The frontier of solid-state chemistry: layered mixed anion compounds

Abstract

  Recently mixed anion compounds are paid attention due to their variety of crystal structures as well as functionalities. Especially, layered mixed-anion perovskites have several merits such as controllability of local structures and dimensionality, formation of natural superlattice, specific energy levels due to anisotropic coordination of anions and so on. In this paper, we will introduce feature of this system and summarize our recent research. In the Sr-Sc-Cu-Se-O system we have discovered two phases; Sr₃Sc₂Cu₂Se₂O₅ and Sr₂ScCuSeO₃. Due to its longer blocking layer, Sr₂ScCuSeO₃ has larger confinement effect. We have also established the method to estimate the stable phases by DFT calculations. Sr₂ScAgSeO₃ phase is energetically favorable than Sr₃Sc₂Ag₂Se₂O₅, and the phase formed by optimization of synthesis conditions. Characteristic luminescence with high efficiency is also observed in the compound of this system. These results suggest that layered mixed anion compounds are promising to develop new functional materials.