Low lattice thermal conductivity and high figure of merit in n‐type doped full‐Heusler compounds X 2 YAu (X = Sr, Ba; Y = as, Sb)

2021 ◽  
Author(s):  
Weiqiang Wang ◽  
Zhenhong Dai ◽  
Xichang Wang ◽  
Qi Zhong ◽  
Yinchang Zhao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Heusler Compounds ◽  
High Figure ◽  
Full Heusler

Low lattice thermal conductivity and high figure of merit in p-type doped K3IO

2020 ◽  
Vol 29 (12) ◽  
pp. 126501
Author(s):  
Weiqiang Wang ◽  
Zhenhong Dai ◽  
Qi Zhong ◽  
Yinchang Zhao ◽  
Sheng Meng
Keyword(s):  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
High Figure ◽  
P Type

Reductions in the Lattice Thermal Conductivity of Ball-milled and Shock compacted TiNiSn1−XSbX Half-Heusler alloys

2001 ◽  
Vol 691 ◽  
Author(s):  
S. Bhattacharya ◽  
Y. Xia ◽  
V. Ponnambalam ◽  
S.J. Poon ◽  
N. Thadani ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Lattice Thermal Conductivity ◽  
Heusler Alloys ◽  
Lattice Contribution ◽  
Grain Sizes ◽  
Shock Compaction ◽  
High Figure

ABSTRACTHalf-Heusler alloys are currently being investigated for their potential as thermoelectric materials [1], [2]. They exhibit high negative thermopower (40-250μV/K) and favorable electrical resistivity (0.1-8mW•cm) at room temperature. Attractive power factors (α2σT) of about (0.2-1.0W/m•K) at room temperature and about 4W/m•K at 600K [3] have been reported in these materials. But in order to achieve a high figure-of-merit in the half-Heusler alloys, the relatively high thermal conductivity in these materials (∼ 10 W/m•K) must be reduced. The thermal conductivity in these materials is composed of mainly a lattice contribution, compared to a very small electronic component. The challenge is to reduce the relatively high lattice thermal conductivity in these materials. Reported in this paper is a significant reduction of lattice thermal conductivity (∼1.5 - 3.5W/m•K) in some Ti-based half-Heusler alloys. Samples have been prepared by ball milling and followed by shock-compaction that has resulted into reduced grain sizes in these materials. The effects of the microstructure on the thermal transport properties of the Half-Heusler alloys have been investigated and are presented and discussed herein.

High figure of merit of monolayer Sb2Te2Se of ultra low lattice thermal conductivity

2020 ◽  
Vol 177 ◽  
pp. 109588 ◽  
Author(s):  
Bin Xu ◽  
Qiong Xia ◽  
Jing Zhang ◽  
Shanshan Ma ◽  
Yusheng Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
High Figure

scholarly journals Improved Thermoelectric Performance in N-Type Half-Heusler NbCoSn by Heavy-Element Pt Doping

2020 ◽  
Author(s):  
Federico Serrano Sanchez ◽  
Ting Luo ◽  
Junjie Yu ◽  
Wenjie Xie ◽  
Gudrun Auffermann ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Carrier Mobility ◽  
Figure Of Merit ◽  
Heavy Element ◽  
Lattice Thermal Conductivity ◽  
Electrical Power ◽  
Heusler Compounds ◽  
Strong Point

Half-Heusler compounds with a valence electron count of 18, including ZrNiSn, ZrCoSb, and NbFeSb, are good thermoelec-tric materials owing to favourable electronic structures. Previous computational studies had predicted a high electrical power factor in another half-Heusler compound NbCoSn, but it has not been extensively investigated experimentally. Herein, the synthesis, structural characterization, and thermoelectric properties of the heavy-element Pt-doped NbCoSn compounds are reported. Pt is found to be an effective dopant enabling the optimization of electrical power factor, simul-taneously leading to a strong point defect scattering of phonons, and thereby suppressing the lattice thermal conductivity. Annealing significantly improves the carrier mobility, which is ascribed to the decreased grain boundary scattering. As a result, a maximum power factor of ~3.4 mWm-1K-2 is obtained at 600 K. In conjunction with the reduced lattice thermal conductivity, a maximum figure of merit zT of ~0.6 is achieved at 773 K for the post-annealed NbCo0.95Pt0.05Sn, an increase of 100% compared to the undoped NbCoSn. This work highlights the important roles of the doping element and micro-structure on the thermoelectric properties of half-Heusler compounds<br><p></p>

scholarly journals Half-Heusler-like compounds with wide continuous compositions and tunable p- to n-type semiconducting thermoelectrics

