1
|
Kirievsky K, Fuks D, Gelbstein Y. Composition conserving defects and their influence on the electronic properties of thermoelectric TiNiSn. Phys Chem Chem Phys 2020; 22:8035-8047. [PMID: 32239005 DOI: 10.1039/d0cp00956c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Formation of composition conserving defects is an inherent feature that appears in compounds for thermoelectric applications during the processes of their fabrication. Different types of such defects including exchange antisite defects, Schottky defects, and triple-, quatro- and penta-defects in TiNiSn are considered. Density functional theory calculations of the energy of formation of these defects are carried out. It is demonstrated that their formation may lead to a significant decrease of the band gap (Eg), simultaneously causing a transformation to p-type or semi-metal conductivity in this material. The role of nanopores is discussed. It is shown that preparing nanoporous compounds may be an efficient way to create p-type TiNiSn, simultaneously decreasing the thermal conductivity and improving its thermoelectric parameters.
Collapse
Affiliation(s)
- K Kirievsky
- Materials Engineering Department, Ben Gurion University of the Negev, Beer Sheva, Israel.
| | - D Fuks
- Materials Engineering Department, Ben Gurion University of the Negev, Beer Sheva, Israel.
| | - Y Gelbstein
- Materials Engineering Department, Ben Gurion University of the Negev, Beer Sheva, Israel.
| |
Collapse
|
2
|
Komisarchik G, Gelbstein Y, Fuks D. Combined electronic and thermodynamic approaches for enhancing the thermoelectric properties of Ti-doped PbTe. Phys Chem Chem Phys 2016; 18:32429-32437. [PMID: 27869263 DOI: 10.1039/c6cp06364k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Lead telluride based compounds are of great interest due to their enhanced thermoelectric transport properties. Nevertheless, the donor type impurities in this class of materials are currently mainly limited and alternative types of donor impurities are still required for optimizing the thermoelectric performance. In the current research titanium as a donor impurity in PbTe is examined. Although titanium is known to form resonant levels above the conduction band in PbTe, it does not enhance the thermo-power beyond the classical predictions. Recent experiments showed that alloying with a small amount of Ti (∼0.1 at%) gives a significant increase in the figure of merit. In the current research ab initio calculations were applied in order to correlate the reported experimental results with a thermoelectric optimization model. It was found that a Ti concentration of ∼1.4 at% in the Pb sublattice is expected to maximize the thermoelectric power factor. Using a statistical thermodynamic approach and in agreement with the previously reported appearance of a secondary intermetallic phase, the actual Ti solubility limit in PbTe is found to be ∼0.3 at%. Based on the proposed model, the mechanism for the formation of the previously observed secondary phase is attributed to phase separation reactions, characterized by a positive enthalpy of formation in the system. With extrapolation of the obtained ab initio results, it is demonstrated that lower Ti-doping concentrations than previously experimentally reported ones are expected to provide power factor values close to the maximal one, making doping with Ti a promising opportunity for the generation of highly efficient n-type PbTe-based thermoelectric materials.
Collapse
Affiliation(s)
- G Komisarchik
- Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
| | - Y Gelbstein
- Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
| | - D Fuks
- Department of Materials Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
| |
Collapse
|
4
|
Kirievsky K, Shlimovich M, Fuks D, Gelbstein Y. An ab initio study of the thermoelectric enhancement potential in nano-grained TiNiSn. Phys Chem Chem Phys 2015; 16:20023-9. [PMID: 25123783 DOI: 10.1039/c4cp02868f] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Novel approaches for the development of highly efficient thermoelectric materials capable of a direct conversion of heat into electricity, are being constantly investigated. TiNiSn based half-Heusler alloys exhibit a high thermoelectric potential for practical, renewable power generation applications. The main challenge of further enhancement of the thermoelectric efficiency of these alloys lies in the reduction of the associated high lattice thermal conductivity values without adversely affecting the electronic transport properties. The current manuscript theoretically investigates two possible routes for overcoming this limitation in TiNiSn alloys. On the one hand, the influence of nano-grained structure of TiNiSn on the electronic structure of the material is theoretically demonstrated. On the other hand, the potential for thermal conductivity reduction upon increasing the Ni fraction in the intermetallic TiNiSn compound via the formation of metallic TiNi2Sn nanoparticles is also shown. Using the applied approach, a useful route for optimizing both the electronic and thermal properties of half-Heusler TiNiSn, for practical thermoelectric applications, is demonstrated.
