Exploration of zinc borophosphate glasses as dispersion media for SiAlON phosphors

Abstract Ca‐α‐SiAlON:Eu ²⁺ oxynitride phosphors are typical luminescent materials with high thermal tolerances. A series of zinc borophosphate glass samples (ZnO–B ₂ O ₃ –P ₂ O ₅ ) were prepared to investigate their ability to disperse Ca‐α‐SiAlON:Eu ²⁺ phosphor powders and to obtain phosphor‐in‐glass (PiG). PiG was prepared with SiAlON and zinc borophosphate glass through a melting process, and seven types of PiGs were successfully obtained without obvious degradation of SiAlON. In particular, PiGs prepared from 30ZnO–40B ₂ O ₃ –30P ₂ O ₅ and 60ZnO–30B ₂ O ₃ –10P ₂ O ₅ (mol%) glasses showed the highest quantum efficiency (QE). The glass structures of the mother glasses were investigated by nuclear magnetic resonance spectroscopy (NMR) and Raman spectroscopy; it was important to reduce the Q ⁰ species of PO ₄ units and 4‐coordinate boron for a high QE. From the X‐ray diffraction (XRD) and scanning electron microscopy (SEM) images, it was established that ZnAl ₂ O ₄ was formed around the SiAlON powders in PiG composed of the 60ZnO–30B ₂ O ₃ –10P ₂ O ₅ (mol%) glass.