Lone-Pair Electrons Do Not Necessarily Lead to Low Lattice Thermal Conductivity: An Exception of Two-Dimensional Penta-CN2

2018 ◽  
Vol 9 (10) ◽  
pp. 2474-2483 ◽  
Author(s):  
Huimin Wang ◽  
Guangzhao Qin ◽  
Zhenzhen Qin ◽  
Guojian Li ◽  
Qiang Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Lattice Thermal Conductivity ◽  
Lone Pair ◽  
Two Dimensional ◽  
Lone Pair Electrons

Promising thermoelectric materials of Cu3VX4 (X=S, Se, Te): A Cu-V-X framework plus void tunnels

2019 ◽  
Vol 30 (08) ◽  
pp. 1950045
Author(s):  
Xiao-Peng Liu ◽  
Zhen-Zhen Feng ◽  
Shu-Ping Guo ◽  
Yi Xia ◽  
Yongsheng Zhang
Keyword(s):  
Crystal Structure ◽  
Thermal Conductivity ◽  
First Principles ◽  
High Performance ◽  
Lattice Thermal Conductivity ◽  
Lone Pair ◽  
Heusler Compounds ◽  
Filled Skutterudites ◽  
Structure Result ◽  
Lone Pair Electrons

Skutterudites and half-Heusler compounds are well-studied promising thermoelectric (TE) materials due to favorable electrical properties. However, their intrinsic lattice thermal conductivities are so high that various methodologies have been developed to decrease them. Based on our first-principles phonon calculations, we find that thermodynamically stable Cu3VX4 ([Formula: see text], Se, Te) compounds exhibit good thermoelectric properties due to their special crystal structure (a Cu-V-X framework plus large void tunnels). The mechanically stable framework is the favorite pathway for the carrier conduction, which induces high electrical conductivity and power factor (comparative to those of filled-skutterudites and half-Heusler systems). Moreover, the void tunnels in the crystal structure result in unsaturated coordinations at the X sites and corresponding lone-pair electrons, which lower the lattice thermal conductivity. The calculated intrinsic lattice thermal conductivity of Cu3VX4 is much lower than those of the well-studied skutterudites and half-Heusler compounds. Thus, the maximum ZT values approach 1.6 (at 900[Formula: see text]K, [Formula: see text][Formula: see text][Formula: see text]) and 1.2 (at 1000[Formula: see text]K, [Formula: see text][Formula: see text][Formula: see text]) for the p- and n-type Cu3VTe4 compounds, respectively. Our work provides not only distinctive high-performance TE materials (Cu3VX4), but also a guideline for future promising thermoelectric discoveries.

scholarly journals The impact of lone-pair electrons on the lattice thermal conductivity of the thermoelectric compound CuSbS2

2017 ◽  
Vol 5 (7) ◽  
pp. 3249-3259 ◽  
Author(s):  
Baoli Du ◽  
Ruizhi Zhang ◽  
Kan Chen ◽  
Amit Mahajan ◽  
Mike J. Reece
Keyword(s):  
Crystal Structure ◽  
Thermal Conductivity ◽  
Lattice Thermal Conductivity ◽  
Lone Pair ◽  
Low Thermal Conductivity ◽  
Lone Pair Electrons ◽  
The Impact

The discovery and design of compounds with intrinsically low thermal conductivity, especially compounds with a special bonding nature and stable crystal structure, is a new direction to broaden the scope of potential thermoelectric (TE) materials.

Lone pair electrons minimize lattice thermal conductivity

2013 ◽  
Vol 6 (2) ◽  
pp. 570-578 ◽  
Author(s):  
Michele D. Nielsen ◽  
Vidvuds Ozolins ◽  
Joseph P. Heremans
Keyword(s):  
Thermal Conductivity ◽  
Lattice Thermal Conductivity ◽  
Lone Pair ◽  
Lone Pair Electrons

Synergistic optimization of carrier transport and thermal conductivity in Sn-doped Cu2Te

2018 ◽  
Vol 6 (39) ◽  
pp. 18928-18937 ◽  
Author(s):  
Yuchong Qiu ◽  
Ying Liu ◽  
Jinwen Ye ◽  
Jun Li ◽  
Lixian Lian
Keyword(s):  
Thermal Conductivity ◽  
Fermi Level ◽  
Carrier Concentration ◽  
Power Factor ◽  
Carrier Transport ◽  
Lone Pair ◽  
Thermoelectric Performance ◽  
Degenerate Semiconductors ◽  
Lone Pair Electrons

Doping Sn into the Cu2Te lattice can synergistically enhance the power factor and decrease thermal conductivity, leading to remarkably optimized zTs. The lone pair electrons from the 5s orbital of Sn can increase the DOS near the Fermi level of Cu2Te to promote PF and reduce κe by decreasing the carrier concentration. This study explores a scalable strategy to optimize the thermoelectric performance for intrinsically highly degenerate semiconductors.

Fabrication and Surface Engineering of Two-Dimensional SnS Toward Piezoelectric Nanogenerator Application

MRS Advances ◽  
2018 ◽  
Vol 3 (45-46) ◽  
pp. 2809-2814 ◽  
Author(s):  
Naoki Higashitarumizu ◽  
Hayami Kawamoto ◽  
Keiji Ueno ◽  
Kosuke Nagashio
Keyword(s):  
Thermal Stability ◽  
Surface Morphology ◽  
Oxide Layer ◽  
Chemical Treatment ◽  
Surface Engineering ◽  
Lone Pair ◽  
Covalent Bonding ◽  
Two Dimensional ◽  
Lone Pair Electrons ◽  
Thermal Stability Of

ABSTRACTMechanical exfoliation is performed to fabricate ultrathin SnS layers, and chemical/thermal stability of SnS layers is discussed in comparison with GeS, toward piezoelectric nanogenerator application. Both SnS and GeS are difficult to be exfoliated under 10 nm using tape exfoliation due to strong interlayer ionic bonding by lone pair electrons in Sn or Ge atoms. Au-mediated exfoliation enables to fabricate larger-scale ultrathin SnS and GeS layers thinner than 10 nm owing to strong semi-covalent bonding between Au and S atoms, but GeS surface immediately degrades during Au etching in an oxidative KI/I2 solution. Although the surface of SnS after the Au-mediated exfoliation reveals several-nm oxide layer of SnOx, the surface morphology retains the flatness unlike the case of GeS. The SnS layers are more robust than GeS against the thermal annealing as well as the chemical treatment, suggesting that SnOx works as a passivation layer for SnS. Self-passivated SnS monolayer can be obtained by a controlled post-oxidation.

Anomalous in-plane lattice thermal conductivity in an atomically thin two-dimensional α-GeTe layer

2020 ◽  
Vol 22 (21) ◽  
pp. 12273-12280 ◽  
Author(s):  
Brahim Marfoua ◽  
Young Soo Lim ◽  
Jisang Hong
Keyword(s):  
Thermal Conductivity ◽  
Lattice Thermal Conductivity ◽  
2D Materials ◽  
Two Dimensional ◽  
Plane Lattice

The bilayer α-GeTe displayed an exceptionally low lattice thermal conductivity never reported in the atomically thin 2D materials.

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