Thermoelectric Properties of Zn-Doped YbMg<sub>1.85−<i>x</i></sub>Zn<i><sub>x</sub></i>Bi<sub>1.98</sub>
Bi-based YbMg<sub>2</sub>Bi<sub>1.98</sub> Zintl compounds represent promising thermoelectric materials. Precise composition and appropriate doping are of great importance for this complex semiconductor. Here, the influence of Zn substitution for Mg on the microstructure and...
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2024-02-01
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| Online Access: | https://www.mdpi.com/1996-1944/17/5/973 |
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| author | Simin Wei Nailing Qin Guiying Wu Zhengbing Xu Lei Miao Xiyong Chen Jialin Yan |
| author_facet | Simin Wei Nailing Qin Guiying Wu Zhengbing Xu Lei Miao Xiyong Chen Jialin Yan |
| author_sort | Simin Wei |
| collection | DOAJ |
| description | Bi-based YbMg<sub>2</sub>Bi<sub>1.98</sub> Zintl compounds represent promising thermoelectric materials. Precise composition and appropriate doping are of great importance for this complex semiconductor. Here, the influence of Zn substitution for Mg on the microstructure and thermoelectric properties of <i>p</i>-type YbMg<sub>1.85−<i>x</i></sub>Zn<i><sub>x</sub></i>Bi<sub>1.98</sub> (<i>x</i> = 0, 0.05, 0.08, 0.13, 0.23) was investigated. Polycrystalline samples were prepared using induction melting and densified with spark plasma sintering. X-ray diffraction confirmed that the major phase of the samples possesses the trigonal CaAl<sub>2</sub>Si<sub>2</sub>-type crystal structure, and SEM/EDS indicated the presence of minor secondary phases. The electrical conductivity increases and the lattice thermal conductivity decreases with more Zn doping in YbMg<sub>1.85−<i>x</i></sub>Zn<i><sub>x</sub></i>Bi<sub>1.98</sub>, whereas the Seebeck coefficient has a large reduction. The band gap decreases with increasing Zn concentration and leads to bipolar conduction, resulting in an increase in the thermal conductivity at higher temperatures. Figure of merit <i>ZT</i> values of 0.51 and 0.49 were found for the samples with <i>x</i> = 0 and 0.05 at 773 K, respectively. The maximum amount of Zn doping is suggested to be less than <i>x</i> = 0.1. |
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| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-04-25T00:25:40Z |
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| spelling | doaj.art-93b790ae32c843c08f42e1ca45cfdcc72024-03-12T16:48:47ZengMDPI AGMaterials1996-19442024-02-0117597310.3390/ma17050973Thermoelectric Properties of Zn-Doped YbMg<sub>1.85−<i>x</i></sub>Zn<i><sub>x</sub></i>Bi<sub>1.98</sub>Simin Wei0Nailing Qin1Guiying Wu2Zhengbing Xu3Lei Miao4Xiyong Chen5Jialin Yan6School of Resources, Environment and Materials, Guangxi University, Nanning 530004, ChinaSchool of Resources, Environment and Materials, Guangxi University, Nanning 530004, ChinaSchool of Resources, Environment and Materials, Guangxi University, Nanning 530004, ChinaSchool of Resources, Environment and Materials, Guangxi University, Nanning 530004, ChinaState Key Laboratory of Featured Metal Materials and Life-Cycle Safety for Composite Structures, Nanning 530004, ChinaSchool of Resources, Environment and Materials, Guangxi University, Nanning 530004, ChinaSchool of Resources, Environment and Materials, Guangxi University, Nanning 530004, ChinaBi-based YbMg<sub>2</sub>Bi<sub>1.98</sub> Zintl compounds represent promising thermoelectric materials. Precise composition and appropriate doping are of great importance for this complex semiconductor. Here, the influence of Zn substitution for Mg on the microstructure and thermoelectric properties of <i>p</i>-type YbMg<sub>1.85−<i>x</i></sub>Zn<i><sub>x</sub></i>Bi<sub>1.98</sub> (<i>x</i> = 0, 0.05, 0.08, 0.13, 0.23) was investigated. Polycrystalline samples were prepared using induction melting and densified with spark plasma sintering. X-ray diffraction confirmed that the major phase of the samples possesses the trigonal CaAl<sub>2</sub>Si<sub>2</sub>-type crystal structure, and SEM/EDS indicated the presence of minor secondary phases. The electrical conductivity increases and the lattice thermal conductivity decreases with more Zn doping in YbMg<sub>1.85−<i>x</i></sub>Zn<i><sub>x</sub></i>Bi<sub>1.98</sub>, whereas the Seebeck coefficient has a large reduction. The band gap decreases with increasing Zn concentration and leads to bipolar conduction, resulting in an increase in the thermal conductivity at higher temperatures. Figure of merit <i>ZT</i> values of 0.51 and 0.49 were found for the samples with <i>x</i> = 0 and 0.05 at 773 K, respectively. The maximum amount of Zn doping is suggested to be less than <i>x</i> = 0.1.https://www.mdpi.com/1996-1944/17/5/973YbMg<sub>2</sub>Bi<sub>2</sub>Zintl compoundsmicrostructurethe bipolar effectthermoelectric properties |
| spellingShingle | Simin Wei Nailing Qin Guiying Wu Zhengbing Xu Lei Miao Xiyong Chen Jialin Yan Thermoelectric Properties of Zn-Doped YbMg<sub>1.85−<i>x</i></sub>Zn<i><sub>x</sub></i>Bi<sub>1.98</sub> Materials YbMg<sub>2</sub>Bi<sub>2</sub> Zintl compounds microstructure the bipolar effect thermoelectric properties |
| title | Thermoelectric Properties of Zn-Doped YbMg<sub>1.85−<i>x</i></sub>Zn<i><sub>x</sub></i>Bi<sub>1.98</sub> |
| title_full | Thermoelectric Properties of Zn-Doped YbMg<sub>1.85−<i>x</i></sub>Zn<i><sub>x</sub></i>Bi<sub>1.98</sub> |
| title_fullStr | Thermoelectric Properties of Zn-Doped YbMg<sub>1.85−<i>x</i></sub>Zn<i><sub>x</sub></i>Bi<sub>1.98</sub> |
| title_full_unstemmed | Thermoelectric Properties of Zn-Doped YbMg<sub>1.85−<i>x</i></sub>Zn<i><sub>x</sub></i>Bi<sub>1.98</sub> |
| title_short | Thermoelectric Properties of Zn-Doped YbMg<sub>1.85−<i>x</i></sub>Zn<i><sub>x</sub></i>Bi<sub>1.98</sub> |
| title_sort | thermoelectric properties of zn doped ybmg sub 1 85 i x i sub zn i sub x sub i bi sub 1 98 sub |
| topic | YbMg<sub>2</sub>Bi<sub>2</sub> Zintl compounds microstructure the bipolar effect thermoelectric properties |
| url | https://www.mdpi.com/1996-1944/17/5/973 |
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