Thermoelectric Properties of Bi2Te3 Nanocrystals with Diverse Morphologies Obtained via Modified Hydrothermal Method

• Published in: Journal of electronic materials Vol. 46; no. 5; pp. 3012 - 3019
• Main Authors: Dharmaiah, Peyala, Hong, Soon-Jik
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-05-2017
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Electronics and Microelectronics; Instrumentation; Materials Science; Optical and Electronic Materials; Solid State Physics; thermoelectric materials; hydrothermal synthesis; grain boundaries; spark plasma sintering; Bismuth telluride
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-016-5104-2

Single-phase Bi
2
Te
3
nanostructures (spherical and flower-like) have been synthesized using a modified hydrothermal method at different reaction temperatures (70°C, 100°C, and 150°C) and subsequently consolidated by spark plasma sintering. Their crystal structure, morphology, and thermoelectric and mechanical properties were investigated. The results suggest that the reaction temperature had a significant effect on the morphology and thermoelectric properties. The presence of nanostructures in bulk samples led to a remarkable decrease in thermal conductivity with a lesser effect on electrical conductivity. As a result, the figure␣of merit (
ZT
) of the spark-plasma-sintered sample processed from spherical nanoparticles reached 0.54 at 400 K. The Vickers microhardness of the bulk sample processed from spherical nanoparticles was higher than the best results found in literature.