Cu2EuMQ4 (M = Si, Ge; Q = S, Se): syntheses, structure study and physical properties determination

Publication date: Available online 25 September 2018Source: Journal of Solid State ChemistryAuthor(s): Zong-Dong Sun, Yang Chi, Sheng-Ping GuoAbstractThree europium chalcogenides, Cu2EuSiS4 (1), Cu2EuGeS4 (2), and Cu2EuGeSe4 (3) were obtained by a high-temperature solid-state method. They crystallize in the noncentrosymmetric space groups P3121 (1), P3221 (2), and Ama2 (3), respectively. Their structures can be described as EuQ8 bicapped trigonal prisms (btps) constructed 3D frameworks, and Cu and Si/Ge atoms occupying the tetrahedral cavities. The 3D network built by CuQ4 and Si/GeQ. 4 tetrahedra in 3 is different from that in 1 and 2. Their energy band gaps are determined to 2.36, 2.32, and 1.74 eV for 1–3, respectively. Compound 1 shows typical photoluminescence of Eu2+ ion. All of them show antiferromagnetic-like behaviors, and are not second-harmonic generation-active. Theoretical calculations indicate that 1 and 2 show direct band gaps, while 3 indirect.Graphical abstractThree Cu2EuMQ4 (M = Si, Ge; Q = S, Se) chalcogenides are obtained by solid-state reactions. They crystallize in different structures and their rich optical and physical properties are studied, together with their electronic structures.

Source: Journal of Solid State Chemistry - October 5, 2018 Category: Chemistry Source Type: research