Ternary Chalcogenides GeSb 2 Se 3 and Ge 3 Sb 4 Se 7 Containing a ∞ 1 [Sb 2 Se 2 ] 2- 1D Chain and a 2D Structure Related to SnSe.

Ternary chalcogenides, GeSb ₂ Se ₃ and Ge ₃ Sb ₄ Se ₇ , were synthesized and characterized. These chalcogenides are the first ternary selenides in a ternary Ge-Sb-Se system that feature a layer structure related to black phosphorus and SnSe-type structures. Both compounds contain a _∞ ¹ [Sb ₂ Se ₂ ] ^2- unit with Sb ⁺ cations in a zigzag Sb-Sb chain structure, and Sb ³⁺ cations in a distorted NaCl ¹⁰⁰ -type of _∞ ¹ [Ge _{n -2} Sb ₂ Se _n ] ²⁺ unit ( n = 4, 5). These materials exhibit n-type semiconducting properties with thermal conductivity significantly lower than that of GeSe and Sb ₂ Se ₃ , which could be correlated to the 1D Sb ⁺ chain and disordered sites with different Ge/Sb compositions. It is anticipated that these newly discovered ternary chalcogenides may provide unique properties with enhanced thermoelectric properties.