High thermoelectric and mechanical performance achieved by a hyperconverged electronic structure and low lattice thermal conductivity in GeTe through CuInTe<sub>2</sub> alloying

Kim, Hyunji; Kihoi, Samuel Kimani; Shenoy, Sulakshana; Kahiu, Joseph N; Shin, Dong Hyun; Bhat, D. Krishna; Lee, Ho Seong

doi:10.1039/d2ta09280h

Cited by 25 publications

(3 citation statements)

References 90 publications

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“…Most importantly, research on high performance over a wide temperature range, cost-effectiveness, and eco-friendly thermoelectric materials has continued to muster significant interest. Archetypal examples are the exemplary SnTe and GeTe, which are some of the chalcogenide materials. − To enhance the thermoelectric performance of these materials, strategies such as band engineering (band gap enlargement, , band convergence, hyperconvergence, , flat bands, and resonant doping , ), phonon engineering, , microstructural control, − modulation doping, entropy engineering, − and recently metavalent bonding , have been successfully adopted.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Electrical, Thermal, and Mechanical Properties of SnTe through Equimolar Multication Alloying for Suitable Device Applications

Kihoi,

Shenoy,

Kim

et al. 2024

ACS Appl. Energy Mater.

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With the ever-growing demand for eco-friendly energy sources to mitigate the global rising temperatures, the universal insatiable need for sustainable and efficient energy sources are earnestly being intensively sought after. The ubiquitous heat within, if successfully tapped, is an utterly promising source of energy. To achieve this, a thermoelectric device (TED) is needed. To enhance the conversion efficiency from heat to useful electrical power, we developed a strategy to improve the thermoelectric performance of the materials involved. In this work, equimolar multication alloying (EMMCA) is proposed for the first time and employed to enhance the performance of SnTe-based thermoelectric materials. Beyond the cation's solubility limit, in situ compositing is observed with an increasing doping ratio, whereby distinct CuInTe 2 ternary second phases are dispersed within the SnTe matrix. The electronic properties of the ensuing alloy are significantly enhanced by the resulting carrier concentration modulation and the unique electronic band engineering. A decrease in the thermal transport properties is likewise reported, benefiting from enhanced phonon scattering and diminished electronic contribution. The mechanical properties are also shown to increase with increased alloying. As a result, single-leg TED performance shows substantial output power in comparison with the pristine sample. The outcomes stemming from EMMCA are documented as significantly impactful, contributing to superior overall thermoelectric performance.

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Section: Introductionmentioning

confidence: 99%

Enhanced Electrical, Thermal, and Mechanical Properties of SnTe through Equimolar Multication Alloying for Suitable Device Applications

Kihoi,

Shenoy,

Kim

et al. 2024

ACS Appl. Energy Mater.

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“…In this work, however, we propose a chemical composition modulation strategy trying to realize electro-acoustic coordination: , that is, alloying GeTe in CIT at first, aiming to gain degenerated or converged valence bands through improving its structural symmetry. − After that, we introduce a proper Cu deficiency (V Cu ) , to adjust the carrier concentration ( n H ) through unpinning the Fermi level ( F r ) in the madgap and, at the same time, suppress the phonon velocity and/or strengthen the structural anharmonicity through increasing lattice disorder. ,− By utilizing this strategy, we realize the electro-acoustic coordination effectively in the present material and improve the TE performance significantly with the highest ZT value of 1.51 at 838 K. This value ranks at a higher level among the CIT-based materials.…”

Section: Introductionmentioning

confidence: 99%

Chemical Composition Modulation Realizing Remarkable Improvement of Thermoelectric Performance in CuInTe₂-Based Alloy

Qu,

Luo,

et al. 2024

ACS Appl. Mater. Interfaces

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CuInTe 2 (CIT) is one of the typical ternary chalcogenides known for its characteristic mixed polyanionic/polycationic site defects, making it a subject of continuous interest in the field of thermoelectrics. In this work, we propose a chemical composition modulation strategy for CIT by alloying GeTe and then introducing a copper deficiency (denoted by V Cu ). This strategy aims to unpin its Fermi level (F r ) and shift F r into the valence band (VB) while simultaneously enabling coupling between the optical and acoustic phonon, thereby providing an extra phonon scattering path at low frequencies. The simultaneous composition regulations not only enhance the carrier concentration (n H ) to 10 19 −10 20 cm −3 but also significantly reduce the lattice thermal conductivity (κ L ) to ∼0.48 W m −1 K −1 , thus effectively realizing electro-acoustic coordination in the present material. As a consequence, the thermoelectric (TE) performance is remarkably improved with the highest TE figure of merit (ZT) of 1.51 at ∼838 K. This value ranks at a higher level among CIT-based materials, which showcases the great significance of chemical composition modulation.

