide‐doped Mg3.2Sb1.5Bi0.5. The highest ZT value ≈1.6 is achieved in Mg3.19La0.01Sb1.5Bi0.5 at 693 K, along with a ZT ≈1.50 in Mg3.19Ce0.01Sb1.5Bi0.5 at 693 K, indicating that lanthanides provide a promising doping strategy for Mg3.2Sb1.5Bi0.5‐based materials.

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Grain boundary dominated charge transport in Mg₃Sb₂-based compounds

Abstract: The influence of grain boundaries is modelled to show that there is much room for improvement in some thermoelectric materials.

Cited by 287 publications

References 38 publications

Graphene/Strontium Titanate: Approaching Single Crystal–Like Charge Transport in Polycrystalline Oxide Perovskite Nanocomposites through Grain Boundary Engineering

Graphene/Strontium Titanate: Approaching Single Crystal–Like Charge Transport in Polycrystalline Oxide Perovskite Nanocomposites through Grain Boundary Engineering

High Thermoelectric Performance in PbSe–NaSbSe₂ Alloys from Valence Band Convergence and Low Thermal Conductivity

Enhanced Thermoelectric Performance in N‐Type Mg_3.2Sb_1.5Bi_0.5 by La or Ce Doping into Mg

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Grain boundary dominated charge transport in Mg3Sb2-based compounds

Abstract: The influence of grain boundaries is modelled to show that there is much room for improvement in some thermoelectric materials.

Cited by 287 publications

References 38 publications

Graphene/Strontium Titanate: Approaching Single Crystal–Like Charge Transport in Polycrystalline Oxide Perovskite Nanocomposites through Grain Boundary Engineering

Graphene/Strontium Titanate: Approaching Single Crystal–Like Charge Transport in Polycrystalline Oxide Perovskite Nanocomposites through Grain Boundary Engineering

High Thermoelectric Performance in PbSe–NaSbSe2 Alloys from Valence Band Convergence and Low Thermal Conductivity

Enhanced Thermoelectric Performance in N‐Type Mg3.2Sb1.5Bi0.5 by La or Ce Doping into Mg

Contact Info

Product

Resources

About

Grain boundary dominated charge transport in Mg₃Sb₂-based compounds

High Thermoelectric Performance in PbSe–NaSbSe₂ Alloys from Valence Band Convergence and Low Thermal Conductivity

Enhanced Thermoelectric Performance in N‐Type Mg_3.2Sb_1.5Bi_0.5 by La or Ce Doping into Mg