Please use this identifier to cite or link to this item:
Title: Interface driven energy filtering of thermoelectric power in spark plasma sintered Bi2Te2.7Se0.3 nanoplatelet composites
Authors: Soni, Ajay
Shen, Yiqiang
Yin, Ming
Zhao, Yanyuan
Yu, Ligen
Hu, Xiao
Dong, Zhili
Khor, Khiam Aik
Xiong, Qihua
Dresselhaus, Mildred S.
Issue Date: 2012
Source: Soni, A., Shen, Y., Yin, M., Zhao, Y., Yu, L., Hu, X., et al. (2012). Interface Driven Energy Filtering of Thermoelectric Power in Spark Plasma Sintered Bi2Te2.7Se0.3 Nanoplatelet Composites. Nano Letters, 12(8), 4305-4310.
Series/Report no.: Nano letters
Abstract: Control of competing parameters such as thermoelectric (TE) power and electrical and thermal conductivities is essential for the high performance of thermoelectric materials. Bulk-nanocomposite materials have shown a promising improvement in the TE performance due to poor thermal conductivity and charge carrier filtering by interfaces and grain boundaries. Consequently, it has become pressingly important to understand the formation mechanisms, stability of interfaces and grain boundaries along with subsequent effects on the physical properties. We report here the effects of the thermodynamic environment during spark plasma sintering (SPS) on the TE performance of bulk-nanocomposites of chemically synthesized Bi2Te2.7Se0.3 nanoplatelets. Four pellets of nanoplatelets powder synthesized in the same batch have been made by SPS at different temperatures of 230, 250, 280, and 350 °C. The X-ray diffraction, transmission electron microscopy, thermoelectric, and thermal transport measurements illustrate that the pellet sintered at 250 °C shows a minimum grain growth and an optimal number of interfaces for efficient TE figure of merit, ZT0.55. For the high temperature (350 °C) pelletized nanoplatelet composites, the concurrent rise in electrical and thermal conductivities with a deleterious decrease in thermoelectric power have been observed, which results because of the grain growth and rearrangements of the interfaces and grain boundaries. Cross section electron microscopy investigations indeed show significant grain growth. Our study highlights an optimized temperature range for the pelletization of the nanoplatelet composites for TE applications. The results provide a subtle understanding of the grain growth mechanism and the filtering of low energy electrons and phonons with thermoelectric interfaces.
ISSN: 1530-6984
DOI: 10.1021/nl302017w
Rights: © 2012 American Chemical Society.
Fulltext Permission: none
Fulltext Availability: No Fulltext
Appears in Collections:EEE Journal Articles
MAE Journal Articles
MSE Journal Articles
SPMS Journal Articles

Google ScholarTM




Items in DR-NTU are protected by copyright, with all rights reserved, unless otherwise indicated.