Crystal structure, characterization and thermoelectric properties of the type-I clathrate Ba8−ySryAl14Si32 (0.6≤y≤1.3) prepared by aluminum flux

The title compound was prepared as single crystals using an aluminum flux technique. Single crystal and powder X-ray diffraction indicate that this composition crystallizes in the clathrate type-I structure, space group Pm3̄n. Electron microprobe characterization indicates the composition to be Ba8−ySryAl14.2(2)Si31.8(2) (0.77

Graphical abstractThe inorganic type-I clathrate phase with nominal composition Ba7Sr1Al14Si32 has been prepared by Al flux. Single crystal diffraction at 90 and 12 K reveal that the framework is fully occupied with the cation sites nearly fully occupied. The lattice thermal conductivity is low thereby suggesting further optimization of the carrier concentration will lead to a high zT.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Ba7Sr1Al14Si32 is a light element phase ideal for thermoelectric power generation. ► Ba7Sr1Al14Si32 is a high melting point cubic structure ideal for efficient power generation. ► The framework is fully occupied with the cation sites nearly fully occupied. ► Further optimization of the carrier concentration is expected to lead to a high zT.