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Zirui Dong ◽  
Jun Luo ◽  
Chenyang Wang ◽  
Ying Jiang ◽  
Shihua Tan ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electronic Structures ◽  
Lattice Thermal Conductivity ◽  
Composition Range ◽  
Tetrahedral Site ◽  
Site Occupancy ◽  
Structure Change ◽  
Heusler Compounds ◽  
Wide Homogeneity Range ◽  
Full Heusler

AbstractHalf-Heusler and full-Heusler compounds were considered as independent phases with a natural composition gap. Here we report the discovery of TiRu1+xSb (x = 0.15 ~ 1.0) solid solution with wide homogeneity range and tunable p- to n-type semiconducting thermoelectrics, which bridges the composition gap between half- and full-Heusler phases. At the high-Ru end, strange glass-like thermal transport behavior with unusually low lattice thermal conductivity (~1.65 Wm−1K−1 at 340 K) is observed for TiRu1.8Sb, being the lowest among reported half-Heusler phases. In the composition range of 0.15 < x < 0.50, TiRu1+xSb shows abnormal semiconducting behaviors because tunning Ru composition results in band structure change and carrier-type variation simultaneously, which seemingly correlates with the localized d electrons. This work reveals the possibility of designing fascinating half-Heusler-like materials by manipulating the tetrahedral site occupancy, and also demonstrates the potential of tuning crystal and electronic structures simultaneously to realize intriguing physical properties.

scholarly journals Improved Thermoelectric Performance in N-Type Half-Heusler NbCoSn by Heavy-Element Pt Doping

2020 ◽  
Author(s):  
Federico Serrano Sanchez ◽  
Ting Luo ◽  
Junjie Yu ◽  
Wenjie Xie ◽  
Gudrun Auffermann ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Carrier Mobility ◽  
Figure Of Merit ◽  
Heavy Element ◽  
Lattice Thermal Conductivity ◽  
Electrical Power ◽  
Heusler Compounds ◽  
Strong Point

Half-Heusler compounds with a valence electron count of 18, including ZrNiSn, ZrCoSb, and NbFeSb, are good thermoelec-tric materials owing to favourable electronic structures. Previous computational studies had predicted a high electrical power factor in another half-Heusler compound NbCoSn, but it has not been extensively investigated experimentally. Herein, the synthesis, structural characterization, and thermoelectric properties of the heavy-element Pt-doped NbCoSn compounds are reported. Pt is found to be an effective dopant enabling the optimization of electrical power factor, simul-taneously leading to a strong point defect scattering of phonons, and thereby suppressing the lattice thermal conductivity. Annealing significantly improves the carrier mobility, which is ascribed to the decreased grain boundary scattering. As a result, a maximum power factor of ~3.4 mWm-1K-2 is obtained at 600 K. In conjunction with the reduced lattice thermal conductivity, a maximum figure of merit zT of ~0.6 is achieved at 773 K for the post-annealed NbCo0.95Pt0.05Sn, an increase of 100% compared to the undoped NbCoSn. This work highlights the important roles of the doping element and micro-structure on the thermoelectric properties of half-Heusler compounds<br><p></p>

scholarly journals Local ferroelectric polarization switching driven by nanoscale distortions in thermoelectric $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aastha Vasdev ◽  
Moinak Dutta ◽  
Shivam Mishra ◽  
Veerpal Kaur ◽  
Harleen Kaur ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Lattice Thermal Conductivity ◽  
Direct Evidence ◽  
Temperature Dependent ◽  
Force Microscopy ◽  
Ferroelectric Domains ◽  
Pdf Analysis ◽  
Ferroelectric Transition Temperature

