Facile fabrication of heat-conducting phosphor-in-glass with dual-sapphire plates for laser-driven white lighting

Abstract

Phosphor-in-glass (PiG) is considered as a stable and efficient color converter for high-power white lighting due to its high thermal stability, excellent mechanical strength, and facile preparation process. However, the low thermal conductivity of PiG hinders the heat dissipation of phosphor, which limits its application in high-brightness white laser diodes (LDs). In this work, we proposed a heat-conducting PiG with dual-sapphire plates for laser-driven white lighting. The PiG_sapphire was fabricated by screen-printing and sintering a phosphor glass film between the dual-sapphire plates. In order to avoid the film delamination, a low-melting borosilicate glass matrix with similar expansion coefficient of sapphire was prepared. The optical performances of PiG_sapphire based white LDs were adjusted by varying the thickness of phosphor glass film. Furthermore, the PiG_sapphire exhibits low working temperature (<50 °C) at the up/down surfaces under various laser powers compared with the traditional PiG, which is attributed to the effective heat transfer channels of dual-sapphire plates. The PiG_sapphire maintains high emission intensity and stable luminescence at much higher laser power. The results demonstrate that the heat-conducting PiG_sapphire is a promising color converter for high-brightness laser-driven white lighting.