Improved Thermoelectric Properties of SrTiO<sub>3</sub> via (La, Dy and N) Co-Doping: DFT Approach
This work considers the enhancement of the thermoelectric figure of merit, ZT, of SrTiO<sub>3</sub> (STO) semiconductors by (La, Dy and N) co-doping. We have focused on SrTiO<sub>3</sub> because it is a semiconductor with a high Seebeck coefficient compared to that of metals....
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MDPI AG
2022-11-01
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| author | Pornsawan Sikam Ruhan Thirayatorn Thanayut Kaewmaraya Prasit Thongbai Pairot Moontragoon Zoran Ikonic |
| author_facet | Pornsawan Sikam Ruhan Thirayatorn Thanayut Kaewmaraya Prasit Thongbai Pairot Moontragoon Zoran Ikonic |
| author_sort | Pornsawan Sikam |
| collection | DOAJ |
| description | This work considers the enhancement of the thermoelectric figure of merit, ZT, of SrTiO<sub>3</sub> (STO) semiconductors by (La, Dy and N) co-doping. We have focused on SrTiO<sub>3</sub> because it is a semiconductor with a high Seebeck coefficient compared to that of metals. It is expected that SrTiO<sub>3</sub> can provide a high power factor, because the capability of converting heat into electricity is proportional to the Seebeck coefficient squared. This research aims to improve the thermoelectric performance of SrTiO<sub>3</sub> by replacing host atoms by La, Dy and N atoms based on a theoretical approach performed with the Vienna Ab Initio Simulation Package (VASP) code. Here, undoped SrTiO<sub>3</sub>, Sr<sub>0.875</sub>La<sub>0.125</sub>TiO<sub>3</sub>, Sr<sub>0.875</sub>Dy<sub>0.125</sub>TiO<sub>3</sub>, SrTiO<sub>2.958</sub>N<sub>0.042</sub>, Sr<sub>0.750</sub>La<sub>0.125</sub>Dy<sub>0.125</sub>TiO<sub>3</sub> and Sr<sub>0.875</sub>La<sub>0.125</sub>TiO<sub>2.958</sub>N<sub>0.042</sub> are studied to investigate the influence of La, Dy and N doping on the thermoelectric properties of the SrTiO<sub>3</sub> semiconductor. The undoped and La-, Dy- and N-doped STO structures are optimized. Next, the density of states (DOS), band structures, Seebeck coefficient, electrical conductivity per relaxation time, thermal conductivity per relaxation time and figure of merit (ZT) of all the doped systems are studied. From first-principles calculations, STO exhibits a high Seebeck coefficient and high figure of merit. However, metal and nonmetal doping, i.e., (La, N) co-doping, can generate a figure of merit higher than that of undoped STO. Interestingly, La, Dy and N doping can significantly shift the Fermi level and change the DOS of SrTiO<sub>3</sub> around the Fermi level, leading to very different thermoelectric properties than those of undoped SrTiO<sub>3</sub>. All doped systems considered here show greater electrical conductivity per relaxation time than undoped STO. In particular, (La, N) co-doped STO exhibits the highest ZT of 0.79 at 300 K, and still a high value of 0.77 at 1000 K, as well as high electrical conductivity per relaxation time. This renders it a viable candidate for high-temperature applications. |
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| spelling | doaj.art-c83c4307affa4f75bafa3d4e72afbaaf2023-11-24T09:23:28ZengMDPI AGMolecules1420-30492022-11-012722792310.3390/molecules27227923Improved Thermoelectric Properties of SrTiO<sub>3</sub> via (La, Dy and N) Co-Doping: DFT ApproachPornsawan Sikam0Ruhan Thirayatorn1Thanayut Kaewmaraya2Prasit Thongbai3Pairot Moontragoon4Zoran Ikonic5Research Center for Quantum Technology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, ThailandDepartment of Physics, Khon Kaen University, Khon Kaen 40002, ThailandDepartment of Physics, Khon Kaen University, Khon Kaen 40002, ThailandDepartment of