ORCID Profile
0000-0002-9093-7117
Current Organisation
National Institute of Advanced Industrial Science and Technology (AIST)
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: American Chemical Society (ACS)
Date: 26-05-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TA02614J
Abstract: The thermoelectric performance of room temperature Ag 2 Se was greatly enhanced by stabilizing the crystal structure and eliminating metastability.
Publisher: Wiley
Date: 12-07-2018
Publisher: MDPI AG
Date: 21-09-2015
DOI: 10.3390/MA8095315
Publisher: MDPI AG
Date: 18-09-2021
Abstract: CrSi2 is a promising thermoelectric material constituted of non-toxic and earth abundant elements that offer good perspectives for the mass production of inexpensive and reliable thermoelectric modules for waste heat recovery. Realization of robust metallic contacts with low electrical and thermal resistances on thermoelectric materials is crucial to maximize the conversion efficiency of such a device. In this article, the metallization of an undoped CrSi2 with Ti and Nb using a conventional Spark Plasma Sintering process is explored and discussed. These contact metals were selected because they have compatible thermal expansion coefficients with those of CrSi2, which were determined in this study by X-ray Diffraction in the temperature range 299–899 K. Ti was found to be a promising contact metal offering both strong adhesion on CrSi2 and negligible electrical contact resistance ( μΩ cm2). However, metallization with Nb resulted in the formation of cracks caused by large internal stress inside the s le during the fabrication process and the diffusion of Si in the metallic layer. A maximum conversion efficiency of 0.3% was measured for a sandwiched Ti/CrSi2/Ti thermoelectric leg placed inside a thermal gradient of 427 K. The preliminary results obtained and discussed in this article on a relatively simple case study aim to initiate the development of more reliable and efficient CrSi2 thermoelectric legs with an optimized design.
Publisher: Elsevier BV
Date: 07-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5EE02979A
Abstract: In this work, we demonstrate the use of high performance nanostructured PbTe-based materials in high conversion efficiency thermoelectric modules.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6RA20542A
Abstract: First time investigation of the thermoelectric properties of misfit layered (SnSe) 1.16 NbSe 2 and new insights into the charge transfer tuning in misfit systems.
Publisher: MDPI AG
Date: 16-03-2015
DOI: 10.3390/MA8031124
Publisher: Springer Science and Business Media LLC
Date: 07-07-2015
Publisher: American Chemical Society (ACS)
Date: 07-08-2020
DOI: 10.1021/JACS.0C07067
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TC00508H
Abstract: We demonstrate the high power factor (∼830 μW m −1 K −2 ) at 670 K for x = 0.5 in Cu 26+x Nb 2 Ge 6−x S 32 .
Publisher: American Chemical Society (ACS)
Date: 04-04-2014
DOI: 10.1021/CM5004559
Publisher: AIP Publishing
Date: 03-01-2022
DOI: 10.1063/5.0077154
Abstract: Thermoelectric power generation from the prototype π-shaped module composed of p-type colusite (Cu26Cr2Ge6S32) and n-type nanostructured PbTe (Pb0.98Ga0.02Te-3% GeTe) was demonstrated in this study. The thermoelectric figure of merit zT of Cu26Cr2Ge6S32 and Pb0.98Ga0.02Te-3% GeTe was ∼0.8 and ∼1.2 at 665 K, respectively. In PbTe, transmission electron microscopic images and energy-dispersive x-ray elemental maps reveal the insertion of nanoscale precipitates induced by the GeTe alloying. Contact layers based on Au and Co-Fe were used for p- and n-type thermoelectric legs, respectively, which allow the low electrical specific contact resistances of ≤10 × 10−10 Ω m2 at room temperature. Maximum thermoelectric conversion efficiency ηmax of ∼5.5% was obtained for the Cu26Cr2Ge6S32 and Pb0.98Ga0.02Te-3% GeTe-based two-pair module when the hot-side Th and cold-side Tc temperatures were maintained at 673 and 283 K, respectively. A three-dimensional finite-element simulation predicts the ηmax of ∼7.1% for the module at Th and Tc of 673 and 283 K, respectively.
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7TC00762K
Abstract: The thermoelectric performance of colusite materials Cu 26 A 2 E 6 S 32 (A = Nb, Ta E = Sn, Ge) has been successfully enhanced using E-site non stoichiometry. Value of ZT near unity is achieved at 670 K.
Publisher: Springer Science and Business Media LLC
Date: 08-01-2015
Publisher: Wiley
Date: 11-11-2022
Abstract: Material stability and mechanical properties of nanostructured p‐type Pb 0.993− x Na x Ge 0.007 Te ( x = 0.02, 0.04) are improved by tuning dopant Na content, while maintaining a high thermoelectric figure of merit zT . Na‐rich impurity phases detrimental to the material stability, present in heavily Na‐doped p‐type PbTe, are absent after reducing the Na doping from 4% to 2%. The flexural strength of 2% Na‐doped p‐type PbTe measured at 773 K is significantly improved compared to that of the 4% Na‐doped p‐type PbTe, but lower than that of n‐type Pb 0.98 Ga 0.02 Te measured in comparison. Excellent thermoelectric performance is maintained for nanostructured Pb 0.973 Na 0.02 Ge 0.007 Te ( zT ≈ 2.2 at 810 K). For n‐type Pb 0.98 Ga 0.02 Te, zT ≈ 1.3 at 760 K is confirmed. Single‐leg elements of Pb 0.973 Na 0.02 Ge 0.007 Te and Pb 0.98 Ga 0.02 Te with Co 80 Fe 20 contact layers display maximum conversion efficiency η max ≈ 8.4% and η max ≈ 8.2% for temperature difference Δ T ≈ 470 K, respectively. After 240 h operation with Δ T ≈ 470 K, η max decreases by ≈33% for the p‐type and ≈13% for the n‐type legs. Lower η max compared to the estimation from the material properties and degradation during operation are attributed to crack formation due to thermal expansion mismatch between PbTe and Co 80 Fe 20 and sublimation from the hot side.
Publisher: AIP Publishing
Date: 04-2015
DOI: 10.1063/1.4916545
Abstract: Thermoelectric efficiency measurements were carried out on n-type bismuth telluride legs with the hot-side temperature at 100 and 150ߙ°C. The electric power and heat flow were measured in idually. Water coolant was utilized to maintain the cold-side temperature and to measure heat flow out of the cold side. Leg length and vacuum pressure were studied in terms of temperature difference across the leg, open-circuit voltage, internal resistance, and heat flow. Finite-element simulation on thermoelectric generation was performed in COMSOL Multiphysics, by inputting two-side temperatures and thermoelectric material properties. The open-circuit voltage and resistance were in good agreement between the measurement and simulation. Much larger heat flows were found in measurements, since they were comprised of conductive, convective, and radiative contributions. Parasitic heat flow was measured in the absence of bismuth telluride leg, and the conductive heat flow was then available. Finally, the maximum thermoelectric efficiency was derived in accordance with the electric power and the conductive heat flow.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5TC01652E
Abstract: The average thermoelectric figure of merit ZT of n-type PbTe 1−x I x –MgTe is successfully enhanced through nano and meso structuring.
Publisher: Elsevier BV
Date: 02-2018
Publisher: American Chemical Society (ACS)
Date: 30-01-2020
Publisher: American Chemical Society (ACS)
Date: 04-11-2015
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9TC00868C
Abstract: A conversion efficiency of ∼3.3% has been successfully demonstrated in colusite (Cu 26 Nb 2 Ge 6 S 32 )-based single thermoelectric element with Au diffusion barrier.
Location: Japan
No related grants have been discovered for Michihiro Ohta.