Collapse
Affiliation(s)
- K Kirievsky
- Materials Engineering Department, Ben Gurion University of the Negev, Beer Sheva, Israel.
| | | | | | | |
Collapse
|
5
|
Wu D, Zhao LD, Hao S, Jiang Q, Zheng F, Doak JW, Wu H, Chi H, Gelbstein Y, Uher C, Wolverton C, Kanatzidis M, He J. Origin of the high performance in GeTe-based thermoelectric materials upon Bi2Te3 doping. J Am Chem Soc 2014; 136:11412-9. [PMID: 25072797 DOI: 10.1021/ja504896a] [Citation(s) in RCA: 275] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
As a lead-free material, GeTe has drawn growing attention in thermoelectrics, and a figure of merit (ZT) close to unity was previously obtained via traditional doping/alloying, largely through hole carrier concentration tuning. In this report, we show that a remarkably high ZT of ∼1.9 can be achieved at 773 K in Ge0.87Pb0.13Te upon the introduction of 3 mol % Bi2Te3. Bismuth telluride promotes the solubility of PbTe in the GeTe matrix, thus leading to a significantly reduced thermal conductivity. At the same time, it enhances the thermopower by activating a much higher fraction of charge transport from the highly degenerate Σ valence band, as evidenced by density functional theory calculations. These mechanisms are incorporated and discussed in a three-band (L + Σ + C) model and are found to explain the experimental results well. Analysis of the detailed microstructure (including rhombohedral twin structures) in Ge0.87Pb0.13Te + 3 mol % Bi2Te3 was carried out using transmission electron microscopy and crystallographic group theory. The complex microstructure explains the reduced lattice thermal conductivity and electrical conductivity as well.
Collapse
Affiliation(s)
- Di Wu
- Department of Physics, South University of Science and Technology of China , Shenzhen 518055, P. R. China
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Rao R, Graffeo CS, Gulati R, Jamal M, Narayan S, Zambirinis CP, Barilla R, Deutsch M, Greco SH, Ochi A, Tomkötter L, Blobstein R, Avanzi A, Tippens DM, Gelbstein Y, Van Heerden E, Miller G. Interleukin 17-producing γδT cells promote hepatic regeneration in mice. Gastroenterology 2014; 147:473-84.e2. [PMID: 24801349 PMCID: PMC4123443 DOI: 10.1053/j.gastro.2014.04.042] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 03/25/2014] [Accepted: 04/29/2014] [Indexed: 12/11/2022]
Abstract
BACKGROUND & AIMS Subsets of leukocytes synergize with regenerative growth factors to promote hepatic regeneration. γδT cells are early responders to inflammation-induced injury in a number of contexts. We investigated the role of γδT cells in hepatic regeneration using mice with disruptions in Tcrd (encodes the T-cell receptor δ chain) and Clec7a (encodes C-type lectin domain family 7 member a, also known as DECTIN1). METHODS We performed partial hepatectomies on wild-type C57BL/6, CD45.1, Tcrd(-/-), or Clec7a(-/-) mice. Cells were isolated from livers of patients and mice via mechanical and enzymatic digestion. γδT cells were purified by fluorescence-activated cell sorting. RESULTS In mice, partial hepatectomy up-regulated expression of CCL20 and ligands of Dectin-1, which was associated with recruitment and activation of γδT cells and their increased production of interleukin (IL)-17 family cytokines. Recruited γδT cells induced production of IL-6 by antigen-presenting cells and suppressed expression of interferon gamma by natural killer T cells, promoting hepatocyte proliferation. Absence of IL-17-producing γδT cells or deletion of Dectin-1 prevented development of regenerative phenotypes in subsets of innate immune cells. This slowed liver regeneration and was associated with reduced expression of regenerative growth factors and cell cycle regulators. Conversely, exogenous administration of IL-17 family cytokines or Dectin-1 ligands promoted regeneration. More broadly, we found that γδT cells are required for inflammatory responses mediated by IL-17 and Dectin-1. CONCLUSIONS γδT cells regulate hepatic regeneration by producing IL-22 and IL-17, which have direct mitogenic effects on hepatocytes and promote a regenerative phenotype in hepatic leukocytes, respectively. Dectin-1 ligation is required for γδT cells to promote hepatic regeneration.
