Exploring interfacial reactions and optical properties of ZBLAN-based phosphor-in-glass color converters via spark plasma sintering for laser-driven lighting

Phosphor-in-glass (PiG) is extensively utilized as a color converter in laser-driven lighting. Despite its popularity, a noteworthy concern is the potential for interfacial reactions to occur between the phosphors and the glass matrix during high-temperature processing, leading to subsequent corrosion. Previous research suggests that spark plasma sintering (SPS) may effectively limit these reactions in silica glass-based PiGs. However, the reactivity of silica glass, lacking glass modifiers, towards phosphors is diminished, raising uncertainty about whether SPS can truly fabricate a PiG with improved interfacial morphology. Nonetheless, research pertaining to PiG fabrication using SPS with multi-component glass compositions remains scarce. In this study, an attempt is made to address this gap by employing a multi-component glass matrix - ZrF4–BaF2–LaF3–AlF3–NaF (ZBLAN), which is known for its high reactivity with phosphors, in the creation of PiGs through SPS. Lu3Al5O12:Ce3+ (LuAG) was embedded within ZBLAN glass, fabricated using SPS in merely 5 min at a temperature of 255 °C. The subsequent analysis focused on the interfacial microstructure and the optical properties of the thus prepared PiG samples. The results demonstrate that the lower-temperature and time-efficient sintering process of SPS successfully mitigate the interfacial reactions between the phosphor and the glass matrix. Consequently, a commendable luminous flux of 597 lm and luminous efficacy of 242 lm/W is achieved.