Structure and thermoelectric properties of the new quaternary tin selenide K1 − xSn5 − xBi11 + xSe22
- 9 June 2000
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of Materials Chemistry
- Vol. 10 (7) , 1667-1672
- https://doi.org/10.1039/b000045k
Abstract
Silver colored ribbon-like crystals of K1 − xSn5 − xBi11 + xSe22 (x ≈ 0.33) were prepared by direct combination of K2Se, Bi2Se3, Sn and Se at 800 °C. A structure determination was carried out for K0.66Sn4.82Bi11.18Se22. Bi2Te3-type and NaCl-type building units are connected to form a new kind of three-dimensional anionic framework with K+ filled tunnels. The building units are assembled from distorted, edge-sharing (Bi,Sn)Se6 octahedra. Bi and Sn atoms are disordered over all metal sites of the chalcogenide network while the K site is only one third occupied. The charge transport measurements of K0.66Sn4.82Bi11.18Se22 at room temperature reveal an electrical conductivity of 450 S cm−1 and a thermopower of −43 µV K−1. The thermal conductivity is 1.5 W m−1 K−1. An optical band gap of approximately 0.12 eV was determined at room temperature. K0.66Sn4.82Bi11.18Se22 melts congruently at 680 °C.Keywords
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