Enhanced zT due to non-stoichiometric induced defects for bismuth telluride thermoelectric materials
Thermoelectric materials have potential applications in energy conversion and waste heat recovery. Thermoelectric materials with non-stoichiometric composition may exhibit improved thermoelectric properties compared to the stoichiometric composition material. Bi2Te3 is one of the best-known thermoel...
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| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2023-07-01
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| Series: | Kuwait Journal of Science |
| Subjects: | |
| Online Access: | https://www.sciencedirect.com/science/article/pii/S2307410823000445 |
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| Summary: | Thermoelectric materials have potential applications in energy conversion and waste heat recovery. Thermoelectric materials with non-stoichiometric composition may exhibit improved thermoelectric properties compared to the stoichiometric composition material. Bi2Te3 is one of the best-known thermoelectric materials having optimum performance near room temperature. In the present study, non-stoichiometric bismuth telluride (Bi2±x Te3), x = (0, 0.01, 0.02, 0.03), was synthesized using the co-precipitate method to create imperfections and strains in the crystal structure of the material. The crystal structure of the synthesized bismuth telluride revealed significant changes in the c direction when examined using X-ray diffraction (XRD). Scanning electron microscopy (SEM) revealed the formation of micro-particles. Energy dispersive spectroscopy (EDX) also confirmed the non-stoichiometric elemental composition of Bi and Te rich bismuth telluride. Thermogravimetric analysis (TGA) was performed in a non-inert environment, and an oxidation temperature of 685 K was recorded in non-stoichiometric samples. The post-oxidation of stoichiometric and non-stoichiometric Bi Rich and Te Rich bismuth tellurides was also confirmed by XRD and TGA comparison. The thermal conductivity was reduced by the imperfections and defects for all non-stoichiometric compositions, and a zT value of 0.54 at 420 K was obtained in the Tellurium Rich bismuth telluride, which is about a 12% improvement compared to the pure sample. |
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| ISSN: | 2307-4116 |