Lithium-aluminium-silicate glass: A novel high-quality glass for preparing LuAG: Ce colour converter for laser illumination

Abstract

Phosphor-in-glass (PiG) plays an indispensable role as a highly tunable and easily prepared phosphor material for new-generation high-brightness and high-collimation laser lighting (blue laser diodes + colour converters). However, at low power (<5 W), the poor thermal stability and brittleness of PiGs make it challenging to develop high-intensity, high-brightness PiG materials because of their susceptibility to rupture and sudden drop in luminous efficiency (LE) owing to thermal accumulation under high-energy laser irradiation. In this study, a performance-tunable lithium-aluminium-silicate (LAS) glass system was used to adjust the glass composition and synthesise LAS-glasses that can be sintered at low temperatures. In addition to LuAG: Ce phosphor, LuAG: Ce phosphor-in-LAS (LuAG: Ce-PiGLAS) has been successfully developed, which can withstand an 8.24-W laser irradiation without heat dissipation, achieving a luminous flux of 1248 lm and LE of 204 lm/W. Furthermore, a pre-thermal treatment was used to precipitate the lithium disilicate phase to enhance the resistance of the glass to laser ablation, resulting in a power increase to 8.62 W at 1485 lm and maximum LE increase to 212 lm/W with a 2.5% attenuation at 498 K. High-brightness illumination performance was demonstrated in both transmission and reflection modules. This study is anticipated to generate new prospects for PiG applications and accelerate the development of laser lighting.