AbstractA remarkable decrease in the lattice thermal conductivity and enhancement of thermoelectric figure of merit were recently observed in rock-salt cubic SnTe, when doped with germanium (Ge). Primarily, based on theoretical analysis, the decrease in lattice thermal conductivity was attributed to local ferroelectric fluctuations induced softening of the optical phonons which may strongly scatter the heat carrying acoustic phonons. Although the previous structural analysis indicated that the local ferroelectric transition temperature would be near room temperature in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te , a direct evidence of local ferroelectricity remained elusive. Here we report a direct evidence of local nanoscale ferroelectric domains and their switching in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te using piezoeresponse force microscopy(PFM) and switching spectroscopy over a range of temperatures near the room temperature. From temperature dependent (250–300 K) synchrotron X-ray pair distribution function (PDF) analysis, we show the presence of local off-centering distortion of Ge along the rhombohedral direction in global cubic $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te . The length scale of the $${\text {Ge}}^{2+}$$ Ge 2 + off-centering is 0.25–0.10 Å near the room temperatures (250–300 K). This local emphatic behaviour of cation is the cause for the observed local ferroelectric instability, thereby low lattice thermal conductivity in $${\text {Sn}}_{0.7}{\text {Ge}}_{0.3}{\text {Te}}$$ Sn 0.7 Ge 0.3 Te .

Investigation of Thermoelectric Materials: Substitution effect of Bi on the Ag1-xPb18MTe20 (M = Sb, Bi) (x = 0, 0.14, 0.3)

2007 ◽  
Vol 1044 ◽  
Author(s):  
Mi-kyung Han ◽  
Huijun Kong ◽  
Ctirad Uher ◽  
Mercouri G Kanatzidis
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Substitution Effect ◽  
Dimensionless Figure Of Merit ◽  
The Matrix ◽  
Mass Fluctuation

AbstractWe performed comparative investigations of the Ag1-xPb18MTe20 (M = Bi, Sb) (x = 0, 0.14, 0.3) system to better understand the roles of Sb and Bi on the thermoelectric properties. In both systems, the electrical conductivity nearly keeps the same values, while the Seebeck coefficient decreases dramatically in going from Sb to Bi. Compared to the lattice thermal conductivity of PbTe, that of AgPb18BiTe20 is substantially reduced. The lattice thermal conductivity of the Bi analog, however, is higher than that of AgPb18SbTe20 and this is attributed largely to the decrease in the degree of mass fluctuation between the nanostructures and the matrix (for the Bi analog). As a result the dimensionless figure of merit ZT of Ag1-xPb18MTe20 (M = Bi) is found to be smaller than that of Ag1-xPb18MTe20 (M = Sb).

Effects of Ce filling fraction and Fe content on the thermoelectric properties of Co-rich CeyFexCo4−xSb12

2001 ◽  
Vol 16 (3) ◽  
pp. 837-843 ◽  
Author(s):  
Xinfeng Tang ◽  
Lidong Chen ◽  
Takashi Goto ◽  
Toshio Hirai
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Single Phase ◽  
Lattice Thermal Conductivity ◽  
Hole Concentration ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Filling Fraction ◽  
Fe Content

Single-phase filled skutterudite compounds, CeyFexCo4−xSb12 (x = 0 to 3.0, y = 0 to 0.74), were synthesized by a melting method. The effects of Fe content and Ce filling fraction on the thermoelectric properties of CeyFexCo4−xSb12 were investigated. The lattice thermal conductivity of Ce-saturated CeyFexCo4−xSb12, y being at the maximum corresponding to x, decreased with increasing Fe content (x) and reached its minimum at about x = 1.5. When x was 1.5, lattice thermal conductivity decreased with increasing Ce filling fraction till y = 0.3 and then began to increase after reaching the minimum at y = 0.3. Hole concentration and electrical conductivity of Cey Fe1.5Co2.5Sb12 decreased with increasing Ce filling fraction. The Seebeck coefficient increased with increasing Ce filling fraction. The greatest dimensionless thermoelectric figure of merit T value of 1.1 was obtained at 750 K for the composition of Ce0.28Fe1.52Co2.48Sb12.

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