Realizing Superior Luminescence in Oxyfluoride Glass-Ceramics by Enhancing Nano-Micro Phase Separation

In this work, a novel series of oxyfluoride glasses-ceramics (GCs) is developed by enhancing the phase separation through the substitution of LaF 3 for La 2 O 3 . The thus-derived GCs exhibit a remarkable 2700-fold increase in up-conversion (UC) luminescence of Er 3+ ions compared to the precursor glass. From the 19 F Nuclear Magnetic Resonance analysis, this enhancement is attributed to the structural disorder-to-order transition in the fluoride-rich phase. Upon isothermal heat treatment, the translucent GCs transform into transparent ones, making UC luminescence even stronger. The enhanced UC luminescence leads to strong temperature-sensing ability of the studied glasses. The nano-micro phase separation is clarified by atomistic simulations and scanning electron microscopy. This study implies that phase separation engineering is a powerful way to achieve superior photonic performances.