Thermoelectric GeTe with Diverse Degrees of Freedom Having Secured Superhigh Performance

Hong, Min; Zou, Jin; Chen, Zhigang

doi:10.1002/adma.201807071

Cited by 224 publications

(179 citation statements)

References 184 publications

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“…It is assumed that the valence band maximum of rhombohedral GeTe is at degenerate T and L points . Recent density functional theory (DFT) calculations imply that it could also be at the Σ‐point . Then, the trend of the effective mass tensor with respect to changes in bond parameters can be inferred from the corresponding changes in the bandwidths along the principal axes.…”

Section: Band Engineering By Tuning the Chemical Bondmentioning

confidence: 99%

“…First, most of them can easily be doped into p‐type or n‐type, which is critical for the assembly of thermoelectric devices . Second, they consist of heavy elements and soft chemical bonds, resulting in low thermal conductivity . Third, they possess a variety of structures, providing a good platform for manipulating the thermoelectric performance.…”

Section: Introductionmentioning

confidence: 99%

“…Some rare‐earth chalcogenides can even be used above 1000 K due to their high thermal stability, such as La 3− x Te 4 which exhibits a maximum zT of ≈1.1 at 1275 K . More comprehensive discussions of the thermoelectric properties of chalcogenide compounds can be found elsewhere …”

Section: Introductionmentioning

confidence: 99%

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Chalcogenide Thermoelectrics Empowered by an Unconventional Bonding Mechanism

Cagnoni

Cojocaru‐Mirédin

et al. 2019

Adv Funct Materials

179

214

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Thermoelectric materials have attracted significant research interest in recent decades due to their promising application potential in interconverting heat and electricity. Unfortunately, the strong coupling between the material parameters that determine thermoelectric efficiency, i.e., the Seebeck coefficient, electrical conductivity, and thermal conductivity, complicates the optimization of thermoelectric energy converters. Main‐group chalcogenides provide a rich playground to alleviate the interdependence of these parameters. Interestingly, only a subgroup of octahedrally coordinated chalcogenides possesses good thermoelectric properties. This subgroup is also characterized by other outstanding characteristics suggestive of an exceptional bonding mechanism, which has been coined metavalent bonding. This conclusion is further supported by a map that separates different bonding mechanisms. In this map, all octahedrally coordinated chalcogenides with good performance as thermoelectrics are located in a well‐defined region, implying that the map can be utilized to identify novel thermoelectrics. To unravel the correlation between chemical bonding mechanism and good thermoelectric properties, the consequences of this unusual bonding mechanism on the band structure are analyzed. It is shown that features such as band degeneracy and band anisotropy are typical for this bonding mechanism, as is the low lattice thermal conductivity. This fundamental understanding, in turn, guides the rational materials design for improved thermoelectric performance by tailoring the chemical bonding mechanism.

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Section: Band Engineering By Tuning the Chemical Bondmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Chalcogenide Thermoelectrics Empowered by an Unconventional Bonding Mechanism

Cagnoni

Cojocaru‐Mirédin

et al. 2019

Adv Funct Materials

179

214

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“…[9,10] Figure 1a shows the development timeline for all SnSe-based bulk thermoelectric materials, from which a record high ZT of ≈2.8 at 773 K was found in the n-type SnSe single crystal, [11] derived from its ultralow κ l of ≈0.18 W m −1 K −1 and high S 2 σ of ≈9.0 µW cm −1 K −2 at this temperature. [125] Such a high ZT is also very competitive to other state-of-the-art thermoelectric systems which possess ZTs > 2, such as PbTe, [126][127][128][129][130][131][132][133][134] GeTe, [135][136][137][138][139][140][141][142][143][144][145][146][147] Cu 2 Se/Cu 2 S, [148][149][150][151][152][153][154][155][156][157] and AgSbTe 2 . [158] Inspired by the full potentials for further improving ZT via reducing κ l and tuning carrier concentration n (for electrons) and/or p (for holes), SnSe-based thermoelectric materials have attracted much attentions in recent years.…”

mentioning

confidence: 99%

High‐Performance Thermoelectric SnSe: Aqueous Synthesis, Innovations, and Challenges