Collapse
MESH Headings
- Animals
- Cell Proliferation
- Cells, Cultured
- Chemokine CCL20/metabolism
- Genotype
- Hepatectomy
- Hepatocytes/immunology
- Hepatocytes/metabolism
- Humans
- Inflammation Mediators/metabolism
- Interferon-gamma/metabolism
- Interleukin-17/metabolism
- Interleukin-6/metabolism
- Interleukins/metabolism
- Lectins, C-Type/deficiency
- Lectins, C-Type/genetics
- Lectins, C-Type/metabolism
- Liver/immunology
- Liver/metabolism
- Liver/surgery
- Liver Regeneration
- Lymphocyte Activation
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Phenotype
- Receptors, Antigen, T-Cell, gamma-delta/deficiency
- Receptors, Antigen, T-Cell, gamma-delta/genetics
- Receptors, Antigen, T-Cell, gamma-delta/metabolism
- Signal Transduction
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
- Time Factors
- Interleukin-22
Collapse
Affiliation(s)
- Raghavendra Rao
- S. Arthur Localio Laboratory, Department of Surgery, New York University School of Medicine, New York, New York
| | - Christopher S Graffeo
- S. Arthur Localio Laboratory, Department of Cell Biology, New York University School of Medicine, New York, New York
| | - Rishabh Gulati
- S. Arthur Localio Laboratory, Department of Surgery, New York University School of Medicine, New York, New York
| | - Mohsin Jamal
- S. Arthur Localio Laboratory, Department of Surgery, New York University School of Medicine, New York, New York
| | - Suchithra Narayan
- S. Arthur Localio Laboratory, Department of Cell Biology, New York University School of Medicine, New York, New York
| | - Constantinos P Zambirinis
- S. Arthur Localio Laboratory, Department of Surgery, New York University School of Medicine, New York, New York
| | - Rocky Barilla
- S. Arthur Localio Laboratory, Department of Cell Biology, New York University School of Medicine, New York, New York
| | - Michael Deutsch
- S. Arthur Localio Laboratory, Department of Surgery, New York University School of Medicine, New York, New York
| | - Stephanie H Greco
- S. Arthur Localio Laboratory, Department of Surgery, New York University School of Medicine, New York, New York
| | - Atsuo Ochi
- S. Arthur Localio Laboratory, Department of Surgery, New York University School of Medicine, New York, New York
| | - Lena Tomkötter
- S. Arthur Localio Laboratory, Department of Surgery, New York University School of Medicine, New York, New York
| | - Reuven Blobstein
- S. Arthur Localio Laboratory, Department of Surgery, New York University School of Medicine, New York, New York
| | - Antonina Avanzi
- S. Arthur Localio Laboratory, Department of Surgery, New York University School of Medicine, New York, New York
| | - Daniel M Tippens
- S. Arthur Localio Laboratory, Department of Surgery, New York University School of Medicine, New York, New York
| | - Yisroel Gelbstein
- S. Arthur Localio Laboratory, Department of Surgery, New York University School of Medicine, New York, New York
| | - Eliza Van Heerden
- S. Arthur Localio Laboratory, Department of Surgery, New York University School of Medicine, New York, New York
| | - George Miller
- S. Arthur Localio Laboratory, Department of Surgery, New York University School of Medicine, New York, New York; S. Arthur Localio Laboratory, Department of Cell Biology, New York University School of Medicine, New York, New York.
| |
Collapse
|