Effect of adding Er3+ on the precipitated crystalline phase of SrF2–ZnO–B2O3 glass and upconversion luminescence

Abstract

Elucidating the relationship between nucleation and its structure in glasses is essential for the efficient development of new glass-ceramics. In this study, we developed new oxyfluoride nanocrystallized glass-ceramics with potential for upconversion luminescence, phosphor for LEDs, and fiber laser hosts. We investigated the glass-forming region in the SrF₂–ZnO–B₂O₃ system and the crystallization behavior, glass structure, and optical properties of the xSrF₂–(50−x)ZnO–50B₂O₃ system with the lowest quantity of glass-forming oxides. Whereas both the x = 10 and x = 20 samples precipitated more than 100 nm diameter of Zn₄B₆O₁₃ by heat treatment, the Er³⁺-doped samples with x = 10 and x = 20 precipitated SrF₂ nanocrystals of less than 20 nm. The resulting SrF₂ nanocrystallized glass was transparent, and upconversion luminescence was observed by irradiating with a 980-nm LD. We found that the addition of Er³⁺ ions has a significant impact on crystallization, and the proposed mechanism for this is that the bond selectivity arising from the polarizability forms fluoride-rich domains, and Er³⁺ further assists the nucleation of SrF₂ by serving as a crystal nucleation site. This study is expected to provide a guideline for the development of new transparent nanocrystallized glasses.