Functionally Graded (PbTe)1–x(SnTe)x Thermoelectrics

Hedegaard, Ellen M. J.; Mamakhel, Aref; Reardon, Hazel; Iversen, Bo B.

doi:10.1021/acs.chemmater.7b04473

Cited by 23 publications

(10 citation statements)

References 68 publications

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“…[6] Both results seem to fortify explanation (1) above, as adding Sn to PbTe increases the L-Σ gap and reduces Σ contributions to transport while Cd does the opposite. [38,39] However, the defects and strain inserted from the chosen additions must be considered. Alloying PbTe with Sn forms a large number of p-type cation vacancies, and Cd is known to increase internal dislocation strain.…”

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confidence: 99%

Dislocations Stabilized by Point Defects Increase Brittleness in PbTe

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Abdellaoui

et al. 2021

Adv Funct Materials

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Dislocations and the residual strain they produce are instrumental for the high thermoelectric figure of merit, zT ≈ 2, in lead chalcogenides. However, these materials tend to be brittle, barring them from practical green energy and deep space applications. Nonetheless, the bulk of thermoelectrics research focuses on increasing zT without considering mechanical performance. Optimized thermoelectric materials always involve high point defect concentrations for doping and solid solution alloying. Brittle materials show limited plasticity (dislocation motion), yet clear links between crystallographic defects and embrittlement are hitherto unestablished in PbTe. This study identifies connections between dislocations, point defects, and the brittleness (correlated with Vickers hardness) in single crystal and polycrystalline PbTe with various n‐ and p‐type dopants. Speed of sound measurements show a lack of electronic bond stiffening in p‐type PbTe, contrary to the previous speculation. Instead, varied routes of point defect–dislocation interaction restrict dislocation motion and drive embrittlement: dopants with low doping efficiency cause high defect concentrations, interstitial n‐type dopants (Ag and Cu) create highly strained obstacles to dislocation motion, and highly mobile dopants can distribute inhomogeneously or segregate to dislocations. These results illustrate the consequences of excessive defect engineering and the necessity to consider both mechanical and thermoelectric performance when researching thermoelectric materials for practical applications.

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confidence: 99%

Dislocations Stabilized by Point Defects Increase Brittleness in PbTe

Male

Abdellaoui

et al. 2021

Adv Funct Materials

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“…An approach to enhance the conversion efficiency of a FGTEM is to optimize the zT by tuning the amount of dopant at different spatial positions in the material 52 . Analytical models and numerical simulations found that a carrier concentration or a composition gradient could widen the temperature range of optimum zT of a material [53][54][55][56][57][58][59][60][61] . These FGTEMs showed increases in the temperature range of their optimum zT s. FGTEM through grading carrier concentration has the advantages to have a gradual phase transition without inducing any contact resistances.…”

Section: Introductionmentioning

confidence: 99%

Optimizing thermocouple’s ZT through design innovation

Zhang

2021

Preprint

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In this work, we demonstrate that in parallel with the one existed at high doping concentration, there also exists an optimal combination of the transport properties of a thermoelectric material at low doping concentration as the curve of the relationship between electrical conductivity and doping concentration is rigidly shifted toward lower doping concentration without disturbing the Seebeck coefficient and the thermal conductivity. Based on this finding, a new concept for thermocouple design is developed to improve the thermocouple’s efficiency and power output. The analytical model developed for the new thermocouple indicated that its efficiency and power output can be more than tripled as compared to those of the original design. A single thermocouple made of Silicon semiconductors was simulated numerically using different sets of input parameters. The results showed that the new thermocouple’s efficiency and power output can be improved significantly.

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“…Januszko et al prepared gradient samples using sedimentation of atoms under a strong gravitational field and obtained a large diffusion area in a Bi 1-x Sb x alloy [25]. Hedegaard et al prepared the (PbTe) 1-x (SnTe) x [26] and Ge 1-x Si x [27] gradient samples by the Bridgman and Czochralski crystal growth method and used the Potential-Seebeck Microprobe (PSM) to investigate the electrical-transport properties. By the Bridgman method, Kohri et al grew a Ge-graded (PbTe) 1-x (GeTe) x sample and investigated the influence of the Ge content on the thermoelectric transport properties [28].…”

Section: Introductionmentioning

confidence: 99%

High Thermoelectric Performance of Cu-Doped PbSe-PbS System Enabled by High-Throughput Experimental Screening

You

et al. 2020

Research

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Recent advances in high-throughput (HTP) computational power and machine learning have led to great achievements in exploration of new thermoelectric materials. However, experimental discovery and optimization of thermoelectric materials have long relied on the traditional Edisonian trial and error approach. Herein, we demonstrate that ultrahigh thermoelectric performance in a Cu-doped PbSe-PbS system can be realized by HTP experimental screening and precise property modulation. Combining the HTP experimental technique with transport model analysis, an optimal Se/S ratio showing high thermoelectric performance has been efficiently screened out. Subsequently, based on the screened Se/S ratio, the doping content of Cu has been subtly adjusted to reach the optimum carrier concentration. As a result, an outstanding peak zT~1.6 is achieved at 873 K for a 1.8 at% Cu-doped PbSe0.6S0.4 sample, which is the superior value among the n-type Te-free lead chalcogenides. We anticipate that current work will stimulate large-scale unitization of the HTP experimental technique in the thermoelectric field, which can greatly accelerate the research and development of new high-performance thermoelectric materials.

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Functionally Graded (PbTe)_1–x(SnTe)_x Thermoelectrics

Cited by 23 publications

References 68 publications

Dislocations Stabilized by Point Defects Increase Brittleness in PbTe

Dislocations Stabilized by Point Defects Increase Brittleness in PbTe

Optimizing thermocouple’s ZT through design innovation

High Thermoelectric Performance of Cu-Doped PbSe-PbS System Enabled by High-Throughput Experimental Screening

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