Exceptionally low thermal conductivity realized in the chalcopyrite CuFeS2 via atomic-level lattice engineering

Ge, Bangzhi; Lee, Hyungseok; Zhou, Chenyang; Lu, Wei; Hu, Jiabin; Yang, Jian; Cho, Sung‐Pyo; Qiao, Guanjun; Shi, Zhongqi; Chung, In Jae

doi:10.1016/j.nanoen.2022.106941

Cited by 23 publications

(42 citation statements)

References 55 publications

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“…4b) corresponding to Fe 2+ is observed in the Fe 2p spectrum, suggesting that Ge substitution results in a reduction of a fraction of the Fe 3+ ions to Fe 2+ . A similar observation has been made for tin and indium substitution in chalcopyrite 30,31 Significantly, the 3d spectrum of Ge (Fig. 4d) indicates that this cation is in a mixed oxidation state, with peaks assignable to both Ge 2+ and Ge 4+ present; the latter having the higher intensity.…”

Section: Resultssupporting

confidence: 81%

“…This represents an almost six-fold improvement. Furthermore, the maximum value of zT attained in this work, is higher than the values reported for many of the substituted CuFeS 2 compositions, 20,25–27,29–31,57–59 and is one of the highest achieved in substituted chalcopyrite; thus, making Ge substitution a promising approach to fabricating high-performing n-type CuFeS 2 materials for thermoelectric applications.…”

Section: Resultscontrasting

confidence: 54%

“…Such features can have a marked impact on the phonon density of states and contribute to reductions in the lattice thermal conductivity. 29,30 High oxidation state substituents offer the potential to achieve greater increases in the charge-carrier concentration than is possible with the more usual 2+ transition-metal cations. Although, as we have demonstrated recently, 31 in the case of substitution with Sn 4+ , the increase in charge-carrier concentration can deviate from expected values due to the presence of localised states, associated with the formation of small polarons.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Local structural distortions and reduced thermal conductivity in Ge-substituted chalcopyrite

et al. 2022

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Section: Resultssupporting

confidence: 81%

Section: Resultscontrasting

confidence: 54%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Local structural distortions and reduced thermal conductivity in Ge-substituted chalcopyrite

et al. 2022

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“…A comparison of the thermoelectric figure-of-merit ( zT ) at 673 K of potential n -type sulfide-based materials. ,,,− …”

Section: Resultsmentioning

confidence: 99%

Tin-Substituted Chalcopyrite: An n-Type Sulfide with Enhanced Thermoelectric Performance

et al. 2022

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The dearth of n -type sulfides with thermoelectric performance comparable to that of their p- type analogues presents a problem in the fabrication of all-sulfide devices. Chalcopyrite (CuFeS 2 ) offers a rare example of an n -type sulfide. Chemical substitution has been used to enhance the thermoelectric performance of chalcopyrite through preparation of Cu 1- x Sn x FeS 2 (0 ≤ x ≤ 0.1). Substitution induces a high level of mass and strain field fluctuation, leading to lattice softening and enhanced point-defect scattering. Together with dislocations and twinning identified by transmission electron microscopy, this provides a mechanism for scattering phonons with a wide range of mean free paths. Substituted materials retain a large density-of-states effective mass and, hence, a high Seebeck coefficient. Combined with a high charge-carrier mobility and, thus, high electrical conductivity, a 3-fold improvement in power factor is achieved. Density functional theory (DFT) calculations reveal that substitution leads to the creation of small polarons, involving localized Fe 2+ states, as confirmed by X-ray photoelectron spectroscopy. Small polaron formation limits the increase in carrier concentration to values that are lower than expected on electron-counting grounds. An improved power factor, coupled with substantial reductions (up to 40%) in lattice thermal conductivity, increases the maximum figure-of-merit by 300%, to zT ≈ 0.3 at 673 K for Cu 0.96 Sn 0.04 FeS 2 .

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Copper Iron Chalcogenide Semiconductor Nanocrystals in Energy and Optoelectronics Applications—State of the Art, Challenges, and Future Potential

Bhattacharyya

Balischewski

Pacholski

et al. 2023

Advanced Optical Materials

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I‐III‐VI2 semiconductor nanocrystals have been explored in countless optoelectronics and green energy applications. While indium‐based compounds are arguably the best‐known variants of these semiconductors and have been widely studied for their photophysical properties, other I‐III‐VI2 semiconductors are emerging as serious competitors. This review focuses on the current state of the art and recent progress made in the research and technology of one of the most promising competitors to indium‐based I‐III‐VI2 semiconductor nanocrystals, CuFeS2 nanocrystals. CuFeS2 is a promising alternative to indium‐based systems, mostly because many properties are competitive and because iron is much more abundant than indium. Replacing In(III) with Fe(III) would thus significantly alleviate the issue of raw material availability. The article highlights new synthesis approaches and summarizes and discusses advanced optical properties including surface plasmon resonance and luminescence properties. Moreover, potential applications in thermoelectric, photodetection, photothermal, and photovoltaics are illustrated and discussed. Finally, future perspectives for materials development, upscaling, and application in new processes and devices, such as self‐assembly, patterning, or plasmonic catalysis, are presented as well.

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Exceptionally low thermal conductivity realized in the chalcopyrite CuFeS2 via atomic-level lattice engineering

Cited by 23 publications

References 55 publications

Local structural distortions and reduced thermal conductivity in Ge-substituted chalcopyrite

Local structural distortions and reduced thermal conductivity in Ge-substituted chalcopyrite

Tin-Substituted Chalcopyrite: An n-Type Sulfide with Enhanced Thermoelectric Performance

Copper Iron Chalcogenide Semiconductor Nanocrystals in Energy and Optoelectronics Applications—State of the Art, Challenges, and Future Potential

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