Abstract
Simultaneous control of the stoichiometry, microstructure, and compositional homogeneity is a prerequisite for understanding the properties of Ag2Se. These are difficult to attain because of the highly mobile Ag+ ions above the superionic phase transition at 407 K. Here we report on a novel synthesis of well crystallized orthorhombic Ag2Se carried out at room temperature, which requires no expensive instrumentation, and yields a single-phase material in a very short time. Our facile reaction process is a self-sustaining room temperature synthesis driven by the dissociative adsorption of Se by Ag and promoted by stirring and intermittent grinding under ambient conditions. Systematic experimental and theoretical studies of chemical reactions between Ag and Q (Te, Se, and S) revealed that the reaction mechanism between Ag and Q is in line with the Hard Soft Acid Base (HSAB) scheme (rate order Ag2Te > Ag2Se > Ag2S). The low carrier concentration achieved ∼1018 cm-3 and the optimized weighted majority-to-minority carrier mobility ratio observed in the samples as corroborated by the state-of-the-art thermoelectric performance of ZT ∼1.2 at 390 K attest to the superiority of the synthesis route in yielding highly stoichiometric Ag2Se samples.
Original language | English (US) |
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Pages (from-to) | 23243-23251 |
Number of pages | 9 |
Journal | Journal of Materials Chemistry A |
Volume | 5 |
Issue number | 44 |
DOIs | |
State | Published - 2017 |
Funding
We acknowledge support from the National Basic Research Program of China (973 program) under project 2013CB632502, the fundamental research funds for central campus (2015-III-061-061), the Natural Science Foundation of China (grant no. 51402222, 51172174, 51521001, and 51401153) and the 111 project of China (grant no. B07040). C.U. acknowledges support from the CERC-CVC, the joint U.S.–China Program supported by the U.S. Department of Energy under the award number DE-PI0000012 in verication of high temperature transport property measurements. F.M. and J.H. acknowledge support from the NSF DMR 1307740. Besides, D.Y. is grateful to Meijun Yang, Xiaolei Nie and Xinya Yang for their help with EPMA and C80 in Materials Research and Test Center of WHUT. This work was supported in part by a grant by the U.S. Department of Energy, Office of Science, and Office of Basic Energy Sciences under award number DE-SC0001054 (X.S and M.G.K., sample synthesis and transport characterization).
ASJC Scopus subject areas
- General Chemistry
- Renewable Energy, Sustainability and the Environment
- General Materials Science