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Rana N, Mukherjee S, Singha P, Das S, Bandyopadhyay S, Banerjee A. Tailoring thermoelectric performance of n-type Bi 2Te 3through defect engineering and conduction band convergence. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:365703. [PMID: 38815604 DOI: 10.1088/1361-648x/ad5245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 05/30/2024] [Indexed: 06/01/2024]
Abstract
Bi2Te3, an archetypical tetradymite, is recognised as a thermoelectric (TE) material of potential application around room temperature. However, large energy gap (ΔEc) between the light and heavy conduction bands results in inferior TE performance in pristine bulkn-type Bi2Te3. Herein, we propose enhancement in TE performance of pristinen-type Bi2Te3through purposefully manipulating defect profile and conduction band convergence mechanism. Twon-type Bi2Te3samples, S1 and S2, are prepared by melting method under different synthesis condition. The structural as well as microstructural evidence of the samples are obtained through powder x-ray diffraction and transmission electron microscopic study. Optothermal Raman spectroscopy is utilized for comprehensive study of temperature dependent phonon vibrational modes and total thermal conductivity (κ) of the samples which further validates the experimentally measured thermal conductivity. The Seebeck coefficient value is significantly increased from 235 μVK-1(sample S1) to 310 μVK-1(sample S2). This is further justified by conduction band convergence, where ΔEcis reduced from 0.10 eV to 0.05 eV, respectively. To verify the band convergence, the double band Pisarenko model is employed. Large power factor (PF) of 2190 μWm-1K-2and lowerκvalue leading toZTof 0.56 at 300 K is gained in S2. The obtainedPFandZTvalue are among the highest values reported for pristinen-type bulk Bi2Te3. In addition, appreciable value of TE quality factor and compatibility factor (2.7 V-1) at room temperature are also achieved, indicating the usefulness of the material in TE module.
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Affiliation(s)
- Nabakumar Rana
- Department of Physics, University of Calcutta, 92 A P C Road, Kolkata, West Bengal 700 009, India
| | - Suchandra Mukherjee
- Department of Physics, University of Calcutta, 92 A P C Road, Kolkata, West Bengal 700 009, India
| | - Pintu Singha
- School of Physics, Indian Institute of Science Education and Research, Maruthamala PO, Thiruvananthapuram, Kerala 695 551, India
| | - Subarna Das
- New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur PO, Bangalore 560064, India
| | - Sudipta Bandyopadhyay
- Department of Physics, University of Calcutta, 92 A P C Road, Kolkata, West Bengal 700 009, India
- Center for Research in Nanoscience and Nanotechnology, University of Calcutta, JD-2, Sector-III, Saltlake, Kolkata 700 106, India
| | - Aritra Banerjee
- Department of Physics, University of Calcutta, 92 A P C Road, Kolkata, West Bengal 700 009, India
- Center for Research in Nanoscience and Nanotechnology, University of Calcutta, JD-2, Sector-III, Saltlake, Kolkata 700 106, India
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Baláž P, Dutková E, Baláž M, Daneu N, Findoráková L, Hejtmánek J, Levinský P, Knížek K, Bali Hudáková M, Džunda R, Bureš R, Puchý V. The manipulation of natural mineral chalcopyrite CuFeS 2via mechanochemistry: properties and thermoelectric potential. Phys Chem Chem Phys 2023; 25:31125-31136. [PMID: 37947379 DOI: 10.1039/d3cp01788e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
In this study, the properties of the natural mineral chalcopyrite CuFeS2 after mechanical activation in a planetary mill were studied. The intensity of mechanical activation was controlled by changing the revolutions of the mill in the range 100-600 min-1. A series of characterization techniques, such as XRD, SEM, TEM, TA (DTA, TG, and DTG), particle size analysis, and UV-vis spectroscopy was applied and reactivity studies were also performed. Several new features were revealed for the mechanically activated chalcopyrite, e.g. the poly-modal distribution of produced nanoparticles on the micrometer scale, agglomeration effects by prolonged milling, possibility to modify the shape of the particles, X-ray amorphization and a shift from a non-cubic (tetragonal) structure to pseudo-cubic structure. The thermoelectric response was evaluated on the "softly" compacted powder via the spark plasma sintering method (very short holding time, low sintering temperature, and moderate pressure) by measuring the Seebeck coefficient and electrical and thermal conductivity above room temperature. The milling process produced samples with lower resistivity compared to the original non-activated sample. The Seebeck data close to zero confirmed the "compensated" character of natural chalcopyrite, reflecting its close-to stoichiometric composition with low concentration of both n- and p-type charge carriers. Alternatively, an evident correlation between thermal conductivity and energy supply by milling was observed with the possibility of band gap manipulation, which is associated with the energy delivered by the milling procedure.
