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

Abstract 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 Sr 2 SiO 4 :Eu 2 + glass ceramic (GC) through chemical doping of Eu 2 + ions, where the Eu 2 + ions act dual‐functionally as structural modulator and stabilizer. Molecular dynamics simulations reveal that Eu 2 ⁺ 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.