Eu2+ Doping Driven Polymorphic Transition in Sr2SiO4 Glass Ceramic for Optical Property Tailoring and Multifunctional Photonic Applications

Polycrystalline phase transition provides an effective method to modulate structure of luminescent materials, offering a promising pathway for expanding optical properties and adaptive optoelectronic applications. In this study, for the first time the controlled β → ɑ phase-transition engineering is reported in Sr₂SiO₄:Eu²⁺ glass ceramic (GC) through chemical doping of Eu²⁺ ions, where the Eu²⁺ ions act dual-functionally as structural modulator and stabilizer. Molecular dynamics simulations reveal that Eu²⁺ doping does not significantly modify the short-range order of glass, indicating that the β → α phase transition primarily results from dopant-induced crystallization dynamics. Interestingly, the α-phase variant demonstrates thermochromic properties, enabling fluorescent anti-counterfeiting applications; while the β-phase variant shows superior thermal stability (82% photoluminescence remained at 423 K), excellent water-resistance, and extraordinarily stable color emission, making it suitable for high-quality lighting with color rendering index up to 95. This work provides a new thought of designing a GC platform via controllable polymorphic phase transition toward multifunctional photonic applications.