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Affiliation(s)
- Peter Baláž
- Institute of Geotechnics, Slovak Academy of Sciences, Watsonova 45, 04001 Košice, Slovakia.
| | - Erika Dutková
- Institute of Geotechnics, Slovak Academy of Sciences, Watsonova 45, 04001 Košice, Slovakia.
| | - Matej Baláž
- Institute of Geotechnics, Slovak Academy of Sciences, Watsonova 45, 04001 Košice, Slovakia.
| | - Nina Daneu
- Jozef Stefan Institute, Jamova cesta 3, S1-1000 Ljubljana, Slovenia.
| | - Lenka Findoráková
- Institute of Geotechnics, Slovak Academy of Sciences, Watsonova 45, 04001 Košice, Slovakia.
| | - Jiří Hejtmánek
- Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10/112, 16200 Prague, Czech Republic.
| | - Petr Levinský
- Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10/112, 16200 Prague, Czech Republic.
| | - Karel Knížek
- Institute of Physics of the Czech Academy of Sciences, Cukrovarnická 10/112, 16200 Prague, Czech Republic.
| | - Mária Bali Hudáková
- Institute of Geotechnics, Slovak Academy of Sciences, Watsonova 45, 04001 Košice, Slovakia.
| | - Róbert Džunda
- Institute of Materials Research, Slovak Academy of Sciences, Watsonova 47, 04001 Košice, Slovakia.
| | - Radovan Bureš
- Institute of Materials Research, Slovak Academy of Sciences, Watsonova 47, 04001 Košice, Slovakia.
| | - Viktor Puchý
- Institute of Materials Research, Slovak Academy of Sciences, Watsonova 47, 04001 Košice, Slovakia.
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Gayner C, Natanzon Y, Kauffmann Y, Amouyal Y. Topologically-Enhanced Thermoelectric Properties in Bi 2Te 3-Based Compounds: Effects of Grain Size and Misorientation. ACS APPLIED MATERIALS & INTERFACES 2022; 14:49730-49745. [PMID: 36286236 DOI: 10.1021/acsami.2c12843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Topological insulators (TIs) and thermoelectric (TE) materials seem to belong to distinct physical realms; however, in practice, they both share common characteristics. Introducing concepts from TIs into TE materials to enhance their performance and achieve better understanding of electronic transport requires extensive research. Particularly, grain size, misorientation, and grain boundary (GB) character are of utmost importance to attain effective charge carrier transport in TE polycrystals; these factors, however, have not been thoroughly explored. Herein, we investigate the correlation between grain size, misorientation, and lattice strain in Bi2Te3 and its TI signature, aiming to improve its TE performance. We reveal an unusual behavior showing that electron mobility increases upon the increase of grain size, reaching at a maximum value of 495 cm2/V·s for an optimum grain size of 600 nm and most-frequent GB misorientation angle of 60° and then decreases with increasing grain size. It is also indicated that the combined effects of grain size reduction and point defects induce lattice strain in the Bi2Te3-matrix that is essential to trigger the TI contribution to TE transport. This trend is corroborated by first-principles calculations showing that compressive strains form multiple valleys in the valence band and opens the TI band gap. Such a combination of physical phenomena in a well-known TE material is unique and can promote our understanding of the nature of TE transport with implications for TE energy conversion.
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Affiliation(s)
- Chhatrasal Gayner
- Department of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa32000, Israel
| | - Yuriy Natanzon
- Department of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa32000, Israel
| | - Yaron Kauffmann
- Department of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa32000, Israel
| | - Yaron Amouyal
- Department of Materials Science and Engineering, Technion - Israel Institute of Technology, Haifa32000, Israel
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