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“…There have been a few reports of layered AB 2 Te 4 (A = Sn, Pb; B = Sb, Bi) ternary compounds that reveal their perspective as high-performance thermoelectrics, either through first principles-based transport theory or experiments. − These layered compounds have a rhombohedral crystal structure ( R 3̅ m ), where septuple (7 atoms) layers are stacked along the c -axis with van der Waals interactions between the layers . There exists a huge potential for improving the thermoelectric properties of these layered materials in comparison to other state-of-the-art thermoelectric materials such as SnTe, − GeTe, − PbTe, half-Heuslers, , and among others.…”

Section: Introductionmentioning

confidence: 99%

Tailoring the Thermoelectric Performance of the Layered Topological Insulator SnSb₂Te₄ through Bi Positional Doping at the Sn and Sb Cation Sites

Kihoi

Shenoy²,

Kahiu

et al. 2023

ACS Appl. Electron. Mater.

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Ongoing research and development focus on emerging thermoelectric materials with enhanced performance, continually making the possibility of waste heat recovery a reality. In this work, we engineer the thermoelectric properties of the layered SnSb2Te4 topological insulators. To date, there is little research reporting on these materials as potential state-of-the-art thermoelectric materials. Thus, there is a need to formulate effective strategies to realize this potential. Since these materials are known to have intrinsically low lattice thermal conductivity, we shift our attention to improving the electrical transport properties. For the first time, positional Bi doping at both the Sn and Sb cation sites is adopted. The aliovalent and isovalent nature of Bi at these sites, respectively, is shown to cause significant improvements in the performance of these layered materials. The electronic band structure of the pure and doped samples, where we considered various occupancies, is studied whereby we reveal the occurrence of band convergence and resonant levels resulting in a high power factor of ∼10.8 μW cm–1 K–2 at 623 K. Overall, a high ZT of ∼0.46 at a relatively lower temperature of 673 K is recorded. The potential of these materials for thermoelectric applications is shown, especially in the case of Bi doping at the Sn cation site. Continued efforts to enhance the thermoelectric performance of these topological insulators are needed for them to gain a substantial competitive edge in comparison to other state-of-the-art thermoelectric materials.

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High thermoelectric and mechanical performance achieved by a hyperconverged electronic structure and low lattice thermal conductivity in GeTe through CuInTe₂ alloying

Abstract: GeTe-based thermoelectric materials have a very high hole carrier concentration (~ 1021 cm-3), thus improving the figure of merit, ZT, is substantially challenging. In this work, we foremost dope Bi...

Cited by 25 publications

References 90 publications

Enhanced Electrical, Thermal, and Mechanical Properties of SnTe through Equimolar Multication Alloying for Suitable Device Applications

Enhanced Electrical, Thermal, and Mechanical Properties of SnTe through Equimolar Multication Alloying for Suitable Device Applications

Chemical Composition Modulation Realizing Remarkable Improvement of Thermoelectric Performance in CuInTe₂-Based Alloy

Tailoring the Thermoelectric Performance of the Layered Topological Insulator SnSb₂Te₄ through Bi Positional Doping at the Sn and Sb Cation Sites

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High thermoelectric and mechanical performance achieved by a hyperconverged electronic structure and low lattice thermal conductivity in GeTe through CuInTe2 alloying

Abstract: GeTe-based thermoelectric materials have a very high hole carrier concentration (~ 1021 cm-3), thus improving the figure of merit, ZT, is substantially challenging. In this work, we foremost dope Bi...

Cited by 25 publications

References 90 publications

Enhanced Electrical, Thermal, and Mechanical Properties of SnTe through Equimolar Multication Alloying for Suitable Device Applications

Enhanced Electrical, Thermal, and Mechanical Properties of SnTe through Equimolar Multication Alloying for Suitable Device Applications

Chemical Composition Modulation Realizing Remarkable Improvement of Thermoelectric Performance in CuInTe2-Based Alloy

Tailoring the Thermoelectric Performance of the Layered Topological Insulator SnSb2Te4 through Bi Positional Doping at the Sn and Sb Cation Sites

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High thermoelectric and mechanical performance achieved by a hyperconverged electronic structure and low lattice thermal conductivity in GeTe through CuInTe₂ alloying

Chemical Composition Modulation Realizing Remarkable Improvement of Thermoelectric Performance in CuInTe₂-Based Alloy

Tailoring the Thermoelectric Performance of the Layered Topological Insulator SnSb₂Te₄ through Bi Positional Doping at the Sn and Sb Cation Sites