ORCID Profile
0000-0002-0515-4864
Current Organisation
Kyushu University
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: 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: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3DT51328A
Abstract: We report detailed structural investigations of the dimorphic clathrate Ba8Ga16Sn30 that crystallizes in both type I and VIII clathrate structures. Single crystals of type I and VIII have been examined using single crystal X-ray and Laue neutron diffraction in the temperature range T = 10 K-500 K. The utilization of both X-ray and neutron diffraction gives a unique ability to reveal the occurrence of minute vacancy occupancies in the host structure. The vacancies are shown to be located on the 6c (type I) and 24g (type VIII) framework sites. Largest vacancy densities are observed for type I p-Ba8Ga16Sn30, 1.3(4)%, and type VIII n-Ba8Ga16Sn30, 0.7(2)%. The relation between guest atom disorder and occurrence of glasslike thermal conductivity in intermetallic clathrates was also investigated. In type VIII Ba8Ga16Sn30 neither n-type (crystalline thermal conductivity) nor p-type (glasslike thermal conductivity) showed any significant disorder of the guest atoms they do however show anharmonic motion. The glasslike thermal conductivity of p-type Ba8Ga16Sn30 is interpretable as a result of higher effective mass of p-type charge-carriers affecting phonon scattering. In type I Ba8Ga16Sn30 guest atoms are highly disordered for both carrier types and s les of both charge carrier types have glasslike thermal conductivity.
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: American Chemical Society (ACS)
Date: 22-05-2019
Publisher: Elsevier BV
Date: 02-2018
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.
No related grants have been discovered for Koichiro Suekuni.