2020

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Tin selenide (SnSe) is one of the most promising candidates to realize environmentally friendly, cost‐effective, and high‐performance thermoelectrics, derived from its outstanding electrical transport properties by appropriate bandgaps and intrinsic low lattice thermal conductivity from its anharmonic layered structure. Advanced aqueous synthesis possesses various unique advantages including convenient morphology control, exceptional high doping solubility, and distinctive vacancy engineering. Considering that there is an urgent demand for a comprehensive survey on the aqueous synthesis technique applied to thermoelectric SnSe, herein, a thorough overview of aqueous synthesis, characterization, and thermoelectric performance in SnSe is provided. New insights into the aqueous synthesis‐based strategies for improving the performance are provided, including vacancy synergy, crystallization design, solubility breakthrough, and local lattice imperfection engineering, and an attempt to build the inherent links between the aqueous synthesis‐induced structural characteristics and the excellent thermoelectric performance is presented. Furthermore, the significant advantages and potentials of an aqueous synthesis route for fabricating SnSe‐based 2D thermoelectric generators, including nanorods, nanobelts, and nanosheets, are also discussed. Finally, the controversy, strategy, and outlook toward future enhancement of SnSe‐based thermoelectric materials are also provided. This Review guides the design of thermoelectric SnSe with high performance and provides new perspectives as a reference for other thermoelectric systems.

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“…[109] Extending their range of applications further, PCMs are also rapidly garnering interest as candidate materials for photonic devices such as switchable displays (Figure 3b) [110][111][112] or thermoelectrics for waste heat recovery (e.g., by alloying GeTe with guest atoms to modify the atomic and electronic structure). [113][114][115] Adv. Mater.…”

Section: Structure Dynamics and Function In Phase-change Materialsmentioning

confidence: 99%

Machine Learning Interatomic Potentials as Emerging Tools for Materials Science

2019

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In pursuit of this goal, atomic-scale computer simulations have long been a central approach, and two major families of methods are routinely used today. On the one hand, there are quantum-mechanical simulations, in which we solve Schrödinger's equation for the electronic structure of molecular and periodic systems, most widely based on density-functional theory (DFT). [6][7][8] These methods provide (largely) reliable results for structural models of materials that normally contain a few tens or hundreds of atoms. State-of-the-art DFT methods can be applied to many material classes, and they are increasingly used for high-throughput screening and "in silico" (computer-based) design of materials: new compositions and previously unknown structures have been identified in DFT searches and subsequently experimentally realized. [5,[9][10][11] On the other hand, interatomic potential models ("force fields"), parameterizing interactions between atoms with (relatively) simple functional forms, are widely used in materials science to describe matter in molecular dynamics (MD) simulations. These simulations grant access to larger time and length scales, reaching system sizes of up to hundreds of thousands of atoms. [12] In parameterizing these potentials, a certain physical form of the atomic interactions is assumed, often in terms of bond distances, angles, and so on, and physical properties such as equilibrium lattice parameters or elastic constants enter the fitting of the potential. For this reason, such potentials are often called "empirical." They are several orders of magnitude faster than DFT, but necessarily less accurate and less easily transferable.In this Progress Report, we highlight recent developments in "machine-learned" interatomic potentials, which represent a rapidly growing field that promises to do away with the aforementioned trade-offs. Over the last year, there has been a surge of interest in machine learning (ML) methodology: part of it is due to the dramatic growth of ML throughout the scientific disciplines, and part of it is due to tangible success stories of ML-based interatomic potentials that are now beginning to emerge. We will argue that this is an exciting development with very practical implications, currently on the verge of moving from a somewhat specialized new technology to everyday applicability, poised to enhance and complement the communities' existing strengths in computational materials modeling. We will show selected applications of ML potentials to problems in materials science, discuss the current limitations (and possible pitfalls), and outline what we expect to be interesting directions for the development of the field in the coming years.Atomic-scale modeling and understanding of materials have made remarkable progress, but they are still fundamentally limited by the large computational cost of explicit electronic-structure methods such as density-functional theory. This Progress Report shows how machine learning (ML) is currently enabling a new degree of realism in materi...

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Thermoelectric GeTe with Diverse Degrees of Freedom Having Secured Superhigh Performance

Cited by 224 publications

References 184 publications

Chalcogenide Thermoelectrics Empowered by an Unconventional Bonding Mechanism

Chalcogenide Thermoelectrics Empowered by an Unconventional Bonding Mechanism

High‐Performance Thermoelectric SnSe: Aqueous Synthesis, Innovations, and Challenges

Machine Learning Interatomic Potentials as Emerging Tools for Materials Science

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