Optimization of sodium hydroxide for securing high thermoelectric performance in polycrystalline Sn1 − xSe via anisotropy and vacancy synergy
Abstract The morphology and composition are two key factors to determine the thermoelectric performance of aqueously synthesized tin selenide (SnSe) crystals; however, their controlling is still under exploring. In this study, we report a high figure‐of‐merit (ZT) of ∼1.5 at 823 K in p‐type polycrys...
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doaj-99725d9adf57432b83472e08d5a819ce2020-11-25T02:35:51ZengWileyInfoMat2567-31652020-11-01261201121510.1002/inf2.12057Optimization of sodium hydroxide for securing high thermoelectric performance in polycrystalline Sn1 − xSe via anisotropy and vacancy synergyXiao‐Lei Shi0Wei‐Di Liu1Ang‐Yin Wu2Van T. Nguyen3Han Gao4Qiang Sun5Raza Moshwan6Jin Zou7Zhi‐Gang Chen8Centre for Future Materials University of Southern Queensland Springfield Central Queensland AustraliaMaterials Engineering The University of Queensland Brisbane Queensland AustraliaMaterials Engineering The University of Queensland Brisbane Queensland AustraliaMaterials Engineering The University of Queensland Brisbane Queensland AustraliaMaterials Engineering The University of Queensland Brisbane Queensland AustraliaMaterials Engineering The University of Queensland Brisbane Queensland AustraliaMaterials Engineering The University of Queensland Brisbane Queensland AustraliaMaterials Engineering The University of Queensland Brisbane Queensland AustraliaCentre for Future Materials University of Southern Queensland Springfield Central Queensland AustraliaAbstract The morphology and composition are two key factors to determine the thermoelectric performance of aqueously synthesized tin selenide (SnSe) crystals; however, their controlling is still under exploring. In this study, we report a high figure‐of‐merit (ZT) of ∼1.5 at 823 K in p‐type polycrystalline Sn1 − xSe resulted from a synergy of morphology control and vacancy optimization, realized by carefully tuning the sodium hydroxide (NaOH) concentration during solvothermal synthesis. After a comprehensive investigation on various NaOH concentrations, it was found that an optimized NaOH amount of 10 mL with a concentration of 10 mol L−1 can simultaneously achieve a large average crystal size and a high Sn vacancy concentration of ∼2.5%. The large microplate‐like crystals lead to a considerable anisotropy in the sintered pellets, and the high Sn vacancy level contributes to an optimum hole concentration to the level of ∼2.3 × 1019 cm−3, and in turn a high power factor of ∼7.4 μW cm−1 K−2 at 823 K, measured along the direction perpendicular to the sintering pressure. In addition, a low thermal conductivity of ∼0.41 W m−1 K−1 is achieved by effective phonon scattering at localized crystal imperfections including lattice distortions, grain boundaries, and vacancy domains, as observed by detailed structural characterizations. Furthermore, a competitive compressive strength of ∼52.1 MPa can be achieved along the direction of high thermoelectric performance, indicating a mechanically robust feature. This study provides a new avenue in achieving high thermoelectric performance in SnSe‐based thermoelectric materials.https://doi.org/10.1002/inf2.12057anisotropysodium hydroxidethermoelectrictin selenidevacancy |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Xiao‐Lei Shi Wei‐Di Liu Ang‐Yin Wu Van T. Nguyen Han Gao Qiang Sun Raza Moshwan Jin Zou Zhi‐Gang Chen |
spellingShingle |
Xiao‐Lei Shi Wei‐Di Liu Ang‐Yin Wu Van T. Nguyen Han Gao Qiang Sun Raza Moshwan Jin Zou Zhi‐Gang Chen Optimization of sodium hydroxide for securing high thermoelectric performance in polycrystalline Sn1 − xSe via anisotropy and vacancy synergy InfoMat anisotropy sodium hydroxide thermoelectric tin selenide vacancy |
author_facet |
Xiao‐Lei Shi Wei‐Di Liu Ang‐Yin Wu Van T. Nguyen Han Gao Qiang Sun Raza Moshwan Jin Zou Zhi‐Gang Chen |
author_sort |
Xiao‐Lei Shi |
title |
Optimization of sodium hydroxide for securing high thermoelectric performance in polycrystalline Sn1 − xSe via anisotropy and vacancy synergy |
title_short |
Optimization of sodium hydroxide for securing high thermoelectric performance in polycrystalline Sn1 − xSe via anisotropy and vacancy synergy |
title_full |
Optimization of sodium hydroxide for securing high thermoelectric performance in polycrystalline Sn1 − xSe via anisotropy and vacancy synergy |
title_fullStr |
Optimization of sodium hydroxide for securing high thermoelectric performance in polycrystalline Sn1 − xSe via anisotropy and vacancy synergy |
title_full_unstemmed |
Optimization of sodium hydroxide for securing high thermoelectric performance in polycrystalline Sn1 − xSe via anisotropy and vacancy synergy |
title_sort |
optimization of sodium hydroxide for securing high thermoelectric performance in polycrystalline sn1 − xse via anisotropy and vacancy synergy |
publisher |
Wiley |
series |
InfoMat |
issn |
2567-3165 |
publishDate |
2020-11-01 |
description |
Abstract The morphology and composition are two key factors to determine the thermoelectric performance of aqueously synthesized tin selenide (SnSe) crystals; however, their controlling is still under exploring. In this study, we report a high figure‐of‐merit (ZT) of ∼1.5 at 823 K in p‐type polycrystalline Sn1 − xSe resulted from a synergy of morphology control and vacancy optimization, realized by carefully tuning the sodium hydroxide (NaOH) concentration during solvothermal synthesis. After a comprehensive investigation on various NaOH concentrations, it was found that an optimized NaOH amount of 10 mL with a concentration of 10 mol L−1 can simultaneously achieve a large average crystal size and a high Sn vacancy concentration of ∼2.5%. The large microplate‐like crystals lead to a considerable anisotropy in the sintered pellets, and the high Sn vacancy level contributes to an optimum hole concentration to the level of ∼2.3 × 1019 cm−3, and in turn a high power factor of ∼7.4 μW cm−1 K−2 at 823 K, measured along the direction perpendicular to the sintering pressure. In addition, a low thermal conductivity of ∼0.41 W m−1 K−1 is achieved by effective phonon scattering at localized crystal imperfections including lattice distortions, grain boundaries, and vacancy domains, as observed by detailed structural characterizations. Furthermore, a competitive compressive strength of ∼52.1 MPa can be achieved along the direction of high thermoelectric performance, indicating a mechanically robust feature. This study provides a new avenue in achieving high thermoelectric performance in SnSe‐based thermoelectric materials. |
topic |
anisotropy sodium hydroxide thermoelectric tin selenide vacancy |
url |
https://doi.org/10.1002/inf2.12057 |
work_keys_str_mv |
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