Modeling phase separation mechanisms in oxy‐fluoride glass‐ceramics containing SrF₂:Ln³⁺ and ZnAl₂O₄:Cr³⁺ nanocrystals

It is imperative to develop a comprehensive understanding of phase separation mechanisms in multi‐phase oxy‐fluoride glass ceramics (GCs) to customize their structural and optical characteristics for particular applications in photonics. The manuscript utilizes molecular dynamics (MD) simulations to examine the phase separation mechanisms in SiO 2 –Al 2 O 3 –SrF 2 –ZnF 2 –LnF 3 ‐CrF 3 (where Ln represents the lanthanide elements) GCs during the simultaneous precipitation of SrF 2 : Ln 3+ and ZnAl 2 O 4 : Cr 3+ nanocrystals. Insights into the atomic‐level interactions that regulate the separation and formation of distinct phases rich in fluoride and oxide are obtained through MD simulations. The results reveal that Sr 2+ and Ln 3+ ions partition preferentially into the fluoride phase, whereas Zn 2+ and Cr 3+ associate with the oxide aluminosilicate network. Remarkably, the separated fluoride and oxide phases bear structural similarities with the existing experimental outcomes. The introduction of SrF 2 facilitates phase separation in oxy‐fluoride glass system by causing the formation of SrF 2 : Ln 3+ nanocrystals in regions abundant in fluoride, while the substitution of ZnF 2 for SrF 2 results in the formation of ZnAl 2 O 4 : Cr 3+ nanocrystals originating from the separated oxide phase. Therefore, the reported simulations offer molecular‐level insights into the mechanisms underlying phase separation and the functions of various glass components, thereby facilitating the development of customized oxy‐fluoride GCs with tailored properties.