Physics, Khon Kaen University, Khon Kaen 40002, ThailandDepartment of Physics, Khon Kaen University, Khon Kaen 40002, ThailandSchool of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT, UKThis work considers the enhancement of the thermoelectric figure of merit, ZT, of SrTiO<sub>3</sub> (STO) semiconductors by (La, Dy and N) co-doping. We have focused on SrTiO<sub>3</sub> because it is a semiconductor with a high Seebeck coefficient compared to that of metals. It is expected that SrTiO<sub>3</sub> can provide a high power factor, because the capability of converting heat into electricity is proportional to the Seebeck coefficient squared. This research aims to improve the thermoelectric performance of SrTiO<sub>3</sub> by replacing host atoms by La, Dy and N atoms based on a theoretical approach performed with the Vienna Ab Initio Simulation Package (VASP) code. Here, undoped SrTiO<sub>3</sub>, Sr<sub>0.875</sub>La<sub>0.125</sub>TiO<sub>3</sub>, Sr<sub>0.875</sub>Dy<sub>0.125</sub>TiO<sub>3</sub>, SrTiO<sub>2.958</sub>N<sub>0.042</sub>, Sr<sub>0.750</sub>La<sub>0.125</sub>Dy<sub>0.125</sub>TiO<sub>3</sub> and Sr<sub>0.875</sub>La<sub>0.125</sub>TiO<sub>2.958</sub>N<sub>0.042</sub> are studied to investigate the influence of La, Dy and N doping on the thermoelectric properties of the SrTiO<sub>3</sub> semiconductor. The undoped and La-, Dy- and N-doped STO structures are optimized. Next, the density of states (DOS), band structures, Seebeck coefficient, electrical conductivity per relaxation time, thermal conductivity per relaxation time and figure of merit (ZT) of all the doped systems are studied. From first-principles calculations, STO exhibits a high Seebeck coefficient and high figure of merit. However, metal and nonmetal doping, i.e., (La, N) co-doping, can generate a figure of merit higher than that of undoped STO. Interestingly, La, Dy and N doping can significantly shift the Fermi level and change the DOS of SrTiO<sub>3</sub> around the Fermi level, leading to very different thermoelectric properties than those of undoped SrTiO<sub>3</sub>. All doped systems considered here show greater electrical conductivity per relaxation time than undoped STO. In particular, (La, N) co-doped STO exhibits the highest ZT of 0.79 at 300 K, and still a high value of 0.77 at 1000 K, as well as high electrical conductivity per relaxation time. This renders it a viable candidate for high-temperature applications.https://www.mdpi.com/1420-3049/27/22/7923thermoelectric propertiesSrTiO<sub>3</sub>rare-earth doping |
| spellingShingle | Pornsawan Sikam Ruhan Thirayatorn Thanayut Kaewmaraya Prasit Thongbai Pairot Moontragoon Zoran Ikonic Improved Thermoelectric Properties of SrTiO<sub>3</sub> via (La, Dy and N) Co-Doping: DFT Approach Molecules thermoelectric properties SrTiO<sub>3</sub> rare-earth doping |
| title | Improved Thermoelectric Properties of SrTiO<sub>3</sub> via (La, Dy and N) Co-Doping: DFT Approach |
| title_full | Improved Thermoelectric Properties of SrTiO<sub>3</sub> via (La, Dy and N) Co-Doping: DFT Approach |
| title_fullStr | Improved Thermoelectric Properties of SrTiO<sub>3</sub> via (La, Dy and N) Co-Doping: DFT Approach |
| title_full_unstemmed | Improved Thermoelectric Properties of SrTiO<sub>3</sub> via (La, Dy and N) Co-Doping: DFT Approach |
| title_short | Improved Thermoelectric Properties of SrTiO<sub>3</sub> via (La, Dy and N) Co-Doping: DFT Approach |
| title_sort | improved thermoelectric properties of srtio sub 3 sub via la dy and n co doping dft approach |
| topic | thermoelectric properties SrTiO<sub>3</sub> rare-earth doping |
| url | https://www.mdpi.com/1420-3049/27/22/7923 |
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