Effect of Sm-doping on microstructure and thermoelectric properties of textured n-type Bi2Te2.7Se0.3 compound due to change in ionic bonding fraction
| Autor: | Marina Zhezhu, Maxim Yaprintsev, Ekaterina Yaprintseva, Alexei Vasil’ev, Oleg Ivanov |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
Doping Analytical chemistry Spark plasma sintering Ionic bonding 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics Microstructure 01 natural sciences 0104 chemical sciences Electronic Optical and Magnetic Materials Degree (temperature) Inorganic Chemistry Electronegativity chemistry.chemical_compound chemistry Thermoelectric effect Materials Chemistry Ceramics and Composites Bismuth telluride Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | Journal of Solid State Chemistry. 297:122047 |
| ISSN: | 0022-4596 |
| DOI: | 10.1016/j.jssc.2021.122047 |
| Popis: | Textured n-type Bi2-xSmxTe2.7Se0.3 compounds with x = 0; 0.005; 0.02 and 0.05 have been prepared by microwave-solvothermal synthesis of starting powders and spark plasma sintering of bulk materials. Texturing [001] axis coincided with direction of spark plasma sintering pressuring. With increasing x, (i) an average lateral size of grains in the samples is decreasing; (ii) the Lotgering factor characterizing a degree of preferential orientation of the grains is increasing; (iii) anomalies of all the thermoelectric properties, related to onset of intrinsic conductivity, are shifted to higher temperatures. The Sm-doping effect on the grain structure and thermoelectric properties of samples is attributed to increasing in ionic bonding fraction, which can occur at increasing Sm content due to a difference in electronegativity of Bi and Sm atoms. Maxima in temperature dependences of the thermoelectric figure-of-merit, typical for Bi2Te3-based compounds and due to the intrinsic conductivity, were observed. The highest value of the thermoelectric figure-of-merit was found to be weakly dependent on x and falling into ~0.6 ÷ ~0.7 interval, whereas temperature position of the maxima is remarkably shifted to higher temperatures with increasing Sm content. |
| Databáze: | OpenAIRE |
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