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Degenerated Hole Doping and Ultra‐Low Lattice Thermal Conductivity in Polycrystalline SnSe by Nonequilibrium Isovalent Te Substitution.

Authors :
He, Xinyi
Zhang, Haoyun
Nose, Takumi
Katase, Takayoshi
Tadano, Terumasa
Ide, Keisuke
Ueda, Shigenori
Hiramatsu, Hidenori
Hosono, Hideo
Kamiya, Toshio
Source :
Advanced Science. May2022, Vol. 9 Issue 13, p1-8. 8p.
Publication Year :
2022

Abstract

Tin mono‐selenide (SnSe) exhibits the world record of thermoelectric conversion efficiency ZT in the single crystal form, but the performance of polycrystalline SnSe is restricted by low electronic conductivity (σ) and high thermal conductivity (κ), compared to those of the single crystal. Here an effective strategy to achieve high σ and low κ simultaneously is reported on p‐type polycrystalline SnSe with isovalent Te ion substitution. The nonequilibrium Sn(Se1−xTex) solid solution bulks with x up to 0.4 are synthesized by the two‐step process composed of high‐temperature solid‐state reaction and rapid thermal quenching. The Te ion substitution in SnSe realizes high σ due to the 103‐times increase in hole carrier concentration and effectively reduced lattice κ less than one‐third at room temperature. The large‐size Te ion in Sn(Se1−xTex) forms weak SnTe bonds, leading to the high‐density formation of hole‐donating Sn vacancies and the reduced phonon frequency and enhanced phonon scattering. This result—doping of large‐size ions beyond the equilibrium limit—proposes a new idea for carrier doping and controlling thermal properties to enhance the ZT of polycrystalline SnSe. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
21983844
Volume :
9
Issue :
13
Database :
Academic Search Index
Journal :
Advanced Science
Publication Type :
Academic Journal
Accession number :
156712925
Full Text :
https://doi.org/10.1002/advs.202105958