Advanced

New Insight on Tuning Electrical Transport Properties via Chalcogen Doping in n-type Mg3Sb2-Based Thermoelectric Materials

Zhang, Jiawei; Song, Lirong; Borup, Kasper Andersen; Jørgensen, Mads Ry Vogel LU and Iversen, Bo Brummerstedt (2018) In Advanced Energy Materials
Abstract

n-type Mg3Sb1.5Bi0.5 has recently been discovered to be a promising thermoelectric material, yet the effective n-type dopants are mainly limited to the chalcogens. This may be attributed to the limited chemical insight into the effects from different n-type dopants. By comparing the effects of different chalcogen dopants Q (Q = S, Se, and Te) on thermoelectric properties, it is found that the chalcogen dopants Q become more efficient with decreasing electronegativity difference between Q and Mg, which is mainly due to the increasing carrier concentration and mobility. Using density functional theory calculations, it is shown that the improving carrier concentration originates from the increasing doping... (More)

n-type Mg3Sb1.5Bi0.5 has recently been discovered to be a promising thermoelectric material, yet the effective n-type dopants are mainly limited to the chalcogens. This may be attributed to the limited chemical insight into the effects from different n-type dopants. By comparing the effects of different chalcogen dopants Q (Q = S, Se, and Te) on thermoelectric properties, it is found that the chalcogen dopants Q become more efficient with decreasing electronegativity difference between Q and Mg, which is mainly due to the increasing carrier concentration and mobility. Using density functional theory calculations, it is shown that the improving carrier concentration originates from the increasing doping limit induced by the stabilizing extrinsic defect. Moreover, the increasing electron mobility with decreasing electronegativity difference between Q and Mg is attributed to the smaller effective mass resulting from the enhancing chemical bond covalency, which is supported by the decreasing theoretical density of states. According to the above trends, a simple guiding principle based on electronegativity is proposed to shed new light on n-type doping in Zintl antimonides.

(Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
Bond covalency, Doping limits, Electronegativity, Extrinsic defects, Thermoelectric
in
Advanced Energy Materials
publisher
Wiley-Blackwell
external identifiers
  • scopus:85042070859
ISSN
1614-6832
DOI
10.1002/aenm.201702776
language
English
LU publication?
yes
id
7495fed9-39e4-4358-a296-67441a986a54
date added to LUP
2018-03-07 10:55:27
date last changed
2018-05-29 12:27:27
@article{7495fed9-39e4-4358-a296-67441a986a54,
  abstract     = {<p>n-type Mg<sub>3</sub>Sb<sub>1.5</sub>Bi<sub>0.5</sub> has recently been discovered to be a promising thermoelectric material, yet the effective n-type dopants are mainly limited to the chalcogens. This may be attributed to the limited chemical insight into the effects from different n-type dopants. By comparing the effects of different chalcogen dopants Q (Q = S, Se, and Te) on thermoelectric properties, it is found that the chalcogen dopants Q become more efficient with decreasing electronegativity difference between Q and Mg, which is mainly due to the increasing carrier concentration and mobility. Using density functional theory calculations, it is shown that the improving carrier concentration originates from the increasing doping limit induced by the stabilizing extrinsic defect. Moreover, the increasing electron mobility with decreasing electronegativity difference between Q and Mg is attributed to the smaller effective mass resulting from the enhancing chemical bond covalency, which is supported by the decreasing theoretical density of states. According to the above trends, a simple guiding principle based on electronegativity is proposed to shed new light on n-type doping in Zintl antimonides.</p>},
  author       = {Zhang, Jiawei and Song, Lirong and Borup, Kasper Andersen and Jørgensen, Mads Ry Vogel and Iversen, Bo Brummerstedt},
  issn         = {1614-6832},
  keyword      = {Bond covalency,Doping limits,Electronegativity,Extrinsic defects,Thermoelectric},
  language     = {eng},
  month        = {02},
  publisher    = {Wiley-Blackwell},
  series       = {Advanced Energy Materials},
  title        = {New Insight on Tuning Electrical Transport Properties via Chalcogen Doping in n-type Mg<sub>3</sub>Sb<sub>2</sub>-Based Thermoelectric Materials},
  url          = {http://dx.doi.org/10.1002/aenm.201702776},
  year         = {2018},
}